Sample records for ice cap svalbard

  1. Calibrating a surface mass-balance model for Austfonna ice cap, Svalbard

    NASA Astrophysics Data System (ADS)

    Schuler, Thomas Vikhamar; Loe, Even; Taurisano, Andrea; Eiken, Trond; Hagen, Jon Ove; Kohler, Jack

    2007-10-01

    Austfonna (8120 km2) is by far the largest ice mass in the Svalbard archipelago. There is considerable uncertainty about its current state of balance and its possible response to climate change. Over the 2004/05 period, we collected continuous meteorological data series from the ice cap, performed mass-balance measurements using a network of stakes distributed across the ice cap and mapped the distribution of snow accumulation using ground-penetrating radar along several profile lines. These data are used to drive and test a model of the surface mass balance. The spatial accumulation pattern was derived from the snow depth profiles using regression techniques, and ablation was calculated using a temperature-index approach. Model parameters were calibrated using the available field data. Parameter calibration was complicated by the fact that different parameter combinations yield equally acceptable matches to the stake data while the resulting calculated net mass balance differs considerably. Testing model results against multiple criteria is an efficient method to cope with non-uniqueness. In doing so, a range of different data and observations was compared to several different aspects of the model results. We find a systematic underestimation of net balance for parameter combinations that predict observed ice ablation, which suggests that refreezing processes play an important role. To represent these effects in the model, a simple PMAX approach was included in its formulation. Used as a diagnostic tool, the model suggests that the surface mass balance for the period 29 April 2004 to 23 April 2005 was negative (-318 mm w.e.).

  2. The influence of topographic feedback on a coupled mass balance and ice-flow model for Vestfonna ice-cap, Svalbard

    NASA Astrophysics Data System (ADS)

    Schäfer, Martina; Möller, Marco; Zwinger, Thomas; Moore, John

    2016-04-01

    Using a coupled simulation set-up between a by statistical climate data forced and to ice-cap resolution downscaled mass balance model and an ice-dynamic model, we study coupling effects for the Vestfonna ice cap, Nordaustlandet, Svalbard, by analysing the impacts of different imposed coupling intervals on mass-balance and sea-level rise (SLR) projections. Based on a method to estimate errors introduced by different coupling schemes, we find that neglecting the topographic feedback in the coupling leads to underestimations of 10-20% in SLR projections on century time-scales in our model compared to full coupling (i.e., exchange of properties using smallest occurring time-step). Using the same method it also is shown that parametrising mass-balance adjustment for changes in topography using lapse rates is a - in computational terms - cost-effective reasonably accurate alternative applied to an ice-cap like Vestfonna. We test the forcing imposed by different emission pathways (RCP 2.4, 4.5, 6.0 and 8.5). For most of them, over the time-period explored (2000-2100), fast-flowing outlet glaciers decrease in impacting SLR due to their deceleration and reduced mass flux as they thin and retreat from the coast, hence detaching from the ocean and thereby losing their major mass drainage mechanism, i.e., calving.

  3. Temporal constraints on future accumulation-area loss of a major Arctic ice cap due to climate change (Vestfonna, Svalbard)

    PubMed Central

    Möller, Marco; Schneider, Christoph

    2015-01-01

    Arctic glaciers and ice caps are major contributors to past, present and future sea-level fluctuations. Continued global warming may eventually lead to the equilibrium line altitudes of these ice masses rising above their highest points, triggering unstoppable downwasting. This may feed future sea-level rise considerably. We here present projections for the timing of equilibrium-line loss at the major Arctic ice cap Vestfonna, Svalbard. The projections are based on spatially distributed climatic mass balance modelling driven by the outputs of multiple climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) forced by the Representative Concentration Pathways (RCPs) 2.6, 4.5, 6.0 and 8.5. Results indicate strongly decreasing climatic mass balances over the 21st century for all RCPs considered. Glacier-wide mass-balance rates will drop down to −4 m a−1 w.e. (water equivalent) at a maximum. The date at which the equilibrium line rises above the summit of Vestfonna (630 m above sea level) is calculated to range between 2040 and 2150, depending on scenario. PMID:25628045

  4. The Secret of the Svalbard Sea Ice Barrier

    NASA Technical Reports Server (NTRS)

    Nghiem, Son V.; Van Woert, Michael L.; Neumann, Gregory

    2004-01-01

    An elongated sea ice feature called the Svalbard sea ice barrier rapidly formed over an area in the Barents Sea to the east of Svalbard posing navigation hazards. The secret of its formation lies in the bottom bathymetry that governs the distribution of cold Arctic waters masses, which impacts sea ice growth on the water surface.

  5. Destabilisation of an Arctic ice cap triggered by a hydro-thermodynamic feedback to summer-melt

    NASA Astrophysics Data System (ADS)

    Dunse, T.; Schellenberger, T.; Kääb, A.; Hagen, J. O.; Schuler, T. V.; Reijmer, C. H.

    2014-05-01

    Mass loss from glaciers and ice sheets currently accounts for two-thirds of the observed global sea-level rise and has accelerated since the 1990s, coincident with strong atmospheric warming in the Polar Regions. Here we present continuous GPS measurements and satellite synthetic aperture radar based velocity maps from the Austfonna ice cap, Svalbard, that demonstrate strong links between surface-melt and multiannual ice-flow acceleration. We identify a hydro-thermodynamic feedback that successively mobilizes stagnant ice regions, initially frozen to their bed, thereby facilitating fast basal motion over an expanding area. By autumn 2012, successive destabilization of the marine terminus escalated in a surge of the ice cap's largest drainage basin, Basin-3. The resulting iceberg discharge of 4.2 ± 1.6 Gt a-1 over the period April 2012 to May 2013 triples the calving loss from the entire ice cap. After accounting for the terminus advance, the related sea-level rise contribution of 7.2 ± 2.6 Gt a-1 matches the recent annual ice-mass loss from the entire Svalbard archipelago. Our study highlights the importance of dynamic glacier wastage and illuminates mechanisms that may trigger a sustained increase in dynamic glacier wastage or the disintegration of ice-sheets in response to climate warming, which is acknowledged but not quantified in global projections of sea-level rise.

  6. The Svalbard-Barents Sea ice-sheet - Historical, current and future perspectives

    NASA Astrophysics Data System (ADS)

    Ingólfsson, Ólafur; Landvik, Jon Y.

    2013-03-01

    The history of research on the Late Quaternary Svalbard-Barents Sea ice sheet mirrors the developments of ideas and the shifts of paradigms in glacial theory over the past 150 years. Since the onset of scientific research there in the early 19th Century, Svalbard has been a natural laboratory where ideas and concepts have been tested, and played an important (but rarely acknowledged) role in the break-through of the Ice Age theory in the 1870's. The history of how the scientific perception of the Svalbard-Barents sea ice sheet developed in the mid-20th Century also tells a story of how a combination of fairly scattered and often contradictory observational data, and through both deductive and inductive reasoning, could outline a major ice sheet that had left but few tangible fingerprints. Since the 1980's, with increased terrestrial stratigraphical data, ever more marine geological evidence and better chronological control of glacial events, our perception of the Svalbard-Barents Sea ice sheet has changed. The first reconstructions depicted it as a static, concentric, single-domed ice sheet, with ice flowing from an ice divide over the central northern Barents Sea that expanded and declined in response to large-scale, Late Quaternary climate fluctuations, and which was more or less in tune with other major Northern Hemisphere ice sheets. We now increasingly perceive it as a very dynamic, multidomed ice sheet, controlled by climate fluctuations, relative sea-level change, as well as subglacial topography, substrate properties and basal temperature. In this respect, the Svalbard-Barents Sea ice sheet will increasingly hold the key for understanding the dynamics and processes of how marine-based ice sheets build-up and decay.

  7. Rapid Collapse of the Vavilov Ice Cap, Russian High Arctic.

    NASA Astrophysics Data System (ADS)

    Willis, M. J.; Zheng, W.; Durkin, W. J., IV; Pritchard, M. E.; Ramage, J. M.; Dowdeswell, J. A.; Benham, T. J.; Glazovsky, A.; Macheret, Y.; Porter, C. C.

    2016-12-01

    of the interior portion of the ice cap to a point from which it cannot recover. A second, similar collapse seems to be underway at basin-2 on the southern margin of the Austfonna Ice cap in Svalbard.

  8. Taxon interactions control the distributions of cryoconite bacteria colonizing a High Arctic ice cap.

    PubMed

    Gokul, Jarishma K; Hodson, Andrew J; Saetnan, Eli R; Irvine-Fynn, Tristram D L; Westall, Philippa J; Detheridge, Andrew P; Takeuchi, Nozomu; Bussell, Jennifer; Mur, Luis A J; Edwards, Arwyn

    2016-08-01

    Microbial colonization of glacial ice surfaces incurs feedbacks which affect the melting rate of the ice surface. Ecosystems formed as microbe-mineral aggregates termed cryoconite locally reduce ice surface albedo and represent foci of biodiversity and biogeochemical cycling. Consequently, greater understanding the ecological processes in the formation of functional cryoconite ecosystems upon glacier surfaces is sought. Here, we present the first bacterial biogeography of an ice cap, evaluating the respective roles of dispersal, environmental and biotic filtration occurring at local scales in the assembly of cryoconite microbiota. 16S rRNA gene amplicon semiconductor sequencing of cryoconite colonizing a Svalbard ice cap coupled with digital elevation modelling of physical parameters reveals the bacterial community is dominated by a ubiquitous core of generalist taxa, with evidence for a moderate pairwise distance-decay relationship. While geographic position and melt season duration are prominent among environmental predictors of community structure, the core population of taxa appears highly influential in structuring the bacterial community. Taxon co-occurrence network analysis reveals a highly modular community structured by positive interactions with bottleneck taxa, predominantly Actinobacteria affiliated to isolates from soil humus. In contrast, the filamentous cyanobacterial taxon (assigned to Leptolyngbya/Phormidesmis pristleyi) which dominates the community and binds together granular cryoconite are poorly connected to other taxa. While our study targeted one ice cap, the prominent role of generalist core taxa with close environmental relatives across the global cryosphere indicate discrete roles for cosmopolitan Actinobacteria and Cyanobacteria as respective keystone taxa and ecosystem engineers of cryoconite ecosystems colonizing ice caps. © 2016 John Wiley & Sons Ltd.

  9. Future projections of the climate and surface mass balance of Svalbard with the regional climate model MAR

    NASA Astrophysics Data System (ADS)

    Lang, C.; Fettweis, X.; Erpicum, M.

    2015-01-01

    We have performed future projections of the climate and surface mass balance (SMB) of Svalbard with the MAR regional climate model forced by the MIROC5 global model, following the RCP8.5 scenario at a spatial resolution of 10 km. MAR predicts a similar evolution of increasing surface melt everywhere in Svalbard followed by a sudden acceleration of the melt around 2050, with a larger melt increase in the south compared to the north of the archipelago and the ice caps. This melt acceleration around 2050 is mainly driven by the albedo-melt feedback associated with the expansion of the ablation/bare ice zone. This effect is dampened in part as the solar radiation itself is projected to decrease due to cloudiness increase. The near-surface temperature is projected to increase more in winter than in summer as the temperature is already close to 0 °C in summer. The model also projects a strong winter west-to-east temperature gradient, related to the large decrease of sea ice cover around Svalbard. At the end of the century (2070-2099 mean), SMB is projected to be negative over the entire Svalbard and, by 2085, all glaciated regions of Svalbard are predicted to undergo net ablation, meaning that, under the RCP8.5 scenario, all the glaciers and ice caps are predicted to start their irreversible retreat before the end of the 21st century.

  10. Polar Ice Caps: a Canary for the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Honsaker, W.; Lowell, T. V.; Sagredo, E.; Kelly, M. A.; Hall, B. L.

    2010-12-01

    Ice caps are glacier masses that are highly sensitive to climate change. Because of their hypsometry they can have a binary state. When relatively slight changes in the equilibrium line altitude (ELA) either intersect or rise above the land the ice can become established or disappear. Thus these upland ice masses have a fast response time. Here we consider a way to extract the ELA signal from independent ice caps adjacent to the Greenland Ice Sheet margin. It may be that these ice caps are sensitive trackers of climate change that also impact the ice sheet margin. One example is the Istorvet Ice Cap located in Liverpool Land, East Greenland (70.881°N, 22.156°W). The ice cap topography and the underlying bedrock surface dips to the north, with peak elevation of the current ice ranging in elevation from 1050 to 745 m.a.s.l. On the eastern side of the ice mass the outlet glaciers extending down to sea level. The western margin has several small lobes in topographic depressions, with the margin reaching down to 300 m.a.s.l. Topographic highs separate the ice cap into at least 5 main catchments, each having a pair of outlet lobes toward either side of the ice cap. Because of the regional bedrock slope each catchment has its own elevation range. Therefore, as the ELA changes it is possible for some catchments of the ice cap to experience positive mass balance while others have a negative balance. Based on weather observations we estimate the present day ELA to be ~1000 m.a.s.l, meaning mass balance is negative for the majority of the ice cap. By tracking glacier presence/absence in these different catchments, we can reconstruct small changes in the ELA. Another example is the High Ice Cap (informal name) in Milne Land (70.903°N, 25.626°W, 1080 m), East Greenland. Here at least 4 unconformities in ice layers found near the southern margin of the ice cap record changing intervals of accumulation and ablation. Therefore, this location may also be sensitive to slight

  11. Improved parameterization of marine ice dynamics and flow instabilities for simulation of the Austfonna ice cap using a large-scale ice sheet model

    NASA Astrophysics Data System (ADS)

    Dunse, T.; Greve, R.; Schuler, T.; Hagen, J. M.; Navarro, F.; Vasilenko, E.; Reijmer, C.

    2009-12-01

    The Austfonna ice cap covers an area of 8120 km2 and is by far the largest glacier on Svalbard. Almost 30% of the entire area is grounded below sea-level, while the figure is as large as 57% for the known surge-type basins in particular. Marine ice dynamics, as well as flow instabilities presumably control flow regime, form and evolution of Austfonna. These issues are our focus in numerical simulations of the ice cap. We employ the thermodynamic, large-scale ice sheet model SICOPOLIS (http://sicopolis.greveweb.net/) which is based on the shallow-ice approximation. We present improved parameterizations of (a) the marine extent and calving and (b) processes that may initiate flow instabilities such as switches from cold to temperate basal conditions, surface steepening and hence, increases in driving stress, enhanced sliding or deformation of unconsolidated marine sediments and diminishing ice thicknesses towards flotation thickness. Space-borne interferometric snapshots of Austfonna revealed a velocity structure of a slow moving polar ice cap (< 10m/a) interrupted by distinct fast flow units with velocities in excess of 100m/a. However, observations of flow variability are scarce. In spring 2008, we established a series of stakes along the centrelines of two fast-flowing units. Repeated DGPS and continuous GPS measurements of the stake positions give insight in the temporal flow variability of these units and provide constrains to the modeled surface velocity field. Austfonna’s thermal structure is described as polythermal. However, direct measurements of the temperature distribution is available only from one single borehole at the summit area. The vertical temperature profile shows that the bulk of the 567m thick ice column is cold, only underlain by a thin temperate basal layer of approximately 20m. To acquire a spatially extended picture of the thermal structure (and bed topography), we used low-frequency (20 MHz) GPR profiling across the ice cap and the

  12. Late Weichselian ice-sheet dynamics and deglaciation history of the northern Svalbard margin

    NASA Astrophysics Data System (ADS)

    Fransner, O.; Noormets, R. R. N. N.; Flink, A.; Hogan, K.; Dowdeswell, J. A.; O'Regan, M.; Jakobsson, M.

    2016-12-01

    The glacial evolution of the northern Svalbard margin is poorly known compared with the western margin. Gravity cores, swath bathymetric, sub-bottom acoustic and 2D airgun data are used to investigate the Late Weichselian Svalbard-Barents Ice Sheet history on the northern Svalbard margin. Prograding sequences in Kvitøya and Albertini trough mouths (TMs) indicate ice streaming to the shelf edge multiple times during the Quaternary. While Kvitøya Trough has an associated trough-mouth fan (TMF), Albertini TM is cut back into the shelf edge. Down-faulted bedrock below Albertini TM suggests larger sediment accommodation space there, explaining the absence of a TMF. The bathymetry indicates that ice flow in Albertini Trough was sourced from Duvefjorden and Albertinibukta. Exposed crystalline bedrock likely kept the two ice flows separated before merging north of Karl XII-Øya. Subglacial landforms in Rijpfjorden and Duvefjorden indicate that both fjords accommodated northward-flowing ice streams during the LGM. The deeper fjord basin and higher elongation ratios of landforms in Duvefjorden suggest a more focused and/or larger ice flow there. Easily erodible sedimentary rocks are common in Duvefjorden, which may explain different ice flow dynamics in these fjords. Kvitøya TMF is flanked by gullies, probably formed through erosive downslope gravity flows triggered by sediment-laden meltwater during early deglaciation. Glacial landforms in Albertini Trough comprise retreat-related landforms indicating slow deglaciation. Iceberg scours in Albertini Trough suggest the importance of calving for mass-loss. Sets of De Geer moraines in Rijpfjorden imply that slow, grounded retreat continued in <210 m water depth. Lack of retreat-related landforms in deeper areas of Rijpfjorden and in Duvefjorden indicates floating glacier fronts influenced by calving. 14C ages suggest that deglaciation of inner Rijpfjorden and central Duvefjorden were complete before 10,434 cal a BP and 10

  13. Paleo ice-cap surfaces and extents

    NASA Astrophysics Data System (ADS)

    Gillespie, A.; Pieri, D.

    2008-12-01

    The distribution, equilibrium-line altitude (ELA) and timing of Pleistocene alpine glaciers are used to constrain paleoclimatic reconstructions. Attention has largely focused on the geomorphic evidence for the former presence of simple valley glaciers; paleo alpine ice caps and their outlet glaciers have proven to be more problematical. This is especially so in the remote continental interior of Asia, where the research invested in the Alps or Rocky Mountains has yet to be duplicated. Even the putative existence and size of paleo ice caps in Tibet and the Kyrgyz Tien Shan is controversial. Remote sensing offers the opportunity to assess vast tracts of land quickly, with images and co-registered digital elevation models (DEMs) offering the most information for studies of paleoglaciers. We pose several questions: (1) With what confidence can nunataks be identified remotely? (2) What insights do their physiographic characteristics offer? (3) What characteristics of the bed of a paleo ice cap can be used to identify its former presence remotely? and (4) Can the geomorphic signatures of the edges of paleo ice caps be recognized and mapped? Reconstruction of the top surface of a paleo ice cap depends on the recognition of nunataks, typically rougher at 1 m to 100 m scales than their surroundings. Nunataks in southern Siberia are commonly notched by multiple sub- horizontal bedrock terraces. These step terraces appear to originate from freeze-thaw action on the rock-ice interface during periods of stability, and presence of multiple terraces suggests stepwise lowering of ice surfaces during deglaciation. An older generation of step-terraced nunataks, distinguished by degraded and eroded terraces, delineates a larger paleo ice cap in the Sayan Range (Siberian - Mongolian border) that significantly pre-dates the last glacial maximum (LGM). Large ice caps can experience pressure melting at their base and can manifest ice streams within the ice cap. Valleys left behind differ

  14. Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements

    NASA Astrophysics Data System (ADS)

    Dunse, T.; Schuler, T. V.; Hagen, J. O.; Reijmer, C. H.

    2011-12-01

    A large part of the ice discharge from ice caps and ice sheets occurs through spatially limited flow units that may operate in a mode of steady flow or cyclic surge behaviour. Changes in the dynamics of distinct flow units play a key role in the mass balance of Austfonna, the largest ice cap on Svalbard. The recent net mass loss of Austfonna was dominated by calving from marine terminating outlet glaciers. Previous ice-surface velocity maps of the ice cap were derived by satellite radar interferometry (InSAR) and rely on data acquired in the mid-1990s with limited information concerning the temporal variability. Here, we present continuous Global Positioning System (GPS) observations along the central flowlines of two fast flowing outlet glaciers over 2008-2010. The data show prominent summer speed-ups with ice-surface velocities as high as 240 % of the pre-summer mean. Acceleration follows the onset of the summer melt period, indicating enhanced basal motion due to input of surface meltwater into the subglacial drainage system. In 2008, multiple velocity peaks coincide with successive melt periods. In 2009, the principle melt was of higher amplitude than in 2008. Flow velocities appear unaffected by subsequent melt periods, suggesting a transition towards a hydraulically more efficient drainage system. The observed annual mean velocities of Duvebreen and Basin-3 exceed those from the mid-1990s by factors two and four, respectively, implying increased ice discharge at the calving front. Measured summer velocities up to 2 m d-1 for Basin-3 are close to that of Kronebreen, often referred to as the fastest glacier on Svalbard.

  15. Devon island ice cap: core stratigraphy and paleoclimate.

    PubMed

    Koerner, R M

    1977-04-01

    Valuable paleoclimatic information can be gained by studying the distribution of melt layers in deep ice cores. A profile representing the percentage of ice in melt layers in a core drilled from the Devon Island ice cap plotted against both time and depth shows that the ice cap has experienced a period of very warm summers since 1925, following a period of colder summers between about 1600 and 1925. The earlier period was coldest between 1680 and 1730. There is a high correlation between the melt-layer ice percentage and the mass balance of the ice cap. The relation between them suggests that the ice cap mass balance was zero (accumulation equaled ablation) during the colder period but is negative in the present warmer one. There is no firm evidence of a present cooling trend in the summer conditions on the ice cap. A comparison with the melt-layer ice percentage in cores from the other major Canadian Arctic ice caps shows that the variation of summer conditions found for the Devon Island ice cap is representative for all the large ice caps for about 90 percent of the time. There is also a good correlation between melt-layer percentage and summer sea-ice conditions in the archipelago. This suggests that the search for the northwest passage was influenced by changing climate, with the 19th-century peak of the often tragic exploration coinciding with a period of very cold summers.

  16. Winter ocean-ice interactions under thin sea ice observed by IAOOS platforms during N-ICE2015: Salty surface mixed layer and active basal melt

    NASA Astrophysics Data System (ADS)

    Koenig, Zoé; Provost, Christine; Villacieros-Robineau, Nicolas; Sennéchael, Nathalie; Meyer, Amelie

    2016-10-01

    IAOOS (Ice Atmosphere Arctic Ocean Observing System) platforms, measuring physical parameters at the atmosphere-snow-ice-ocean interface deployed as part of the N-ICE2015 campaign, provide new insights on winter conditions North of Svalbard. The three regions crossed during the drifts, the Nansen Basin, the Sofia Deep, and the Svalbard northern continental slope featured distinct hydrographic properties and ice-ocean exchanges. In the Nansen Basin, the quiescent warm layer was capped by a stepped halocline (60 and 110 m) and a deep thermocline (110 m). Ice was forming and the winter mixed layer salinity was larger by ˜0.1 g/kg than previously observed. Over the Svalbard continental slope, the Atlantic Water (AW) was very shallow (20 m from the surface) and extended offshore from the 500 m isobath by a distance of about 70 km, sank along the slope (40 m from the surface) and probably shed eddies into the Sofia Deep. In the Sofia Deep, relatively warm waters of Atlantic origin extended from 90 m downward. Resulting from different pathways, these waters had a wide range of hydrographic characteristics. Sea-ice melt was widespread over the Svalbard continental slope and ocean-to-ice heat fluxes reached values of 400 W m-2 (mean of ˜150 W m-2 over the continental slope). Sea-ice melt events were associated with near 12 h fluctuations in the mixed-layer temperature and salinity corresponding to the periodicity of tides and near-inertial waves potentially generated by winter storms, large barotropic tides over steep topography, and/or geostrophic adjustments.

  17. Little Ice Age Fluctuations of Quelccaya Ice Cap, Peru

    NASA Astrophysics Data System (ADS)

    Stroup, J. S.; Kelly, M. A.; Lowell, T.

    2009-12-01

    A record of the past extents of Quelccaya Ice Cap (QIC) provides valuable information about tropical climate change from late glacial to recent time. Here, we examine the timing and regional significance of fluctuations of QIC during the Little Ice Age (LIA; ~1300-1850 AD). One prominent set of moraines, known as the Huancane I moraines, is located ~1 km from the present-day western ice cap margin and provides a near-continuous outline of the most recent advance of QIC. This moraine set was radiocarbon dated (~298 ± 134 and 831 ± 87 yr BP) by Mercer and Palacios (1977) and presented as some of the first evidence for cooling in the tropics during the Little Ice Age. Recent field investigations in the QIC region focused on refining the chronology of the Huancane I moraines. In 2008, new stratigraphic sections exposed by local lake-flooding events revealed multiple layers of peat within the Huancane I moraines. In both 2008 and 2009, samples were obtained for 10Be dating of boulders on Huancane I moraines. A combination of radiocarbon and 10Be ages indicate that the Huancane I moraines were deposited by ice cap expansion after ~3800 yr BP and likely by multiple advances at approximately 1000, 600, 400, and 200 yr BP. Radiocarbon and 10Be chronologies of the Huancane I moraines are compared with the Quelccaya ice core records (Thompson et al., 1985; 1986; 2006). Accumulation data from the ice core records are interpreted to indicate a significant wet period at ~1500-1700 AD followed by a significant drought at ~1720-1860 AD. We examine ice marginal fluctuations during these times to determine influence of such events on the ice cap extent.

  18. Frontal destabilization of Stonebreen, Edgeøya, Svalbard

    NASA Astrophysics Data System (ADS)

    Strozzi, Tazio; Kääb, Andreas; Schellenberger, Thomas

    2017-02-01

    In consideration of the strong atmospheric warming that has been observed since the 1990s in polar regions there is a need to quantify mass loss of Arctic ice caps and glaciers and their contribution to sea level rise. In polar regions a large part of glacier ablation is through calving of tidewater glaciers driven by ice velocities and their variations. The Svalbard region is characterized by glaciers with rapid dynamic fluctuations of different types, including irreversible adjustments of calving fronts to a changing mass balance and reversible, surge-type activities. For large areas, however, we do not have much past and current information on glacier dynamic fluctuations. Recently, through frequent monitoring based on repeat optical and synthetic aperture radar (SAR) satellite data, a number of zones of velocity increases have been observed at formerly slow-flowing calving fronts on Svalbard. Here we present the dynamic evolution of the southern lobe of Stonebreen on Edgeøya. We observe a slowly steady retreat of the glacier front from 1971 until 2011, followed by a strong increase in ice surface velocity along with a decrease of volume and frontal extension since 2012. The considerable losses in ice thickness could have made the tide-water calving glacier, which is grounded below sea level some 6 km inland from the 2014 front, more sensitive to surface meltwater reaching its bed and/or warm ocean water increasing frontal ablation with subsequent strong multi-annual ice-flow acceleration.

  19. Geodetic glacier mass balancing on ice caps - inseparably connected to firn modelling?

    NASA Astrophysics Data System (ADS)

    Saß, Björn L.; Sauter, Tobias; Seehaus, Thorsten; Braun, Matthias H.

    2017-04-01

    Observed melting of glaciers and ice caps in the polar regions contribute to the ongoing global sea level rise (SLR). A rising sea level and its consequences are one of the major challenges for coastal societies in the next decades to centuries. Gaining knowledge about the main drivers of SLR and bringing it together is one recent key-challenge for environmental science. The high arctic Svalbard archipelago faced a strong climatic change in the last decades, associated with a change in the cryosphere. Vestfonna, a major Arctic ice cap in the north east of Svalbard, harbors land and marine terminating glaciers, which expose a variability of behavior. We use high resolution remote sensing data from space-borne radar (TanDEM-X, TerraSAR-X, Sentinel-1a), acquired between 2009 and 2015, to estimate glacier velocity and high accurate surface elevation changes. For DEM registration we use space-borne laser altimetry (ICESat) and an existing in-situ data archive (IPY Kinnvika). In order to separate individual glacier basin changes for a detailed mass balance study and for further SLR contribution estimates, we use glacier outlines from the Global Land Ice Measurements from Space (GLIMS) project. Remaining challenges of space-borne observations are the reduction of measurement uncertainties, in the case of Synthetic Aperture Radar most notably signal penetration into the glacier surface. Furthermore, in order to convert volume to mass change one has to use the density of the changed mass (conversion factor) and one has to account for the mass conservation processes in the firn package (firn compaction). Both, the conversion factor and the firn compaction are not (yet) measurable for extensive ice bodies. They have to be modelled by coupling point measurements and regional gridded climate data. Results indicate a slight interior thickening contrasted with wide spread thinning in the ablation zone of the marine terminating outlets. While one glacier system draining to the

  20. Holocene history of North Ice Cap, northwestern Greenland

    NASA Astrophysics Data System (ADS)

    Corbett, L. B.; Kelly, M. A.; Osterberg, E. C.; Axford, Y.; Bigl, M.; Roy, E. P.; Thompson, J. T.

    2013-12-01

    Although much research has focused on the past extents of the Greenland Ice Sheet, less is known about the smaller ice caps on Greenland and how they have evolved over time. These small ice caps respond sensitively to summer temperatures and, to a lesser extent, winter precipitation, and provide valuable information about climatic conditions along the Greenland Ice Sheet margins. Here, we investigate the Holocene history of North Ice Cap (76°55'N 68°00'W), located in the Nunatarssuaq region near Thule, northwest Greenland. Our results are based on glacial geomorphic mapping, 10Be dating, and analyses of sediment cores from a glacially fed lake. Fresh, unweathered and unvegetated boulders comprise moraines and drift that mark an extent of North Ice Cap ~25 m outboard of the present ice margin. It is likely that these deposits were formed during late Holocene time and we are currently employing 10Be surface exposure dating to examine this hypothesis. Just outboard of the fresh moraines and drift, boulders and bedrock show significant weathering and are covered with lichen. Based on glacial geomorphic mapping and detailed site investigations, including stone counts, we suggest that the weathered boulders and bedrock were once covered by erosive Greenland Ice Sheet flow from southeast to northwest over the Nunatarssuaq region. Five 10Be ages from the more weathered landscape only 100-200 m outboard of the modern North Ice Cap margin are 52 and 53 ka (bedrock) and 16, 23, and 31 ka (boulders). These ages indicate that recent ice cover has likely been cold-based and non-erosive, failing to remove inherited cosmogenic nuclides from previous periods of exposure, although the youngest boulder may provide a maximum limiting deglaciation age. Sediment cores collected from Delta Sø, a glacially-fed lake ~1.5 km outside of the modern North Ice Cap margin, contain 130 cm of finely laminated sediments overlying coarse sands and glacial till. Radiocarbon ages from just above

  1. State of Arctic Sea Ice North of Svalbard during N-ICE2015

    NASA Astrophysics Data System (ADS)

    Rösel, Anja; King, Jennifer; Gerland, Sebastian

    2016-04-01

    The N-ICE2015 cruise, led by the Norwegian Polar Institute, was a drift experiment with the research vessel R/V Lance from January to June 2015, where the ship started the drift North of Svalbard at 83°14.45' N, 21°31.41' E. The drift was repeated as soon as the vessel drifted free. Altogether, 4 ice stations where installed and the complex ocean-sea ice-atmosphere system was studied with an interdisciplinary Approach. During the N-ICE2015 cruise, extensive ice thickness and snow depth measurements were performed during both, winter and summer conditions. Total ice and snow thickness was measured with ground-based and airborne electromagnetic instruments; snow depth was measured with a GPS snow depth probe. Additionally, ice mass balance and snow buoys were deployed. Snow and ice thickness measurements were performed on repeated transects to quantify the ice growth or loss as well as the snow accumulation and melt rate. Additionally, we collected independent values on surveys to determine the general ice thickness distribution. Average snow depths of 32 cm on first year ice, and 52 cm on multi-year ice were measured in January, the mean snow depth on all ice types even increased until end of March to 49 cm. The average total ice and snow thickness in winter conditions was 1.92 m. During winter we found a small growth rate on multi-year ice of about 15 cm in 2 months, due to above-average snow depths and some extraordinary storm events that came along with mild temperatures. In contrast thereto, we also were able to study new ice formation and thin ice on newly formed leads. In summer conditions an enormous melt rate, mainly driven by a warm Atlantic water inflow in the marginal ice zone, was observed during two ice stations with melt rates of up to 20 cm per 24 hours. To reinforce the local measurements around the ship and to confirm their significance on a larger scale, we compare them to airborne thickness measurements and classified SAR-satellite scenes. The

  2. The future of the Devon Ice cap: results from climate and ice dynamics modelling

    NASA Astrophysics Data System (ADS)

    Mottram, Ruth; Rodehacke, Christian; Boberg, Fredrik

    2017-04-01

    The Devon Ice Cap is an example of a relatively well monitored small ice cap in the Canadian Arctic. Close to Greenland, it shows a similar surface mass balance signal to glaciers in western Greenland. Here we use high resolution (5km) simulations from HIRHAM5 to drive the PISM glacier model in order to model the present day and future prospects of this small Arctic ice cap. Observational data from the Devon Ice Cap in Arctic Canada is used to evaluate the surface mass balance (SMB) data output from the HIRHAM5 model for simulations forced with the ERA-Interim climate reanalysis data and the historical emissions scenario run by the EC-Earth global climate model. The RCP8.5 scenario simulated by EC-Earth is also downscaled by HIRHAM5 and this output is used to force the PISM model to simulate the likely future evolution of the Devon Ice Cap under a warming climate. We find that the Devon Ice Cap is likely to continue its present day retreat, though in the future increased precipitation partly offsets the enhanced melt rates caused by climate change.

  3. Episodic Neoglacial snowline descent and glacier expansion on Svalbard reconstructed from the 14C ages of ice-entombed plants

    NASA Astrophysics Data System (ADS)

    Miller, Gifford H.; Landvik, Jon Y.; Lehman, Scott J.; Southon, John R.

    2017-01-01

    The response of the Northern Hemisphere cryosphere to the monotonic decline in summer insolation and variable radiative forcing during the Holocene has been one of irregular expansion culminating in the Little Ice Age, when most glaciers attained their maximum late Holocene dimensions. Although periods of intervening still-stand or ice-retreat can be reconstructed by direct dating of ice-recessional features, defining times of Neoglacial ice growth has been limited to indirect proxies preserved in distal archives. Here we report 45 precise radiocarbon dates on in situ plants emerging from beneath receding glaciers on Svalbard that directly date the onset of snowline descent and glacier expansion, entombing the plants. Persistent snowline lowering occurred between 4.0 and 3.4 ka, but with little additional persistent lowering until early in the first millennium AD. Populations of individual 14C calendar age results and their aggregate calendar age probabilities define discrete episodes of vegetation kill and snowline lowering 240-340 AD, 410-540 AD and 670-750 AD, each with a lower snowline than the preceding episode, followed by additional snowline lowering between 1000 and 1220 AD, and between 1300 and 1450 AD. Snowline changes after 1450 AD, including the maximum ice extent of the Little Ice Age are not resolved by our collections, although snowlines remained lower than their 1450 AD level until the onset of modern warming. A time-distance diagram derived from a 250-m-long transect of dated ice-killed plants documents ice-margin advances ∼750, ∼1100 and after ∼1500 AD, concordant with distributed vegetation kill ages seen in the aggregate data set, supporting our central thesis that vegetation kill ages provide direct evidence of snowline lowering and cryospheric expansion. The mid- to late-Holocene history of snowline lowering on Svalbard is similar to ELA reconstructions of Norwegian and Svalbard cirque glaciers, and consistent with a cryospheric response

  4. What Lies Below a Martian Ice Cap

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for larger annotated version

    This image (top) taken by the Shallow Radar instrument on NASA's Mars Reconnaissance Orbiter reveals the layers of ice, sand and dust that make up the north polar ice cap on Mars. It is the most detailed look to date at the insides of this ice cap. The colored map below the radar picture shows the topography of the corresponding Martian terrain (red and white represent higher ground, and green and yellow lower).

    The radar image reveals four never-before-seen thick layers of ice and dust separated by layers of nearly pure ice. According to scientists, these thick ice-free layers represent approximately one-million-year-long cycles of climate change on Mars caused by variations in the planet's tilted axis and its eccentric orbit around the sun. Adding up the entire stack of ice gives an estimated age for the north polar ice cap of about 4 million years a finding that agrees with previous theoretical estimates. The ice cap is about 2 kilometers (1.2 miles) thick.

    The radar picture also shows that the boundary between the ice layers and the surface of Mars underneath is relatively flat (bottom white line on the right). This implies that the surface of Mars is not sagging, or bending, under the weight of the ice cap and this, in turn, suggests that the planet's lithosphere, a combination of the crust and the strong parts of the upper mantle, is thicker than previously thought.

    A thicker lithosphere on Mars means that temperatures increase more gradually with depth toward the interior. Temperatures warm enough for water to be liquid are therefore deeper than previously thought. Likewise, if liquid water does exist in aquifers below the surface of Mars, and if there are any organisms living in that water, they would have to be located deeper in the planet.

    The topography data are from Mars Orbiter Laser Altimeter, which was flown on NASA's Mars Global

  5. Winter ocean-ice interactions under thin sea ice observed by IAOOS platforms during NICE2015:salty surface mixed layer and active basal melt

    NASA Astrophysics Data System (ADS)

    Provost, C.; Koenig, Z.; Villacieros-Robineau, N.; Sennechael, N.; Meyer, A.; Lellouche, J. M.; Garric, G.

    2016-12-01

    IAOOS platforms, measuring physical parameters at the atmosphere-snow-ice-ocean interface deployed as part of the N-ICE2015 campaign, provide new insights on winter conditions North of Svalbard. The three regions crossed during the drifts, the Nansen Basin, the Sofia Deep and the Svalbard northern continental slope featured distinct hydrographic properties and ice-ocean exchanges. In the Nansen Basin the quiescent warm layer was capped by a stepped halocline (60 and 110 m) and a deep thermocline (110 m). Ice was forming and the winter mixed layer salinity was larger by 0.1 g/kg than previously observed. Over the Svalbard continental slope, the Atlantic Water (AW) was very shallow (20 m from the surface) and extended offshore from the 500 m isobath by a distance of about 70 km, sank along the slope (40 m from the surface) and probably shedded eddies into the Sofia Deep. In the Sofia Deep, relatively warm waters of Atlantic origin extended from 90 m downward. Resulting from different pathways, these waters had a wide range of hydrographic characteristics. Sea-ice melt was widespread over the Svalbard continental slope and ocean-to-ice heat fluxes reached values of 400 Wm-2 (mean of 150 Wm-2 over the continentalslope). Sea-ice melt events were associated with near 12-hour fluctuations in the mixed-layer temperature and salinity corresponding to the periodicity of tides and near-inertial waves potentially generated by winter storms, large barotropic tides over steep topography and/or geostrophic adjustments.

  6. Devon Ice cap's future: results from climate and ice dynamics modelling via surface mass balance modelling

    NASA Astrophysics Data System (ADS)

    Rodehacke, C. B.; Mottram, R.; Boberg, F.

    2017-12-01

    The Devon Ice Cap is an example of a relatively well monitored small ice cap in the Canadian Arctic. Close to Greenland, it shows a similar surface mass balance signal to glaciers in western Greenland. Here we various boundary conditions, ranging from ERA-Interim reanalysis data via global climate model high resolution (5km) output from the regional climate model HIRHAM5, to determine the surface mass balance of the Devon ice cap. These SMB estimates are used to drive the PISM glacier model in order to model the present day and future prospects of this small Arctic ice cap. Observational data from the Devon Ice Cap in Arctic Canada is used to evaluate the surface mass balance (SMB) data output from the HIRHAM5 model for simulations forced with the ERA-Interim climate reanalysis data and the historical emissions scenario run by the EC-Earth global climate model. The RCP8.5 scenario simulated by EC-Earth is also downscaled by HIRHAM5 and this output is used to force the PISM model to simulate the likely future evolution of the Devon Ice Cap under a warming climate. We find that the Devon Ice Cap is likely to continue its present day retreat, though in the future increased precipitation partly offsets the enhanced melt rates caused by climate change.

  7. Late-glacial and Holocene history of changes in Quelccaya Ice Cap, Peru

    NASA Astrophysics Data System (ADS)

    Kelly, M. A.; Lowell, T. V.; Schaefer, J. M.; Finkel, R. C.

    2008-12-01

    Quelccaya Ice Cap in the southeastern Peruvian Andes (~13-14° S latitude) is an icon for climate change. Its rapidly receding outlet, Qori Kalis Glacier, has been monitored since the 1970's. Cores from Quelccaya Ice Cap provide high-resolution information about temperature and precipitation during the past 1,500 years. We extend the understanding of past changes in Quelccaya Ice Cap based on mapping and dating of glacial moraines and associated deposits. Our results include fifty 10Be ages of moraines and bedrock as well as twenty-nine 14C ages of organic material associated with moraines. These results form the basis of a chronology of changes in Quelccaya Ice Cap from ~16,000 yr BP to late Holocene time. Results from 10Be and 14C dating indicate that Quelccaya Ice Cap experienced a significant advance at 12,700-11,400 yr BP. Subsequent to this advance, the ice margin deposited at least three recessional moraine sets. Quelccaya Ice Cap receded to near its present-day margin by ~10,000 yr BP. Neoglacial advances began by ~3,000 yr BP and culminated with a maximum advance during the Little Ice Age. This chronology fits well with prior work which indicates a restricted Quelccaya Ice Cap during middle Holocene time. Moreover, the overlap between moraine and ice core data for the last 1,500 years provides a unique opportunity to assess the influences of temperature and precipitation on past ice cap extents.

  8. Perennial water ice identified in the south polar cap of Mars

    NASA Astrophysics Data System (ADS)

    Bibring, Jean-Pierre; Langevin, Yves; Poulet, François; Gendrin, Aline; Gondet, Brigitte; Berthé, Michel; Soufflot, Alain; Drossart, Pierre; Combes, Michel; Bellucci, Giancarlo; Moroz, Vassili; Mangold, Nicolas; Schmitt, Bernard; OMEGA Team; Erard, S.; Forni, O.; Manaud, N.; Poulleau, G.; Encrenaz, T.; Fouchet, T.; Melchiorri, R.; Altieri, F.; Formisano, V.; Bonello, G.; Fonti, S.; Capaccioni, F.; Cerroni, P.; Coradini, A.; Kottsov, V.; Ignatiev, N.; Titov, D.; Zasova, L.; Pinet, P.; Sotin, C.; Hauber, E.; Hoffman, H.; Jaumann, R.; Keller, U.; Arvidson, R.; Mustard, J.; Duxbury, T.; Forget, F.

    2004-04-01

    The inventory of water and carbon dioxide reservoirs on Mars are important clues for understanding the geological, climatic and potentially exobiological evolution of the planet. From the early mapping observation of the permanent ice caps on the martian poles, the northern cap was believed to be mainly composed of water ice, whereas the southern cap was thought to be constituted of carbon dioxide ice. However, recent missions (NASA missions Mars Global Surveyor and Odyssey) have revealed surface structures, altimetry profiles, underlying buried hydrogen, and temperatures of the south polar regions that are thermodynamically consistent with a mixture of surface water ice and carbon dioxide. Here we present the first direct identification and mapping of both carbon dioxide and water ice in the martian high southern latitudes, at a resolution of 2km, during the local summer, when the extent of the polar ice is at its minimum. We observe that this south polar cap contains perennial water ice in extended areas: as a small admixture to carbon dioxide in the bright regions; associated with dust, without carbon dioxide, at the edges of this bright cap; and, unexpectedly, in large areas tens of kilometres away from the bright cap.

  9. Holocene Fluctuations of North Ice Cap, a Proxy for Climate Conditions along the Northwestern Margin of the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Kelly, M. A.; Osterberg, E. C.; Lasher, G. E.; Farnsworth, L. B.; Howley, J. A.; Axford, Y.; Zimmerman, S. R. H.

    2015-12-01

    North Ice Cap (~76.9°N, 68°W, summit elevation 1322 m asl), a small, independent ice cap in northwestern Greenland, is located within ~25 km of the Greenland Ice Sheet margin and Harald Molkte Bræ outlet glacier. We present geochronological, geomorphic and sedimentological data constraining the Holocene extents of North Ice Cap and suggest that its past fluctuations can be used as a proxy for climate conditions along the northwestern margin of the Greenland Ice Sheet. Prior work by Goldthwait (1960) used glacial geomorphology and radiocarbon ages of subfossil plants emerging along shear planes in the ice cap margin to suggest that that North Ice Cap was not present during the early Holocene and nucleated in the middle to late Holocene time, with the onset of colder conditions. Subfossil plants emerging at shear planes in the North Ice Cap margin yield radiocarbon ages of ~4.8-5.9 cal kyr BP (Goldthwait, 1960) and ~AD 1000-1350 (950-600 cal yr BP), indicating times when the ice cap was smaller than at present. In situ subfossil plants exposed by recent ice cap retreat date to ~AD 1500-1840 (450-110 cal yr BP) and indicate small fluctuations of the ice cap margin. 10Be ages of an unweathered, lichen-free drift <100 m from the present North Ice Cap margin range from ~500 to 8000 yrs ago. We suggest that the drift was deposited during the last ~500 yrs and that the older 10Be ages are influenced by 10Be inherited from a prior period of exposure. We also infer ice cap fluctuations using geochemical data from a Holocene-long sediment core from Deltasø, a downstream lake that currently receives meltwater from North Ice Cap. The recent recession of the North Ice Cap margin influenced a catastrophic drainage of a large proglacial lake, Søndre Snesø, that our field team documented in August 2012. To our knowledge, this is the first significant lowering of Søndre Snesø in historical time.

  10. Rapid wastage of the Hazen Plateau ice caps, northeastern Ellesmere Island, Nunavut, Canada

    NASA Astrophysics Data System (ADS)

    Serreze, Mark C.; Raup, Bruce; Braun, Carsten; Hardy, Douglas R.; Bradley, Raymond S.

    2017-01-01

    Two pairs of small stagnant ice bodies on the Hazen Plateau of northeastern Ellesmere Island, the St. Patrick Bay ice caps and the Murray and Simmons ice caps, are rapidly shrinking, and the remnants of the St. Patrick Bay ice caps are likely to disappear entirely within the next 5 years. Vertical aerial photographs of these Little Ice Age relics taken during August of 1959 show that the larger of the St. Patrick Bay ice caps had an area of 7.48 km2 and the smaller one 2.93 km2; the Murray and Simmons ice caps covered 4.37 and 7.45 km2 respectively. Outlines determined from ASTER satellite data for July 2016 show that, compared to 1959, the larger and the smaller of the St. Patrick Bay ice caps had both been reduced to only 5 % of their former area, with the Murray and Simmons ice caps faring better at 39 and 25 %, likely reflecting their higher elevation. Consistent with findings from other glaciological studies in the Queen Elizabeth Islands, ASTER imagery in conjunction with past GPS surveys documents a strikingly rapid wastage of the St. Patrick Bay ice caps over the last 15 years. These two ice caps shrank noticeably even between 2014 and 2015, apparently in direct response to the especially warm summer of 2015 over northeastern Ellesmere Island. The well-documented recession patterns of the Hazen Plateau ice caps over the last 55+ years offer an opportunity to examine the processes of plant recolonization of polar landscapes.

  11. Diversity of bacteria in surface ice of Austre Lovénbreen glacier, Svalbard.

    PubMed

    Zeng, Yin-Xin; Yan, Ming; Yu, Yong; Li, Hui-Rong; He, Jian-Feng; Sun, Kun; Zhang, Fang

    2013-05-01

    Two 16S rRNA gene clone libraries Cores 1U and 2U were constructed using two ice core samples collected from Austre Lovénbreen glacier in Svalbard. The two libraries yielded a total of 262 clones belonging to 59 phylotypes. Sequences fell into 10 major lineages of the domain Bacteria, including Proteobacteria (alpha, beta, gamma and delta subdivisions), Bacteroidetes, Actinobacteria, Firmicutes, Acidobacteria, Deinococcus-Thermus, Chloroflexi, Planctomycetes, Cyanobacteria and candidate division TM7. Among them, Bacteroidetes, Actinobacteria, Alphaproteobacteria and Cyanobacteria were most abundant. UniFrac data showed no significant differences in community composition between the two ice cores. A total of nineteen bacterial strains from the genera Pseudoalteromonas and Psychrobacter were isolated from the ice cores. Phylogenetic and phenotypic analyses revealed a close relationship between the ice core isolates and bacteria in marine environments, indicating a wide distribution of some bacterial phylotypes in both terrestrial and marine ecosystems.

  12. Elevation Changes of Ice Caps in the Canadian Arctic Archipelago

    NASA Technical Reports Server (NTRS)

    Abdalati, W.; Krabill, W.; Frederick, E.; Manizade, S.; Martin, C.; Sonntag, J.; Swift, R.; Thomas, R.; Yungel, J.; Koerner, R.

    2004-01-01

    Precise repeat airborne laser surveys were conducted over the major ice caps in the Canadian Arctic Archipelago in the spring of 1995 and 2000 in order to measure elevation changes in the region. Our measurements reveal thinning at lower elevations (below 1600 m) on most of the ice caps and glaciers, but either very little change or thickening at higher elevations in the ice cap accumulation zones. Recent increases in precipitation in the area can account for the slight thickening where it was observed, but not for the thinning at lower elevations. For the northern ice caps on the Queen Elizabeth Islands, thinning was generally less than 0.5 m/yr , which is consistent with what would be expected from the warm temperature anomalies in the region for the 5-year period between surveys and appears to be a continuation of a trend that began in the mid 1980s. Further south, however, on the Barnes and Penny ice caps on Baffin Island, this thinning was much more pronounced at over 1 m/yr in the lower elevations. Here temperature anomalies were very small, and the thinning at low elevations far exceeds any associated enhanced ablation. The observations on Barnes, and perhaps Penny are consistent with the idea that the observed thinning is part of a much longer term deglaciation, as has been previously suggested for Barnes Ice Cap. Based on the regional relationships between elevation and elevation-change in our data, the 1995-2000 mass balance for the region is estimated to be 25 cu km/yr of ice, which corresponds to a sea level increase of 0.064 mm/ yr . This places it among the more significant sources of eustatic sea level rise, though not as substantial as Greenland ice sheet, Alaskan glaciers, or the Patagonian ice fields.

  13. Surface mass balance of Greenland mountain glaciers and ice caps

    NASA Astrophysics Data System (ADS)

    Benson, R. J.; Box, J. E.; Bromwich, D. H.; Wahr, J. M.

    2009-12-01

    Mountain glaciers and ice caps contribute roughly half of eustatic sea-level rise. Greenland has thousands of small mountain glaciers and several ice caps > 1000 sq. km that have not been included in previous mass balance calculations. To include small glaciers and ice caps in our study, we use Polar WRF, a next-generation regional climate data assimilation model is run at grid resolution less than 10 km. WRF provides surface mass balance data at sufficiently high resolution to resolve not only the narrow ice sheet ablation zone, but provides information useful in downscaling melt and accumulation rates on mountain glaciers and ice caps. In this study, we refine Polar WRF to simulate a realistic surface energy budget. Surface melting is calculated in-line from surface energy budget closure. Blowing snow sublimation is computed in-line. Melt water re-freeze is calculated using a revised scheme. Our results are compared with NASA's Gravity Recovery and Climate Experiment (GRACE) and associated error is calculated on a regional and local scale with validation from automated weather stations (AWS), snow pits and ice core data from various regions along the Greenland ice sheet.

  14. Field-calibrated model of melt, refreezing, and runoff for polar ice caps: Application to Devon Ice Cap

    NASA Astrophysics Data System (ADS)

    Morris, Richard M.; Mair, Douglas W. F.; Nienow, Peter W.; Bell, Christina; Burgess, David O.; Wright, Andrew P.

    2014-09-01

    Understanding the controls on the amount of surface meltwater that refreezes, rather than becoming runoff, over polar ice masses is necessary for modeling their surface mass balance and ultimately for predicting their future contributions to global sea level change. We present a modified version of a physically based model that includes an energy balance routine and explicit calculation of near-surface meltwater refreezing capacity, to simulate the evolution of near-surface density and temperature profiles across Devon Ice Cap in Arctic Canada. Uniquely, our model is initiated and calibrated using high spatial resolution measurements of snow and firn densities across almost the entire elevation range of the ice cap for the summer of 2004 and subsequently validated with the same type of measurements obtained during the very different meteorological conditions of summer 2006. The model captures the spatial variability across the transect in bulk snowpack properties although it slightly underestimates the flow of meltwater into the firn of previous years. The percentage of meltwater that becomes runoff is similar in both years; however, the spatial pattern of this melt-runoff relationship is different in the 2 years. The model is found to be insensitive to variation in the depth of impermeable layers within the firn but is very sensitive to variation in air temperature, since the refreezing capacity of firn decreases with increasing temperature. We highlight that the sensitivity of the ice cap's surface mass balance to air temperature is itself dependent on air temperature.

  15. Thin Sea Ice, Thick Snow, and Widespread Negative Freeboard Observed During N-ICE2015 North of Svalbard

    NASA Astrophysics Data System (ADS)

    Rösel, Anja; Itkin, Polona; King, Jennifer; Divine, Dmitry; Wang, Caixin; Granskog, Mats A.; Krumpen, Thomas; Gerland, Sebastian

    2018-02-01

    In recent years, sea-ice conditions in the Arctic Ocean changed substantially toward a younger and thinner sea-ice cover. To capture the scope of these changes and identify the differences between individual regions, in situ observations from expeditions are a valuable data source. We present a continuous time series of in situ measurements from the N-ICE2015 expedition from January to June 2015 in the Arctic Basin north of Svalbard, comprising snow buoy and ice mass balance buoy data and local and regional data gained from electromagnetic induction (EM) surveys and snow probe measurements from four distinct drifts. The observed mean snow depth of 0.53 m for April to early June is 73% above the average value of 0.30 m from historical and recent observations in this region, covering the years 1955-2017. The modal total ice and snow thicknesses, of 1.6 and 1.7 m measured with ground-based EM and airborne EM measurements in April, May, and June 2015, respectively, lie below the values ranging from 1.8 to 2.7 m, reported in historical observations from the same region and time of year. The thick snow cover slows thermodynamic growth of the underlying sea ice. In combination with a thin sea-ice cover this leads to an imbalance between snow and ice thickness, which causes widespread negative freeboard with subsequent flooding and a potential for snow-ice formation. With certainty, 29% of randomly located drill holes on level ice had negative freeboard.

  16. Acoustic Monitoring of the Arctic Ice Cap

    NASA Astrophysics Data System (ADS)

    Porter, D. L.; Goemmer, S. A.; Chayes, D. N.

    2012-12-01

    Introduction The monitoring of the Arctic Ice Cap is important economically, tactically, and strategically. In the scenario of ice cap retreat, new paths of commerce open, e.g. waterways from Northern Europe to the Far East. Where ship-going commerce is conducted, the U.S. Navy and U.S. Coast Guard have always stood guard and been prepared to assist from acts of nature and of man. It is imperative that in addition to measuring the ice from satellites, e.g. Icesat, that we have an ability to measure the ice extent, its thickness, and roughness. These parameters play an important part in the modeling of the ice and the processes that control its growth or shrinking and its thickness. The proposed system consists of three subsystems. The first subsystem is an acoustic source, the second is an array of geophones and the third is a system to supply energy and transmit the results back to the analysis laboratory. The subsystems are described below. We conclude with a plan on how to tackle this project and the payoff to the ice cap modeler and hence the users, i.e. commerce and defense. System Two historically tested methods to generate a large amplitude multi-frequency sound source include explosives and air guns. A new method developed and tested by the University of Texas, ARL is a combustive Sound Source [Wilson, et al., 1995]. The combustive sound source is a submerged combustion chamber that is filled with the byproducts of the electrolysis of sea water, i.e. Hydrogen and Oxygen, an explosive mixture which is ignited via a spark. Thus, no additional compressors, gases, or explosives need to be transported to the Arctic to generate an acoustic pulse capable of the sediment and the ice. The second subsystem would be geophones capable of listening in the O(10 Hz) range and transmitting that data back to the laboratory. Thus two single arrays of geophones arranged orthogonal to each other with a range of 1000's of kilometers and a combustive sound source where the two

  17. Form and flow of the Academy of Sciences Ice Cap, Severnaya Zemlya, Russian High Arctic

    NASA Astrophysics Data System (ADS)

    Dowdeswell, J. A.; Bassford, R. P.; Gorman, M. R.; Williams, M.; Glazovsky, A. F.; Macheret, Y. Y.; Shepherd, A. P.; Vasilenko, Y. V.; Savatyuguin, L. M.; Hubberten, H.-W.; Miller, H.

    2002-04-01

    The 5,575-km2 Academy of Sciences Ice Cap is the largest in the Russian Arctic. A 100-MHz airborne radar, digital Landsat imagery, and satellite synthetic aperture radar (SAR) interferometry are used to investigate its form and flow, including the proportion of mass lost through iceberg calving. The ice cap was covered by a 10-km-spaced grid of radar flight paths, and the central portion was covered by a grid at 5-km intervals: a total of 1,657 km of radar data. Digital elevation models (DEMs) of ice surface elevation, ice thickness, and bed elevation data sets were produced (cell size 500 m). The DEMs were used in the selection of a deep ice core drill site. Total ice cap volume is 2,184 km3 (~5.5 mm sea level equivalent). The ice cap has a single dome reaching 749 m. Maximum ice thickness is 819 m. About 200 km, or 42%, of the ice margin is marine. About 50% of the ice cap bed is below sea level. The central divide of the ice cap and several major drainage basins, in the south and east of the ice cap and of up to 975 km2, are delimited from satellite imagery. There is no evidence of past surge activity on the ice cap. SAR interferometric fringes and phase-unwrapped velocities for the whole ice cap indicate slow flow in the interior and much of the margin, punctuated by four fast flowing features with lateral shear zones and maximum velocity of 140 m yr-1. These ice streams extend back into the slower moving ice to within 5-10 km of the ice cap crest. They have lengths of 17-37 km and widths of 4-8 km. Mass flux from these ice streams is ~0.54 km3 yr-1. Tabular icebergs up to ~1.7 km long are produced. Total iceberg flux from the ice cap is ~0.65 km3 yr-1 and probably represents ~40% of the overall mass loss, with the remainder coming from surface melting. Driving stresses are generally lowest (<40 kPa) close to the ice cap divides and in several of the ice streams. Ice stream motion is likely to include a significant basal component and may involve deformable

  18. Snow contribution to first-year and second-year Arctic sea ice mass balance north of Svalbard

    NASA Astrophysics Data System (ADS)

    Granskog, Mats A.; Rösel, Anja; Dodd, Paul A.; Divine, Dmitry; Gerland, Sebastian; Martma, Tõnu; Leng, Melanie J.

    2017-03-01

    The salinity and water oxygen isotope composition (δ18O) of 29 first-year (FYI) and second-year (SYI) Arctic sea ice cores (total length 32.0 m) from the drifting ice pack north of Svalbard were examined to quantify the contribution of snow to sea ice mass. Five cores (total length 6.4 m) were analyzed for their structural composition, showing variable contribution of 10-30% by granular ice. In these cores, snow had been entrained in 6-28% of the total ice thickness. We found evidence of snow contribution in about three quarters of the sea ice cores, when surface granular layers had very low δ18O values. Snow contributed 7.5-9.7% to sea ice mass balance on average (including also cores with no snow) based on δ18O mass balance calculations. In SYI cores, snow fraction by mass (12.7-16.3%) was much higher than in FYI cores (3.3-4.4%), while the bulk salinity of FYI (4.9) was distinctively higher than for SYI (2.7). We conclude that oxygen isotopes and salinity profiles can give information on the age of the ice and enables distinction between FYI and SYI (or older) ice in the area north of Svalbard.Plain Language SummaryThe role of snow in sea <span class="hlt">ice</span> mass balance is largely two fold. Firstly, it can slow down growth and melt due to its high insulation and high reflectance, but secondly it can actually contribute to sea <span class="hlt">ice</span> growth if the snow cover is turned into <span class="hlt">ice</span>. The latter is largely a consequence of high mass of snow on top of sea <span class="hlt">ice</span> that can push the surface of the sea <span class="hlt">ice</span> below sea level and seawater can flood the <span class="hlt">ice</span>. This mixture of seawater and snow can then freeze and add to the growth of sea <span class="hlt">ice</span>. This is very typical in the Antarctic but not believed to be so important in the Arctic. In this work we show, for the first time, that snow actually contributes significantly to the growth of Arctic sea <span class="hlt">ice</span>. This is likely a consequence of the thinning of the Arctic sea <span class="hlt">ice</span>. The conditions in the Arctic, with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017TCry...11..805Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017TCry...11..805Z"><span>Sensitivity, stability and future evolution of the world's northernmost <span class="hlt">ice</span> <span class="hlt">cap</span>, Hans Tausen Iskappe (Greenland)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zekollari, Harry; Huybrechts, Philippe; Noël, Brice; van de Berg, Willem Jan; van den Broeke, Michiel R.</p> <p>2017-03-01</p> <p>In this study the dynamics and sensitivity of Hans Tausen Iskappe (western Peary Land, Greenland) to climatic forcing is investigated with a coupled <span class="hlt">ice</span> flow-mass balance model. The surface mass balance (SMB) is calculated from a precipitation field obtained from the Regional Atmospheric Climate Model (RACMO2.3), while runoff is calculated from a positive-degree-day runoff-retention model. For the <span class="hlt">ice</span> flow a 3-D higher-order thermomechanical model is used, which is run at a 250 m resolution. A higher-order solution is needed to accurately represent the <span class="hlt">ice</span> flow in the outlet glaciers. Under 1961-1990 climatic conditions a steady-state <span class="hlt">ice</span> <span class="hlt">cap</span> is obtained that is overall similar in geometry to the present-day <span class="hlt">ice</span> <span class="hlt">cap</span>. <span class="hlt">Ice</span> thickness, temperature and flow velocity in the interior agree well with observations. For the outlet glaciers a reasonable agreement with temperature and <span class="hlt">ice</span> thickness measurements can be obtained with an additional heat source related to infiltrating meltwater. The simulations indicate that the SMB-elevation feedback has a major effect on the <span class="hlt">ice</span> <span class="hlt">cap</span> response time and stability. This causes the southern part of the <span class="hlt">ice</span> <span class="hlt">cap</span> to be extremely sensitive to a change in climatic conditions and leads to thresholds in the <span class="hlt">ice</span> <span class="hlt">cap</span> evolution. Under constant 2005-2014 climatic conditions the entire southern part of the <span class="hlt">ice</span> <span class="hlt">cap</span> cannot be sustained, and the <span class="hlt">ice</span> <span class="hlt">cap</span> loses about 80 % of its present-day volume. The projected loss of surrounding permanent sea <span class="hlt">ice</span> and resultant precipitation increase may attenuate the future mass loss but will be insufficient to preserve the present-day <span class="hlt">ice</span> <span class="hlt">cap</span> for most scenarios. In a warmer and wetter climate the <span class="hlt">ice</span> margin will retreat, while the interior is projected to thicken, leading to a steeper <span class="hlt">ice</span> <span class="hlt">cap</span>, in line with the present-day observed trends. For intermediate- (+4 °C) and high- warming scenarios (+8 °C) the <span class="hlt">ice</span> <span class="hlt">cap</span> is projected to disappear around AD 2400 and 2200 respectively, almost independent of the projected</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70127620','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70127620"><span>Interannual observations and quantification of summertime H2O <span class="hlt">ice</span> deposition on the Martian CO2 <span class="hlt">ice</span> south polar <span class="hlt">cap</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brown, Adrian J.; Piqueux, Sylvain; Titus, Timothy N.</p> <p>2014-01-01</p> <p>The spectral signature of water <span class="hlt">ice</span> was observed on Martian south polar <span class="hlt">cap</span> in 2004 by the Observatoire pour l'Mineralogie, l'Eau les Glaces et l'Activite (OMEGA) ( Bibring et al., 2004). Three years later, the OMEGA instrument was used to discover water <span class="hlt">ice</span> deposited during southern summer on the polar <span class="hlt">cap</span> ( Langevin et al., 2007). However, temporal and spatial variations of these water <span class="hlt">ice</span> signatures have remained unexplored, and the origins of these water deposits remains an important scientific question. To investigate this question, we have used observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on the Mars Reconnaissance Orbiter (MRO) spacecraft of the southern <span class="hlt">cap</span> during austral summer over four Martian years to search for variations in the amount of water <span class="hlt">ice</span>. We report below that for each year we have observed the <span class="hlt">cap</span>, the magnitude of the H2O <span class="hlt">ice</span> signature on the southern <span class="hlt">cap</span> has risen steadily throughout summer, particularly on the west end of the <span class="hlt">cap</span>. The spatial extent of deposition is in disagreement with the current best simulations of deposition of water <span class="hlt">ice</span> on the south polar <span class="hlt">cap</span> (Montmessin et al., 2007). This increase in water <span class="hlt">ice</span> signatures is most likely caused by deposition of atmospheric H2O <span class="hlt">ice</span> and a set of unusual conditions makes the quantification of this transport flux using CRISM close to ideal. We calculate a ‘minimum apparent‘ amount of deposition corresponding to a thin H2O <span class="hlt">ice</span> layer of 0.2 mm (with 70% porosity). This amount of H2O <span class="hlt">ice</span> deposition is 0.6–6% of the total Martian atmospheric water budget. We compare our ‘minimum apparent’ quantification with previous estimates. This deposition process may also have implications for the formation and stability of the southern CO2 <span class="hlt">ice</span> <span class="hlt">cap</span>, and therefore play a significant role in the climate budget of modern day Mars.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_2 --> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996LPI....27...19A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996LPI....27...19A"><span>The Search for Subsurface <span class="hlt">Ice</span> <span class="hlt">Caps</span> on Mercury</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Allen, R. A.; Barlow, N. G.; Vilas, F.</p> <p>1996-03-01</p> <p>Recent ground-based radar observations of Mercury have detected strong, highly depolarized echoes from the north and south polar regions which have been interpreted as possible polar <span class="hlt">ice</span> deposits. These radar echoes have been correlated with a number of impact craters. Theoretical studies indicate that such surface <span class="hlt">ice</span> can be stable within permanently shadowed areas, such as the floors of high latitude impact craters. One proposed hypothesis suggests that stable subsurface <span class="hlt">ice</span> <span class="hlt">caps</span> exist at the poles of Mercury, and that several of the impact events that created the high latitude craters exposed this subsurface <span class="hlt">ice</span>. Thus, our study focused on the possibility of <span class="hlt">ice</span> <span class="hlt">caps</span> extending below the mercurian surface, down to some unknown latitude in the polar regions. We used the experiences from Mars, where the depth/diameter ratio (d/D) is smaller for <span class="hlt">ice</span> rich areas, to investigate whether a comparable latitudinal change in d/D is detectable on Mercury. We found no significant latitudinal differences within the two polar regions of our study or between the north polar and equatorial quadrangles, but craters in the south polar region tend to have slightly lower d/D than those in the north polar region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMGC24B..02L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMGC24B..02L"><span>Holocene Activity of the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>: A Working Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lowell, T. V.; Smith, C. A.; Kelly, M. A.; Stroup, J. S.</p> <p>2012-12-01</p> <p>The patterns and magnitudes of past climate change in the topics are still under discussion. We contribute here by reporting on patterns of glacier length changes of the largest glacier in the tropics, Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> (~13.9°S, 70.9°W, summit at 5645 m). This <span class="hlt">ice</span> <span class="hlt">cap</span> has several local domes that may have different patterns of length changes because of differing elevations of the domes (high to the north, lower to the south). Prior work (Mark et al. 2003, Abbott et al., 2004; Thompson et al., 2005; Buffen, et al., 2009), new radiocarbon ages, and stratigraphic and geomorphic relationships are used to determine the general pattern of length changes for the outlets from this <span class="hlt">ice</span> <span class="hlt">cap</span>. We exploit geomorphic relationships and present new radiocarbon ages on interpreted stratigraphic sections to determine the pattern of length changes for this <span class="hlt">ice</span> <span class="hlt">cap</span>. <span class="hlt">Ice</span> retreated during late glacial times (Rodbell and Seltzer, 2000; Kelly et al., in press). By 11,400 yr BP it had reached a position ~1.2 km beyond its present (2000 AD) extent. While length during the early Holocene is problematic, present evidence permits, but does not prove, extents of 0.5 to 1.0 km down-valley from the present margin. Between 6400 and 4400 yr BP the <span class="hlt">ice</span> <span class="hlt">cap</span> was smaller than present, but it advanced multiple times during the late Holocene. Lengths of up to 1 km beyond present were achieved at 3400 yr BP and ~500 yr BP. Additionally, the <span class="hlt">ice</span> advanced to 0.8 km beyond its present margin at 1600 yr BP. Because these glaciers were temperate, we take these lengths to represent primarily changes in temperature. This may suggest that lowering insolation values in the northern hemisphere during the Holocene provide a first order control on tropical temperatures. Alternatively, it may be that major reorganization of the topical circulation belts about 5000 yr BP yields two configurations of the QIC and hence Holocene temperatures - one at the present <span class="hlt">ice</span> margin and and the second about 1 km beyond the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1814695S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1814695S"><span>N-<span class="hlt">ICE</span>2015: Multi-disciplinary study of the young sea <span class="hlt">ice</span> system north of <span class="hlt">Svalbard</span> from winter to summer.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steen, Harald; Granskog, Mats; Assmy, Philipp; Duarte, Pedro; Hudson, Stephen; Gerland, Sebastian; Spreen, Gunnar; Smedsrud, Lars H.</p> <p>2016-04-01</p> <p>The Arctic Ocean is shifting to a new regime with a thinner and smaller sea-<span class="hlt">ice</span> area cover. Until now, winter sea <span class="hlt">ice</span> extent has changed less than during summer, as the heat loss to the atmosphere during autumn and winter is large enough form an <span class="hlt">ice</span> cover in most regions. The insulating snow cover also heavily influences the winter <span class="hlt">ice</span> growth. Consequently, the older, thicker multi-year sea <span class="hlt">ice</span> has been replace by a younger and thinner sea. These large changes in the sea <span class="hlt">ice</span> cover may have dramatic consequences for ecosystems, energy fluxes and ultimately atmospheric circulation and the Northern Hemisphere climate. To study the effects of the changing Arctic the Norwegian Polar Institute, together with national and international partners, launched from January 11 to June 24, 2015 the Norwegian Young Sea <span class="hlt">ICE</span> cruise 2015 (N-<span class="hlt">ICE</span>2015). N-<span class="hlt">ICE</span>2015 was a multi-disciplinary cruise aimed at simultaneously studying the effect of the Arctic Ocean changes in the sea <span class="hlt">ice</span>, the atmosphere, in radiation, in ecosystems. as well as water chemistry. R/V Lance was frozen into the drift <span class="hlt">ice</span> north of <span class="hlt">Svalbard</span> at about N83 E25 and drifted passively southwards with the <span class="hlt">ice</span> until she was broken loose. When she was loose, R/V Lance was brought back north to a similar starting position. While fast in the <span class="hlt">ice</span>, she served as a living and working platform for 100 scientist and engineers from 11 countries. One aim of N-<span class="hlt">ICE</span>2015 is to present a comprehensive data-set on the first year <span class="hlt">ice</span> dominated system available for the scientific community describing the state and changes of the Arctic sea <span class="hlt">ice</span> system from freezing to melt. Analyzing the data is progressing and some first results will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.7246Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.7246Z"><span>Present-day dynamics and future evolution of the world's northernmost <span class="hlt">ice</span> <span class="hlt">cap</span>, Hans Tausen Iskappe (Greenland)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zekollari, Harry; Huybrechts, Philippe; Noël, Brice; van de Berg, Willem Jan; van den Broeke, Michiel R.</p> <p>2017-04-01</p> <p>In this study the dynamics of Hans Tausen Iskappe (western Peary Land, Greenland) are investigated with a coupled <span class="hlt">ice</span> flow - mass balance model. Precipitation is obtained from the Regional Climate Model RACMO 2.3 and the surface mass balance is calculated from a Positive Degree-Day runoff/retention model, for which the input parameters are derived from field observations. For the <span class="hlt">ice</span> flow a 3-D higher-order thermo-mechanical model is used, which is run at a 250 m resolution. Under 1961-1990 climatic conditions a steady state <span class="hlt">ice</span> <span class="hlt">cap</span> is obtained that is overall similar in geometry to the present-day <span class="hlt">ice</span> <span class="hlt">cap</span>. <span class="hlt">Ice</span> thickness, temperature and flow velocity in the interior agree well with observations. For the outlet glaciers a reasonable agreement with temperature and <span class="hlt">ice</span> thickness measurements can only be obtained with an additional heat source related to infiltrating meltwater. The simulations indicate that the SMB-elevation feedback has a major effect on the <span class="hlt">ice</span> <span class="hlt">cap</span> response time and stability. This causes the southern part of the <span class="hlt">ice</span> <span class="hlt">cap</span> to be extremely sensitive to a change in climatic conditions and leads to thresholds in the <span class="hlt">ice</span> <span class="hlt">cap</span> evolution. Under constant 2005-2014 climatic conditions the entire southern part of the <span class="hlt">ice</span> <span class="hlt">cap</span> cannot be sustained and the <span class="hlt">ice</span> <span class="hlt">cap</span> loses about 80% of its present-day volume. The future projected loss of surrounding permanent sea-<span class="hlt">ice</span> and corresponding potential sharp precipitation increase may however lead to an attenuation of the retreat and even potential stabilization of the <span class="hlt">ice</span> <span class="hlt">cap</span> for a warming of up to 2-3°C. In a warmer and wetter climate the <span class="hlt">ice</span> margin will retreat while the interior is projected to grow, leading to a steeper <span class="hlt">ice</span> <span class="hlt">cap</span>, in line with the present-day observed trends. For intermediate (+4°C) and high warming scenarios (+8°C) the <span class="hlt">ice</span> <span class="hlt">cap</span> is projected to disappear respectively around 2400 and 2200 A.D., almost irrespective of the projected precipitation regime and the simulated present-day geometry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911565K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911565K"><span>Dansgaard-Oeschger cycles observed in the Greenland Re<span class="hlt">CAP</span> <span class="hlt">ice</span> core project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kjær, Helle Astrid; Vallelonga, Paul; Vinther, Bo; Simonsen, Marius; Maffezzoli, Niccoló; Gkinis, Vasileios; Svensson, Anders; Jensen, Camilla Marie; Dallmayr, Remi; Spolaor, Andrea; Edwards, Ross</p> <p>2017-04-01</p> <p>The new REnland <span class="hlt">ice</span> <span class="hlt">CAP</span> (RECAP) <span class="hlt">ice</span> core was drilled in summer 2015 in Greenland and measured by means of Continuous flow analysis (CFA) during the last 3 months of 2015. The Renland <span class="hlt">ice</span> core was obtained as part of the Re<span class="hlt">CAP</span> project, extending 584.11 meters to the bottom of the Renland <span class="hlt">ice</span> <span class="hlt">cap</span> located in east Greenland. The unique position on a mountain saddle above 2000 meters altitude, but close to the coast, ensures that the Renland <span class="hlt">ice</span> core offers high accumulation, but also reaches far back in time. Results show that despite the short length the RECAP <span class="hlt">ice</span> core holds <span class="hlt">ice</span> all the way back to the past warm interglacial period, the Eemian. The glacial section is strongly thinned and covers on 20 meters of the Re<span class="hlt">CAP</span> core, but nonetheless due to the high resolution of the measurements all 25 expected DO events could be identified. The record was analyzed for multiple elements including the water isotopes, forest fire tracers NH4+ and black carbon, insoluble dust particles by means of Abakus laser particle counter and the dust ion Ca2+, sea salt Na+, and sea <span class="hlt">ice</span> proxies as well as acidity useful for finding volcanic layers to date the core. Below the glacial section another 20 meters of warm Eemian <span class="hlt">ice</span> have been analysed. Here we present the chemistry results as obtained by continuous flow analysis (CFA) and compare the glacial section with the chemistry profile from other Greenland <span class="hlt">ice</span> cores.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.2810G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.2810G"><span>The projected demise of Barnes <span class="hlt">Ice</span> <span class="hlt">Cap</span>: Evidence of an unusually warm 21st century Arctic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gilbert, A.; Flowers, G. E.; Miller, G. H.; Refsnider, K. A.; Young, N. E.; Radić, V.</p> <p>2017-03-01</p> <p>As a remnant of the Laurentide <span class="hlt">Ice</span> Sheet, Barnes <span class="hlt">Ice</span> <span class="hlt">Cap</span> owes its existence and present form in part to the climate of the last glacial period. The <span class="hlt">ice</span> <span class="hlt">cap</span> has been sustained in the present interglacial climate by its own topography through the mass balance-elevation feedback. A coupled mass balance and <span class="hlt">ice</span>-flow model, forced by Coupled Model Intercomparison Project Phase 5 climate model output, projects that the current <span class="hlt">ice</span> <span class="hlt">cap</span> will likely disappear in the next 300 years. For greenhouse gas Representative Concentration Pathways of +2.6 to +8.5 Wm-2, the projected <span class="hlt">ice-cap</span> survival times range from 150 to 530 years. Measured concentrations of cosmogenic radionuclides 10Be, 26Al, and 14C at sites exposed near the <span class="hlt">ice-cap</span> margin suggest the pending disappearance of Barnes <span class="hlt">Ice</span> <span class="hlt">Cap</span> is very unusual in the last million years. The data and models together point to an exceptionally warm 21st century Arctic climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1611692N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1611692N"><span>Retrieving improved multi-temporal CryoSat elevations over <span class="hlt">ice</span> <span class="hlt">caps</span> and glaciers - a case study of Barnes <span class="hlt">ice</span> <span class="hlt">cap</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nilsson, Johan; Burgess, David</p> <p>2014-05-01</p> <p>The CryoSat mission was launched in 2010 to observe the Earth's cryosphere. In contrast to previous satellite radar altimeters, this mission is expected to monitor the elevation of small <span class="hlt">ice</span> <span class="hlt">caps</span> and glaciers, which according to the IPCC will be the largest contributor to 21st century sea level rise. To date the ESA CryoSat SARiN level-2 (L2) elevation product is not yet fully optimized for use over these types of glaciated regions, as its processed with a more universal algorithm. Thus the aim of this study is to demonstrate that with the use of improved processing CryoSat SARiN data can be used for more accurate topography mapping and elevation change detection for <span class="hlt">ice</span> <span class="hlt">caps</span> and glaciers. To demonstrate this, elevations and elevation changes over Barnes <span class="hlt">ice</span> <span class="hlt">cap</span>, located on Baffin Island in the Canadian Arctic, have been estimated from available data from the years 2010-2013. ESA's CryoSat level-1b (L1b) SARiN baseline "B" data product was used and processed in-house to estimate surface elevations. The resulting product is referred to as DTU-L2. The processing focused on improving the retracker, reducing phase noise and correcting phase ambiguities. The accuracy of the DTU-L2 and the ESA-L2 product was determined by comparing the measured elevations against NASA's <span class="hlt">Ice</span>Bridge Airborne Topographic Mapper (ATM) elevations from May 2011. The resulting difference in accuracy was determined by comparing their associated errors. From the multi-temporal measurements spanning the period 2010-2013, elevation changes where estimated and compared to ICESat derived changes from 2003-2009. The result of the study shows good agreement between the NASA measured ATM elevations and the DTU-L2 data. It also shows that the pattern of elevation change is similar to that derived from ICESat data. The accuracy of the DTU-L2 estimated elevations is on average several factors higher compared to the ESA-L2 elevation product. These preliminary results demonstrates that CryoSat elevation data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.P42A0562K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.P42A0562K"><span>Martian Polar <span class="hlt">Caps</span>: Folding, Faulting, Flowing Glaciers of Multiple Interbedded <span class="hlt">Ices</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kargel, J. S.</p> <p>2001-12-01</p> <p>The Martian south polar <span class="hlt">cap</span> (permanent CO2 <span class="hlt">cap</span> and polar layered deposits), exhibit abundant, varied, and widespread deformational phenomena. Folding and boudinage are very common. Strike-slip or normal faults are rarer. Common in the vicinity of major troughs and scarps are signs of convergent flow tectonics manifested as wrinkle-ridge-like surface folds, thrust faults, and viscous forebulges with thin-skinned extensional crevasses and wrinkle-ridge folds. Such flow convergence is predicted by theory. Boudinage and folding at the 300-m wavelength scale, indicating rheologically contrasting materials, is widely exposed at deep levels along erosional scarps. Independent morphologic evidence indicates south polar materials of contrasting volatility. Hence, the south polar <span class="hlt">cap</span> appears to be a multiphase structure of interbedded <span class="hlt">ices</span>. The north polar <span class="hlt">cap</span> locally also exhibits flow indicators, though they are neither as common nor as varied as in the south. The large-scale quasi-spiral structure of the polar <span class="hlt">caps</span> could be a manifestation of large-scale boudinage. According to this scenario, deep-level boudinage continuously originates under the glacial divide (the polar <span class="hlt">cap</span> summit). Rod-like boudin structures are oriented transverse to flow and migrate outward with the large-scale flow field. Troughs develop over areas between major boudins. A dynamic competition, and possibly a rough balance, develops between the local flow field in the vicinity of a trough (which tends to close the trough by lateral closure and upwelling flow) and sublimation erosion (which tends to widen and deepen them). Over time, the troughs flow to the margins of the polar <span class="hlt">cap</span> where they, along with other polar structures, are destroyed by sublimation. Major <span class="hlt">ice</span> types contributing to rheological and volatility layering may include, in order of highest to lowest mechanical strength, CO2 clathrate hydrate, water <span class="hlt">ice</span> containing inert/insoluble dust, pure water <span class="hlt">ice</span>, water <span class="hlt">ice</span> containing traces of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70028279','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70028279"><span>CO2 jets formed by sublimation beneath translucent slab <span class="hlt">ice</span> in Mars' seasonal south polar <span class="hlt">ice</span> <span class="hlt">cap</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kieffer, H.H.; Christensen, P.R.; Titus, T.N.</p> <p>2006-01-01</p> <p>The martian polar <span class="hlt">caps</span> are among the most dynamic regions on Mars, growing substantially in winter as a significant fraction of the atmosphere freezes out in the form of CO2 <span class="hlt">ice</span>. Unusual dark spots, fans and blotches form as the south-polar seasonal CO2 <span class="hlt">ice</span> <span class="hlt">cap</span> retreats during spring and summer. Small radial channel networks are often associated with the location of spots once the <span class="hlt">ice</span> disappears. The spots have been proposed to be simply bare, defrosted ground; the formation of the channels has remained uncertain. Here we report infrared and visible observations that show that the spots and fans remain at CO2 <span class="hlt">ice</span> temperatures well into summer, and must be granular materials that have been brought up to the surface of the <span class="hlt">ice</span>, requiring a complex suite of processes to get them there. We propose that the seasonal <span class="hlt">ice</span> <span class="hlt">cap</span> forms an impermeable, translucent slab of CO2 <span class="hlt">ice</span> that sublimates from the base, building up high-pressure gas beneath the slab. This gas levitates the <span class="hlt">ice</span>, which eventually ruptures, producing high-velocity CO 2 vents that erupt sand-sized grains in jets to form the spots and erode the channels. These processes are unlike any observed on Earth. ?? 2006 Nature Publishing Group.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.amap.no/documents/doc/snow-water-ice-and-permafrost-in-the-arctic-swipa-climate-change-and-the-cryosphere/743','USGSPUBS'); return false;" href="http://www.amap.no/documents/doc/snow-water-ice-and-permafrost-in-the-arctic-swipa-climate-change-and-the-cryosphere/743"><span>Mountain Glaciers and <span class="hlt">Ice</span> <span class="hlt">Caps</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ananichheva, Maria; Arendt, Anthony; Hagen, Jon-Ove; Hock, Regine; Josberger, Edward G.; Moore, R. Dan; Pfeffer, William Tad; Wolken, Gabriel J.</p> <p>2011-01-01</p> <p>Projections of future rates of mass loss from mountain glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> in the Arctic focus primarily on projections of changes in the surface mass balance. Current models are not yet capable of making realistic forecasts of changes in losses by calving. Surface mass balance models are forced with downscaled output from climate models driven by forcing scenarios that make assumptions about the future rate of growth of atmospheric greenhouse gas concentrations. Thus, mass loss projections vary considerably, depending on the forcing scenario used and the climate model from which climate projections are derived. A new study in which a surface mass balance model is driven by output from ten general circulation models (GCMs) forced by the IPCC (Intergovernmental Panel on Climate Change) A1B emissions scenario yields estimates of total mass loss of between 51 and 136 mm sea-level equivalent (SLE) (or 13% to 36% of current glacier volume) by 2100. This implies that there will still be substantial glacier mass in the Arctic in 2100 and that Arctic mountain glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> will continue to influence global sea-level change well into the 22nd century.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6764B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6764B"><span>The fast-<span class="hlt">ice</span> growth and freezing of the bottom in the Braganzavagen Gulf (Van Mijenfjorden, <span class="hlt">Svalbard</span>)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bogorodsky, Petr; Marchenko, Aleksey; Pnyushkov, Andrey; Filchuk, Kirill; Morozov, Yevgenii; Ryzhov, Ivan</p> <p>2017-04-01</p> <p>The results of oceanographic and sea <span class="hlt">ice</span> studies in the shallow Braganzavågen Gulf (Van Mijenfjorden, <span class="hlt">Svalbard</span>) in March 2016 are presented. These studies are a continuation of observational efforts initiated by UNIS (<span class="hlt">Svalbard</span>, Norway) in 2014. 2016 field campaign includes instrumental measurements of snow and <span class="hlt">ice</span> properties in the fjord (e.g., <span class="hlt">ice</span> thicknesses, temperatures, and salinities), as well as high-resolution CTD measurements within the under-<span class="hlt">ice</span> water column. Collected observations were accompanied by freezing simulations of adjacent water and bottom ground layers performed with a one-dimensional thermodynamic model (Bogorodskii and Pnyushkov, 2015). The model uses two methods to reproduce phase transition areas - a "classic" (frontal) method for the fast <span class="hlt">ice</span>, and transition in the continuous media (mushy zone) for the bottom sediments. Meteorological observations during the winter 2015-16 at Sveagruva (northwest coast) were used in these simulations as the atmospheric forcing. Numerical experiments were carried out for the initial salinity of 35 psu and 2 m water depth. The simulations start with the beginning of water freezing determined by a steady air temperature transition through the freezing point. The start of freezing was also verified by comparison with sea <span class="hlt">ice</span> charts available for the Van Mijenfjorden for the period of simulations. Model simulations showed that the growth of sea <span class="hlt">ice</span> in shallow (<1 m) areas of the basin significantly increases water salinity in the under-<span class="hlt">ice</span> layer. For instance, at a 0.5 m depth the salinity in the under <span class="hlt">ice</span> water layer exceeds 160 psu, which corresponds to the freezing temperature below -9C. In fact, the water salinity does not reach high values because of the horizontal mixing. However, available hydrological observations showed relatively small (0.2-0.5 m) amplitudes of tides - the major contributor to the horizontal exchange in this area. These small amplitudes likely suggest small advective salt fluxes</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA00809&hterms=magazine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmagazine','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA00809&hterms=magazine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmagazine"><span>Textures in south polar <span class="hlt">ice</span> <span class="hlt">cap</span> #1</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1998-01-01</p> <p>Textures of the south polar permanent residual <span class="hlt">ice</span> <span class="hlt">cap</span> and polar layered terrains. This 30 x 29 km area image (frame 7709) is centered near 87 degrees south, 77 degrees west.<p/>Figure caption from Science Magazine</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA00810&hterms=magazine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmagazine','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA00810&hterms=magazine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmagazine"><span>Textures in south polar <span class="hlt">ice</span> <span class="hlt">cap</span> #2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1998-01-01</p> <p>Textures of the south polar permanent residual <span class="hlt">ice</span> <span class="hlt">cap</span> and polar layered terrains. This 15 x 14 km area image (frame 7306) is centered near 87 degrees south, 341 degrees west.<p/>Figure caption from Science Magazine</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.4371R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.4371R"><span>Last deglaciation of the <span class="hlt">Svalbard</span>/Barents Sea <span class="hlt">Ice</span> Sheet - a swath bathymetric and sub-bottom seismic study from the Kveithola Trough</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rebesco, Michele; Liu, Yanguang; Camerlenghi, Angelo; Winsborrow, Monica; Sverre Laberg, Jan; Caburlotto, Andrea; Diviacco, Paolo; Accettella, Daniela; Sauli, Chiara; Wardell, Nigel</p> <p>2010-05-01</p> <p>Kveithola Trough, an E-W trending cross-shelf glacial trough in the NW Barents Sea, was surveyed for the first time during the EGLACOM cruise between 8th July and 4th August 2008 on board R/V OGS-Explora. EGLACOM (Evolution of a GLacial Arctic COntinental Margin: the southern <span class="hlt">Svalbard</span> <span class="hlt">ice</span> stream-dominated sedimentary system) project is the Italian contribution to the International Polar Year (IPY) Activity 367 (Neogene <span class="hlt">ice</span> streams and sedimentary processes on high- latitude continental margins - NICE STREAMS). Such IPY activity included as well the Spanish SVAIS 2008 cruise on board BIO Hesperides. EGLACOM data acquisition, focused on the Storfjorden Fan and Kveithola Trough, included a multi-channel seismic (MCS) reflection survey and the simultaneous collection of swath bathymetry and sub-bottom CHIRP profiles. Swath bathymetry in the Kveithola Trough shows that the seafloor is characterized by E-W trending mega-scale glacial lineations (MSGL). These include large-scale ridges about 2 km wide and 15 m high as well as smaller grooves about 100 m wide and a few metres deep. Such MSGL record the fast flow of an <span class="hlt">ice</span> stream draining the <span class="hlt">Svalbard</span>/Barents Sea <span class="hlt">Ice</span> Sheet (SBSIS) during the Last Glacial Maximum (LGM). MSGL are overprinted by transverse sediment ridges about 15 km apart which give rise to a staircase long profile of the trough. Such transverse ridges are interpreted as grounding-zone wedges (GZW) formed by deposition of unconsolidated, saturated subglacial till during <span class="hlt">ice</span> stream retreat. Sub-bottom (CHIRP) and multi-channel reflection seismic data show that the morphology is controlled by stacked sets of lensoidal transparent units (tills) overlain by a draping glaciomarine unit up to over 15 m thick. Formed during temporary stillstands in grounding-zone position before complete deglaciation, GZW ridges are diagnostic of episodic retreat. Our data allow the reconstruction of deglaciation in the Spitsbergen Bank area, with each stage during deglaciation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.4464P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.4464P"><span>Reconstructing the post-LGM decay of the Eurasian <span class="hlt">Ice</span> Sheets with <span class="hlt">Ice</span> Sheet Models; data-model comparison and focus on the Storfjorden (<span class="hlt">Svalbard</span>) <span class="hlt">ice</span> stream dynamics history</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petrini, Michele; Kirchner, Nina; Colleoni, Florence; Camerlenghi, Angelo; Rebesco, Michele; Lucchi, Renata G.; Forte, Emanuele; Colucci, Renato R.</p> <p>2017-04-01</p> <p>The challenge of reconstructing palaeo-<span class="hlt">ice</span> sheets past growth and decay represent a critical task to better understand mechanisms of present and future global climate change. Last Glacial Maximum (LGM), and the subsequent deglaciation until Pre-Industrial time (PI) represent an excellent testing ground for numerical <span class="hlt">Ice</span> Sheet Models (ISMs), due to the abundant data available that can be used in an ISM as boundary conditions, forcings or constraints to test the ISMs results. In our study, we simulate with ISMs the post-LGM decay of the Eurasian <span class="hlt">Ice</span> Sheets, with a focus on the marine-based <span class="hlt">Svalbard</span>-Barents Sea-Kara Sea <span class="hlt">Ice</span> Sheet. In particular, we aim to reconstruct the Storfjorden <span class="hlt">ice</span> stream dynamics history by comparing the model results with the marine geological data (MSGLs, GZWs, sediment cores analysis) available from the area, e.g., Pedrosa et al. 2011, Rebesco et al. 2011, 2013, Lucchi et al. 2013. Two hybrid SIA/SSA ISMs are employed, GRISLI, Ritz et al. 2001, and PSU, Pollard&DeConto 2012. These models differ mainly in the complexity with which grounding line migration is treated. Climate forcing is interpolated by means of climate indexes between LGM and PI climate. Regional climate indexes are constructed based on the non-accelerated deglaciation transient experiment carried out with CCSM3, Liu et al. 2009. Indexes representative of the climate evolution over Siberia, <span class="hlt">Svalbard</span> and Scandinavia are employed. The impact of such refined representation as opposed to the common use of the NGRIP δ18O index for transient experiments is analysed. In this study, the <span class="hlt">ice</span>-ocean interaction is crucial to reconstruct the Storfjorden <span class="hlt">ice</span> stream dynamics history. To investigate the sensitivity of the <span class="hlt">ice</span> shelf/stream retreat to ocean temperature, we allow for a space-time variation of basal melting under the <span class="hlt">ice</span> shelves by testing two-equations implementations based on Martin et al. 2011 forced with simulated ocean temperature and salinity from the TraCE-21ka coupled</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C11E..04T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C11E..04T"><span>CryoSat swath altimetry to measure <span class="hlt">ice</span> <span class="hlt">cap</span> and glacier surface elevation change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tepes, P.; Gourmelen, N.; Escorihuela, M. J.; Wuite, J.; Nagler, T.; Foresta, L.; Brockley, D.; Baker, S.; Roca, M.; Shepherd, A.; Plummer, S.</p> <p>2016-12-01</p> <p>Satellite altimetry has been used extensively in the past few decades to observe changes affecting large and remote regions covered by land <span class="hlt">ice</span> such as the Greenland and Antarctic <span class="hlt">ice</span> sheets. Glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> have been studied less extensively due to limitation of altimetry over complex topography. However their role in current sea-level budgets is significant and is expected to continue over the next century and beyond (Gardner et al., 2011), particularly in the Arctic where mean annual surface temperatures have recently been increasing twice as fast as the global average (Screen and Simmonds, 2010). Radar altimetry is well suited to monitor elevation changes over land <span class="hlt">ice</span> due to its all-weather year-round capability of observing <span class="hlt">ice</span> surfaces. Since 2010, the Synthetic Interferometric Radar Altimeter (SIRAL) on board the European Space Agency (ESA) radar altimetry CryoSat (CS) mission has been collecting <span class="hlt">ice</span> elevation measurements over glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span>. Its Synthetic Aperture Radar Interferometric (SARIn) processing feature reduces the size of the footprint along-track and locates the across-track origin of a surface reflector in the presence of a slope. This offers new perspectives for the measurement of regions marked by complex topography. More recently, data from the CS-SARIn mode have been used to infer elevation beyond the point of closest approach (POCA) with a novel approach known as "swath processing" (Hawley et al., 2009; Gray et al., 2013; Christie et al., 2016; Smith et al., 2016). Together with a denser ground track interspacing of the CS mission, the swath processing technique provides unprecedented spatial coverage and resolution for space borne altimetry, enabling the study of key processes that underlie current changes of <span class="hlt">ice</span> <span class="hlt">caps</span> and glaciers. In this study, we use CS swath observations to generate maps of <span class="hlt">ice</span> elevation change for selected <span class="hlt">ice</span> <span class="hlt">caps</span> and glaciers. We present a validation exercise and discuss the benefit of swath</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004SPIE.5163..191H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004SPIE.5163..191H"><span>Microorganisms on comets, Europa, and the polar <span class="hlt">ice</span> <span class="hlt">caps</span> of Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoover, Richard B.; Pikuta, Elena V.</p> <p>2004-02-01</p> <p>Microbial extremophiles live on Earth wherever there is liquid water and a source of energy. Observations by ground-based observatories, space missions, and satellites have provided strong evidence that water <span class="hlt">ice</span> exists today on comets, Europa, Callisto, and Ganymede and in the snow, permafrost, glaciers and polar <span class="hlt">ice</span> <span class="hlt">caps</span> of Mars. Studies of the cryoconite pools and <span class="hlt">ice</span> bubble systems of Antarctica suggest that solar heating of dark rocks entrained in <span class="hlt">ice</span> can cause localized melting of <span class="hlt">ice</span> providing ideal conditions for the growth of microbial communities with the creation of micro-environments where trapped metabolic gasses produce entrained isolated atmospheres as in the Antarctic <span class="hlt">ice</span>-bubble systems. It is suggested that these considerations indicate that several groups of microorganisms should be capable of episodic growth within liquid water envelopes surrounding dark rocks in cometary <span class="hlt">ices</span> and the permafrost and polar <span class="hlt">caps</span> of Mars. We discuss some of the types of microorganisms we have encountered within the permafrost and snow of Siberia, the cryoconite pools of Alaska, and frozen deep within the Antarctic <span class="hlt">ice</span> sheet above Lake Vostok.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1611965L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1611965L"><span>The influence of supraglacial debris cover variability on de-<span class="hlt">icing</span> processes - examples from <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lukas, Sven; Benn, Douglas I.; Boston, Clare M.; Hawkins, Jack; Lehane, Niall E.; Lovell, Harold; Rooke, Michael</p> <p>2014-05-01</p> <p>Extensive supraglacial debris covers are widespread near the margins of many cold-based and polythermal surging and non-surging glaciers in <span class="hlt">Svalbard</span>. Despite their importance for current glacier dynamics and a detailed understanding of how they will affect the de-<span class="hlt">icing</span> of <span class="hlt">ice</span>-marginal areas, little work has been carried out to shed light on the sedimentary processes operating in these debris covers. We here present data from five different forelands in <span class="hlt">Svalbard</span>. In all five cases, surfaces within the debris cover can be regarded as stable where debris cover thickness exceeds that of the active layer; vegetation development and absence of buried <span class="hlt">ice</span> exposures at the surface support this conclusion, although test pits and geophysical investigations have revealed the presence of buried <span class="hlt">ice</span> at greater depths (> 1-3 m). These findings imply that even seemingly stable surfaces at present will be subject to change by de-<span class="hlt">icing</span> in the future. Factors and processes that contribute towards a switch from temporarily stable to unstable conditions have been identified as: 1. The proximity to englacial or supraglacial meltwater channels. These channels enlarge due to thermo-erosion, which can lead to the eventual collapse of tunnel roofs and the sudden generation of linear instabilities in the system. Along such channels, ablation is enhanced compared to adjacent debris-covered <span class="hlt">ice</span>, and continued thermo-erosion continuously exposes new areas of buried <span class="hlt">ice</span> at the surface. This works in conjunction with 2. Debris flows that occur on all sloping ground and transfer material from stable to less stable (sloping) locations within the debris cover and eventually into supraglacial channels, from where material is then removed from the system. Several generations of debris flows have been identified in all five debris covers, strongly suggesting that these processes are episodic and that the loci of these processes switch. This in turn indicates that transfer of material by debris flows</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911372D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911372D"><span>Towards multi-decadal to multi-millennial <span class="hlt">ice</span> core records from coastal west Greenland <span class="hlt">ice</span> <span class="hlt">caps</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Das, Sarah B.; Osman, Matthew B.; Trusel, Luke D.; McConnell, Joseph R.; Smith, Ben E.; Evans, Matthew J.; Frey, Karen E.; Arienzo, Monica; Chellman, Nathan</p> <p>2017-04-01</p> <p>The Arctic region, and Greenland in particular, is undergoing dramatic change as characterized by atmospheric warming, decreasing sea <span class="hlt">ice</span>, shifting ocean circulation patterns, and rapid <span class="hlt">ice</span> sheet mass loss, but longer records are needed to put these changes into context. <span class="hlt">Ice</span> core records from the Greenland <span class="hlt">ice</span> sheet have yielded invaluable insight into past climate change both regionally and globally, and provided important constraints on past surface mass balance more directly, but these <span class="hlt">ice</span> cores are most often from the interior <span class="hlt">ice</span> sheet accumulation zone, at high altitude and hundreds of kilometers from the coast. Coastal <span class="hlt">ice</span> <span class="hlt">caps</span>, situated around the margins of Greenland, have the potential to provide novel high-resolution records of local and regional maritime climate and sea surface conditions, as well as contemporaneous glaciological changes (such as accumulation and surface melt history). But obtaining these records is extremely challenging. Most of these <span class="hlt">ice</span> <span class="hlt">caps</span> are unexplored, and thus their thickness, age, stratigraphy, and utility as sites of new and unique paleoclimate records is largely unknown. Access is severely limited due to their high altitude, steep relief, small surface area, and inclement weather. Furthermore, their relatively low elevation and marine moderated climate can contribute to significant surface melting and degradation of the <span class="hlt">ice</span> stratigraphy. We recently targeted areas near the Disko Bay region of central west Greenland where maritime <span class="hlt">ice</span> <span class="hlt">caps</span> are prevalent but unsampled, as potential sites for new multi-decadal to multi-millennial <span class="hlt">ice</span> core records. In 2014 & 2015 we identified two promising <span class="hlt">ice</span> <span class="hlt">caps</span>, one on Disko Island (1250 m. asl) and one on Nuussuaq Peninsula (1980 m. asl) based on airborne and ground-based geophysical observations and physical and glaciochemical stratigraphy from shallow firn cores. In spring 2015 we collected <span class="hlt">ice</span> cores at both sites using the Badger-Eclipse electromechanical drill, transported by a medley</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMPP52A..10M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMPP52A..10M"><span>Rapid onset of Little <span class="hlt">Ice</span> Age summer cold in the northern North Atlantic derived from precisely dated <span class="hlt">ice</span> <span class="hlt">cap</span> records (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, G. H.; Larsen, D.; Geirsdottir, A.; Refsnider, K. A.; Anderson, C.</p> <p>2009-12-01</p> <p>Precise radiocarbon dates on dead vegetation emerging beneath retreating non-erosive <span class="hlt">ice</span> <span class="hlt">caps</span> in NE Arctic Canada define the onset of <span class="hlt">ice</span> <span class="hlt">cap</span> growth, and provide a Holocene context for 20th Century warming. Although most plateau <span class="hlt">ice</span> <span class="hlt">caps</span> melted during the Medieval Warm Period, a few that are now disappearing remained intact since at least 350 AD. Little <span class="hlt">Ice</span> Age <span class="hlt">ice</span> <span class="hlt">cap</span> inception occurred in two pulses, centered on 1250-1300 AD and around 1450 AD, with <span class="hlt">ice</span> <span class="hlt">caps</span> remaining in an expanded state until the warming of the past few decades. <span class="hlt">Ice</span> <span class="hlt">cap</span> inception occurred simultaneously (±10 years) over a 200 m elevational range, suggesting an abrupt onset of Little <span class="hlt">Ice</span> Age cold, rather than a slow cooling over many decades. Similarly, a 3000 year annually resolved lacustrine record of glacier power and a complementary independent proxy for landscape instability in the highlands of central Iceland show an initial jump in both glacier power and landscape instability between 1250 and 1300 AD, with a second step-increase around 1450 AD, and dramatic increases in both proxies around 1800 AD, retracting in the 20th Century. A sub-decadal record of hillslope stability and within-lake primary productivity in sediments from a low-elevation lake in northern Iceland shows parallel changes at similar times. Sea <span class="hlt">ice</span> proxies and historical records document the first appearance of sea <span class="hlt">ice</span> around Iceland following Medieval time about 1250 AD. The similarity in the onset and intensification of Little <span class="hlt">Ice</span> Age cold-weather proxies across a wide region of the northern North Atlantic suggests at least a regional driver of abrupt climate change. The time intervals for which these abrupt changes occur coincide with the three most intense episodes of multiple explosive volcanic eruptions that introduced large volumes of sulfate aerosols into the stratosphere during the past millennium. Although the direct impacts of volcanic aerosols have a duration of only a few years, the memory stored by the</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14..251N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14..251N"><span>Dual-sensor mapping of mass balance on Russia's northernmost <span class="hlt">ice</span> <span class="hlt">caps</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nikolskiy, D.; Malinnikov, V.; Sharov, A.; Ukolova, M.</p> <p>2012-04-01</p> <p>Mass balance of Russia's northernmost <span class="hlt">ice</span> <span class="hlt">caps</span> is poorly known and scarcely mapped. Thorough information about glacier fluctuations in the outer periphery of Russian shelf seas is both lacking and highly desired since it may constitute the relevant benchmark for judging and projecting climate change impacts in the entire Arctic. The present study is focussed on geodetic measurements and medium-scale mapping of the mass balance on a dozen insular <span class="hlt">ice</span> <span class="hlt">caps</span>, some large and some smaller, homogeneously situated along the Eurasian boundary of Central Arctic Basin. The study region extends for approx. 2.200 km from Victoria and Arthur islands in the west across Rudolph, Eva-Liv, Ushakova, Schmidt and Komsomolets islands in the north to Bennett and Henrietta islands in the east thereby comprising the most distant and least studied <span class="hlt">ice</span> <span class="hlt">caps</span> in the Russian Arctic. The situation of insular <span class="hlt">ice</span> masses close to the edge of summer minimum sea <span class="hlt">ice</span> proved helpful in analysing spatial asymmetry of glacier accumulation signal. The overall mapping of glacier elevation changes and quantification of mass balance characteristics in the study region was performed by comparing reference elevation models of study glaciers derived from Russian topographic maps 1:200,000 (CI = 20 or 40 m) representing the glacier state as in the 1950s-1960s with modern elevation data obtained from satellite radar interferometry and lidar altimetry. In total, 14 ERS and 4 TanDEM-X high-quality SAR interferograms of 1995/96 and 2011 were acquired, processed in the standard 2-pass DINSAR manner, geocoded, calibrated, mosaicked and interpreted using reference elevation models and co-located ICESat altimetry data of 2003-2010. The DINSAR analysis revealed the existence of fast-flowing outlet glaciers at Arthur, Rudolph, Eva-Liv and Bennett islands. The calculation of separate mass-balance components is complicated in this case because of generally unknown glacier velocities and <span class="hlt">ice</span> discharge values for the mid-20</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1814608M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1814608M"><span>Present and Future Surface Mass Budget of Small Arctic <span class="hlt">Ice</span> <span class="hlt">Caps</span> in a High Resolution Regional Climate Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mottram, Ruth; Langen, Peter; Koldtoft, Iben; Midefelt, Linnea; Hesselbjerg Christensen, Jens</p> <p>2016-04-01</p> <p>Globally, small <span class="hlt">ice</span> <span class="hlt">caps</span> and glaciers make a substantial contribution to sea level rise; this is also true in the Arctic. Around Greenland small <span class="hlt">ice</span> <span class="hlt">caps</span> are surprisingly important to the total mass balance from the island as their marginal coastal position means they receive a large amount of precipitation and also experience high surface melt rates. Since small <span class="hlt">ice</span> <span class="hlt">caps</span> and glaciers have had a disproportionate number of long-term monitoring and observational schemes in the Arctic, likely due to their relative accessibility, they can also be a valuable source of data. However, in climate models the surface mass balance contributions are often not distinguished from the main <span class="hlt">ice</span> sheet and the presence of high relief topography is difficult to capture in coarse resolution climate models. At the same time, the diminutive size of marginal <span class="hlt">ice</span> masses in comparison to the <span class="hlt">ice</span> sheet makes modelling their <span class="hlt">ice</span> dynamics difficult. Using observational data from the Devon <span class="hlt">Ice</span> <span class="hlt">Cap</span> in Arctic Canada and the Renland <span class="hlt">Ice</span> <span class="hlt">Cap</span> in Eastern Greenland, we assess the success of a very high resolution (~5km) regional climate model, HIRHAM5 in capturing the surface mass balance (SMB) of these small <span class="hlt">ice</span> <span class="hlt">caps</span>. The model is forced with ERA-Interim and we compare observed mean SMB and the interannual variability to assess model performance. The steep gradient in topography around Renland is challenging for climate models and additional statistical corrections are required to fit the calculated surface mass balance to the high relief topography. Results from a modelling experiment at Renland <span class="hlt">Ice</span> <span class="hlt">Cap</span> shows that this technique produces a better fit between modelled and observed surface topography. We apply this statistical relationship to modelled SMB on the Devon <span class="hlt">Ice</span> <span class="hlt">Cap</span> and use the long time series of observations from this glacier to evaluate the model and the smoothed SMB. Measured SMB values from a number of other small <span class="hlt">ice</span> <span class="hlt">caps</span> including Mittivakkat and A.P. Olsen <span class="hlt">ice</span> <span class="hlt">cap</span> are also compared</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.P31A0118B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.P31A0118B"><span>Landscape Evolution and the Reincarnation of the Residual CO2 <span class="hlt">Ice</span> <span class="hlt">Cap</span> of Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Byrne, S.; Zuber, M.</p> <p>2006-12-01</p> <p>Observations of the southern residual CO2 <span class="hlt">cap</span> of Mars reveal a wide range of landforms including flat-floored quasi-circular pits with steep walls (dubbed Swiss-cheese features). Interannual comparisons show that these depressions are expanding laterally at rates of ~2m/yr to ~4m/yr, prompting suggestions of climate change. The residual CO2 <span class="hlt">ice</span> <span class="hlt">cap</span> is up to 10m thick and underlain by an involatile basement, it also contains layers roughly 2m thick representing different accumulation episodes in the recent past. Changes in the appearance of the residual <span class="hlt">ice</span> between the Mariner 9 and Viking missions indicate that the top-most layer was deposited in that time-frame, soon after the global dust storm of 1971. The spatial density of the Swiss-cheese features, and the rate at which they expand, mean that it is unlikely that any part of the residual <span class="hlt">ice</span> <span class="hlt">cap</span> is older than a few centuries. Given this, we may ask: how can there be a residual <span class="hlt">cap</span> present today for us to observe? To answer this and other questions we have developed a model to examine the evolution of a CO2 <span class="hlt">ice</span> landscape. This model reproduces the morphologies and expansion rates seen in the actual residual CO2 <span class="hlt">ice</span> <span class="hlt">cap</span>. Our model results indicate that the fate of CO2 <span class="hlt">ice</span> surfaces is controlled by their surface roughness. Surface roughness always increases with time, which results in an unstable situation. When the surface roughness exceeds a critical point small pits can begin to develop. The walls of these pits rapidly steepen and begin retreating which enlarges and deepens the pit. This situation always occurs even if the surface of the CO2 slab has a high enough albedo to have a net mass gain each year. Once these pits begin expanding they quickly erode the entire <span class="hlt">ice</span> slab. When the underlying non-CO2 material is exposed, it will not frost over again if Mars were to repeat like clockwork every year. We conclude that interannual climatic variability is actually a requirement for the continued existence of a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMGC23H..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMGC23H..08S"><span>Correlating <span class="hlt">Ice</span> Cores from Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> with Chronology from Little <span class="hlt">Ice</span> Age Glacial Extents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stroup, J. S.; Kelly, M. A.; Lowell, T. V.</p> <p>2010-12-01</p> <p>Proxy records indicate Southern Hemisphere climatic changes during the Little <span class="hlt">Ice</span> Age (LIA; ~1300-1850 AD). In particular, records of change in and around the tropical latitudes require attention because these areas are sensitive to climatic change and record the dynamic interplay between hemispheres (Oerlemans, 2005). Despite this significance, relatively few records exist for the southern tropics. Here we present a reconstruction of glacial fluctuations of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> (QIC), Peruvian Andes, from pre-LIA up to the present day. In the Qori Kalis valley, extensive sets of moraines exist beginning with the 1963 AD <span class="hlt">ice</span> margin (Thompson et al., 2006) and getting progressively older down valley. Several of these older moraines can be traced and are continuous with moraines in the Challpa Cocha valley. These moraines have been dated at <1050-1350-AD (Mercer and Palacios, 1977) and interpreted to have been deposited during the Little <span class="hlt">Ice</span> Age. We present a new suite of surface exposure and radiocarbon dates collected in 2008 and 2009 that constrain the ages of these moraines. Preliminary 10Be ages of boulder surfaces atop the moraines range from ~350-1370 AD. Maximum and minimum-limiting radiocarbon ages bracketing the moraines are ~0-1800 AD. The chronology of past <span class="hlt">ice</span> <span class="hlt">cap</span> extents are correlated with <span class="hlt">ice</span> core records from QIC which show an accumulation increase during ~1500-1700 AD and an accumulation decrease during ~1720-1860 AD (Thompson et al., 1985; 1986; 2006). In addition, other proxy records from Peru and the tropics are correlated with the records at QIC as a means to understand climate conditions during the LIA. This work forms the basis for future modeling of the glacial system during the LIA at QIC and for modeling of past temperature and precipitation regimes at high altitude in the tropics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA04474&hterms=swiss+cheese&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dswiss%2Bcheese','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA04474&hterms=swiss+cheese&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dswiss%2Bcheese"><span>South Polar <span class="hlt">Ice</span> <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2003-01-01</p> <p>MGS MOC Release No. MOC2-337, 21 April 2003<p/>This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the 'swiss cheese' pattern of frozen carbon dioxide on the south polar residual <span class="hlt">cap</span>. Observation of these materials over two Mars years has revealed that the scarps that bound the mesas and small buttes are retreating-the carbon dioxide <span class="hlt">ice</span> is subliming away-at a rate of about 3 meters (3 yards) per Mars year in some places. The picture covers an area about 900 m (about 900 yards) wide near 87.1oS, 93.7oW. Sunlight illuminates the scene from the upper left.<p/></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C41A1185F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C41A1185F"><span>Erosion patterns produced by the paleo Haizishan <span class="hlt">ice</span> <span class="hlt">cap</span>, SE Tibetan Plateau</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fu, P.; Stroeven, A. P.; Harbor, J.; Hättestrand, C.; Heyman, J.; Caffee, M. W.</p> <p>2017-12-01</p> <p>Erosion is a primary driver of landscape evolution, topographic relief production, geochemical cycles, and climate change. Combining in situ 10Be and 26Al exposure age dating, geomorphological mapping, and field investigations, we examine glacial erosion patterns of the almost 4,000 km2 paleo Haizishan <span class="hlt">ice</span> <span class="hlt">cap</span> on the southeastern Tibetan Plateau. Our results show that <span class="hlt">ice</span> <span class="hlt">caps</span> on the low relief Haizishan Plateau produced a zonal pattern of landscape modification. In locations where apparent exposure ages on bedrock are consistent with the last deglaciation, complete resetting of the cosmogenic exposure age clock indicates glacial erosion of at least a few meters. However, older apparent exposure ages on bedrock in areas known to have been covered by the paleo <span class="hlt">ice</span> <span class="hlt">cap</span> during the Last Glacial Maximum indicate inheritance and thus limited glacial erosion. Inferred surface exposure ages from cosmogenic depth profiles through two saprolites vary from resetting and thus saprolite profile truncation to nuclide inheritance indicating limited erosion. Finally, significant nuclide inheritance in river sand samples from basins on the scoured plateau surface also indicate limited glacial erosion during the last glaciation. Hence, for the first time, our study shows clear evidence of preservation under non-erosive <span class="hlt">ice</span> on the Tibetan Plateau. As patterns of glacial erosion intensity are largely driven by the basal thermal regime, our results confirm earlier inferences from geomorphology for a concentric basal thermal pattern for the paleo Haizishan <span class="hlt">ice</span> <span class="hlt">cap</span> during the LGM.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.7488S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.7488S"><span>Integrated firn elevation change model for glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saß, Björn; Sauter, Tobias; Braun, Matthias</p> <p>2016-04-01</p> <p>We present the development of a firn compaction model in order to improve the volume to mass conversion of geodetic glacier mass balance measurements. The model is applied on the Arctic <span class="hlt">ice</span> <span class="hlt">cap</span> Vestfonna. Vestfonna is located on the island Nordaustlandet in the north east of <span class="hlt">Svalbard</span>. Vestfonna covers about 2400 km² and has a dome like shape with well-defined outlet glaciers. Elevation and volume changes measured by e.g. satellite techniques are becoming more and more popular. They are carried out over observation periods of variable length and often covering different meteorological and snow hydrological regimes. The elevation change measurements compose of various components including dynamic adjustments, firn compaction and mass loss by downwasting. Currently, geodetic glacier mass balances are frequently converted from elevation change measurements using a constant conversion factor of 850 kg m-³ or the density of <span class="hlt">ice</span> (917 kg m-³) for entire glacier basins. However, the natural conditions are rarely that static. Other studies used constant densities for the ablation (900 kg m-³) and accumulation (600 kg m-³) areas, whereby density variations with varying meteorological and climate conditions are not considered. Hence, each approach bears additional uncertainties from the volume to mass conversion that are strongly affected by the type and timing of the repeat measurements. We link and adapt existing models of surface energy balance, accumulation and snow and firn processes in order to improve the volume to mass conversion by considering the firn compaction component. Energy exchange at the surface is computed by a surface energy balance approach and driven by meteorological variables like incoming short-wave radiation, air temperature, relative humidity, air pressure, wind speed, all-phase precipitation, and cloud cover fraction. Snow and firn processes are addressed by a coupled subsurface model, implemented with a non-equidistant layer discretisation. On</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Geomo.258....1T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Geomo.258....1T"><span><span class="hlt">Ice</span>-cored moraine degradation mapped and quantified using an unmanned aerial vehicle: A case study from a polythermal glacier in <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tonkin, T. N.; Midgley, N. G.; Cook, S. J.; Graham, D. J.</p> <p>2016-04-01</p> <p><span class="hlt">Ice</span>-cored lateral-frontal moraines are common at the margins of receding high-Arctic valley glaciers, but the preservation potential of these features within the landform record is unclear. Recent climatic amelioration provides an opportunity to study the morphological evolution of these landforms as they de-<span class="hlt">ice</span>. This is important because high-Arctic glacial landsystems have been used as analogues for formerly glaciated areas in the mid-latitudes. This study uses SfM (Structure-from-Motion) photogrammetry and a combination of archive aerial and UAV (unmanned aerial vehicle) derived imagery to investigate the degradation of an <span class="hlt">ice</span>-cored lateral-frontal moraine at Austre Lovénbreen, <span class="hlt">Svalbard</span>. Across the study area as a whole, over an 11-year period, the average depth of surface lowering was - 1.75 ± 0.89 m. The frontal sections of the moraine showed low or undetectable rates of change. Spatially variable rates of surface lowering are associated with differences in the quantity of buried <span class="hlt">ice</span> within the structure of the moraine. Morphological change was dominated by surface lowering, with limited field evidence of degradation via back-wastage. This permits the moraine a greater degree of stability than previously observed at other sites in <span class="hlt">Svalbard</span>. It is unclear whether the end point will be a fully stabilised <span class="hlt">ice</span>-cored moraine, in equilibrium with its environment, or an <span class="hlt">ice</span>-free lateral-frontal moraine complex. Controls on geomorphological change (e.g. topography and climate) and the preservation potential of the lateral-frontal moraine are discussed. The methods used by this research also demonstrate the potential value of SfM photogrammetry and unmanned aerial vehicles for monitoring environmental change and are likely to have wider applications in other geoscientific sub-disciplines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.U44A..01A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.U44A..01A"><span>Recent Changes in Arctic Glaciers, <span class="hlt">Ice</span> <span class="hlt">Caps</span>, and the Greenland <span class="hlt">Ice</span> Sheet: Cold Facts About Warm <span class="hlt">Ice</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abdalati, W.</p> <p>2005-12-01</p> <p>One of the major manifestations of Arctic change can be observed in the state of balance of Arctic glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> and the Greenland <span class="hlt">ice</span> sheet. These <span class="hlt">ice</span> masses are estimated to contain nearly 3 million cubic kilometers of <span class="hlt">ice</span>, which is more than six times greater than all the water stored in the Earth's lakes, rivers, and snow combined and is the equivalent of over 7 meters of sea level. Most of these <span class="hlt">ice</span> masses have been shrinking in recent in years, but their mass balance is highly variable on a wide range of spatial and temporal scales. On the Greenland <span class="hlt">ice</span> sheet most of the coastal regions have thinned substantially as melt has increased and some of its outlet glaciers have accelerated. Near the equilibrium line in West Greenland, we have seen evidence of summer acceleration that is linked to surface meltwater production, suggesting a relatively rapid response mechanism of the <span class="hlt">ice</span> sheet change to a warming climate. At the same time, however, the vast interior regions of the Greenland <span class="hlt">ice</span> sheet have shown little change or slight growth, as accumulation in these areas may have increased. Throughout much of the rest of the Arctic, many glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> have been shrinking in the past few decades, and in Canada and Alaska, the rate of <span class="hlt">ice</span> loss seems to have accelerated during the late 1990s. These recent observations offer only a snapshot in time of the long-term behavior, but they are providing crucial information about the current state of <span class="hlt">ice</span> mass balance and the mechanisms that control it in one of the most climatically sensitive regions on Earth. As we continue to learn more through a combination of remote sensing observations, in situ measurements and improved modeling capabilities, it is important that we coordinate and integrate these approaches effectively in order to predict future changes and their impact on sea level, freshwater discharge, and ocean circulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PolSc..10..239S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PolSc..10..239S"><span>Surface elevation change on <span class="hlt">ice</span> <span class="hlt">caps</span> in the Qaanaaq region, northwestern Greenland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saito, Jun; Sugiyama, Shin; Tsutaki, Shun; Sawagaki, Takanobu</p> <p>2016-09-01</p> <p>A large number of glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> (GICs) are distributed along the Greenland coast, physically separated from the <span class="hlt">ice</span> sheet. The total area of these GICs accounts for 5% of Greenland's <span class="hlt">ice</span> cover. Melt water input from the GICs to the ocean substantially contributed to sea-level rise over the last century. Here, we report surface elevation changes of six <span class="hlt">ice</span> <span class="hlt">caps</span> near Qaanaaq (77°28‧N, 69°13‧W) in northwestern Greenland based on photogrammetric analysis of stereo pair satellite images. We processed the images with a digital map plotting instrument to generate digital elevation models (DEMs) in 2006 and 2010 with a grid resolution of 500 m. Generated DEMs were compared to measure surface elevation changes between 2006 and 2010. Over the study area of the six <span class="hlt">ice</span> <span class="hlt">caps</span>, covering 1215 km2, the mean rate of elevation change was -1.1 ± 0.1 m a-1. This rate is significantly greater than that previously reported for the 2003-2008 period (-0.6 ± 0.1 m a-1) for GICs all of northwestern Greenland. This increased mass loss is consistent with the rise in summer temperatures in this region at a rate of 0.12 °C a-1 for the 1997-2013 period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C53A0283P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C53A0283P"><span>Emergent Dead Vegetation and Paired Cosmogenic Isotope Constraints on <span class="hlt">Ice</span> <span class="hlt">Cap</span> Activity, Baffin Island, Arctic Canada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pendleton, S.; Miller, G. H.</p> <p>2014-12-01</p> <p>Recent summer warming has now raised the equilibrium line above almost all <span class="hlt">ice</span> <span class="hlt">caps</span> on Baffin Island, resulting in surface lowering and marginal recession everywhere. As cold-based <span class="hlt">ice</span> recedes it frequently exposes in situ tundra plants that were living at the time <span class="hlt">ice</span> expanded across the site. Radiocarbon dates for each plant records when cold summers dropped regional snowline below the site, killing the plants, and snowline remained below the site until the collection date. The kill dates also represent the last time that the climate was warm enough to expose the sampling location. Seventy-six vegetation samples collected in 2013 from the Penny <span class="hlt">Ice</span> <span class="hlt">Cap</span> region have been dated, with significant age populations at ~0.5, 1.8, 2.3, and 3.6 ka. The absence of ages around ~1, 2, 3, 4.5, and 5.5 ka suggest periods of either no snowline depression or stability. Sixteen vegetation samples returned ages of >45 ka (2 revisited sites from 2010, 14 new). It is postulated that these radiocarbon dead samples were last exposed during the last interglaciation (~120 ka), the last time climate was as warm as present. In addition to plant collections, bedrock exposures at the <span class="hlt">ice</span> margins were sampled for 26Al/10Be cosmogenic nuclide dating. Seven samples from and around the Penny <span class="hlt">Ice</span> <span class="hlt">cap</span> have returned maximum exposure ages from ~ 0.6-0.9 ma and total histories of ~0.6-1.5 ma. In general, samples from the larger Penny <span class="hlt">Ice</span> <span class="hlt">Cap</span> exhibited lower amounts of exposure (~20% of total history) than those samples from smaller, localized <span class="hlt">ice</span> <span class="hlt">caps</span> (~55%). Radiocarbon dead sites north of the Penny <span class="hlt">Ice</span> <span class="hlt">cap</span> experienced significantly more exposure over their lifetimes than their counterparts east of the Penny <span class="hlt">Ice</span> <span class="hlt">cap</span>, suggesting significant differences in local and regional land <span class="hlt">ice</span> fluctuations over the last 2 million years. Utilizing both the method of in situ moss and 26Al/10Be dating provides new insight into both the recent activity and long-term evolution of <span class="hlt">ice</span> on Baffin Island. In particular</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMEP23A0944S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMEP23A0944S"><span>High Arctic Coasts At Risk - The Impact of Coastal Hazards on Scientific and Community Infrastructure in <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strzelecki, M. C.; Pawlowski, L.; Jaskolski, M.; Lim, M.; Zagorski, P.; Long, A. J.; Jensen, M.</p> <p>2015-12-01</p> <p>The rapid climate warming being observed in the <span class="hlt">Svalbard</span> is leading to an increase in human activities in the coastal zone, leading to an increased need for coastal hazard assessment. Present-day <span class="hlt">Svalbard</span> coastal landscapes are modified by increased degradation of permafrost accelerated sediment supply from deglaciated catchments, and prolonged periods of open-water conditions and wave activity. Since the second half of 20thcentury there is also an observed increase in the number and intensity of storms entering the Arctic particularly in summer months when coastlines are free of protective <span class="hlt">ice</span> cover. Despite the potential significance of these coastal hazards on the security of scientific (research bases and devices) and community (ports, airports, roads, buildings) infrastructure on <span class="hlt">Svalbard</span>, relatively little is known on the present-day rate of <span class="hlt">Svalbard</span> coastal zone changes and how they might impact the nearshore infrastructure in the future. Here we report the results of a project that focused on rates of coastal zone changes in <span class="hlt">Svalbard</span> and examined the impact of extreme coastal processes on scientific and community infrastructure. The project applied combination of remote sensing and field-based mapping techniques to characterise coastal changes observed in the surroundings of main research stations in <span class="hlt">Svalbard</span> in Hornsund (PPS), Petuniabukta (AMUPS) and Bellsund (Calypsobyen) as well as a major towns: Longyearbyen, Piramiden, Barentsburg and Svea. Our results document dramatic changes of <span class="hlt">Svalbard</span> coastal zone under intervals characterised by a warming climate, retreating local <span class="hlt">ice</span> masses, a shortened winter sea-<span class="hlt">ice</span> season and melting permafrost. The study confirmed the growing importance of extreme processes in shaping coasts of <span class="hlt">Svalbard</span> and the impact of these changes on human infrastructure. Our study proposes a risk assessment for a development and protection of infrastructure along the coasts of <span class="hlt">Svalbard</span> under scenarios of climate change, sea level rise</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP31C1304I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP31C1304I"><span>Extensive Glacier Advances During the Pleistocene-Holocene Transition on <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ingolfsson, O.; Farnsworth, W. R.; Allaart, L.; Håkansson, L.; Schomacker, A.</p> <p>2017-12-01</p> <p>A variety of data suggest extensive glacier advances on <span class="hlt">Svalbard</span> in connection with the Pleistocene-Holocene transition, during period of regional warming. We present a study of a well-constrained end moraine formed during the Lateglacial-early Holocene transition in De Geerbukta, NE <span class="hlt">Svalbard</span>. The landform was deposited by an outlet glacier re-advancing into a fjord suggesting a far more extended position than the late Holocene maximum. We compare the synchronicity of this glacier advance to climate and 15 other proposed Lateglacial-Early Holocene glacier advances in <span class="hlt">Svalbard</span>. The evidence suggests that the Lateglacial-Early Holocene glaciers were much more dynamic than hitherto recognized, exhibited re-advances and extended well beyond the extensively studied late Holocene glacial expansion. We suggest that the culmination of the Neoglacial advances during the Little <span class="hlt">Ice</span> Age does not mark the Holocene maximum extent of most <span class="hlt">Svalbard</span> glaciers; it is just the most studied and most visible in the geological record. Furthermore, the evidence suggests that the final phase of <span class="hlt">Svalbard</span> deglaciation, after the last major glaciation, was characterized by widespread advances of <span class="hlt">Svalbard</span> outlet glaciers. The presentation will discuss the implications of this.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C31B0283C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C31B0283C"><span>Change in the Extent of Baffin Island's Penny <span class="hlt">Ice</span> <span class="hlt">Cap</span> in Response to Regional Warming, 1969 - 2014</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cox, M. C.; Cormier, H. M.; Gardner, A. S.</p> <p>2014-12-01</p> <p>Glaciers are retreating globally in response to warmer atmospheric temperatures, adding large volumes of melt water to the world's oceans. The largest glacierized region and present-day contributor to sea level rise outside of the massive <span class="hlt">ice</span> sheets is the Canadian Arctic. Recent work has shown that the glaciers of the southern Canadian Arctic (Baffin and Bylot Island) have experienced accelerated rates of <span class="hlt">ice</span> loss in recent decades, but little is known regarding the spatial and temporal variations in rates of loss. For this study we examine in detail changes in the extent of the Penny <span class="hlt">Ice</span> <span class="hlt">Cap</span> (a proxy for <span class="hlt">ice</span> loss) between 1969 and 2014 to better understand the climatic drivers of the recently observed accelerated rates of <span class="hlt">ice</span> loss on Baffin Island. To do this, we reconstruct the extent of the <span class="hlt">ice</span> <span class="hlt">cap</span> for the year 1969 from historical maps and for the years 1985, 1995, 2010, and 2014 from Landsat 5 TM and Landsat 8 OLI imagery. We use 2009 SPOT HRS imagery and a novel extent comparison algorithm to assess the accuracy of glacier extents derived from Landsat imagery. Regional temperature and precipitation records were used to explain the spatial pattern of change. Due to large variation in elevations, hypsometry was also investigated as a contributor to differences in rates of change across the <span class="hlt">ice</span> <span class="hlt">cap</span>. Preliminary results show overall retreat throughout the <span class="hlt">ice</span> <span class="hlt">cap</span> but with regional differences in area and length change on either side of the <span class="hlt">Ice</span> <span class="hlt">Cap</span> divide.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA01247&hterms=retreated&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dretreated','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA01247&hterms=retreated&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dretreated"><span>Seasonal Changes in Mars' North Polar <span class="hlt">Ice</span> <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1997-01-01</p> <p>These images, which seem to have been taken while NASA's Hubble Space Telescope (HST) was looking directly down on the Martian North Pole, were actually created by assembling mosaics of three sets of images taken by HST in October, 1996 and in January and March, 1997 and projecting them to appear as they would if seen from above the pole. This first mosaic is a view which could not actually be seen in nature because at this season a portion of the pole would have actually been in shadow; the last view, taken near the summer solstice, would correspond to the Midnight Sun on Earth with the pole fully illuminated all day. The resulting polar maps begin at 50 degrees N latitude and are oriented with 0 degrees longitude at the 12 o'clock position. This series of pictures captures the seasonal retreat of Mars' north polar <span class="hlt">cap</span>.<p/>October 1996 (early spring in the Northern hemisphere): In this map, assembled from images obtained between Oct. 8 and 15, the <span class="hlt">cap</span> extends down to 60 degrees N latitude, nearly it's maximum winter extent. (The notches are areas where Hubble data were not available). A thin, comma-shaped cloud of dust can be seen as a salmon-colored crescent at the 7 o'clock position. The <span class="hlt">cap</span> is actually fairly circular about the geographic pole at this season; the bluish 'knobs' where the <span class="hlt">cap</span> seems to extend further are actually clouds that occurred near the edges of the three separate sets of images used to make the mosaic.<p/>January 1997 (mid-spring): Increased warming as spring progresses in the northern hemisphere has sublimated the carbon dioxide <span class="hlt">ice</span> and frost below 70 degrees north latitude. The faint darker circle inside the <span class="hlt">cap</span> boundary marks the location of circumpolar sand dunes (see March '97 map); these dark dunes are warmed more by solar heating than are the brighter surroundings, so the surface frost sublimates from the dunes earlier than from the neighboring areas. Particularly evident is the marked hexagonal shape of the polar <span class="hlt">cap</span> at this season</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17834534','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17834534"><span>The little <span class="hlt">ice</span> age as recorded in the stratigraphy of the tropical quelccaya <span class="hlt">ice</span> <span class="hlt">cap</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thompson, L G; Mosley-Thompson, E; Dansgaard, W; Grootes, P M</p> <p>1986-10-17</p> <p>The analyses of two <span class="hlt">ice</span> cores from a southern tropical <span class="hlt">ice</span> <span class="hlt">cap</span> provide a record of climatic conditions over 1000 years for a region where other proxy records are nearly absent. Annual variations in visible dust layers, oxygen isotopes, microparticle concentrations, conductivity, and identification of the historical (A.D. 1600) Huaynaputina ash permit accurate dating and time-scale verification. The fact that the Little <span class="hlt">Ice</span> Age (about A.D. 1500 to 1900) stands out as a significant climatic event in the oxygen isotope and electrical conductivity records confirms the worldwide character of this event.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.8625J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.8625J"><span>Paleoenvironmental changes during the past 2000 years, evidence from Kongsfjorden, <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jernas, P.; Kristensen, D.; Koc, N.; Skirbekk, K.</p> <p>2009-04-01</p> <p> of fine grained sediment and decrease in <span class="hlt">ice</span> rafting indicating less influence from glaciers. The foraminiferal species composition show decreasing content of agglutinated foraminifera down core caused by their low preservation potential. For this core site it confirms the importance of calcareous foraminifera as a fossil record tool. The two dominant species in the core are Elphidium excavatum and Nonionellina labradorica. During the last 2000 years the percentage of E. excavatum shows a general tendency to decrease while N. labradorica increases toward present. Elphidium excavatum is typical for arctic glaciomarine environments close to glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span>, indicating harsh conditions (cold bottom waters temperatures, lower salinity) and probably extensive <span class="hlt">ice</span> cover. Nonionellina labradorica indicates the vicinity of oceanographic fronts and high productivity. Another species Islandiella spp., often associated with increased productivity and presence of the sea <span class="hlt">ice</span> edge, shows significant increase in percentage from 1000 to 800 cal yr BP. From 600 to 400 cal yr BP Bucella spp. start to decline suggesting increased sea <span class="hlt">ice</span> cover and diminished influence of the Coastal Current on the inner shelf of <span class="hlt">Svalbard</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19..816C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19..816C"><span>Cold basal conditions during surges control flow of fringing Arctic <span class="hlt">ice</span> <span class="hlt">caps</span> in Greenland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cook, Samuel; Christoffersen, Poul; Todd, Joe; Palmer, Steven</p> <p>2017-04-01</p> <p>Fringing <span class="hlt">ice</span> <span class="hlt">caps</span> separated from larger <span class="hlt">ice</span> sheets are rarely studied, yet they are an important part of earth's cryosphere, which has become the largest source of global sea-level rise. Understanding marginal <span class="hlt">ice</span> <span class="hlt">caps</span> is crucial for being able to predict sea-level change as they are responsible for up to 20% of Greenland's mass loss for 2003-2008. Studies of fringing <span class="hlt">ice</span> <span class="hlt">caps</span> can furthermore provide useful insights into processes operating on glaciers that surge. Surging has been the focus of much recent glaciological work, especially with reference to thermal evolution of polythermal glaciers in High Mountain Asia and the High Arctic. This has shown that the classic divide between hydrologically-controlled surges ('hard-bed') in Alaska and thermally-regulated ('soft-bed') surges elsewhere is less stark than previously assumed. Studying marginal <span class="hlt">ice</span> <span class="hlt">caps</span> can therefore be valuable in several ways. The largest fringing <span class="hlt">ice</span> <span class="hlt">cap</span> in Greenland is Flade Isblink. Previous work has established that this <span class="hlt">ice</span> <span class="hlt">cap</span> is showing a range of dynamic behaviour, including subglacial lake drainage and varied patterns of mass-balance change. In particular, a substantial surge, assumed to be caused by a version of the thermally-regulated mechanism, occurred between 1996 and 2000, making the <span class="hlt">ice</span> <span class="hlt">cap</span> a useful case study for investigating this process. Here we investigate the surge on Flade Isblink using the open-source, Full-Stokes model Elmer/<span class="hlt">Ice</span> to invert for basal conditions and englacial temperatures using the adjoint method. We specifically study steady-state conditions representative of the active surge phase in 2000, and the subsequent quiescent phase, using patterns of surface velocity observed in 2000, 2005, 2008 and 2015. Under constant geometry, temperature and geothermal heat, it is shown that surging increases basal freezing rates by over 60% across an area that is twice as large as the area over which the bed freezes in the quiescent phase. The process responsible for this</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70022940','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70022940"><span>Variability of Mars' North Polar Water <span class="hlt">Ice</span> <span class="hlt">Cap</span>: I. Analysis of Mariner 9 and Viking Orbiter Imaging Data</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bass, Deborah S.; Herkenhoff, Kenneth; Paige, David A.</p> <p>2000-01-01</p> <p>Previous studies interpreted differences in <span class="hlt">ice</span> coverage between Mariner 9 and Viking Orbiter observations of Mars' north residual polar <span class="hlt">cap</span> as evidence of interannual variability of <span class="hlt">ice</span> deposition on the <span class="hlt">cap</span>. However, these investigators did not consider the possibility that there could be significant changes in the <span class="hlt">ice</span> coverage within the northern residual <span class="hlt">cap</span> over the course of the summer season. Our more comprehensive analysis of Mariner 9 and Viking Orbiter imaging data shows that the appearance of the residual <span class="hlt">cap</span> does not show large-scale variance on an interannual basis. Rather we find evidence that regions that were dark at the beginning of summer look bright by the end of summer and that this seasonal variation of the <span class="hlt">cap</span> repeats from year to year. Our results suggest that this brightening was due to the deposition of newly formed water <span class="hlt">ice</span> on the surface. We find that newly formed <span class="hlt">ice</span> deposits in the summer season have the same red-to-violet band image ratios as permanently bright deposits within the residual <span class="hlt">cap</span>. We believe the newly formed <span class="hlt">ice</span> accumulates in a continuous layer. To constrain the minimum amount of deposited <span class="hlt">ice</span>, we used observed albedo data in conjunction with calculations using Mie theory for single scattering and a delta-Eddington approximation of radiative transfer for multiple scattering. The brightening could have been produced by a minimum of (1) a ~35-μm-thick layer of 50-μm-sized <span class="hlt">ice</span> particles with 10% dust or (2) a ~14-μm-thick layer of 10-μm-sized <span class="hlt">ice</span> particles with 50% dust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25941518','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25941518"><span>Microbial diversity on Icelandic glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lutz, Stefanie; Anesio, Alexandre M; Edwards, Arwyn; Benning, Liane G</p> <p>2015-01-01</p> <p>Algae are important primary colonizers of snow and glacial <span class="hlt">ice</span>, but hitherto little is known about their ecology on Iceland's glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span>. Due do the close proximity of active volcanoes delivering large amounts of ash and dust, they are special ecosystems. This study provides the first investigation of the presence and diversity of microbial communities on all major Icelandic glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> over a 3 year period. Using high-throughput sequencing of the small subunit ribosomal RNA genes (16S and 18S), we assessed the snow community structure and complemented these analyses with a comprehensive suite of physical-, geo-, and biochemical characterizations of the aqueous and solid components contained in snow and <span class="hlt">ice</span> samples. Our data reveal that a limited number of snow algal taxa (Chloromonas polyptera, Raphidonema sempervirens and two uncultured Chlamydomonadaceae) support a rich community comprising of other micro-eukaryotes, bacteria and archaea. Proteobacteria and Bacteroidetes were the dominant bacterial phyla. Archaea were also detected in sites where snow algae dominated and they mainly belong to the Nitrososphaerales, which are known as important ammonia oxidizers. Multivariate analyses indicated no relationships between nutrient data and microbial community structure. However, the aqueous geochemical simulations suggest that the microbial communities were not nutrient limited because of the equilibrium of snow with the nutrient-rich and fast dissolving volcanic ash. Increasing algal secondary carotenoid contents in the last stages of the melt seasons have previously been associated with a decrease in surface albedo, which in turn could potentially have an impact on the melt rates of Icelandic glaciers.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4403510','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4403510"><span>Microbial diversity on Icelandic glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lutz, Stefanie; Anesio, Alexandre M.; Edwards, Arwyn; Benning, Liane G.</p> <p>2015-01-01</p> <p>Algae are important primary colonizers of snow and glacial <span class="hlt">ice</span>, but hitherto little is known about their ecology on Iceland's glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span>. Due do the close proximity of active volcanoes delivering large amounts of ash and dust, they are special ecosystems. This study provides the first investigation of the presence and diversity of microbial communities on all major Icelandic glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> over a 3 year period. Using high-throughput sequencing of the small subunit ribosomal RNA genes (16S and 18S), we assessed the snow community structure and complemented these analyses with a comprehensive suite of physical-, geo-, and biochemical characterizations of the aqueous and solid components contained in snow and <span class="hlt">ice</span> samples. Our data reveal that a limited number of snow algal taxa (Chloromonas polyptera, Raphidonema sempervirens and two uncultured Chlamydomonadaceae) support a rich community comprising of other micro-eukaryotes, bacteria and archaea. Proteobacteria and Bacteroidetes were the dominant bacterial phyla. Archaea were also detected in sites where snow algae dominated and they mainly belong to the Nitrososphaerales, which are known as important ammonia oxidizers. Multivariate analyses indicated no relationships between nutrient data and microbial community structure. However, the aqueous geochemical simulations suggest that the microbial communities were not nutrient limited because of the equilibrium of snow with the nutrient-rich and fast dissolving volcanic ash. Increasing algal secondary carotenoid contents in the last stages of the melt seasons have previously been associated with a decrease in surface albedo, which in turn could potentially have an impact on the melt rates of Icelandic glaciers. PMID:25941518</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912149V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912149V"><span>Long-term evolution of a small <span class="hlt">ice</span> <span class="hlt">cap</span> in Greenland: a dynamic perspective from numerical flow modelling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vieli, Andreas; Lane, Timothy; Adamson, Kathryn</p> <p>2017-04-01</p> <p>Small <span class="hlt">ice</span> <span class="hlt">caps</span> at the periphery of the Greenland <span class="hlt">ice</span> sheet are often close to the limit of existence and are therefore expected to respond more sensitively to climate change than the land-margin of the neighboring <span class="hlt">ice</span> sheet. However, their past evolution and dynamic behavior is poorly understood and their use as climate indicators therefore remains so far limited. We here aim to provide a long-term dynamic reconstruction of Lyngmarksbraeen, a small (32km2) <span class="hlt">ice</span> <span class="hlt">cap</span> on Disko Island in West Greenland, with a particular focus on the little <span class="hlt">ice</span> age (LIA, since 1200AD). We use a 2-dim. time-dependent numerical flow model (SIA) and a PDD-mass balance model in combination with historical observations, geomorphological mapping and exposure dating to simulate its long-term evolution and dynamic behaviour. We specifically focus on retreat since the LIA, which is well constrained by geomorphological evidence and historical maps and length records of several small outlet glaciers and data from local and regional climate stations (Qeqertarssuaq and Ilulisat). We also explore aspects related to flow dynamics and find that the dynamic state of this <span class="hlt">ice</span> <span class="hlt">cap</span> is, at any time, far from being balanced and is highly sensitive to the surface elevation mass balance feedback and results in an asynchronous response of the different outlets and hysteresis-type behaviour. The modelling is able to reproduce the observed LIA-extent and the almost continuous retreat over the last hundred years well. It further indicates that the <span class="hlt">ice</span> <span class="hlt">cap</span> was already dynamically inert since the 1960s. Today, the <span class="hlt">ice</span> <span class="hlt">cap</span> has lost almost its entire accumulation area and even without any further warming in the future, the <span class="hlt">ice</span> <span class="hlt">cap</span> is expected to vanish within a couple of decades.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRC..122.4634K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRC..122.4634K"><span>Bio-optical properties of Arctic drift <span class="hlt">ice</span> and surface waters north of <span class="hlt">Svalbard</span> from winter to spring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kowalczuk, Piotr; Meler, Justyna; Kauko, Hanna M.; Pavlov, Alexey K.; Zabłocka, Monika; Peeken, Ilka; Dybwad, Christine; Castellani, Giulia; Granskog, Mats A.</p> <p>2017-06-01</p> <p>We have quantified absorption by CDOM, aCDOM(λ), particulate matter, ap(λ), algal pigments, aph(λ), and detrital material, aNAP(λ), coincident with chlorophyll a in sea <span class="hlt">ice</span> and surface waters in winter and spring 2015 in the Arctic Ocean north of <span class="hlt">Svalbard</span>. The aCDOM(λ) was low in contrast to other regions of the Arctic Ocean, while ap(λ) has the largest contribution to absorption variability in sea <span class="hlt">ice</span> and surface waters. ap(443) was 1.4-2.8 times and 1.3-1.8 times higher than aCDOM(443) in surface water and sea <span class="hlt">ice</span>, respectively. aph(λ) contributed 90% and 81% to ap(λ), in open leads and under-<span class="hlt">ice</span> waters column, and much less (53%-74%) in sea <span class="hlt">ice</span>, respectively. Both aCDOM(λ) and ap(λ) followed closely the vertical distribution of chlorophyll a in sea <span class="hlt">ice</span> and the water column. We observed a tenfold increase of the chlorophyll a concentration and nearly twofold increase in absorption at 443 nm in sea <span class="hlt">ice</span> from winter to spring. The aCDOM(λ) dominated the absorption budget in the UV both in sea <span class="hlt">ice</span> and surface waters. In the visible range, absorption was dominated by aph(λ), which contributed more than 50% and aCDOM(λ), which contributed 43% to total absorption in water column. Detrital absorption contributed significantly (33%) only in surface <span class="hlt">ice</span> layer. Algae dynamics explained more than 90% variability in ap(λ) and aph(λ) in water column, but less than 70% in the sea <span class="hlt">ice</span>. This study presents detailed absorption budget that is relevant for modeling of radiative transfer and primary production.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018CliPa..14..637G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018CliPa..14..637G"><span>Aromatic acids in an Arctic <span class="hlt">ice</span> core from <span class="hlt">Svalbard</span>: a proxy record of biomass burning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grieman, Mackenzie M.; Aydin, Murat; Isaksson, Elisabeth; Schwikowski, Margit; Saltzman, Eric S.</p> <p>2018-05-01</p> <p>This study presents vanillic acid and para-hydroxybenzoic acid levels in an Arctic <span class="hlt">ice</span> core from Lomonosovfonna, <span class="hlt">Svalbard</span> covering the past 800 years. These aromatic acids are likely derived from lignin combustion in wildfires and long-range aerosol transport. Vanillic and para-hydroxybenzoic acid are present throughout the <span class="hlt">ice</span> core, confirming that these compounds are preserved on millennial timescales. Vanillic and para-hydroxybenzoic acid concentrations in the Lomonosovfonna <span class="hlt">ice</span> core ranged from below the limits of detection to 0.2 and 0.07 ppb, respectively (1 ppb = 1000 ng L-1). Vanillic acid levels are high (maximum of 0.1 ppb) from 1200 to 1400 CE, then gradually decline into the twentieth century. The largest peak in the vanillic acid in the record occurs from 2000 to 2008 CE. In the para-hydrobenzoic acid record, there are three centennial-scale peaks around 1300, 1550, and 1650 CE superimposed on a long-term decline in the baseline levels throughout the record. Ten-day air mass back trajectories for a decade of fire seasons (March-November, 2006-2015) indicate that Siberia and Europe are the principle modern source regions for wildfire emissions reaching the Lomonosovfonna site. The Lomonosovfonna data are similar to those from the Eurasian Arctic Akademii Nauk <span class="hlt">ice</span> core during the early part of the record (1220-1400 CE), but the two <span class="hlt">ice</span> cores diverge markedly after 1400 CE. This coincides with a shift in North Atlantic climate marked by a change of the North Atlantic Oscillation from a positive to a more negative state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOS.A34C2673S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOS.A34C2673S"><span>Wave Measurements in Landfast <span class="hlt">Ice</span> in <span class="hlt">Svalbard</span>: Evolution of Wave Propagation following Wind Waves to Swell Transition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sutherland, G.; Rabault, J.; Jensen, A.; Christensen, K. H.; Ward, B.; Marchenko, A. V.; Morozov, E.; Gundersen, O.; Halsne, T.; Lindstrøm, E.</p> <p>2016-02-01</p> <p>The impact of sea-<span class="hlt">ice</span> cover on propagation of water waves has been studied over five decades, both theoretically and from measurements on the <span class="hlt">ice</span>. Understanding the interaction between water waves and sea-<span class="hlt">ice</span> covers is a topic of interest for a variety of purposes such as formulation of ocean models for climate, weather and sea state predictions, and the analysis of pollution dispersion in the Arctic. Our knowledge of the underlying phenomena is still partial, and more experimental data is required to gain further insight into the associated physics. Three Inertial Motion Units (IMUs) have been assessed in the lab and used to perform measurements on landfast <span class="hlt">ice</span> over 2 days in Tempelfjorden, <span class="hlt">Svalbard</span> during March 2015. The <span class="hlt">ice</span> thickness in the measurement area was approximately 60 to 80 cm. Two IMUs were located close to each other (6 meters) at a distance around 180 m from the <span class="hlt">ice</span> edge. The third IMU was placed 120 m from the <span class="hlt">ice</span> edge. The data collected contains a transition from high frequency, wind generated waves to lower frequency swell. Drastic changes in wave propagation are observed in relation with this transition. The level of reflected energy obtained from rotational spectra is much higher before the transition to low frequency swell than later on. The correlation between the signal recorded by the IMU closer to the <span class="hlt">ice</span> edge and the two others IMUs is low during the wind waves dominated period, and increases with incoming swell. The dispersion relation for waves in <span class="hlt">ice</span> was found to correspond to flexural-gravity waves before the transition and deepwater gravity waves afterwards.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040000884&hterms=melting+ice+caps&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmelting%2Bice%2Bcaps','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040000884&hterms=melting+ice+caps&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmelting%2Bice%2Bcaps"><span>A Case for Microorganisms on Comets, Europa and the Polar <span class="hlt">Ice</span> <span class="hlt">Caps</span> of Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hoover, Richard B.; Pikuta, Elena V.</p> <p>2003-01-01</p> <p>Microbial extremophiles live on Earth wherever there is liquid water and a source of energy. Observations by ground-based observatories, space missions, and satellites have provided strong evidence that water <span class="hlt">ice</span> exists today on comets, Europa, Callisto, and Ganymede and in the snow, permafrost, glaciers and polar <span class="hlt">ice</span> <span class="hlt">caps</span> of Mars. Studies of the cryoconite pools and <span class="hlt">ice</span> bubble systems of Antarctica suggest that solar heating of dark rocks entrained in <span class="hlt">ice</span> can cause localized melting of <span class="hlt">ice</span> providing ideal conditions for the growth of microbial communities with the creation of micro-environments where trapped metabolic gasses produce entrained isolated atmospheres as in the Antarctic <span class="hlt">ice</span>-bubble systems. It is suggested that these considerations indicate that several groups of microorganisms should be capable of episodic growth within liquid water envelopes surrounding dark rocks in cometary <span class="hlt">ices</span> and the permafrost and polar <span class="hlt">caps</span> of Mars. We discuss some of the types of microorganisms we have encountered within the permafrost and snow of Siberia, the cryoconite pools of Alaska, and frozen deep within the Antarctic <span class="hlt">ice</span> sheet above Lake Vostok.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5688916-test-results-thermal-ice-cap-prototype-final-comments-final-report','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5688916-test-results-thermal-ice-cap-prototype-final-comments-final-report"><span>Test results of Thermal <span class="hlt">Ice</span> <span class="hlt">Cap</span> prototype and final comments. Final report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Burley, W.</p> <p>1982-01-01</p> <p>The design and testing of an insulating cover, <span class="hlt">Ice</span> <span class="hlt">Cap</span>, for an <span class="hlt">ice</span> rink are described. The radio-controlled reel system which houses, deploys, and harvests the 17,000 square feet of insulating material is essential to the success of the cover. Photographs showing the use of the system are included. (MHR)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMPP61A0284S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMPP61A0284S"><span>The Holocene and the Late Deglaciation: timing and development on the northern <span class="hlt">Svalbard</span> margin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Slubowska, M. A.; Koc, N.; Rasmussen, T. L.</p> <p>2002-12-01</p> <p><span class="hlt">Svalbard</span> is located in the high Arctic (76§ to 81§ N and 10§ to 28§ E) at the northernmost reach of the warmer West Spitsbergen Current, which forms the continuation of the North Atlantic Current. At this position, close to the Polar Front, even small variations in the current are expected to have large effects on the regional climate. Therefore, the <span class="hlt">Svalbard</span> area is ideal for monitoring past changes in the ocean circulation as well as the timing and the nature of the <span class="hlt">Svalbard</span> <span class="hlt">ice</span> sheet disintegration. We have investigated core NP94-51 SC2 (80§ 21,346 N, 16§ 17,970 E, 400m water depth and 714 cm long) retrieved from the mouth of the Hinlopen Strait in the Arctic Ocean, north of <span class="hlt">Svalbard</span>. The main objective of this study is to document a) the deglaciation history of the area, b) the Holocene climate variability on the decadal time scales using sedimentological, physical and biological analysis. AMS-14C dating gives the age of approximately 14,000 BP for the bottom of the core. The Holocene interglacial is represented by c. 5 m. A detailed analysis of different oceanographic proxies such as: <span class="hlt">ice</span> rafted debris, magnetic susceptibility, spectral reflectance (L*a*b scale), benthic and planktic foraminiferal fauna, diatom flora, grain size and radiocarbon dates (AMS-14C) were used to reconstruct the paleoceanographic evolution of the area. The results show that disintegration of the Hinlopen Strait <span class="hlt">ice</span> sheet and, possibly, the northern margin of the <span class="hlt">Svalbard</span> <span class="hlt">ice</span> sheet began at 14,000 BP. The influx of the subsurface Atlantic waters into the area began during the Bolling interstadial at 12,600 BP, while the surface waters were still cold and of low salinity. The retreat of the sea <span class="hlt">ice</span> cover occurred together with the opening of the surface waters at 10,800 BP. During major part of the Younger Dryas (10,800 - 10,000 BP) the Polar Front was located close to the core site. At 10,100 BP the Polar Front retreated from that area. In comparison to the deglaciation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22102665','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22102665"><span>Rabies in the arctic fox population, <span class="hlt">Svalbard</span>, Norway.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mørk, Torill; Bohlin, Jon; Fuglei, Eva; Åsbakk, Kjetil; Tryland, Morten</p> <p>2011-10-01</p> <p>Arctic foxes, 620 that were trapped and 22 found dead on <span class="hlt">Svalbard</span>, Norway (1996-2004), as well as 10 foxes trapped in Nenets, North-West Russia (1999), were tested for rabies virus antigen in brain tissue by standard direct fluorescent antibody test. Rabies antigen was found in two foxes from <span class="hlt">Svalbard</span> and in three from Russia. Blood samples from 515 of the fox carcasses were screened for rabies antibodies with negative result. Our results, together with a previous screening (1980-1989, n=817) indicate that the prevalence of rabies in <span class="hlt">Svalbard</span> has remained low or that the virus has not been enzootic in the arctic fox population since the first reported outbreak in 1980. Brain tissues from four arctic foxes (one from <span class="hlt">Svalbard</span>, three from Russia) in which rabies virus antigen was detected were further analyzed by reverse-transcriptase polymerase chain reaction direct amplicon sequencing and phylogenetic analysis. Sequences were compared to corresponding sequences from rabies virus isolates from other arctic regions. The <span class="hlt">Svalbard</span> isolate and two of the Russian isolates were identical (310 nucleotides), whereas the third Russian isolate differed in six nucleotide positions. However, when translated into amino acid sequences, none of these substitutions produced changes in the amino acid sequence. These findings suggest that the spread of rabies virus to <span class="hlt">Svalbard</span> was likely due to migration of arctic foxes over sea <span class="hlt">ice</span> from Russia to <span class="hlt">Svalbard</span>. Furthermore, when compared to other Arctic rabies virus isolates, a high degree of homology was found, suggesting a high contact rate between arctic fox populations from different arctic regions. The high degree of homology also indicates that other, and more variable, regions of the genome than this part of the nucleoprotein gene should be used to distinguish Arctic rabies virus isolates for epidemiologic purposes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C53D0773K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C53D0773K"><span>Energy balance and runoff modelling of glaciers in the Kongsfjord basin in northwestern <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kohler, J.; Pramanik, A.; van Pelt, W.</p> <p>2016-12-01</p> <p>Glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> cover 36,000 Km2 or 60% of the land area of the <span class="hlt">Svalbard</span> archipelago. Roughly 60% of the glaciated area drains to the ocean through tidewater glacier fronts. Runoff from tidewater glaciers is posited to have a significant impact on fjord circulation and thereby on fjord ecosystems. Ocean circulation modelling underway in the Kongsfjord system requires specification of the freshwater amounts contributed by both tidewater and land-terminating glaciers in its basin. The total basin area of Kongsfjord is 1850 km2. We use a coupled surface energy-balance and firn model (Van Pelt et al. 2015) to calculate mass balance and runoff from the Kongsfjord glaciers for the period 1969-2015. Meteorological data from the nearby station at Ny-Ålesund is used for climate forcing in the model domain, with mass balance data at four glaciers in the Kongsfjord watershed used to calibrate model parameters. Precipitation and temperature lapse rates are adjusted on the study glaciers through repeated model runs at mass balance stake locations to match observed and modelled surface mass balance. Long-term discharge measurement at two sites in this region are used to validate the modelled runoff. Spatial and temporal evolution of melt, refreezing and runoff are analyzed, along with the vertical evolution of subsurface conditions. Reference: Van Pelt, W.J.J. & J. Kohler. 2015. Modelling the long-term mass balance and firn evolution of glaciers around Kongsfjorden, <span class="hlt">Svalbard</span>. J. Glaciol, 61(228), 731-744. Glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> cover 36,000 Km2 or 60% of the land area of the <span class="hlt">Svalbard</span> archipelago. Roughly 60% of the glaciated area drains to the ocean through tidewater glacier fronts. Runoff from tidewater glaciers is posited to have a significant impact on fjord circulation and thereby on fjord ecosystems. Ocean circulation modelling underway in the Kongsfjord system requires specification of the freshwater amounts contributed by both tidewater and land-terminating glaciers</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060044132&hterms=inclusion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dinclusion','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060044132&hterms=inclusion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dinclusion"><span>Science goals for a Mars Polar <span class="hlt">Cap</span> subsurface mission : optical approaches for investiagations of inclusions in <span class="hlt">ice</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mogensen, Claus T.; Carsey, Frank D.; Behar, Alberto; Engelhardt, Hermann; Lane, Arthur L.</p> <p>2002-01-01</p> <p>The Mars Polar <span class="hlt">Caps</span> are highly interesting features of Mars and have received much recent attention with new and exciting data on morphology, basal units, and layered outcroppings. We have examined the climatological, glaciological, and geological issues associated with a subsurface exploration of the Mars North Polar <span class="hlt">Cap</span> and have determined that a finescale optical examination of <span class="hlt">ice</span> in a borehole, to examine the stratigraphy, geochemistry and geochronology of the <span class="hlt">ice</span>, is feasible. This information will enable reconstruction of the development of the <span class="hlt">cap</span> as well as predication of the properties of its <span class="hlt">ice</span>. We present visible imagery taken of dust inclusions in archived Greenland <span class="hlt">ice</span> cores as well as in-situ images of accreted lithologic inclusions in West Antarctica, and we argue for use of this kind of data in Mars climate reconstruction as has been successful with Greenland and Antarctic <span class="hlt">ice</span> core anlaysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060044215&hterms=inclusion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dinclusion','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060044215&hterms=inclusion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dinclusion"><span>Science goals for a Mars Polar <span class="hlt">Cap</span> subsurface mission : optical approaches for investigations of inclusions in <span class="hlt">ice</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Carsey, Frank; Mogensen, Claus T.; Behar, Alberto; Engelhardt, Hermann; Lane, Arthur L.</p> <p>2002-01-01</p> <p>The Mars Polar <span class="hlt">Caps</span> are highly interesting features of Mars and have received much recent attention with new and exciting data on morphology, basal units, and layered outcroppings. We have examined the climatological, glaciological, and geological issues associated with a subsurface exploration of the Mars North Polar <span class="hlt">Cap</span> and have determined that a finescale optical examination of <span class="hlt">ice</span> in a borehole, to examine the stratigraphy, geochemistry and geochronology of the <span class="hlt">ice</span>, is feasible. This information will enable reconstruction of the development of the <span class="hlt">cap</span> as well as prediction of the properties of its <span class="hlt">ice</span>. We present visible imagery taken of dust inclusions in archived Greenland <span class="hlt">ice</span> cores as well as in-situ images of accreted lithologic inclusions in West Antarctica, and we argue for use of this kind of data in Mars climate reconstruction as has been successful with Greenland and Antarctic <span class="hlt">ice</span> core analysis. .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C34A..08G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C34A..08G"><span>Seasonal thickness changes of Arctic sea <span class="hlt">ice</span> north of <span class="hlt">Svalbard</span> and implications for satellite remote sensing, ecosystem, and environmental management</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gerland, S.; Rösel, A.; King, J.; Spreen, G.; Divine, D.; Eltoft, T.; Gallet, J. C.; Hudson, S. R.; Itkin, P.; Krumpen, T.; Liston, G. E.; Merkouriadi, I.; Negrel, J.; Nicolaus, M.; Polashenski, C.; Assmy, P.; Barber, D. G.; Duarte, P.; Doulgeris, A. P.; Haas, C.; Hughes, N.; Johansson, M.; Meier, W.; Perovich, D. K.; Provost, C.; Richter-Menge, J.; Skourup, H.; Wagner, P.; Wilkinson, J.; Granskog, M. A.; Steen, H.</p> <p>2016-12-01</p> <p>Sea-<span class="hlt">ice</span> thickness is a crucial parameter to consider when assessing the status of Arctic sea <span class="hlt">ice</span>, whether for environmental management, monitoring projects, or regional or pan-arctic assessments. Modern satellite remote sensing techniques allow us to monitor <span class="hlt">ice</span> extent and to estimate sea-<span class="hlt">ice</span> thickness changes; but accurate quantifications of sea-<span class="hlt">ice</span> thickness distribution rely on in situ and airborne surveys. From January to June 2015, an international expedition (N-<span class="hlt">ICE</span>2015) took place in the Arctic Ocean north of <span class="hlt">Svalbard</span>, with the Norwegian research vessel RV Lance frozen into drifting sea <span class="hlt">ice</span>. In total, four drifts, with four different floes were made during that time. Sea-<span class="hlt">ice</span> and snow thickness measurements were conducted on all main <span class="hlt">ice</span> types present in the region, first year <span class="hlt">ice</span>, multiyear <span class="hlt">ice</span>, and young <span class="hlt">ice</span>. Measurement methods included ground and helicopter based electromagnetic surveys, drillings, hot-wire installations, snow-sonde transects, snow stakes, and <span class="hlt">ice</span> mass balance and snow buoys. <span class="hlt">Ice</span> thickness distributions revealed modal thicknesses in spring between 1.6 and 1.7 m, which is lower than reported for the region from comparable studies in 2009 (2.4 m) and 2011 (1.8 m). Knowledge about the <span class="hlt">ice</span> thickness distribution in a region is crucial to the understanding of climate processes, and also relevant to other disciplines. Sea-<span class="hlt">ice</span> thickness data collected during N-<span class="hlt">ICE</span>2015 can also give us insights into how <span class="hlt">ice</span> and snow thicknesses affect ecosystem processes. In this presentation, we will explore the influence of snow cover and ocean properties on <span class="hlt">ice</span> thickness, and the role of sea-<span class="hlt">ice</span> thickness in air-<span class="hlt">ice</span>-ocean interactions. We will also demonstrate how information about <span class="hlt">ice</span> thickness aids classification of different sea <span class="hlt">ice</span> types from SAR satellite remote sensing, which has real-world applications for shipping and <span class="hlt">ice</span> forecasting, and how sea <span class="hlt">ice</span> thickness data contributes to climate assessments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70037436','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70037436"><span>Geochronology and paleoclimatic implications of the last deglaciation of the Mauna Kea <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Hawaii</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Anslow, Faron S.; Clark, P.U.; Kurz, M.D.; Hostetler, S.W.</p> <p>2010-01-01</p> <p>We present new 3He surface exposure ages on moraines and bedrock near the summit of Mauna Kea, Hawaii, which refine the age of the Mauna Kea <span class="hlt">Ice</span> <span class="hlt">Cap</span> during the Local Last Glacial Maximum (LLGM) and identify a subsequent fluctuation of the <span class="hlt">ice</span> margin. The 3He ages, when combined with those reported previously, indicate that the local <span class="hlt">ice-cap</span> margin began to retreat from its LLGM extent at 20.5??2.5ka, in agreement with the age of deglaciation determined from LLGM moraines elsewhere in the tropics. The <span class="hlt">ice-cap</span> margin receded to a position at least 3km upslope for ~4.5-5.0kyr before readvancing nearly to its LLGM extent. The timing of this readvance at ~15.4ka corresponds to a large reduction of the Atlantic meridional overturning circulation (AMOC) following Heinrich Event 1. Subsequent <span class="hlt">ice</span>-margin retreat began at 14.6??1.9ka, corresponding to a rapid resumption of the AMOC and onset of the B??lling warm interval, with the <span class="hlt">ice</span> <span class="hlt">cap</span> melting rapidly to complete deglaciation. Additional 3He ages obtained from a flood deposit date the catastrophic outburst of a moraine-dammed lake roughly coeval with the Younger Dryas cold interval, suggesting a more active hydrological cycle on Mauna Kea at this time. A coupled mass balance and <span class="hlt">ice</span> dynamics model is used to constrain the climate required to generate <span class="hlt">ice</span> <span class="hlt">caps</span> of LLGM and readvance sizes. The depression of the LLGM equilibrium line altitude requires atmospheric cooling of 4.5??1??C, whereas the mass balance modeling indicates an accompanying increase in precipitation of as much as three times that of present. We hypothesize (1) that the LLGM temperature depression was associated with global cooling, (2) that the temperature depression that contributed to the readvance occurred in response to an atmospheric teleconnection to the North Atlantic, and (3) that the precipitation enhancement associated with both events occurred in response to a southward shift in the position of the inter-tropical convergence zone (ITCZ). Such a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25992847','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25992847"><span>Crustal movements due to Iceland's shrinking <span class="hlt">ice</span> <span class="hlt">caps</span> mimic magma inflow signal at Katla volcano.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Spaans, Karsten; Hreinsdóttir, Sigrún; Hooper, Andrew; Ófeigsson, Benedikt Gunnar</p> <p>2015-05-20</p> <p>Many volcanic systems around the world are located beneath, or in close proximity to, <span class="hlt">ice</span> <span class="hlt">caps</span>. Mass change of these <span class="hlt">ice</span> <span class="hlt">caps</span> causes surface movements, which are typically neglected when interpreting surface deformation measurements around these volcanoes. These movements can however be significant, and may closely resemble movements due to magma accumulation. Here we show such an example, from Katla volcano, Iceland. Horizontal movements observed by GPS on the flank of Katla have led to the inference of significant inflow of magma into a chamber beneath the caldera, starting in 2000, and continuing over several years. We use satellite radar interferometry and GPS data to show that between 2001 and 2010, the horizontal movements seen on the flank can be explained by the response to the long term shrinking of <span class="hlt">ice</span> <span class="hlt">caps</span>, and that erratic movements seen at stations within the caldera are also not likely to signify magma inflow. It is important that interpretations of geodetic measurements at volcanoes in glaciated areas consider the effect of <span class="hlt">ice</span> mass change, and previous studies should be carefully reevaluated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C33C1211G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C33C1211G"><span>Is snow-<span class="hlt">ice</span> now a major contributor to sea <span class="hlt">ice</span> mass balance in the western Transpolar Drift region?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Graham, R. M.; Merkouriadi, I.; Cheng, B.; Rösel, A.; Granskog, M. A.</p> <p>2017-12-01</p> <p>During the Norwegian young sea <span class="hlt">ICE</span> (N-<span class="hlt">ICE</span>2015) campaign, which took place in the first half of 2015 north of <span class="hlt">Svalbard</span>, a deep winter snow pack (50 cm) on sea <span class="hlt">ice</span> was observed, that was 50% thicker than earlier climatological studies suggested for this region. Moreover, a significant fraction of snow contributed to the total <span class="hlt">ice</span> mass in second-year <span class="hlt">ice</span> (SYI) (9% on average). Interestingly, very little snow (3% snow by mass) was present in first-year <span class="hlt">ice</span> (FYI). The combination of sea <span class="hlt">ice</span> thinning and increased precipitation north of <span class="hlt">Svalbard</span> is expected to promote the formation of snow-<span class="hlt">ice</span>. Here we use the 1-D snow/<span class="hlt">ice</span> thermodynamic model HIGHTSI forced with reanalysis data, to show that for the case study of N-<span class="hlt">ICE</span>2015, snow-<span class="hlt">ice</span> would even form over SYI with an initial thickness of 2 m. In current conditions north of <span class="hlt">Svalbard</span>, snow-<span class="hlt">ice</span> is ubiquitous and contributes to the thickness growth up to 30%. This contribution is important, especially in the absence of any bottom thermodynamic growth due to the thick insulating snow cover. Growth of FYI north of <span class="hlt">Svalbard</span> is mainly controlled by the timing of growth onset relative to snow precipitation events and cold spells. These usually short-lived conditions are largely determined by the frequency of storms entering the Arctic from the Atlantic Ocean. In our case, a later freeze onset was favorable for FYI growth due to less snow accumulation in early autumn. This limited snow-<span class="hlt">ice</span> formation but promoted bottom thermodynamic growth. We surmise these findings are related to a regional phenomenon in the Atlantic sector of the Arctic, with frequent storm events which bring increasing amounts of precipitation in autumn and winter, and also affect the duration of cold temperatures required for <span class="hlt">ice</span> growth in winter. We discuss the implications for the importance of snow-<span class="hlt">ice</span> in the future Arctic, formerly believed to be non-existent in the central Arctic due to thick perennial <span class="hlt">ice</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JESS..127...57Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JESS..127...57Y"><span>Mid-to-late Holocene climate change record in palaeo-notch sediment from London Island, <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Zhongkang; Sun, Liguang; Zhou, Xin; Wang, Yuhong</p> <p>2018-06-01</p> <p>The Arctic region is very sensitive to climate change and important in the Earth's climate system. However, proxy datasets for Arctic climate are unevenly distributed and especially scarce for <span class="hlt">Svalbard</span> because glaciers during the Little <span class="hlt">Ice</span> Age, the most extensive in the Holocene, destroyed large quantities of sediment records in <span class="hlt">Svalbard</span>. Fortunately, palaeo-notch sediments could withstand glaciers and be well-preserved after deposition. In this study, we reconstructed a mid-to-late Holocene record of climate changes in a palaeo-notch sediment sequence from London Island. Multiple weathering indices were determined, they all showed consistent weathering conditions in the study area, and they were closely linked to climate changes. Total organic carbon (TOC) and total nitrogen (TN) were also determined, and their variation profiles were similar to those of weathering indices. The climate change record in our sediment sequence is consistent with <span class="hlt">ice</span> rafting record from North Atlantic and glacier activity from Greenland, Iceland and <span class="hlt">Svalbard</span>, and four cold periods are clearly present. Our study provides a relatively long-term climate change record for climate conditions from mid-to-late Holocene in <span class="hlt">Svalbard</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMPP33B1564B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMPP33B1564B"><span>Diatoms as Proxies for a Fluctuating <span class="hlt">Ice</span> <span class="hlt">Cap</span> Margin, Hvitarvatn, Iceland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Black, J. L.; Miller, G. H.; Geirsdottir, A.</p> <p>2005-12-01</p> <p>There are no complete records of terrestrial environmental change for the Holocene (11,000yrs) in Iceland and the status of Icelandic glaciers in the early Holocene remains unclear. It is not even known whether Iceland's large <span class="hlt">ice</span> <span class="hlt">caps</span> disappeared in the early Holocene, and if they did, when they re-grew. Icelandic lakes are particularly well suited to address these uncertainties as: 1) Glacial erosion and soft bedrock result in high lacustrine sedimentation rates, 2) Diagnostic tephras aid the geochronology, 3) Iceland's sensitivity to changes in North Atlantic circulation should produce clear signals in key environmental proxies (diatoms) preserved in lacustrine sequences, and 4) <span class="hlt">Ice-cap</span> profiles are relatively flat so small changes in the equilibrium line altitude result in large changes in accumulation area. Hence, large changes in <span class="hlt">ice</span>-sheet margins during the Holocene will impact sedimentation in glacier-dominated lakes and the diatom assemblages at those times. Hvitarvatn is a glacier dominated lake located on the eastern margin of Langjokull <span class="hlt">Ice</span> <span class="hlt">Cap</span> in central-western Iceland. The uppermost Hvitarvatn sediments reflect a glacially dominated system with planktonic, silica-demanding diatom taxa that suggest a high dissolved silica and turbid water environment consistent with high fluxes of glacial flour. Below this are Neoglacial sediments deposited when Langjokull was active, but outlet glaciers were not in contact with Hvitarvatn. The diatom assemblage here shows a small increase in abundance, but is still dominated by planktic, silica-demanding taxa. A distinct shift in lake conditions is reflected in the lowermost sediments, composed of predominantly benthic diatoms and deposited in clear water conditions with long growing seasons likely found in an environment with warmer summers than present and with no glacial erosion. Langjokull must have disappeared in the early Holocene for such a diverse, benthic dominated diatom assemblage to flourish.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.2635A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.2635A"><span>Modelled non-linear response to climate of Hardangerjøkulen <span class="hlt">ice</span> <span class="hlt">cap</span>, southern Norway, since the mid-Holocene</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Åkesson, Henning; Nisancioglu, Kerim H.; Giesen, Rianne H.; Morlighem, Mathieu</p> <p>2016-04-01</p> <p>Glacier and <span class="hlt">ice</span> <span class="hlt">cap</span> volume changes currently amount to half of the total cryospheric contribution to sea-level rise and are projected to remain substantial throughout the 21st century. To simulate glacier behavior on centennial and longer time scales, models rely on simplified dynamics and tunable parameters for processes not well understood. Model calibration is often done using present-day observations, even though the relationship between parameters and parametrized processes may be altered for significantly different glacier states. In this study, we simulate the Hardangerjøkulen <span class="hlt">ice</span> <span class="hlt">cap</span> in southern Norway since the mid-Holocene, through the Little <span class="hlt">Ice</span> Age (LIA) and into the future. We run an ensemble for both calibration and transient experiments, using a two-dimensional <span class="hlt">ice</span> flow model with mesh refinement. For the Holocene, we apply a simple mass balance forcing based on climate reconstructions. For the LIA until 1962, we use geomorphological evidence and measured outlet glacier positions to find a mass balance history, while we use direct mass balance measurements from 1963 until today. Given a linear climate forcing, we show that Hardangerøkulen grew from <span class="hlt">ice</span>-free conditions in the mid-Holocene, to its maximum LIA extent in a highly non-linear fashion. We relate this to local bed topography and demonstrate that volume and area of some but not all outlet glaciers, as well as the entire <span class="hlt">ice</span> <span class="hlt">cap</span>, become decoupled for several centuries during our simulation of the late Holocene, before co-varying approaching the LIA. Our model is able to simulate most recorded <span class="hlt">ice</span> <span class="hlt">cap</span> and outlet glacier changes from the LIA until today. We show that present-day Hardangerøkulen is highly sensitive to mass balance changes, and estimate that the <span class="hlt">ice</span> <span class="hlt">cap</span> will melt completely by the year 2100.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.U11B0019F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.U11B0019F"><span>Effects of deliquescent salts in soils of polar Mars on the flow of the Northern <span class="hlt">Ice</span> <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fisher, D. A.; Hecht, M. H.; Kounaves, S.; Catling, D.</p> <p>2008-12-01</p> <p>The discovery of substantial amounts of magnesium and perchlorate by Phoenix' "Wet Chemistry Lab" (WCL) in the soil of Polar Mars suggests that magnesium perchlorate could be the dominant salt in the polar region's soils. This prospect opens some unexpected doors for moving liquid water around at temperatures as low as -68C. In its fully hydrated form ,this salt water mixture has a high density (~ 1700 kgm /cubic meter) (Besley and Bottomley,1969) and a freezing point of -68C (Pestova et al., 2005).This perchlorate is very deliquescent and gives off heat as it melts <span class="hlt">ice</span>. About 1.8 gram of <span class="hlt">ice</span> can be 'melted' by 1 gm of pure magnesium perchlorate . If the reported 1 percent perchlorate is typical of polar soils and if 5 percent of the Northern Permanent <span class="hlt">Ice</span> <span class="hlt">Cap</span> is soil then the perchorate , makes up about 0.0005 the of the <span class="hlt">ice</span> <span class="hlt">cap</span>. Given the average thickness of the <span class="hlt">ice</span> <span class="hlt">cap</span> is about 2000 meters,this suggests there enough perchorate in the <span class="hlt">ice</span> <span class="hlt">cap</span> to generate about 2m of salty water at the bed. Because of its density the perclorate salty water would pool over impervious layers and make the bed into a perchorate sludge that could be mobilized and deformed by the overburden of <span class="hlt">ice</span>. The deformation of mobile beds is a well known phenomenon on some terrestrial glaciers presently and was thought to have played a major role during the Wisconsinan <span class="hlt">ice</span> age (Fisher et al., 1985) . The perchorate sludge would be deformed and moved outwards possibly resulting its re-introduction to the polar environment. Having a deliquescent salt sludge at the bed whose melting point is -68C would mean that the <span class="hlt">ice</span> <span class="hlt">cap</span> could slide on its deformable bed while the <span class="hlt">ice</span> itself was still very cold and stiff . This possibility has been modeled with a 2D time varying model . Adding the deformable bed material allows <span class="hlt">ice</span> <span class="hlt">cap</span> motion even at <span class="hlt">ice</span> temperatures cold enough to generate and preserve the scarp/trough features. When the perchlorate formation mechanisms and rates are known the ultimate</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1710967V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1710967V"><span>Extending permanent volcano monitoring networks into Iceland's <span class="hlt">ice</span> <span class="hlt">caps</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vogfjörd, Kristín S.; Bergsson, Bergur H.; Kjartansson, Vilhjálmur; Jónsson, Thorsteinn; Ófeigsson, Benedikt G.; Roberts, Matthew J.; Jóhannesson, Tómas; Pálsson, Finnur; Magnússon, Eyjólfur; Erlendsson, Pálmi; Ingvarsson, Thorgils; Pálssson, Sighvatur K.</p> <p>2015-04-01</p> <p>The goals of the FUTUREVOLC project are the establishment of a volcano Supersite in Iceland to enable access to volcanological data from the country's many volcanoes and the development of a multiparametric volcano monitoring and early warning system. However, the location of some of Iceland's most active volcanoes inside the country's largest <span class="hlt">ice</span> <span class="hlt">cap</span>, Vatnajökull, makes these goals difficult to achieve as it hinders access and proper monitoring of seismic and deformation signals from the volcanoes. To overcome these obstacles, one of the developments in the project involves experimenting with extending the permanent real-time networks into the <span class="hlt">ice</span> <span class="hlt">cap</span>, including installation of stations in the glacier <span class="hlt">ice</span>. At the onset of the project, only one permanent seismic and GPS site existed within Vatnajökull, on the caldera rim of the Grímsvötn volcano. Two years into the project both seismic and GPS stations have been successfully installed and operated inside the glacier; on rock outcrops as well as on the glacier surface. The specific problems to overcome are (i) harsh weather conditions requiring sturdy and resilient equipment and site installations, (ii) darkness during winter months shutting down power generation for several weeks, (iii) high snow accumulation burying the instruments, solar panels and communication and GPS antennae, and in some locations (iv) extreme <span class="hlt">icing</span> conditions blocking transmission signals and connection to GPS satellites, as well as excluding the possibility of power generation by wind generators. In 2013, two permanent seismic stations and one GPS station were installed on rock outcrops within the <span class="hlt">ice</span> <span class="hlt">cap</span> in locations with 3G connections and powered by solar panels and enough battery storage to sustain operation during the darkest winter months. These sites have successfully operated for over a year with mostly regular maintenance requirements, transmitting data in real-time to IMO for analysis. Preparations for two permanent seismic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018QSRv..190...39A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018QSRv..190...39A"><span>Holocene glacier and climate variations in Vestfirðir, Iceland, from the modeling of Drangajökull <span class="hlt">ice</span> <span class="hlt">cap</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anderson, Leif S.; Flowers, Gwenn E.; Jarosch, Alexander H.; Aðalgeirsdóttir, Guðfinna Th; Geirsdóttir, Áslaug; Miller, Gifford H.; Harning, David J.; Thorsteinsson, Thorsteinn; Magnússon, Eyjólfur; Pálsson, Finnur</p> <p>2018-06-01</p> <p>Drangajökull is a maritime <span class="hlt">ice</span> <span class="hlt">cap</span> located in northwest (Vestfirðir) Iceland. Drangajökull's evolution is therefore closely linked to atmospheric and ocean variability. In order to better constrain the Holocene climate and glacier history of Vestfirðir we model the past evolution of Drangajökull <span class="hlt">ice</span> <span class="hlt">cap</span>. Simulations from 10 ka to present are forced by general circulation model output, <span class="hlt">ice</span>-core-based temperature reconstructions, and sea-surface temperature reconstructions. Based on these 10-thousand year simulations, Drangajökull did not persist through the Holocene. We estimate that air temperatures were 2.5-3.0 °C higher during the Holocene Thermal Maximum than the local 1960-1990 average. Simulations support Drangajökull's late Holocene inception between 2 and 1 ka, though intermittent <span class="hlt">ice</span> likely occupied cirques as early as 2.6 ka. Drangajökull is primarily a Little <span class="hlt">Ice</span> Age <span class="hlt">ice</span> <span class="hlt">cap</span>: it expanded between 1300 and 1750 CE, with the most rapid growth occurring between 1600 and 1750 CE. The maximum Holocene extent of Drangajökull occurred between 1700 and 1925 CE, despite the lowest late Holocene temperatures, occurring between 1650 and 1720 CE. Between 1700 and 1925 CE temperatures were likely 0.6-0.8 °C lower than the 1950-2015 reference temperature. The modern equilibrium line altitude (ELA) is bracketed by topographic thresholds: a 1 °C temperature increase from the modern ELA would eliminate the <span class="hlt">ice</span> <span class="hlt">cap</span>'s accumulation area, while a reduction of 0.5 °C would lead to the rapid expansion of the <span class="hlt">ice</span> <span class="hlt">cap</span> across Vestfirðir. The proximity of Drangajökull to topographic thresholds may explain its late inception and rapid expansion during the Little <span class="hlt">Ice</span> Age.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70125319','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70125319"><span>Evaluation of remote-sensing techniques to measure decadal-scale changes of Hofsjokull <span class="hlt">ice</span> <span class="hlt">cap</span>, Iceland</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hall, D.K.; Williams, R.S.; Barton, J.S.; Sigurdsson, O.; Smith, L.C.; Garvin, J.B.</p> <p>2000-01-01</p> <p>Dynamic surficial changes and changes in the position of the firn line and the areal extent of Hofsjökull <span class="hlt">ice</span> <span class="hlt">cap</span>, Iceland, were studied through analysis of a time series (1973–98) of synthetic-aperture radar (SAR) and Landsat data. A digital elevation model of Hofsjökull, which was constructed using SAR interferometry, was used to plot the SAR backscatter coefficient (σ°) vs elevation and air temperature along transects across the <span class="hlt">ice</span> <span class="hlt">cap</span>. Seasonal and daily σ° patterns are caused by freezing or thawing of the <span class="hlt">ice-cap</span> surface, and abrupt changes in σ° are noted when the air temperature ranges from ∼−5° to 0°C. Late-summer 1997 σ° (SAR) and reflectance (Landsat) boundaries agree and appear to be coincident with the firn line and a SAR σ° boundary that can be seen in the January 1998 SAR image. In January 1994 through 1998, the elevation of this σ° boundary on the <span class="hlt">ice</span> capwas quite stable, ranging from 1000 to 1300 m, while the equilibrium-line altitude, as measured on the ground, varied considerably. Thus the equilibrium line may be obscured by firn from previous years. Techniques are established to measure long-term changes in the elevation of the firn line and changes in the position of the <span class="hlt">ice</span> margin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www2.ametsoc.org/ams/index.cfm/publications/bulletin-of-the-american-meteorological-society-bams/state-of-the-climate/','USGSPUBS'); return false;" href="https://www2.ametsoc.org/ams/index.cfm/publications/bulletin-of-the-american-meteorological-society-bams/state-of-the-climate/"><span>Glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> outside Greenland</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sharp, Marin; Wolken, G.; Burgess, D.; Cogley, J.G.; Copland, L.; Thomson, L.; Arendt, A.; Wouters, B.; Kohler, J.; Andreassen, L.M.; O'Neel, Shad; Pelto, M.</p> <p>2015-01-01</p> <p>Mountain glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> cover an area of over 400 000 km2 in the Arctic, and are a major influence on global sea level (Gardner et al. 2011, 2013; Jacob et al. 2012). They gain mass by snow accumulation and lose mass by meltwater runoff. Where they terminate in water (ocean or lake), they also lose mass by iceberg calving. The climatic mass balance (Bclim, the difference between annual snow accumulation and annual meltwater runoff) is a widely used index of how glaciers respond to climate variability and change. The total mass balance (ΔM) is defined as the difference between annual snow accumulation and annual mass losses (by iceberg calving plus runoff).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001DPS....33.1915T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001DPS....33.1915T"><span>IR spectral properties of dust and <span class="hlt">ice</span> at the Mars south polar <span class="hlt">cap</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Titus, T. N.; Kieffer, H. H.</p> <p>2001-11-01</p> <p>Removal of atmospheric dust effects is required to derive surface IR spectral emissivity. Commonly, the atmospheric-surface separation is based on radiative transfer (RT) spectral inversion methods using nadir-pointing observations. This methodology depends on a priori knowledge of the spectral shape of each atmospheric aerosol (e.g. dust or water <span class="hlt">ice</span>) and a large thermal contrast between the surface and atmosphere. RT methods fail over the polar <span class="hlt">caps</span> due to low thermal contrast between the atmosphere and the surface. We have used multi-angle Emission Phase Function (EPF) observations to estimate the opacity spectrum of dust over the springtime south polar <span class="hlt">cap</span> and the underlying surface radiance, and thus, the surface emissivity. We include a few EPFs from Hellas Basin as a basis for comparisons between the spectral shape of polar and non-polar dust. Surface spectral emissivities over the seasonal <span class="hlt">cap</span> are compared to CO2 models. Our results show that the spectral shape of the polar dust opacity is not constant, but is a two-parameter family that can be characterized by the 9 um and 20 um opacities. The 9 um opacity varies from 0.15 to 0.45 and characterizes the overall atmospheric conditions. The 9 um to 20 um opacity ratio varies from 2.0 to 5.1, suggesting changes in dust size distribution over the polar <span class="hlt">caps</span>. Derived surface temperatures from the EPFs confirm that the slightly elevated temperatures (relative to CO2 frost temperature) observed in ``cryptic'' regions are a surface effect, not atmospheric. Comparison of broad-band reflectivity and surface emissivities to model spectra suggest the bright regions (e.g. perennial <span class="hlt">cap</span>, Mountains of Mitchell) have higher albedos due to a thin surface layer of fine-grain CO2 (perhaps either frost or fractured <span class="hlt">ice</span>) with an underlying layer of either coarse grain or slab CO2 <span class="hlt">ice</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMPP33B1277K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMPP33B1277K"><span>A Chronology of Late-Glacial and Holocene Advances of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Peru, Based on 10Be and Radiocarbon Dating</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelly, M. A.; Lowell, T. V.; Schaefer, J. M.</p> <p>2007-12-01</p> <p>The Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> region in the southeastern Peruvian Andes (~13-14°S latitude) is a key location for the development of late-glacial and Holocene terrestrial paleoclimate records in the tropics. We present a chronology of past extents of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> based on ~thirty internally consistent 10Be dates of boulders on moraines and bedrock as well as twenty radiocarbon dates of organic material associated with moraines. Based on results from both dating methods, we suggest that significant advances of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> occurred during late-glacial time, at ~12,700-11,400 yr BP, and during Late Holocene time ~400-300 yr BP. Radiocarbon dating of organic material associated with moraines provides maximum and minimum ages for <span class="hlt">ice</span> advances and recessions, respectively, thus providing an independent check on 10Be dates of boulders on moraines. The opportunity to use both 10Be and radiocarbon dating makes the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> region a potentially important low-latitude calibration site for production rates of cosmogenic nuclides. Our radiocarbon chronology provides a tighter constraint on maximum ages of late-glacial and Late Holocene <span class="hlt">ice</span> advances. Upcoming field research will obtain organic material for radiocarbon dating to improve minimum age constrains for late-glacial and Late Holocene <span class="hlt">ice</span> recessions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160010510','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160010510"><span>The Effect of CO2 <span class="hlt">Ice</span> <span class="hlt">Cap</span> Sublimation on Mars Atmosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Batterson, Courtney</p> <p>2016-01-01</p> <p>Sublimation of the polar CO2 <span class="hlt">ice</span> <span class="hlt">caps</span> on Mars is an ongoing phenomenon that may be contributing to secular climate change on Mars. The transfer of CO2 between the surface and atmosphere via sublimation and deposition may alter atmospheric mass such that net atmospheric mass is increasing despite seasonal variations in CO2 transfer. My study builds on previous studies by Kahre and Haberle that analyze and compare data from the Phoenix and Viking Landers 1 and 2 to determine whether secular climate change is happening on Mars. In this project, I use two years worth of temperature, pressure, and elevation data from the MSL Curiosity rover to create a program that allows for successful comparison of Curiosity pressure data to Viking Lander pressure data so a conclusion can be drawn regarding whether CO2 <span class="hlt">ice</span> <span class="hlt">cap</span> sublimation is causing a net increase in atmospheric mass and is thus contributing to secular climate change on Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050169830','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050169830"><span>Tracking Retreat of the North Seasonal <span class="hlt">Ice</span> <span class="hlt">Cap</span> on Mars: Results from the THEMIS Investigation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ivanov, A. B.; Wagstaff, K. L.; Ttus, T. N.</p> <p>2005-01-01</p> <p>The CO2 <span class="hlt">ice</span> <span class="hlt">caps</span> on Mars advance and retreat with the seasons. This phenomenon was first observed by Cassini and then confirmed by numerous ground based observations in 19th and 20th centuries. With the advent of the space age observations of the seasonal <span class="hlt">ice</span> <span class="hlt">cap</span> were done by all orbiting spacecraft starting with Mariner 7. Viking Orbiters and more recently the Mars Global Surveyor (particularly Mars Orbiter Camera (MOC) and Thermal Emission Spectrometer (TES) instruments) have accumulated significant data on the retreat of the CO2 seasonal <span class="hlt">cap</span>. During Mars year 2 of THEMIS operations at Mars, we planned an observational campaign in which the THEMIS instrument (onboard the Mars Odyssey spacecraft) repeatedly observed the north seasonal polar <span class="hlt">cap</span> from midwinter to late spring. THEMIS allows simultaneous observations in both Thermal IR (12.57 m) and Visible wavelengths (0.65 m). One of the goals for this work is to initiate an interannual program for observations of the seasonal <span class="hlt">ice</span> <span class="hlt">caps</span> using the THEMIS instrument. The most efficient way to detect the edge between frost and bare ground is directly onboard of the spacecraft. Prior to onboard software design effort, we have developed two groundbased algorithms for automatically finding the edge of the seasonal polar <span class="hlt">cap</span> in THEMIS IR data. The first algorithm relies on fully calibrated data and can be used for highly reliable groundbased analyses. The second method was specifically developed for processing raw, uncalibrated data in a highly efficient way. It has the potential to enable automatic, onboard detections of the seasonal <span class="hlt">cap</span> retreat. We have experimentally confirmed that both methods produce similar results, and we have validated both methods against a model constructed from the MGS TES data from the same season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GGG....18.2099C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GGG....18.2099C"><span>Short-term variations of Icelandic <span class="hlt">ice</span> <span class="hlt">cap</span> mass inferred from cGPS coordinate time series</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Compton, Kathleen; Bennett, Richard A.; Hreinsdóttir, Sigrún; van Dam, Tonie; Bordoni, Andrea; Barletta, Valentina; Spada, Giorgio</p> <p>2017-06-01</p> <p>As the global climate changes, understanding short-term variations in water storage is increasingly important. Continuously operating Global Positioning System (cGPS) stations in Iceland record annual periodic motion—the elastic response to winter accumulation and spring melt seasons—with peak-to-peak vertical amplitudes over 20 mm for those sites in the Central Highlands. Here for the first time for Iceland, we demonstrate the utility of these cGPS-measured displacements for estimating seasonal and shorter-term <span class="hlt">ice</span> <span class="hlt">cap</span> mass changes. We calculate unit responses to each of the five largest <span class="hlt">ice</span> <span class="hlt">caps</span> in central Iceland at each of the 62 cGPS locations using an elastic half-space model and estimate <span class="hlt">ice</span> mass variations from the cGPS time series using a simple least squares inversion scheme. We utilize all three components of motion, taking advantage of the seasonal motion recorded in the horizontal. We remove secular velocities and accelerations and explore the impact that seasonal motions due to atmospheric, hydrologic, and nontidal ocean loading have on our inversion results. Our results match available summer and winter mass balance measurements well, and we reproduce the seasonal stake-based observations of loading and melting within the 1σ confidence bounds of the inversion. We identify nonperiodic <span class="hlt">ice</span> mass changes associated with interannual variability in precipitation and other processes such as increased melting due to reduced <span class="hlt">ice</span> surface albedo or decreased melting due to <span class="hlt">ice</span> <span class="hlt">cap</span> insulation in response to tephra deposition following volcanic eruptions, processes that are not resolved with once or twice-yearly stake measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Icar..282..118K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Icar..282..118K"><span>Experimental investigation of insolation-driven dust ejection from Mars' CO2 <span class="hlt">ice</span> <span class="hlt">caps</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaufmann, E.; Hagermann, A.</p> <p>2017-01-01</p> <p>Mars' polar <span class="hlt">caps</span> are - depending on hemisphere and season - partially or totally covered with CO2 <span class="hlt">ice</span>. Icy surfaces such as the polar <span class="hlt">caps</span> of Mars behave differently from surfaces covered with rock and soil when they are irradiated by solar light. The latter absorb and reflect incoming solar radiation within a thin layer beneath the surface. In contrast, <span class="hlt">ices</span> are partially transparent in the visible spectral range and opaque in the infrared. Due to this fact, the solar radiation can penetrate to a certain depth and raise the temperature of the <span class="hlt">ice</span> or dust below the surface. This may play an important role in the energy balance of icy surfaces in the solar system, as already noted in previous investigations. We investigated the temperature profiles inside CO2 <span class="hlt">ice</span> samples including a dust layer under Martian conditions. We have been able to trigger dust eruptions, but also demonstrated that these require a very narrow range of temperature and ambient pressure. We discuss possible implications for the understanding of phenomena such as arachneiform patterns or fan shaped deposits as observed in Mars' southern polar region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5468641','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5468641"><span>High Arctic Holocene temperature record from the Agassiz <span class="hlt">ice</span> <span class="hlt">cap</span> and Greenland <span class="hlt">ice</span> sheet evolution</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lecavalier, Benoit S.; Fisher, David A.; Milne, Glenn A.; Vinther, Bo M.; Tarasov, Lev; Lacelle, Denis; Main, Brittany; Zheng, James; Bourgeois, Jocelyne; Dyke, Arthur S.</p> <p>2017-01-01</p> <p>We present a revised and extended high Arctic air temperature reconstruction from a single proxy that spans the past ∼12,000 y (up to 2009 CE). Our reconstruction from the Agassiz <span class="hlt">ice</span> <span class="hlt">cap</span> (Ellesmere Island, Canada) indicates an earlier and warmer Holocene thermal maximum with early Holocene temperatures that are 4–5 °C warmer compared with a previous reconstruction, and regularly exceed contemporary values for a period of ∼3,000 y. Our results show that air temperatures in this region are now at their warmest in the past 6,800–7,800 y, and that the recent rate of temperature change is unprecedented over the entire Holocene. The warmer early Holocene inferred from the Agassiz <span class="hlt">ice</span> core leads to an estimated ∼1 km of <span class="hlt">ice</span> thinning in northwest Greenland during the early Holocene using the Camp Century <span class="hlt">ice</span> core. <span class="hlt">Ice</span> modeling results show that this large thinning is consistent with our air temperature reconstruction. The modeling results also demonstrate the broader significance of the enhanced warming, with a retreat of the northern <span class="hlt">ice</span> margin behind its present position in the mid Holocene and a ∼25% increase in total Greenland <span class="hlt">ice</span> sheet mass loss (∼1.4 m sea-level equivalent) during the last deglaciation, both of which have implications for interpreting geodetic measurements of land uplift and gravity changes in northern Greenland. PMID:28512225</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110013049','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110013049"><span>Tracking the Martian CO2 Polar <span class="hlt">Ice</span> <span class="hlt">Caps</span> in Infrared Images</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wagstaff, Kiri L.; Castano, Rebecca; Chien, Steve</p> <p>2006-01-01</p> <p>Researchers at NASA s Jet Propulsion Laboratory have developed a method for automatically tracking the polar <span class="hlt">caps</span> on Mars as they advance and recede each year (see figure). The seasonal Mars polar <span class="hlt">caps</span> are composed mainly of CO2 <span class="hlt">ice</span> and are therefore cold enough to stand out clearly in infrared data collected by the Thermal Emission Imaging System (THEMIS) onboard the Mars Odyssey spacecraft. The Bimodal Image Temperature (BIT) histogram analysis algorithm analyzes raw, uncalibrated data to identify images that contain both "cold" ("polar <span class="hlt">cap</span>") and "warm" ("not polar <span class="hlt">cap</span>") pixels. The algorithm dynamically identifies the temperature that separates these two regions. This flexibility is critical, because in the absence of any calibration, the threshold temperature can vary significantly from image to image. Using the identified threshold, the algorithm classifies each pixel in the image as "polar <span class="hlt">cap</span>" or "not polar <span class="hlt">cap</span>," then identifies the image row that contains the spatial transition from "polar <span class="hlt">cap</span>" to "not polar <span class="hlt">cap</span>." While this method is useful for analyzing data that has already been returned by THEMIS, it has even more significance with respect to data that has not yet been collected. Instead of seeking the polar <span class="hlt">cap</span> only in specific, targeted images, the simplicity and efficiency of this method makes it feasible for direct, onboard use. That is, THEMIS could continuously monitor its observations for any detections of the polar-<span class="hlt">cap</span> edge, producing detections over a wide range of spatial and temporal conditions. This effort can greatly contribute to our understanding of long-term climatic change on Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820037189&hterms=water+filters&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwater%2Bfilters','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820037189&hterms=water+filters&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwater%2Bfilters"><span>Mars residual north polar <span class="hlt">cap</span> - Earth-based spectroscopic confirmation of water <span class="hlt">ice</span> as a major constituent and evidence for hydrated minerals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Clark, R. N.; Mccord, T. B.</p> <p>1982-01-01</p> <p>A description is presented of new earth-based reflectance spectra of the Martian north residual polar <span class="hlt">cap</span>. The spectra indicate that the composition is at least mostly water <span class="hlt">ice</span> plus another component with a 'gray' reflectance. The other minerals in the <span class="hlt">ice</span> <span class="hlt">cap</span> appear to be hydrated. The data were obtained with a cooled circular variable filter spectrometer on February 20, 1978, using the 2.2-m telescope on Mauna Kea, Hawaii. It is pointed out that the identification of water <span class="hlt">ice</span> in the north polar <span class="hlt">cap</span> alone does not indicate that water makes up all or even most of the bulk of the <span class="hlt">cap</span>. Kieffer (1970) has shown that a small amount of water will mask the spectral features of CO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990025390','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990025390"><span>Mars Secular Obliquity Change Due to Water <span class="hlt">Ice</span> <span class="hlt">Caps</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rubincam, David P.</p> <p>1998-01-01</p> <p>Mars may have substantially changed its average axial tilt over geologic time due to the waxing and waning of water <span class="hlt">ice</span> <span class="hlt">caps</span>. Depending upon Mars' climate and internal structure, the average obliquity could have increased or decreased through climate friction by tens of degrees. A decrease could account for the apparent youthfulness of the polar layered terrain. Alternatively, Mars' average obliquity may have changed until it became "stuck" at its present value of 24.4 deg.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMPP31D1890S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMPP31D1890S"><span>Holocene fluctuations of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Peru based on lacustrine and surficial geologic archives</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stroup, J. S.; Kelly, M. A.; Lowell, T. V.; Beal, S. A.; Smith, C. A.</p> <p>2013-12-01</p> <p>Peru's Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> (QIC; 13.9°S, 70.8°W, ~5200-5670 m asl) is an important site for understanding tropical paleoclimate, mainly because of annually layered <span class="hlt">ice</span> cores that provide an ~1800 year long record of tropical paleoclimatic conditions (e.g., Thompson et al., 2013). Here, we present a detailed record of QIC fluctuations using surficial deposits and lake sediments that extend back to late glacial time. We compare the late Holocene records of QIC 10Be-dated moraines and <span class="hlt">ice</span> core data with lake sediments from a nearby glacially fed lake to establish the framework we use to interpret a Holocene long sediment record from a glacially fed lake. We also examine sediments from a nearby non-glacial lake to constrain non-glacial clastic input. We collected two ~5 m-long sediment cores, one from Laguna Challpacocha, which is currently fed by QIC meltwater, and one from the Laguna Yanacocha, which has not received QIC meltwater since ~12.3 ka. Changes in magnetic susceptibility, loss on ignition, bulk density and X-ray fluorescence chemistry combined with 14C and 210Pb chronologies provide information about sediment transported to the lakes. Retreat from the late Holocene extent defined by the 10Be-dated moraine record (~0.52 ka) is contemporaneous with a sharp transition from organic to clastic sedimentation in the Challpacocha core at ~ 0.52 ka. This implies that glacially-sourced clastic sedimentation, as tracked by loss on ignition, Ti counts and bulk density, increased during <span class="hlt">ice</span> <span class="hlt">cap</span> recession. Based on these same proxy data, we suggest the following Holocene history of QIC: QIC receded from the Challpacocha basin by ~10.6 ka. Increased clastic sedimentation at 8.2 - 4.1, 3.6 - 2.7 ka and from 0.55 ka - present are interpreted as times of <span class="hlt">ice</span> <span class="hlt">cap</span> recession. The increased clastic sedimentation at ~8.2 - 4.1 ka is consistent with surficial deposits near the present-day <span class="hlt">ice</span> margin that indicate that at ~7.0 - 4.6 ka QIC was smaller than at present (Buffen et al</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70026900','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70026900"><span>Reconciling different observations of the CO2 <span class="hlt">ice</span> mass loading of the Martian north polar <span class="hlt">cap</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Haberle, R.M.; Mattingly, B.; Titus, T.N.</p> <p>2004-01-01</p> <p>The GRS measurements of the peak mass loading of the north polar CO2 <span class="hlt">ice</span> <span class="hlt">cap</span> on Mars are about 60% lower than those calculated from MGS TES radiation data and those inferred from the MOLA <span class="hlt">cap</span> thicknesses. However, the GRS data provide the most accurate measurement of the mass loading. We show that the TES and MOLA data can be reconciled with the GRS data if (1) subsurface heat conduction and atmospheric heat transport are included in the TES mass budget calculations, and (2) the density of the polar deposits is ???600 kg m-3. The latter is much less than that expected for slab <span class="hlt">ice</span> (???1600 kg m-3) and suggests that processes unique to the north polar region are responsible for the low <span class="hlt">cap</span> density. Copyright 2004 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C33B0814L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C33B0814L"><span>High-Resolution Mapping of Sea <span class="hlt">Ice</span>, Icebergs and Growlers in Kongsfjorden, <span class="hlt">Svalbard</span>, using Ground Based Radar, Satellite, and UAV</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lauknes, T. R.; Rouyet, L.; Solbø, S. A.; Sivertsen, A.; Storvold, R.; Akbari, V.; Negrel, J.; Gerland, S.</p> <p>2016-12-01</p> <p>The dynamics of sea ­<span class="hlt">ice</span> has a well­ recognized role in the climate system and its extent and evolution is impacted by the global warming. In addition, calving of icebergs and growlers at the tidewater glacier fronts is a component of the mass loss in polar regions. Understanding of calving and <span class="hlt">ice</span> ­ocean interaction, in particular at tidewater glacier front remains elusive, and a problematic uncertainty in climate change projections. Studying the distribution, volumetry and motion of sea ­<span class="hlt">ice</span>, icebergs and growlers is thus essential to understand their interactions with the environment in order to be able to predict at short­term their drifts, e.g. to mitigate the risk for shipping, and at longer term the multiple relations with climate changes. Here, we present the results from an arctic fieldwork campaign conducted in Kongsfjorden, <span class="hlt">Svalbard</span> in April 2016, where we used different remote sensing instruments to observe dynamics of sea <span class="hlt">ice</span>, icebergs, and growlers. We used a terrestrial radar system, imaging the study area every second minute during the observation period. At the front of the Kronebreen glacier, calving events can be detected and the drift of the generated icebergs and growlers tracked with unprecedented spatial and temporal resolution. During the field campaign, we collected four Radarsat-2 quad-pol images, that will be used to classify the different types of sea <span class="hlt">ice</span>. In addition, we used small unmanned aircraft (UAS) instrumented with high resolution cameras capturing HD video and still pictures. This allows to map and measure the size of icebergs and <span class="hlt">ice</span> floes. Such information is essential to validate sensitivity and detection limits from the ground and satellite based measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20060013398','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20060013398"><span>Recent Changes in High-Latitude Glaciers, <span class="hlt">Ice</span> <span class="hlt">Caps</span>, and <span class="hlt">Ice</span> Sheets</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Abdalati, Waleed</p> <p>2006-01-01</p> <p>). While the expansion of the warming oceans is estimated to be about a third of recent sea level rise, (Miller and Douglas 2004) the greatest potential for significantly increasing sea level lies in the Greenland and Antarctic <span class="hlt">ice</span> sheets. For different reasons, each exhibits characteristics that suggest they are potentially unstable. In Antarctica, large portions of the <span class="hlt">ice</span> cover rest on a soft bed that lies below sea level, making it vulnerable to runaway retreat. The Greenland <span class="hlt">ice</span> sheet experiences considerable melt, which has the potential to rapidly accelerate the flow of <span class="hlt">ice</span> toward the sea. While smaller <span class="hlt">ice</span> masses, such as the Alaskan Glaciers and the Canadian <span class="hlt">ice</span> <span class="hlt">caps</span>, do not have anywhere near the same potential to impact sea level as the vast <span class="hlt">ice</span> sheets do, many are melting rapidly, posing a significant near-term threat.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMPP43D..05T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMPP43D..05T"><span>Tropical Glaciers in the Common Era: Papua, Indonesia, Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Peru and Kilimanjaro, Tanzania</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, L. G.; Mosley-Thompson, E. S.; Davis, M. E.</p> <p>2011-12-01</p> <p>High-resolution <span class="hlt">ice</span> core stratigraphic records of δ18O (temperature proxy) demonstrate that the current warming at high elevations in mid- to lower latitudes is unprecedented for at least the last two millennia, although at many sites the Early Holocene was much warmer than at present. Here we discuss the interaction of El Niño-Southern Oscillation (ENSO) variability and warming trends as recorded in <span class="hlt">ice</span> core records from high-altitude tropical glaciers and the implications of the warming trends for the future of these glaciers. ENSO has strong impacts on meteorological phenomena that either directly or indirectly affect most regions on the planet and their populations, particularly throughout the Tropics. Here we examine similarities and differences among <span class="hlt">ice</span> core records from Papua (Indonesia), Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> (Peru) and Kilimanjaro (Tanzania). Quelccaya, Earth's largest tropical <span class="hlt">ice</span> <span class="hlt">cap</span>, has provided continuous, annually-resolved proxy records of climatic and environmental variability preserved in many measurable parameters, especially oxygen and hydrogen isotopic ratios (δ18O, δD) and the net mass balance (accumulation) spanning the last 1800 years. The remarkable similarity between changes in the highland and coastal cultures of Peru and climate variability in the Andes, especially with regard to precipitation, implies a strong connection between prehistoric human activities and climate in this region. The well-documented <span class="hlt">ice</span> loss on Quelccaya, Kilimanjaro in eastern Africa and the <span class="hlt">ice</span> fields near Puncak Jaya in Papua, Indonesia presents a possible analog for glacier response in the tropics during the Holocene. The ongoing melting of these <span class="hlt">ice</span> fields is consistent with model predictions of a vertical amplification of temperature in the Tropics. A sequence of over 50 recently exposed, rooted, soft-bodied plant deposits collected between 2002 and 2011 from the retreating margins of the Quelccaya <span class="hlt">ice</span> <span class="hlt">cap</span> provide a longer term perspective for the recent</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JMS...129..452L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JMS...129..452L"><span>The importance of tidewater glaciers for marine mammals and seabirds in <span class="hlt">Svalbard</span>, Norway</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lydersen, Christian; Assmy, Philipp; Falk-Petersen, Stig; Kohler, Jack; Kovacs, Kit M.; Reigstad, Marit; Steen, Harald; Strøm, Hallvard; Sundfjord, Arild; Varpe, Øystein; Walczowski, Waldek; Weslawski, Jan Marcin; Zajaczkowski, Marek</p> <p>2014-01-01</p> <p>Approximately 60% of <span class="hlt">Svalbard</span>'s land areas are glaciated at the present time. The Archipelago has more than 1100 glaciers (> 1 km2) and 163 of these are “tidewater glaciers” - that is glaciers that terminate (with their calving front) at the sea. It has been known for a long time that these glacier front areas are important feeding areas for seabirds and marine mammals. Herein, we review current knowledge regarding the importance of these areas for these animals and reflect upon the processes that create these apparent “hotspots”. Kittiwakes Rissa tridactyla, routinely dominate avian assemblages in front of glaciers in <span class="hlt">Svalbard</span>, but fulmars Fulmarus glacialis, ivory gulls Pagophila eburnea and glaucous gulls Larus hyperboreus also contribute to aggregations, which can sometimes comprise many thousands of individuals. The birds are often found in the so-called “brown zone”, which is an area in front of tidewater glaciers that is <span class="hlt">ice</span>-free due to currents and muddy due to suspended sediments. Animals at these sites typically have their stomachs full of large zooplankton or fish. These brown zones are also foraging hotspots for <span class="hlt">Svalbard</span>'s ringed seals (Pusa hispida) and white whales (Delphinapterus leucas). Prime breeding habitat for ringed seals in <span class="hlt">Svalbard</span> occurs deep in the fjords where <span class="hlt">ice</span> pieces calved from the glacier fronts become frozen into land-fast sea-<span class="hlt">ice</span>, promoting the accumulation of snow to a depth suitable for ringed seal females to dig out birth lairs above breathing holes in the <span class="hlt">ice</span>. These pupping areas are important hunting areas for polar bears (Ursus maritimus) in spring, especially female bears with cubs of the year during the period following emergence from the winter/birthing den. Glacier-<span class="hlt">ice</span> pieces floating in coastal areas are also important for all seal species in the region as dry platforms during moulting and also as general resting platforms for both birds and seals. During the last decade there have been several years with a</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002QuRes..57..287M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002QuRes..57..287M"><span>Rates of Deglaciation during the Last Glaciation and Holocene in the Cordillera Vilcanota-Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> Region, Southeastern Perú</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mark, Bryan G.; Seltzer, Geoffrey O.; Rodbell, Donald T.; Goodman, Adam Y.</p> <p>2002-05-01</p> <p>Moraine chronology is combined with digital topography to model deglacial rates of paleoglacier volumes in both the Huancané Valley on the west side of the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> and the Upismayo Valley on the northwest side of the Cordillera Vilcanota. The fastest rates of deglaciation (39×10 -5 to 114×10 -5 km 3 yr -1 and 112×10 -5 to 247×10 -5 km 3 yr -1 for each valley, respectively) were calculated for the most recent paleoglaciers, corresponding to the last few centuries. These results are consistent with observations in the Venezuelan Andes showing high rates of deglaciation since the Little <span class="hlt">Ice</span> Age. These rates also fall within the range of 20th century rates of deglaciation measured on the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> (29×10 -5 to 220×10 -5 km 3 yr -1, Brecher and Thompson, 1993; Thompson, 2000). These results imply that rates of deglaciation may fluctuate significantly over time and that high rates of deglaciation may not be exclusive to the late 20th century. Equilibrium line altitude (ELA) depressions for the <span class="hlt">ice</span> volumes of the last glaciation modeled here were computed as 230 m for the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> and 170 m for the Cordillera Vilcanota. Maximum ELA depressions are lower than previously published: <500 m for the Cordillera Vilcanota and <400 m for the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>. These lower values could imply a topographic control over paleoglacier extent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRC..122.4569M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRC..122.4569M"><span>Mixing rates and vertical heat fluxes north of <span class="hlt">Svalbard</span> from Arctic winter to spring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meyer, Amelie; Fer, Ilker; Sundfjord, Arild; Peterson, Algot K.</p> <p>2017-06-01</p> <p>Mixing and heat flux rates collected in the Eurasian Basin north of <span class="hlt">Svalbard</span> during the N-<span class="hlt">ICE</span>2015 drift expedition are presented. The observations cover the deep Nansen Basin, the <span class="hlt">Svalbard</span> continental slope, and the shallow Yermak Plateau from winter to summer. Mean quiescent winter heat flux values in the Nansen Basin are 2 W m-2 at the <span class="hlt">ice</span>-ocean interface, 3 W m-2 in the pycnocline, and 1 W m-2 below the pycnocline. Large heat fluxes exceeding 300 W m-2 are observed in the late spring close to the surface over the Yermak Plateau. The data consisting of 588 microstructure profiles and 50 days of high-resolution under-<span class="hlt">ice</span> turbulence measurements are used to quantify the impact of several forcing factors on turbulent dissipation and heat flux rates. Wind forcing increases turbulent dissipation seven times in the upper 50 m, and doubles heat fluxes at the <span class="hlt">ice</span>-ocean interface. The presence of warm Atlantic Water close to the surface increases the temperature gradient in the water column, leading to enhanced heat flux rates within the pycnocline. Steep topography consistently enhances dissipation rates by a factor of four and episodically increases heat flux at depth. It is, however, the combination of storms and shallow Atlantic Water that leads to the highest heat flux rates observed: <span class="hlt">ice</span>-ocean interface heat fluxes average 100 W m-2 during peak events and are associated with rapid basal sea <span class="hlt">ice</span> melt, reaching 25 cm/d.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010QSRv...29.1301J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010QSRv...29.1301J"><span>A new Late Weichselian and Holocene marine chronology for the western <span class="hlt">Svalbard</span> slope 30,000-0 cal years BP</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jessen, Simon P.; Rasmussen, Tine L.; Nielsen, Tove; Solheim, Anders</p> <p>2010-05-01</p> <p>Data have been compiled from eleven sediment cores from 76° to 80°N on the western <span class="hlt">Svalbard</span> slope. The cores are from water depths between 630 and 1880 m and show clear similarities in lithology and magnetic susceptibility. All cores penetrated into mass transported sediments from glacigenic debris flow events and turbidity flow events. The mass transport probably occurred when the <span class="hlt">ice</span> reached the shelf edge. The deposits date between 24,080 ± 150 and 23,550 ± 185 calibrated (cal) years BP. The records also include laminated, fine grained sediments interpreted as deposits from sediment-laden meltwater plumes dated between 14,780 ± 220 and 14,300 ± 260 cal years BP. In Holocene sediments a diatom-rich fine grained layer dates 10,100 ± 150 to 9840 ± 200 cal years BP. The eleven cores have been stacked into one record with absolute age control from 35 AMS 14C dates. Together with oxygen isotope stratigraphy and contents of <span class="hlt">ice</span> rafted detritus the stacked record provides a useful chronology tool for cores on the western <span class="hlt">Svalbard</span> slope. Our study improves the age control of earlier well documented glacial events and shows that the maximum glacial state and the onset of the deglaciation both occurred 2500-3000 years earlier than previously reconstructed for the western <span class="hlt">Svalbard</span> margin. The results indicate that during the last 30,000 years advance and retreat of the <span class="hlt">Svalbard</span>-Barents Sea <span class="hlt">Ice</span> Sheet was closely linked to the flow of Atlantic Water and Polar Water over the margin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27250039','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27250039"><span>Climate change impacts on wildlife in a High Arctic archipelago - <span class="hlt">Svalbard</span>, Norway.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Descamps, Sébastien; Aars, Jon; Fuglei, Eva; Kovacs, Kit M; Lydersen, Christian; Pavlova, Olga; Pedersen, Åshild Ø; Ravolainen, Virve; Strøm, Hallvard</p> <p>2017-02-01</p> <p>The Arctic is warming more rapidly than other region on the planet, and the northern Barents Sea, including the <span class="hlt">Svalbard</span> Archipelago, is experiencing the fastest temperature increases within the circumpolar Arctic, along with the highest rate of sea <span class="hlt">ice</span> loss. These physical changes are affecting a broad array of resident Arctic organisms as well as some migrants that occupy the region seasonally. Herein, evidence of climate change impacts on terrestrial and marine wildlife in <span class="hlt">Svalbard</span> is reviewed, with a focus on bird and mammal species. In the terrestrial ecosystem, increased winter air temperatures and concomitant increases in the frequency of 'rain-on-snow' events are one of the most important facets of climate change with respect to impacts on flora and fauna. Winter rain creates <span class="hlt">ice</span> that blocks access to food for herbivores and synchronizes the population dynamics of the herbivore-predator guild. In the marine ecosystem, increases in sea temperature and reductions in sea <span class="hlt">ice</span> are influencing the entire food web. These changes are affecting the foraging and breeding ecology of most marine birds and mammals and are associated with an increase in abundance of several temperate fish, seabird and marine mammal species. Our review indicates that even though a few species are benefiting from a warming climate, most Arctic endemic species in <span class="hlt">Svalbard</span> are experiencing negative consequences induced by the warming environment. Our review emphasizes the tight relationships between the marine and terrestrial ecosystems in this High Arctic archipelago. Detecting changes in trophic relationships within and between these ecosystems requires long-term (multidecadal) demographic, population- and ecosystem-based monitoring, the results of which are necessary to set appropriate conservation priorities in relation to climate warming. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.1579W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.1579W"><span>Early 21st-Century Mass loss of the North-Atlantic Glaciers and <span class="hlt">Ice</span> <span class="hlt">Caps</span> (Arne Richter Award for Outstanding Young Scientists Lecture)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wouters, Bert; Ligtenberg, Stefan; Moholdt, Geir; Gardner, Alex S.; Noel, Brice; Kuipers Munneke, Peter; van den Broeke, Michiel; Bamber, Jonathan L.</p> <p>2016-04-01</p> <p>Historically, <span class="hlt">ice</span> loss from mountain glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> has been one of the largest contributors to sea level rise over the last century. Of particular interest are the glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> in the North-Atlantic region of the Arctic. Despite the cold climate in this area, considerable melting and runoff occurs in summer. A small increase in temperature will have an immediate effect on these processes, so that a large change in the Arctic <span class="hlt">ice</span> volume can be expected in response to the anticipated climate change in the coming century. Unfortunately, direct observations of glaciers are sparse and are biased toward glaciers systems in accessible, mostly maritime, climate conditions. Remote sensing is therefore essential to monitor the state of the the North-Atlantic glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span>. In this presentation, we will discuss the progress that has been made in estimating the <span class="hlt">ice</span> mass balance of these regions, with a particular focus on measurements made by ESA's Cryosat-2 radar altimeter mission (2010-present). Compared to earlier altimeter mission, Cryosat-2 provides unprecedented coverage of the cryosphere, with a resolution down to 1 km or better and sampling at monthly intervals. Combining the Cryosat-2 measurements with the laser altimetry data from ICESat (2003-2009) gives us a 12 yr time series of glacial mass loss in the North Atlantic. We find excellent agreement between the altimetry measurements and independent observations by the GRACE mission, which directly 'weighs' the <span class="hlt">ice</span> <span class="hlt">caps</span>, albeit at a much lower resolution. Mass loss in the region has increased from 120 Gigatonnes per year in 2003-2009 to roughly 140 Gt/yr in 2010-2014, with an important contribution from Greenland's peripheral glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span>. Importantly, the mass loss is not stationary, but shows large regional interannual variability, with mass loss shifting between eastern and western regions from year to year. Comparison with regional climate models shows that these shifts can be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.4734V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.4734V"><span><span class="hlt">Ice</span>2sea - the future glacial contribution to sea-level rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vaughan, D. G.; Ice2sea Consortium</p> <p>2009-04-01</p> <p>The melting of continental <span class="hlt">ice</span> (glaciers, <span class="hlt">ice</span> <span class="hlt">caps</span> and <span class="hlt">ice</span> sheets) is a substantial source of current sea-level rise, and one that is accelerating more rapidly than was predicted even a few years ago. Indeed, the most recent report from Intergovernmental Panel on Climate Change highlighted that the uncertainty in projections of future sea-level rise is dominated by uncertainty concerning continental <span class="hlt">ice</span>, and that understanding of the key processes that will lead to loss of continental <span class="hlt">ice</span> must be improved before reliable projections of sea-level rise can be produced. Such projections are urgently required for effective sea-defence management and coastal adaptation planning. <span class="hlt">Ice</span>2sea is a consortium of European institutes and international partners seeking European funding to support an integrated scientific programme to improve understanding concerning the future glacial contribution to sea-level rise. This includes improving understanding of the processes that control, past, current and future sea-level rise, and generation of improved estimates of the contribution of glacial components to sea-level rise over the next 200 years. The programme will include targeted studies of key processes in mountain glacier systems and <span class="hlt">ice</span> <span class="hlt">caps</span> (e.g. <span class="hlt">Svalbard</span>), and in <span class="hlt">ice</span> sheets in both polar regions (Greenland and Antarctica) to improve understanding of how these systems will respond to future climate change. It will include fieldwork and remote sensing studies, and develop a suite of new, cross-validated glacier and <span class="hlt">ice</span>-sheet model. <span class="hlt">Ice</span>2sea will deliver these results in forms accessible to scientists, policy-makers and the general public, which will include clear presentations of the sources of uncertainty. Our aim is both, to provide improved projections of the glacial contribution to sea-level rise, and to leave a legacy of improved tools and techniques that will form the basis of ongoing refinements in sea-level projection. <span class="hlt">Ice</span>2sea will provide exciting opportunities for many</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRC..120.8327H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRC..120.8327H"><span>Short-term sea <span class="hlt">ice</span> forecasting: An assessment of <span class="hlt">ice</span> concentration and <span class="hlt">ice</span> drift forecasts using the U.S. Navy's Arctic <span class="hlt">Cap</span> Nowcast/Forecast System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hebert, David A.; Allard, Richard A.; Metzger, E. Joseph; Posey, Pamela G.; Preller, Ruth H.; Wallcraft, Alan J.; Phelps, Michael W.; Smedstad, Ole Martin</p> <p>2015-12-01</p> <p>In this study the forecast skill of the U.S. Navy operational Arctic sea <span class="hlt">ice</span> forecast system, the Arctic <span class="hlt">Cap</span> Nowcast/Forecast System (ACNFS), is presented for the period February 2014 to June 2015. ACNFS is designed to provide short term, 1-7 day forecasts of Arctic sea <span class="hlt">ice</span> and ocean conditions. Many quantities are forecast by ACNFS; the most commonly used include <span class="hlt">ice</span> concentration, <span class="hlt">ice</span> thickness, <span class="hlt">ice</span> velocity, sea surface temperature, sea surface salinity, and sea surface velocities. <span class="hlt">Ice</span> concentration forecast skill is compared to a persistent <span class="hlt">ice</span> state and historical sea <span class="hlt">ice</span> climatology. Skill scores are focused on areas where <span class="hlt">ice</span> concentration changes by ±5% or more, and are therefore limited to primarily the marginal <span class="hlt">ice</span> zone. We demonstrate that ACNFS forecasts are skilful compared to assuming a persistent <span class="hlt">ice</span> state, especially beyond 24 h. ACNFS is also shown to be particularly skilful compared to a climatologic state for forecasts up to 102 h. Modeled <span class="hlt">ice</span> drift velocity is compared to observed buoy data from the International Arctic Buoy Programme. A seasonal bias is shown where ACNFS is slower than IABP velocity in the summer months and faster in the winter months. In February 2015, ACNFS began to assimilate a blended <span class="hlt">ice</span> concentration derived from Advanced Microwave Scanning Radiometer 2 (AMSR2) and the Interactive Multisensor Snow and <span class="hlt">Ice</span> Mapping System (IMS). Preliminary results show that assimilating AMSR2 blended with IMS improves the short-term forecast skill and <span class="hlt">ice</span> edge location compared to the independently derived National <span class="hlt">Ice</span> Center <span class="hlt">Ice</span> Edge product.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/1548803','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/1548803"><span>The occurrence of rabies in the <span class="hlt">Svalbard</span> Islands of Norway.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Prestrud, P; Krogsrud, J; Gjertz, I</p> <p>1992-01-01</p> <p>After the first recorded outbreak of rabies in the <span class="hlt">Svalbard</span> Islands (Norway) in 1980, brain tissue from 817 trapped arctic foxes (Alopex lagopus) was tested for rabies by a direct fluorescent antibody test. During the same period (1980 to 1990), 29 arctic foxes, 23 polar bears (Ursus maritimus), 19 reindeer (Rangifer tarandus) and five ringed seals (Phoca hispida) were also tested using the same technique. These animals had either been found dead, killed because of abnormal behavior or were apparently healthy when they were collected. Rabies virus antigen was not detected in any of the trapped foxes. Rabies was confirmed in two foxes in 1981, two foxes and one reindeer in 1987, and in one fox in 1990. The presence of rabies in the <span class="hlt">Svalbard</span> archipelago probably resulted from immigration over the sea <span class="hlt">ice</span> of an infected host.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA624416','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA624416"><span>Sea <span class="hlt">Ice</span> Sensitivities in the 0.72 deg and 0.08 deg Arctic <span class="hlt">Cap</span> Coupled HYCOM/CICE Models</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2014-09-30</p> <p>1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Sea <span class="hlt">Ice</span> Sensitivities in the 0.72°and 0.08° Arctic <span class="hlt">Cap</span>...Arctic <span class="hlt">ice</span> extent, which corresponds to the sea <span class="hlt">ice</span> that remains during the summer minimum, has decreased over the years 1979–2007 by more than 10% per...Goosse et al. 2009) with the lowest observed sea <span class="hlt">ice</span> extent in the satellite record (1979-present) occurring in September 2012 (Perovich et al. 2012</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PolSc..10..312M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PolSc..10..312M"><span>Norwegian fisheries in the <span class="hlt">Svalbard</span> zone since 1980. Regulations, profitability and warming waters affect landings</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Misund, Ole Arve; Heggland, Kristin; Skogseth, Ragnheid; Falck, Eva; Gjøsæter, Harald; Sundet, Jan; Watne, Jens; Lønne, Ole Jørgen</p> <p>2016-09-01</p> <p>The <span class="hlt">Svalbard</span> archipelago in the High Arctic is influenced by cold Arctic water masses from the north-east and the warm West Spitsbergen Current flowing northwards along its western coast. The eastern waters and the fjords are normally frozen during the winter months, while the coastal waters west of the archipelago remain open. Norwegian fishers have been harvesting from <span class="hlt">Svalbard</span> waters for decades and detailed records of catches exists from 1980 onwards. We analyze the catch records from the <span class="hlt">Svalbard</span> zone (approximately <span class="hlt">ICES</span> area IIb). The large fishery for capelin in summer yielding annual catches up to 737 000 tons was closed by a Norwegian fishery regulation in the mid nineteen nineties. Demersal fisheries have been continuous, and the results clearly indicate a northward trend in landings of Northeast Arctic cod, haddock, ling and Atlantic halibut. Fisheries of Northern shrimp have been more variable and shown no clear geographic trends. A "gold rush" fishery for scallops north of <span class="hlt">Svalbard</span> lasted for about 10 years (1986-1995) only, and ended due to low profitably. These results are discussed in relation to the possibility of further northward extension of fisheries subjected to climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050167779','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050167779"><span>Mars Water <span class="hlt">Ice</span> and Carbon Dioxide Seasonal Polar <span class="hlt">Caps</span>: GCM Modeling and Comparison with Mars Express Omega Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Forget, F.; Levrard, B.; Montmessin, F.; Schmitt, B.; Doute, S.; Langevin, Y.; Bibring, J. P.</p> <p>2005-01-01</p> <p>To better understand the behavior of the Mars CO2 <span class="hlt">ice</span> seasonal polar <span class="hlt">caps</span>, and in particular interpret the the Mars Express Omega observations of the recession of the northern seasonal <span class="hlt">cap</span>, we present some simulations of the Martian Climate/CO2 cycle/ water cycle as modeled by the Laboratoire de Meteorologie Dynamique (LMD) global climate model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.P23A1705T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.P23A1705T"><span>Azimuthal Structure of the Sand Erg that Encircles the North Polar Water-<span class="hlt">Ice</span> <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Teodoro, L. A.; Elphic, R. C.; Eke, V. R.; Feldman, W. C.; Maurice, S.; Pathare, A.</p> <p>2011-12-01</p> <p>The sand erg that completely encircles the perennial water-<span class="hlt">ice</span> <span class="hlt">cap</span> that covers the Martian north geographic pole displays considerable azimuthal structure as seen in visible and near-IR images. Much of this structure is associated with the terminations of the many steep troughs that cut spiral the approximately 3 km thick polar <span class="hlt">ice</span> <span class="hlt">cap</span>. Other contributions come from the katabatic winds that spill over steep-sided edges of the <span class="hlt">cap</span>, such as what bounds the largest set of dunes that comprise Olympia Undae. During the spring and summer months when these winds initiate from the higher altitudes that contain sublimating CO2 <span class="hlt">ice</span>, which is very cold and dry, heat adiabatically when they compress as they lose altitude. These winds should then remove H2O moisture from the uppermost layer of the sand dunes that are directly in their path. Two likely locations where this desiccation may occur preferentially is at the termination of Chasma Boreale and the <span class="hlt">ice</span> <span class="hlt">cap</span> at Olympia Undae. We will search for this effect by sharpening the spatial structure of the epithermal neutron counting rates measured at northern high latitudes using the Mars Odyssey Neutron Spectrometer (MONS). The epithermal range of neutron energies is nearly uniquely sensitive to the hydrogen content of surface soils, which should likely be in the form of H2O/OH molecules/radicals. We therefore convert epithermal counting rates in terms of Water-Equivalent-Hydrogen, WEH. However, MONS counting-rate data have a FWHM of ~550 km., which is sufficiently broad to prevent a close association of WEH variability with images of geological features. In this study, we reduce spurious features in the instrument smeared neutron counting rates through deconvolution. We choose the PIXON numerical deconvolution technique for this purpose. This technique uses a statistical approach (Pina 2001, Eke 2001), which is capable of removing spurious features in the data in the presence of noise. We have previously carried out a detailed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018OcSci..14..127P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018OcSci..14..127P"><span>Observations of brine plumes below melting Arctic sea <span class="hlt">ice</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peterson, Algot K.</p> <p>2018-02-01</p> <p>In sea <span class="hlt">ice</span>, interconnected pockets and channels of brine are surrounded by fresh <span class="hlt">ice</span>. Over time, brine is lost by gravity drainage and flushing. The timing of salt release and its interaction with the underlying water can impact subsequent sea <span class="hlt">ice</span> melt. Turbulence measurements 1 m below melting sea <span class="hlt">ice</span> north of <span class="hlt">Svalbard</span> reveal anticorrelated heat and salt fluxes. From the observations, 131 salty plumes descending from the warm sea <span class="hlt">ice</span> are identified, confirming previous observations from a <span class="hlt">Svalbard</span> fjord. The plumes are likely triggered by oceanic heat through bottom melt. Calculated over a composite plume, oceanic heat and salt fluxes during the plumes account for 6 and 9 % of the total fluxes, respectively, while only lasting in total 0.5 % of the time. The observed salt flux accumulates to 7.6 kg m-2, indicating nearly full desalination of the <span class="hlt">ice</span>. Bulk salinity reduction between two nearby <span class="hlt">ice</span> cores agrees with accumulated salt fluxes to within a factor of 2. The increasing fraction of younger, more saline <span class="hlt">ice</span> in the Arctic suggests an increase in desalination processes with the transition to the <q>new Arctic</q>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ACP....1712779R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ACP....1712779R"><span>Do contemporary (1980-2015) emissions determine the elemental carbon deposition trend at Holtedahlfonna glacier, <span class="hlt">Svalbard</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ruppel, Meri M.; Soares, Joana; Gallet, Jean-Charles; Isaksson, Elisabeth; Martma, Tõnu; Svensson, Jonas; Kohler, Jack; Pedersen, Christina A.; Manninen, Sirkku; Korhola, Atte; Ström, Johan</p> <p>2017-10-01</p> <p>The climate impact of black carbon (BC) is notably amplified in the Arctic by its deposition, which causes albedo decrease and subsequent earlier snow and <span class="hlt">ice</span> spring melt. To comprehensively assess the climate impact of BC in the Arctic, information on both atmospheric BC concentrations and deposition is essential. Currently, Arctic BC deposition data are very scarce, while atmospheric BC concentrations have been shown to generally decrease since the 1990s. However, a 300-year <span class="hlt">Svalbard</span> <span class="hlt">ice</span> core showed a distinct increase in EC (elemental carbon, proxy for BC) deposition from 1970 to 2004 contradicting atmospheric measurements and modelling studies. Here, our objective was to decipher whether this increase has continued in the 21st century and to investigate the drivers of the observed EC deposition trends. For this, a shallow firn core was collected from the same <span class="hlt">Svalbard</span> glacier, and a regional-to-meso-scale chemical transport model (SILAM) was run from 1980 to 2015. The <span class="hlt">ice</span> and firn core data indicate peaking EC deposition values at the end of the 1990s and lower values thereafter. The modelled BC deposition results generally support the observed glacier EC variations. However, the <span class="hlt">ice</span> and firn core results clearly deviate from both measured and modelled atmospheric BC concentration trends, and the modelled BC deposition trend shows variations seemingly independent from BC emission or atmospheric BC concentration trends. Furthermore, according to the model ca. 99 % BC mass is wet-deposited at this <span class="hlt">Svalbard</span> glacier, indicating that meteorological processes such as precipitation and scavenging efficiency have most likely a stronger influence on the BC deposition trend than BC emission or atmospheric concentration trends. BC emission source sectors contribute differently to the modelled atmospheric BC concentrations and BC deposition, which further supports our conclusion that different processes affect atmospheric BC concentration and deposition trends</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GML....36...81C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GML....36...81C"><span>Glaciomarine sedimentation and bottom current activity on the north-western and northern continental margins of <span class="hlt">Svalbard</span> during the late Quaternary</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chauhan, Teena; Noormets, Riko; Rasmussen, Tine L.</p> <p>2016-04-01</p> <p>Palaeo-bottom current strength of the West Spitsbergen Current (WSC) and the influence of the <span class="hlt">Svalbard</span>-Barents Sea <span class="hlt">Ice</span> Sheet (SBIS) on the depositional environment along the northern <span class="hlt">Svalbard</span> margins are poorly known. Two gravity cores from the southern Yermak Plateau and the upper slope north of Nordaustlandet, covering marine isotope stage (MIS) 1 to MIS 5, are investigated. Five lithofacies, based on grain size distribution, silt/clay ratio, content and mean of sortable silt (SS), are distinguished to characterise the contourite-dominated sedimentary environments. In addition, depositional environments are described using total organic carbon (TOC), total sulphur (TS) and calcium carbonate (CaCO3) contents of sediments. Facies A, containing coarse SS, suggests strong bottom current activity and good bottom water ventilation conditions as inferred from low TOC content. This facies was deposited during the glacial periods MIS 4, MIS 2 and during the late Holocene. Facies B is dominated by fine SS indicating weak bottom current and poor ventilation (cf. high TOC content of 1.2-1.6%), and correlates with the MIS 4/3 and MIS 2/1 transition periods. With an equal amount of clay and sand, fine SS and high content of TOC, facies C indicates reduced bottom current strength for intervals with sediment supply from proximal sources such as icebergs, sea <span class="hlt">ice</span> or meltwater discharge. This facies was deposited during the last glacial maximum. Facies D represents mass-flow deposits on the northern <span class="hlt">Svalbard</span> margin attributed to the SBIS advance at or near the shelf edge. Facies E sediments indicating moderate bottom current strength were deposited during MIS 5 and MIS 3, and during parts of MIS 2. This first late Quaternary proxy record of the WSC flow and sedimentation history from the northern <span class="hlt">Svalbard</span> margin suggests that the oceanographic conditions and <span class="hlt">ice</span> sheet processes have exerted first-order control on sediment properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018QSRv..182...93K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018QSRv..182...93K"><span>Changes in sea <span class="hlt">ice</span> cover and <span class="hlt">ice</span> sheet extent at the Yermak Plateau during the last 160 ka - Reconstructions from biomarker records</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kremer, A.; Stein, R.; Fahl, K.; Ji, Z.; Yang, Z.; Wiers, S.; Matthiessen, J.; Forwick, M.; Löwemark, L.; O'Regan, M.; Chen, J.; Snowball, I.</p> <p>2018-02-01</p> <p>The Yermak Plateau is located north of <span class="hlt">Svalbard</span> at the entrance to the Arctic Ocean, i.e. in an area highly sensitive to climate change. A multi proxy approach was carried out on Core PS92/039-2 to study glacial-interglacial environmental changes at the northern Barents Sea margin during the last 160 ka. The main emphasis was on the reconstruction of sea <span class="hlt">ice</span> cover, based on the sea <span class="hlt">ice</span> proxy IP25 and the related phytoplankton - sea <span class="hlt">ice</span> index PIP25. Sea <span class="hlt">ice</span> was present most of the time but showed significant temporal variability decisively affected by movements of the <span class="hlt">Svalbard</span> Barents Sea <span class="hlt">Ice</span> Sheet. For the first time, we prove the occurrence of seasonal sea <span class="hlt">ice</span> at the eastern Yermak Plateau during glacial intervals, probably steered by a major northward advance of the <span class="hlt">ice</span> sheet and the formation of a coastal polynya in front of it. Maximum accumulation of terrigenous organic carbon, IP25 and the phytoplankton biomarkers (brassicasterol, dinosterol, HBI III) can be correlated to distinct deglaciation events. More severe, but variable sea <span class="hlt">ice</span> cover prevailed at the Yermak Plateau during interglacials. The general proximity to the sea <span class="hlt">ice</span> margin is further indicated by biomarker (GDGT) - based sea surface temperatures below 2.5 °C.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5895444','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5895444"><span>Discovery of a hypersaline subglacial lake complex beneath Devon <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Canadian Arctic</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Blankenship, Donald D.; Schroeder, Dustin M.; Dowdeswell, Julian A.</p> <p>2018-01-01</p> <p>Subglacial lakes are unique environments that, despite the extreme dark and cold conditions, have been shown to host microbial life. Many subglacial lakes have been discovered beneath the <span class="hlt">ice</span> sheets of Antarctica and Greenland, but no spatially isolated water body has been documented as hypersaline. We use radio-echo sounding measurements to identify two subglacial lakes situated in bedrock troughs near the <span class="hlt">ice</span> divide of Devon <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Canadian Arctic. Modeled basal <span class="hlt">ice</span> temperatures in the lake area are no higher than −10.5°C, suggesting that these lakes consist of hypersaline water. This implication of hypersalinity is in agreement with the surrounding geology, which indicates that the subglacial lakes are situated within an evaporite-rich sediment unit containing a bedded salt sequence, which likely act as the solute source for the brine. Our results reveal the first evidence for subglacial lakes in the Canadian Arctic and the first hypersaline subglacial lakes reported to date. We conclude that these previously unknown hypersaline subglacial lakes may represent significant and largely isolated microbial habitats, and are compelling analogs for potential <span class="hlt">ice</span>-covered brine lakes and lenses on planetary bodies across the solar system. PMID:29651462</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.C31A0614C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.C31A0614C"><span>A moderate resolution inventory of small glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> surrounding Greenland and the Antarctic peninsula</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, C.; Box, J. E.; Hock, R. M.; Cogley, J. G.</p> <p>2011-12-01</p> <p>Current estimates of global Mountain Glacier and <span class="hlt">Ice</span> <span class="hlt">Caps</span> (MG&IC) mass changes are subject to large uncertainties due to incomplete inventories and uncertainties in land surface classification. This presentation features mitigative efforts through the creation of a MODIS dependent land <span class="hlt">ice</span> classification system and its application for glacier inventory. Estimates of total area of mountain glaciers [IPCC, 2007] and <span class="hlt">ice</span> <span class="hlt">caps</span> (including those in Greenland and Antarctica) vary 15%, that is, 680 - 785 10e3 sq. km. To date only an estimated 40% of glaciers (by area) is inventoried in the World Glacier Inventory (WGI) and made available through the World Glacier Monitoring System (WGMS) and the National Snow and <span class="hlt">Ice</span> Data Center [NSIDC, 1999]. Cogley [2009] recently compiled a more complete version of WGI, called WGI-XF, containing records for just over 131,000 glaciers, covering approximately half of the estimated global MG&IC area. The glaciers isolated from the conterminous Antarctic and Greenland <span class="hlt">ice</span> sheets remain incompletely inventoried in WGI-XF but have been estimated to contribute 35% to the MG&IC sea-level equivalent during 1961-2004 [Hock et al., 2009]. Together with Arctic Canada and Alaska these regions alone make up almost 90% of the area that is missing in the global WGI-XF inventory. Global mass balance projections tend to exclude <span class="hlt">ice</span> masses in Greenland and Antarctica due to the paucity of data with respect to basic inventory base data such as area, number of glaciers or size distributions. We address the need for an accurate Greenland and Antarctic peninsula land surface classification with a novel glacier surface classification and inventory based on NASA Moderate Resolution Imaging Spectroradiometer (MODIS) data gridded at 250 m pixel resolution. The presentation includes a sensitivity analysis for surface mass balance as it depends on the land surface classification. Works Cited +Cogley, J. G. (2009), A more complete version of the World Glacier</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA06858&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DCAPS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA06858&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DCAPS"><span>North Polar <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2004-01-01</p> <p><p/> 7 September 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a 1.4 m/pixel (5 ft/pixel) view of a typical martian north polar <span class="hlt">ice</span> <span class="hlt">cap</span> texture. The surface is pitted and rough at the scale of several meters. The north polar residual <span class="hlt">cap</span> of Mars consists mainly of water <span class="hlt">ice</span>, while the south polar residual <span class="hlt">cap</span> is mostly carbon dioxide. This picture is located near 85.2oN, 283.2oW. The image covers an area approximately 1 km wide by 1.4 km high (0.62 by 0.87 miles). Sunlight illuminates this scene from the lower left.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850015175&hterms=gardening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgardening','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850015175&hterms=gardening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgardening"><span>Polar <span class="hlt">Cap</span> Formation on Ganymede</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pilcher, C. B.; Shaya, E. J.</p> <p>1985-01-01</p> <p>Since thermal migration is not an effective mechanism for water transport in the polar regions at the Galilean satellites, some other process must be responsible for the formation of Ganymede's polar <span class="hlt">caps</span>. It is proposed that Ganymede's polar <span class="hlt">caps</span> are the optical manifestation of a process that began with the distribution of an <span class="hlt">ice</span> sheet over the surface of Ganymede. The combined processes of impact gardening and thermal migration led, in regions at latitudes less than 40 to 45 deg., to the burial of some fraction of this <span class="hlt">ice</span>, the migration of some to the polar <span class="hlt">caps</span> margins, and a depletion of free <span class="hlt">ice</span> in the optical surface. At higher latitudes, no process was effective in removing <span class="hlt">ice</span> from the optical surface, so the remanants of the sheet are visible today.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C13D0861C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C13D0861C"><span>High Artic Glaciers and <span class="hlt">Ice</span> <span class="hlt">Caps</span> <span class="hlt">Ice</span> Mass Change from GRACE, Regional Climate Model Output and Altimetry.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ciraci, E.; Velicogna, I.; Fettweis, X.; van den Broeke, M. R.</p> <p>2016-12-01</p> <p>The Arctic hosts more than the 75% of the <span class="hlt">ice</span> covered regions outside from Greenland and Antarctica. Available observations show that increased atmospheric temperatures during the last century have contributed to a substantial glaciers retreat in all these regions. We use satellite gravimetry by the NASA's Gravity Recovery and Climate Experiment (GRACE), and apply a least square fit mascon approach to calculate time series of <span class="hlt">ice</span> mass change for the period 2002-2016. Our estimates show that arctic glaciers have constantly contributed to the sea level rise during the entire observation period with a mass change of -170+/-20 Gt/yr equivalent to the 80% of the total <span class="hlt">ice</span> mass change from the world Glacier and <span class="hlt">Ice</span> <span class="hlt">Caps</span> (GIC) excluding the <span class="hlt">Ice</span> sheet peripheral GIC, which we calculated to be -215+/-32 GT/yr, with an acceleration of 9+/-4 Gt/yr2. The Canadian Archipelago is the main contributor to the total mass depletion with an <span class="hlt">ice</span> mass trend of -73+/-9 Gt/yr and a significant acceleration of -7+/-3 Gt/yr2. The increasing mass loss is mainly determined by melting glaciers located in the northern part of the archipelago.In order to investigate the physical processes driving the observed <span class="hlt">ice</span> mass loss we employ satellite altimetry and surface mass balance (SMB) estimates from Regional climate model outputs available for the same time period covered by the gravimetry data. We use elevation data from the NASA ICESat (2003-2009) and ESA CryoSat-2 (2010-2016) missions to estimate <span class="hlt">ice</span> elevation changes. We compare GRACE <span class="hlt">ice</span> mass estimates with time series of surface mass balance from the Regional Climate Model (RACMO-2) and the Modèle Atmosphérique Régional (MAR) and determine the portion of the total mass change explained by the SMB signal. We find that in Iceland and in the and the Canadian Archipelago the SMB signal explains most of the observed mass changes, suggesting that <span class="hlt">ice</span> discharge may play a secondary role here. In other region, e.g. in Svalbar, the SMB signal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.6054P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.6054P"><span>The Navy's First Seasonal <span class="hlt">Ice</span> Forecasts using the Navy's Arctic <span class="hlt">Cap</span> Nowcast/Forecast System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Preller, Ruth</p> <p>2013-04-01</p> <p>As conditions in the Arctic continue to change, the Naval Research Laboratory (NRL) has developed an interest in longer-term seasonal <span class="hlt">ice</span> extent forecasts. The Arctic <span class="hlt">Cap</span> Nowcast/Forecast System (ACNFS), developed by the Oceanography Division of NRL, was run in forward model mode, without assimilation, to estimate the minimum sea <span class="hlt">ice</span> extent for September 2012. The model was initialized with varying assimilative ACNFS analysis fields (June 1, July 1, August 1 and September 1, 2012) and run forward for nine simulations using the archived Navy Operational Global Atmospheric Prediction System (NOGAPS) atmospheric forcing fields from 2003-2011. The mean <span class="hlt">ice</span> extent in September, averaged across all ensemble members was the projected summer <span class="hlt">ice</span> extent. These results were submitted to the Study of Environmental Arctic Change (SEARCH) Sea <span class="hlt">Ice</span> Outlook project (http://www.arcus.org/search/seaiceoutlook). The ACNFS is a ~3.5 km coupled <span class="hlt">ice</span>-ocean model that produces 5 day forecasts of the Arctic sea <span class="hlt">ice</span> state in all <span class="hlt">ice</span> covered areas in the northern hemisphere (poleward of 40° N). The ocean component is the HYbrid Coordinate Ocean Model (HYCOM) and is coupled to the Los Alamos National Laboratory Community <span class="hlt">Ice</span> CodE (CICE) via the Earth System Modeling Framework (ESMF). The ocean and <span class="hlt">ice</span> models are run in an assimilative cycle with the Navy's Coupled Ocean Data Assimilation (NCODA) system. Currently the ACNFS is being transitioned to operations at the Naval Oceanographic Office.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.C21B0729K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.C21B0729K"><span>Peruvian Tropical Glacier May Survive Longer Than Previously Thought: Landsat Image Analysis of Nevado Coropuna <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Peru</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kochtitzky, W. H.; Edwards, B. R.; Marino, J.; Manrique, N.</p> <p>2015-12-01</p> <p>Nevado Coropuna is a large volcanic complex in southern Peru (15.56°S, 72.62°N; 6,425 m). The complex is approximately 12 km east-west and 8 km north-south with elevation from ~4,500 m at the base to over 6,000 m at the highest points. This <span class="hlt">ice</span> <span class="hlt">cap</span> is the largest hosted by a volcano in the tropics, and one of the ten biggest <span class="hlt">ice</span> masses in the tropics. Previous workers have predicted that the Coropuna <span class="hlt">ice</span> <span class="hlt">cap</span> will completely melt by 2050. We present a new analysis of historic satellite imagery to test this hypothesis. In this study, <span class="hlt">ice</span> and snow are classified based on unique spectral signatures including spectral band thresholds, Normalized Difference Snow Index, and Band 4/5 ratio. Landsat scenes (L2, 4, 5, 7, and 8) from 1975 to present in addition to one SPOT scene (2013) are used. Previous workers used images from June and July, which are peak snow periods in southern Peru, leading to overestimates of <span class="hlt">ice</span> area. This study uses November and December images when snow is at an annual minimum. Annual equilibrium line altitudes are calculated for each end of year image (November/December). The glaciers of Nevado Coropuna were found to be shrinking at ~0.5 km2/yr, which is ~1/3 the rate previously published. In this study, SPOT (1.5 m resolution) and Landsat 7 ETM scenes from November 23 and 26, 2013 respectively were used to calibrate the spectral band threshold classification. While this study suggests that the <span class="hlt">ice</span> <span class="hlt">cap</span> of Coropuna will persist until 2100 given current rates, water quantity and security remains a concern for Peruvian agriculture. Coropuna is an active volcano, so it poses great risk to surrounding inhabitants from lahars, flooding, and debris avalanches. Our new data suggest that these will continue to be risks late into this century.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1815224A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1815224A"><span>Numerical modeling of Drangajökull <span class="hlt">Ice</span> <span class="hlt">Cap</span>, NW Iceland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anderson, Leif S.; Jarosch, Alexander H.; Flowers, Gwenn E.; Aðalgeirsdóttir, Guðfinna; Magnússon, Eyjólfur; Pálsson, Finnur; Muñoz-Cobo Belart, Joaquín; Þorsteinsson, Þorsteinn; Jóhannesson, Tómas; Sigurðsson, Oddur; Harning, David; Miller, Gifford H.; Geirsdóttir, Áslaug</p> <p>2016-04-01</p> <p>Over the past century the Arctic has warmed twice as fast as the global average. This discrepancy is likely due to feedbacks inherent to the Arctic climate system. These Arctic climate feedbacks are currently poorly quantified, but are essential to future climate predictions based on global circulation modeling. Constraining the magnitude and timing of past Arctic climate changes allows us to test climate feedback parameterizations at different times with different boundary conditions. Because Holocene Arctic summer temperature changes have been largest in the North Atlantic (Kaufman et al., 2004) we focus on constraining the paleoclimate of Iceland. Glaciers are highly sensitive to changes in temperature and precipitation amount. This sensitivity allows for the estimation of paleoclimate using glacier models, modern glacier mass balance data, and past glacier extents. We apply our model to the Drangajökull <span class="hlt">ice</span> <span class="hlt">cap</span> (~150 sq. km) in NW Iceland. Our numerical model is resolved in two-dimensions, conserves mass, and applies the shallow-<span class="hlt">ice</span>-approximation. The bed DEM used in the model runs was constructed from radio echo data surveyed in spring 2014. We constrain the modern surface mass balance of Drangajökull using: 1) ablation and accumulation stakes; 2) <span class="hlt">ice</span> surface digital elevation models (DEMs) from satellite, airborne LiDAR, and aerial photographs; and 3) full-stokes model-derived vertical <span class="hlt">ice</span> velocities. The modeled vertical <span class="hlt">ice</span> velocities and <span class="hlt">ice</span> surface DEMs are combined to estimate past surface mass balance. We constrain Holocene glacier geometries using moraines and trimlines (e.g., Brynjolfsson, etal, 2014), proglacial-lake cores, and radiocarbon-dated dead vegetation emerging from under the modern glacier. We present a sensitivity analysis of the model to changes in parameters and show the effect of step changes of temperature and precipitation on glacier extent. Our results are placed in context with local lacustrine and marine climate proxies as well</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26PSL.450..140B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26PSL.450..140B"><span>Surges of outlet glaciers from the Drangajökull <span class="hlt">ice</span> <span class="hlt">cap</span>, northwest Iceland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brynjólfsson, Skafti; Schomacker, Anders; Korsgaard, Niels J.; Ingólfsson, Ólafur</p> <p>2016-09-01</p> <p>Surface elevation and volume changes of the Drangajökull surge-type glaciers, Reykjarfjarðarjökull and Leirufjarðarjökull, were studied by comparing digital elevation models that pre-date and post-date their most recent surges. Annual glacier-frontal measurements were used to estimate average <span class="hlt">ice</span> velocities during the last surge of the glaciers. The observations show a distinct <span class="hlt">ice</span> discharge, most of which was from the upper reservoir areas, down to the receiving areas during the surges. The surface draw-down in the reservoir areas was usually 10-30 m during the surges, while the thickening of the receiving areas was significantly more variable, on the order of 10-120 m. Despite a negative geodetic net mass balance derived from the digital elevation models, the reservoir areas have been gaining mass since the surge terminations. This surface thickening along with considerable ablation of the receiving areas will most likely return the glacier surface profiles to the pre-surge stage. Our results indicate that (a) greatest surface thinning in the upper reservoir areas of Drangajökull rather than proximal to the equilibrium line during Vatnajökull surges and (b) development of Drangajökull surges that resembles <span class="hlt">Svalbard</span> surge-type glaciers rather than Vatnajökull surge-type glaciers. The contrasting surge characteristics could be explained by differences in glacier geometry, topography and substratum of the Drangajökull and Vatnajökull surge-type glaciers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012QSRv...35...63G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012QSRv...35...63G"><span>Palaeoglaciology of the Alexander Island <span class="hlt">ice</span> <span class="hlt">cap</span>, western Antarctic Peninsula, reconstructed from marine geophysical and core data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Graham, Alastair G. C.; Smith, James A.</p> <p>2012-03-01</p> <p>The glacial history of the continental shelf northwest of Alexander Island is not well known, due mainly to a lack of targeted marine data on Antarctica's palaeo-<span class="hlt">ice</span> sheets in their inter-<span class="hlt">ice</span>-stream areas. Recently it has been argued that the region was <span class="hlt">ice</span>-free at the Last Glacial Maximum (LGM) and thus a potential site for glacial refugia. In this paper, multibeam swath bathymetry, sub-bottom profiles and sediment cores are used to map the Alexander Island sector of the Antarctic Peninsula margin, in order to reconstruct the shelf's palaeoglaciology. Sea-floor bedforms provide evidence that an independent <span class="hlt">ice</span> <span class="hlt">cap</span> persisted on Alexander Island through the LGM and deglaciation. We show that this <span class="hlt">ice</span> <span class="hlt">cap</span> drained via two major, previously-undescribed tidewater outlets (Rothschild and Charcot Glaciers) sourced from an <span class="hlt">ice</span> dome centred over the west of the island and near-shore areas. The glaciers grounded along deep, fjord-like cross-shelf troughs to within at least ˜10-20 km of the shelf edge, and probably reached the shelf break. Only one small outer-shelf zone appears to have remained free of <span class="hlt">ice</span> throughout an otherwise extensive LGM. During retreat, grounding-line geomorphology indicates periodic stabilisation of Charcot Glacier on the mid-shelf after 13,500 cal yrs BP, while Rothschild Glacier retreated across its mid-shelf by 14,450 cal yrs BP. The timing of these events is in phase with retreat in nearby Marguerite Trough, and we take this as evidence of a common history and forcing with the Antarctic Peninsula <span class="hlt">Ice</span> Sheet. The fine details of <span class="hlt">ice</span> flow documented by our new reconstruction highlight the importance of capturing complex <span class="hlt">ice</span> flow patterns in models (e.g. in inter-stream areas), for understanding how region-specific parts of Antarctica may change in the future. Moreover, the reconstruction shows that glacial refugia, if present, cannot have been extensive on the Alexander Island shelf at the LGM as indicated by previous biological studies; instead</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018QSRv..188....1T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018QSRv..188....1T"><span><span class="hlt">Ice</span> core records of climate variability on the Third Pole with emphasis on the Guliya <span class="hlt">ice</span> <span class="hlt">cap</span>, western Kunlun Mountains</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, Lonnie G.; Yao, Tandong; Davis, Mary E.; Mosley-Thompson, Ellen; Wu, Guangjian; Porter, Stacy E.; Xu, Baiqing; Lin, Ping-Nan; Wang, Ninglian; Beaudon, Emilie; Duan, Keqin; Sierra-Hernández, M. Roxana; Kenny, Donald V.</p> <p>2018-05-01</p> <p>Records of recent climate from <span class="hlt">ice</span> cores drilled in 2015 on the Guliya <span class="hlt">ice</span> <span class="hlt">cap</span> in the western Kunlun Mountains of the Tibetan Plateau, which with the Himalaya comprises the Third Pole (TP), demonstrate that this region has become warmer and moister since at least the middle of the 19th century. Decadal-scale linkages are suggested between <span class="hlt">ice</span> core temperature and snowfall proxies, North Atlantic oceanic and atmospheric processes, Arctic temperatures, and Indian summer monsoon intensity. Correlations between annual-scale oxygen isotopic ratios (δ18O) and tropical western Pacific and Indian Ocean sea surface temperatures are also demonstrated. Comparisons of climate records during the last millennium from <span class="hlt">ice</span> cores acquired throughout the TP illustrate centennial-scale differences between monsoon and westerlies dominated regions. Among these records, Guliya shows the highest rate of warming since the end of the Little <span class="hlt">Ice</span> Age, but δ18O data over the last millennium from TP <span class="hlt">ice</span> cores support findings that elevation-dependent warming is most pronounced in the Himalaya. This, along with the decreasing precipitation rates in the Himalaya region, is having detrimental effects on the cryosphere. Although satellite monitoring of glaciers on the TP indicates changes in surface area, only a few have been directly monitored for mass balance and ablation from the surface. This type of ground-based study is essential to obtain a better understanding of the rate of <span class="hlt">ice</span> shrinkage on the TP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.C41D0434C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.C41D0434C"><span><span class="hlt">Ice</span> Sheet and Sea <span class="hlt">Ice</span> Observations from Unmanned Aircraft Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crocker, R. I.; Maslanik, J. A.</p> <p>2011-12-01</p> <p>A suite of sensors has been assembled to map <span class="hlt">ice</span> sheet and sea <span class="hlt">ice</span> surface topography with fine-resolution from small unmanned aircraft systems (UAS). This payload is optimized to provide coincident surface elevation and imagery data, and with its low cost and ease of reproduction, it has the potential to become a widely-distributed observational resource to complement polar manned-aircraft and satellite missions. To date, it has been deployed to map <span class="hlt">ice</span> sheet elevations near Jakobshavn Isbræ in Greenland, and to measure sea <span class="hlt">ice</span> freeboard and roughness in Fram Strait off the coast of <span class="hlt">Svalbard</span>. Data collected during these campaigns have facilitate a detailed assessment of the system's surface elevation measurement accuracy, and provide a glimpse of the summer 2009 Fram Strait sea <span class="hlt">ice</span> conditions. These findings are presented, along with a brief overview of our future Arctic UAS operations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JASS...33..305L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JASS...33..305L"><span>Abnormal Winter Melting of the Arctic Sea <span class="hlt">Ice</span> <span class="hlt">Cap</span> Observed by the Spaceborne Passive Microwave Sensors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Seongsuk; Yi, Yu</p> <p>2016-12-01</p> <p>The spatial size and variation of Arctic sea <span class="hlt">ice</span> play an important role in Earth’s climate system. These are affected by conditions in the polar atmosphere and Arctic sea temperatures. The Arctic sea <span class="hlt">ice</span> concentration is calculated from brightness temperature data derived from the Defense Meteorological Satellite program (DMSP) F13 Special Sensor Microwave/Imagers (SSMI) and the DMSP F17 Special Sensor Microwave Imager/Sounder (SSMIS) sensors. Many previous studies point to significant reductions in sea <span class="hlt">ice</span> and their causes. We investigated the variability of Arctic sea <span class="hlt">ice</span> using the daily sea <span class="hlt">ice</span> concentration data from passive microwave observations to identify the sea <span class="hlt">ice</span> melting regions near the Arctic polar <span class="hlt">ice</span> <span class="hlt">cap</span>. We discovered the abnormal melting of the Arctic sea <span class="hlt">ice</span> near the North Pole during the summer and the winter. This phenomenon is hard to explain only surface air temperature or solar heating as suggested by recent studies. We propose a hypothesis explaining this phenomenon. The heat from the deep sea in Arctic Ocean ridges and/ or the hydrothermal vents might be contributing to the melting of Arctic sea <span class="hlt">ice</span>. This hypothesis could be verified by the observation of warm water column structure below the melting or thinning arctic sea <span class="hlt">ice</span> through the project such as Coriolis dataset for reanalysis (CORA).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23353800','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23353800"><span>Taxonomic characterization, adaptation strategies and biotechnological potential of cryophilic yeasts from <span class="hlt">ice</span> cores of Midre Lovénbreen glacier, <span class="hlt">Svalbard</span>, Arctic.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Singh, Purnima; Tsuji, Masaharu; Singh, Shiv Mohan; Roy, Utpal; Hoshino, Tamotsu</p> <p>2013-04-01</p> <p>Ten strains of cryophilic yeast were studied from glacier <span class="hlt">ice</span> cores of <span class="hlt">Svalbard</span>, Arctic. The <span class="hlt">ice</span> melt samples contained about 3×10(3) - 1×10(4) colony forming unit (CFUs) per ml. Sequence analysis of the isolates, using D1/D2 domain identified five species of yeasts: Cryptococcus adeliensis (MLB-18 JX192655), Cryptococcus albidosimilis (MLB-19 JX192656), Cryptococcus saitoi (MLB-22 JX192659), Rhodosporidium lusitaniae (MLB-20 JX192657), and Rhodotorula mucilaginosa (MLB-27 JX192664). Effect of temperature on growth of these isolates was studied. The strains are able to grow at temperatures ranging between 1 and 20°C. Screening of the cultures for amylase, cellulase, protease, lipase, urease and catalase activity were carried out indicating varying amounts of enzyme production at different temperatures. Characterization of lipase in strain Cryptococcus sp. MLB-24 was performed. Fatty acid methyl ester (FAME) analysis of the cultures grown at four different temperatures (1, 4, 15, and 20°C) was also done. Decrease in temperature was reported to cause increase in concentration of unsaturated fatty acids. High amount of oleic acid accumulated with increase in temperature. These fatty acids possibly help the strains to survive in glacial <span class="hlt">ice</span> core cold environment. The extracellular and intracellular filtrate of the cultures showed negative antifreeze protein (AFP) activity. The observations indicate that probably the isolates in the present undertaking adapt to low temperatures, by enzyme and PUFA secretion rather than by antifreeze protein secretion. Copyright © 2013 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011GeoJI.184.1119M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011GeoJI.184.1119M"><span>Secular gravity variation at <span class="hlt">Svalbard</span> (Norway) from ground observations and GRACE satellite data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mémin, A.; Rogister, Y.; Hinderer, J.; Omang, O. C.; Luck, B.</p> <p>2011-03-01</p> <p>The <span class="hlt">Svalbard</span> archipelago, Norway, is affected by both the present-day <span class="hlt">ice</span> melting (PDIM) and Glacial Isostatic Adjustment (GIA) subsequent to the Last Pleistocene deglaciation. The induced deformation of the Earth is observed by using different techniques. At the Geodetic Observatory in Ny-Ålesund, precise positioning measurements have been collected since 1991, a superconducting gravimeter (SG) has been installed in 1999, and six campaigns of absolute gravity (AG) measurements were performed between 1998 and 2007. Moreover, the Gravity Recovery and Climate Experiment (GRACE) satellite mission provides the time variation of the Earth gravity field since 2002. The goal of this paper is to estimate the present rate of <span class="hlt">ice</span> melting by combining geodetic observations of the gravity variation and uplift rate with geophysical modelling of both the GIA and Earth's response to the PDIM. We estimate the secular gravity variation by superimposing the SG series with the six AG measurements. We collect published estimates of the vertical velocity based on GPS and VLBI data. We analyse the GRACE solutions provided by three groups (CSR, GFZ, GRGS). The crux of the problem lies in the separation of the contributions from the GIA and PDIM to the Earth's deformation. To account for the GIA, we compute the response of viscoelastic Earth models having different radial structures of mantle viscosity to the deglaciation histories included in the models <span class="hlt">ICE</span>-3G or <span class="hlt">ICE</span>-5G. To account for the effect of PDIM, we compute the deformation of an elastic Earth model for six models of <span class="hlt">ice</span>-melting extension and rates. Errors in the gravity variation and vertical velocity are estimated by taking into account the measurement uncertainties and the variability of the GRACE solutions and GIA and PDIM models. The ground observations agree with models that involve a current <span class="hlt">ice</span> loss of 25 km3 water equivalent yr-1 over <span class="hlt">Svalbard</span>, whereas the space observations give a value in the interval [5, 18] km3</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1813764B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1813764B"><span>Amsterdamøya: a key site for the post-glacial of <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bakke, Jostein; Balascio, Nicholas; van der Bilt, Willem; D`Andrea, William; Bradley, Raymond; Gjerde, Marthe; Hormes, Anne; Olafsdottir, Sædis; Røthe, Torgeir; Vasskog, Kristian; De Wet, Greg; Werner, Johannes</p> <p>2016-04-01</p> <p>No other place on Earth is changing as fast as the Arctic in terms of climate. On average this region is warming twice as fast as the global average with a seasonal bias towards winter. A major retreat in sea <span class="hlt">ice</span> extent accompanied by an even more massive thinning represents one of the most robust trends in the Arctic. This trend is anticipated to continue in the decades to come and, according to some models, will leave the Arctic Ocean open during summer some time between 2050-2100. Unabated reduction in the spring-snow cover represents another significant trend. The current warming is also expressed in the massive melting of the Greenland <span class="hlt">ice</span> sheet as well as local glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> in the Arctic, which causes increased freshwater influx to the Arctic Ocean and adjacent seas. Climate modeling and scenarios are improving and becoming of growing importance, but without a firmer understanding of natural climate variability over longer timescale it is still hard to evaluate and best read the output from these models. In the SHIFTS project we have done an unparalleled effort to overcome this quandary, providing necessary empirical data on past climate which is critical for assessing past changes in atmospheric circulation patterns controlling Arctic hydroclimate. Our study site is located at the northwestern corner of <span class="hlt">Svalbard</span> on the Island of Amsterdamøya, a site sensitive to changes in both oceanic and atmospheric forcing, at tail of the westward moving branch of the North Atlantic current. Here we have cored several lakes with the goal of providing quantitative data on temperature, hydrology and winter precipitation for the Holocene. Our approach has been to combine reconstruction of glaciers with lipid biomarkers and hydrogen isotopes with the goal of unravel the underlying signature of past climate in the Arctic. Chronological control is secured by radiocarbon dates on macrofossils combined with measurement of paleomagnetic secular variations. Here we</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930010624','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930010624"><span>Is CO2 <span class="hlt">ice</span> permanent?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lindner, Bernhard Lee</p> <p>1992-01-01</p> <p>Carbon dioxide <span class="hlt">ice</span> has been inferred to exist at the south pole in summertime, but Earth based measurements in 1969 of water vapor in the Martian atmosphere suggest that all CO2 <span class="hlt">ice</span> sublined from the southern polar <span class="hlt">cap</span> and exposed underlying water <span class="hlt">ice</span>. This implies that the observed summertime CO2 <span class="hlt">ice</span> is of recent origin. It appears possible to construct an energy balance model that maintains seasonal CO2 <span class="hlt">ice</span> at the south pole year round and still reasonably simulates the polar <span class="hlt">cap</span> regression and atmospheric pressure data. This implies that the CO2 <span class="hlt">ice</span> observed in the summertime south polar <span class="hlt">cap</span> could be seasonal in origin, and that minor changes in climate could cause CO2 <span class="hlt">ice</span> to completely vanish, as would appear to have happened in 1969. However, further research remains before it is certain whether the CO2 <span class="hlt">ice</span> observed in the summertime south polar <span class="hlt">cap</span> is seasonal or is part of a permanent reservoir.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA10626&hterms=trust&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dtrust','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA10626&hterms=trust&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dtrust"><span>Longyearbyen, <span class="hlt">Svalbard</span>, Norway</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2008-01-01</p> <p><p/> Longyearbyen is the administrative center of <span class="hlt">Svalbard</span> and is located on Spitsbergen, the largest island of the <span class="hlt">Svalbard</span> archipelago, part of the Kingdom of Norway. It is the world's northernmost town with over 1000 people. The settlement was founded in 1906 by John Longyear, owner of the Arctic Coal Company. Until the early 1990s the coal mining industry was the major employer of Longyearbyen. Near Longyearbyen, the Global Crop Diversity Trust administers the <span class="hlt">Svalbard</span> Global Seed Vault, an Arctic safe capable of storing millions of crop seeds as a safeguard against natural and human disasters. Last week, the first deposit of 250,000 different species of crop seeds was made into the repository. The perspective view was created by draping a simulated natural color image over an ASTER-derived digital elevation model. <p/> The image was acquired July 12, 2003, and is located at 78.2 degrees north latitude, 15.6 degrees east longitude. <p/> The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015TCry....9..945L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015TCry....9..945L"><span>Future climate and surface mass balance of <span class="hlt">Svalbard</span> glaciers in an RCP8.5 climate scenario: a study with the regional climate model MAR forced by MIROC5</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lang, C.; Fettweis, X.; Erpicum, M.</p> <p>2015-05-01</p> <p>We have performed a future projection of the climate and surface mass balance (SMB) of <span class="hlt">Svalbard</span> with the MAR (Modèle Atmosphérique Régional) regional climate model forced by MIROC5 (Model for Interdisciplinary Research on Climate), following the RCP8.5 scenario at a spatial resolution of 10 km. MAR predicts a similar evolution of increasing surface melt everywhere in <span class="hlt">Svalbard</span> followed by a sudden acceleration of melt around 2050, with a larger melt increase in the south compared to the north of the archipelago. This melt acceleration around 2050 is mainly driven by the albedo-melt feedback associated with the expansion of the ablation/bare <span class="hlt">ice</span> zone. This effect is dampened in part as the solar radiation itself is projected to decrease due to a cloudiness increase. The near-surface temperature is projected to increase more in winter than in summer as the temperature is already close to 0 °C in summer. The model also projects a stronger winter west-to-east temperature gradient, related to the large decrease of sea <span class="hlt">ice</span> cover around <span class="hlt">Svalbard</span>. By 2085, SMB is projected to become negative over all of <span class="hlt">Svalbard</span>'s glaciated regions, leading to the rapid degradation of the firn layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ERL....12b4016M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ERL....12b4016M"><span>Mass budget of the glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> of the Queen Elizabeth Islands, Canada, from 1991 to 2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Millan, Romain; Mouginot, Jeremie; Rignot, Eric</p> <p>2017-02-01</p> <p>Recent studies indicate that the glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> in Queen Elizabeth Islands (QEI), Canada have experienced an increase in <span class="hlt">ice</span> mass loss during the last two decades, but the contribution of <span class="hlt">ice</span> dynamics to this loss is not well known. We present a comprehensive mapping of <span class="hlt">ice</span> velocity using a suite of satellite data from year 1991 to 2015, combined with <span class="hlt">ice</span> thickness data from NASA Operation <span class="hlt">Ice</span>Bridge, to calculate <span class="hlt">ice</span> discharge. We find that <span class="hlt">ice</span> discharge increased significantly after 2011 in Prince of Wales Icefield, maintained or decreased in other sectors, whereas glacier surges have little impact on long-term trends in <span class="hlt">ice</span> discharge. During 1991-2005, the QEI mass loss averaged 6.3 ± 1.1 Gt yr-1, 52% from <span class="hlt">ice</span> discharge and the rest from surface mass balance (SMB). During 2005-2014, the mass loss from <span class="hlt">ice</span> discharge averaged 3.5 ± 0.2 Gt yr-1 (10%) versus 29.6 ± 3.0 Gt yr-1 (90%) from SMB. SMB processes therefore dominate the QEI mass balance, with <span class="hlt">ice</span> dynamics playing a significant role only in a few basins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C11B0377L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C11B0377L"><span>The melting sea <span class="hlt">ice</span> of Arctic polar <span class="hlt">cap</span> in the summer solstice month and the role of ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, S.; Yi, Y.</p> <p>2014-12-01</p> <p>The Arctic sea <span class="hlt">ice</span> is becoming smaller and thinner than climatological standard normal and more fragmented in the early summer. We investigated the widely changing Arctic sea <span class="hlt">ice</span> using the daily sea <span class="hlt">ice</span> concentration data. Sea <span class="hlt">ice</span> data is generated from brightness temperature data derived from the sensors: Defense Meteorological Satellite Program (DMSP)-F13 Special Sensor Microwave/Imagers (SSM/Is), the DMSP-F17 Special Sensor Microwave Imager/Sounder (SSMIS) and the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) instrument on the NASA Earth Observing System (EOS) Aqua satellite. We tried to figure out appearance of arctic sea <span class="hlt">ice</span> melting region of polar <span class="hlt">cap</span> from the data of passive microwave sensors. It is hard to explain polar sea <span class="hlt">ice</span> melting only by atmosphere effects like surface air temperature or wind. Thus, our hypothesis explaining this phenomenon is that the heat from deep undersea in Arctic Ocean ridges and the hydrothermal vents might be contributing to the melting of Arctic sea <span class="hlt">ice</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMGC21D0992B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMGC21D0992B"><span>Surface Exposure Dating of the Huancané III Moraines in Peru: A Record of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>'s Maximum Extent during the Last Glacial Period</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baranes, H. E.; Kelly, M. A.; Stroup, J. S.; Howley, J. A.; Lowell, T. V.</p> <p>2012-12-01</p> <p>The climatic conditions that influenced the tropics during the height of the last glacial period are not well defined and controversial. There are disparities in estimates of temperature anomalies (e.g., MARGO, 2009; Rind and Peteet, 1985; CLIMAP, 1976), and critical terrestrial paleotemperature proxy records in tropical regions are poorly dated (e.g., Porter, 2001). Defining these conditions is important for understanding the mechanisms that cause major shifts in climate, as the tropics are a primary driver of atmospheric and oceanic circulation. This study aims to constrain the timing of maximum glacier extents in the Cordillera Oriental in southern Peru during the last glacial period by applying surface exposure (beryllium-10) dating to the Huancané III (Hu-III) moraines. The Hu-III moraines mark the maximum extent of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> (QIC) (13.93°S, 70.83°W), the largest tropical <span class="hlt">ice</span> <span class="hlt">cap</span>, during the last <span class="hlt">ice</span> age. The eight beryllium-10 ages presented here yield 17,056 ± 520 yrs ago as a minimum age for the onset of recession from the <span class="hlt">ice</span> <span class="hlt">cap</span> advance marked by the Hu-III moraines. Comparing this age to other paleoclimate records indicates that the <span class="hlt">ice</span> <span class="hlt">cap</span> advance marked by the Hu-III moraines is more likely associated with a North Atlantic climate event known as Heinrich I (H1; 16,800 yrs ago, Bond et al., 1992, 1993) than with global cooling at the Last Glacial Maximum (LGM; ~21,000 yrs ago, Denton and Hughes, 1981). This result suggests that climate processes in the North Atlantic region are linked to climatic conditions in the tropical Andes. A mesoscale climate model and an <span class="hlt">ice</span>-flow model are currently being developed for QIC. The moraine data presented in this study will be used with these two models to test response of QIC to North Atlantic and global climate events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70011316','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70011316"><span>Norwegian remote sensing experiment in a marginal <span class="hlt">ice</span> zone</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Farrelly, B.; Johannessen, J.A.; Svendsen, E.; Kloster, K.; Horjen, I.; Matzler, C.; Crawford, J.; Harrington, R.; Jones, L.; Swift, C.; Delnore, V.E.; Cavalieri, D.; Gloersen, P.; Hsiao, S.V.; Shemdin, O.H.; Thompson, T.W.; Ramseier, R.O.; Johannessen, O.M.; Campbell, W.J.</p> <p>1983-01-01</p> <p>The Norwegian Remote Sensing Experiment in the marginal <span class="hlt">ice</span> zone north of <span class="hlt">Svalbard</span> took place in fall 1979. Coordinated passive and active microwave measurements were obtained from shipborne, airborne, and satellite instruments together with in situ observations. The obtained spectra of emissivity (frequency range, 5 to 100 gigahertz) should improve identification of <span class="hlt">ice</span> types and estimates of <span class="hlt">ice</span> concentration. Mesoscale features along the <span class="hlt">ice</span> edge were revealed by a 1.215-gigahertz synthetic aperture radar. <span class="hlt">Ice</span> edge location by the Nimbus 7 scanning multichannel microwave radiometer was shown to be accurate to within 10 kilometers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017TCry...11.1501B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017TCry...11.1501B"><span>Winter mass balance of Drangajökull <span class="hlt">ice</span> <span class="hlt">cap</span> (NW Iceland) derived from satellite sub-meter stereo images</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Belart, Joaquín M. C.; Berthier, Etienne; Magnússon, Eyjólfur; Anderson, Leif S.; Pálsson, Finnur; Thorsteinsson, Thorsteinn; Howat, Ian M.; Aðalgeirsdóttir, Guðfinna; Jóhannesson, Tómas; Jarosch, Alexander H.</p> <p>2017-06-01</p> <p>Sub-meter resolution, stereoscopic satellite images allow for the generation of accurate and high-resolution digital elevation models (DEMs) over glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span>. Here, repeated stereo images of Drangajökull <span class="hlt">ice</span> <span class="hlt">cap</span> (NW Iceland) from Pléiades and WorldView2 (WV2) are combined with in situ estimates of snow density and densification of firn and fresh snow to provide the first estimates of the glacier-wide geodetic winter mass balance obtained from satellite imagery. Statistics in snow- and <span class="hlt">ice</span>-free areas reveal similar vertical relative accuracy (< 0.5 m) with and without ground control points (GCPs), demonstrating the capability for measuring seasonal snow accumulation. The calculated winter (14 October 2014 to 22 May 2015) mass balance of Drangajökull was 3.33 ± 0.23 m w.e. (meter water equivalent), with ∼ 60 % of the accumulation occurring by February, which is in good agreement with nearby ground observations. On average, the repeated DEMs yield 22 % less elevation change than the length of eight winter snow cores due to (1) the time difference between in situ and satellite observations, (2) firn densification and (3) elevation changes due to <span class="hlt">ice</span> dynamics. The contributions of these three factors were of similar magnitude. This study demonstrates that seasonal geodetic mass balance can, in many areas, be estimated from sub-meter resolution satellite stereo images.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760012427','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760012427"><span>Sea <span class="hlt">ice</span> studies in the Spitsbergen-Greenland area</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vinje, T. E. (Principal Investigator)</p> <p>1976-01-01</p> <p>The author has identified the following significant results. Data showed unexpected great variations in the drift velocity of the <span class="hlt">ice</span> in the Fram Strait. Land map improvements were achieved by LANDSAT in the eastern part of the <span class="hlt">Svalbard</span> archipelago.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016QSRv..132...74L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016QSRv..132...74L"><span>A new concept for glacial geological investigations of surges, based on High-Arctic examples (<span class="hlt">Svalbard</span>)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lønne, Ida</p> <p>2016-01-01</p> <p><span class="hlt">Svalbard</span> is a key area for the investigation of glacial surges, and almost two centuries worth of field observations exists from this region. Studies have shown that the course of a surge and the associated formation of landforms are strongly influenced by basinal factors, and that the broad range of variables involved can hamper interpretations and comparisons. Based on a review of surges in <span class="hlt">Svalbard</span>, a new concept for glacial geological investigations has been developed that combines <span class="hlt">ice</span>-flows, <span class="hlt">ice</span>-front movements, and morphostratigraphy. The concept is comprised of the following four elements: 1) classification based on the configuration and characteristics of the receiving basin, 2) division of the surge cycle into six stages, 3) guidelines for morphological mapping, and 4) use of an allostratigraphic approach for interpreting <span class="hlt">ice</span>-front movements. In this context, delineation of the active phase is critical, which include the history of terminus movements, and four main categories of receiving basins are recognized. These are (A) terrestrial basins with deformable substrates, (B) terrestrial basins with poorly deformable substrates, (C) shallow water basins, and (D) deep water basins. The <span class="hlt">ice</span>-front movement history is reconstructed by coupling information from the proglacial moraines (syn-surge), the supraglacial moraines (post-surge), and the associated traces of meltwater to the surge stages (I-VI). This approach has revealed a critical relationship between the termination of the active phase and three morphological elements, namely, the maximum <span class="hlt">ice</span>-front position, the maximum moraine extent and the youngest proglacial moraine, which are unique for each of the basins A-D. The concept is thus a novel and more precise approach for mapping the active phase and the active phase duration, as shown by the ∼12-year long surge of Fridtjovbreen, where stage I was 30 months (inception), stage II was 54 months (<span class="hlt">ice</span>-front advance), stage III was 12 months (stillstand</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.A31A0075D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.A31A0075D"><span>The impact of 21st Century sea <span class="hlt">ice</span> decline on the hydrological budget of the Arctic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Day, J. J.; Bamber, J. L.; Valdes, P. J.; Kohler, J.</p> <p>2009-12-01</p> <p>The Arctic is a region particularly susceptible to rapid climate change. GCMs suggest a polar amplification of any global warming signal by about 1.5 due, largely, to sea <span class="hlt">ice</span> feedbacks. The dramatic recent decline in multi-year <span class="hlt">ice</span> cover lies outside the standard deviation of the ensemble GCM predictions and has lead to the suggestion that the Arctic Ocean could be <span class="hlt">ice</span> free in summer as soon as ~2014. Sea <span class="hlt">ice</span> acts as a barrier between cold air and warmer oceans during winter, as well as inhibiting evaporation from the water below during the summer. An <span class="hlt">ice</span> free Arctic would likely have an altered hydrological cycle with more evaporation from the ocean surface leading to changes in precipitation distribution and amount. For example, changes in sea <span class="hlt">ice</span> cover are thought to have caused changes in the mass balance of Europe’s largest <span class="hlt">ice</span> <span class="hlt">cap</span>, Austfona, <span class="hlt">Svalbard</span>, by increasing accumulation. Using the U.K. Met Office Regional Climate Model (RCM), HadRM3, the atmospheric effects of the observed and projected reduction in Arctic sea <span class="hlt">ice</span> are investigated. The RCM is driven by the atmosphere only general circulation model HadAM3. Both models are forced with sea surface temperature and sea <span class="hlt">ice</span> obtained by extrapolating recent changes into the future using bootstrapping based on the HadISST climatology. Here we use an RCM at 25km resolution over the Arctic which captures well the present-day pattern of precipitation and provides a detailed picture of the projected changes in the behaviour of the oceanic-atmosphere moisture fluxes and how they affect precipitation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPP43B2314V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPP43B2314V"><span>Alkenone-based reconstructions show four-phase Holocene temperature history for Arctic <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van der Bilt, W. G. M.; D'Andrea, W. J.; Bakke, J.; Balascio, N.; Werner, J.; Bradley, R. S.</p> <p>2016-12-01</p> <p>Situated at the crossroads of global oceanic and atmospheric circulation patterns, the Arctic is a key component of Earth`s climate system. Amplified by sea-<span class="hlt">ice</span> feedbacks, even modest shifts in regional heat budget drive large climate responses. This is highlighted by the dramatic response of the Arctic to global warming. Assessing the signature of underlying forcings require paleoclimate records, allowing us to expand our knowledge beyond the short instrumental period and contextualize ongoing warming. However, such data are scarce and sparse in the Arctic, limiting our ability to address these issues. We present two quantitative Holocene-length summer temperature reconstructions from the Arctic <span class="hlt">Svalbard</span> archipelago. Temperature estimates are based on alkenone unsaturation ratios measured on sediment cores from two lakes. Our data reveal a dynamic Holocene temperature history, with reconstructed lake water temperatures spanning a range of 6-8 °C, and characterized by four phases. The Early Holocene was marked by an early ( 10.5 ka cal. BP) onset of insolation-driven Hypsithermal conditions, likely compounded by strengthening oceanic heat transport. This warm interval was interrupted by cooling between 10.5-8.3 ka cal. BP that we attribute to cooling effects from the melting Northern Hemisphere <span class="hlt">ice</span> sheets. Temperatures declined throughout the Middle Holocene, following a gradual trend that was accentuated by two cooling steps between 7.8-7 ka cal. BP and 4.4-3.5 ka cal. BP. These transitions coincide with a strengthening influence of Arctic water and sea-<span class="hlt">ice</span> in the adjacent eastern Fram Strait. During the Late Holocene (past 4 ka), temperature change decoupled from the still-declining insolation, and fluctuated around cold mean conditions. This study improves our understanding of Arctic climate dynamics by demonstrating that Holocene <span class="hlt">Svalbard</span> temperatures were governed by an alternation of forcing mechanism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.6838K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.6838K"><span>Late Quaternary sea-<span class="hlt">ice</span> history of northern Fram Strait/Arctic Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kremer, Anne; Stein, Rüdiger; Fahl, Kirsten; Matthießen, Jens; Forwick, Matthias; O'Regan, Matt</p> <p>2016-04-01</p> <p>One of the main characteristics of the Arctic Ocean is its seasonal to perennial sea-<span class="hlt">ice</span> cover. Variations of sea-<span class="hlt">ice</span> conditions affect the Earth's albedo, primary production, rate of deep-water etc.. During the last decades, a drastic decrease in sea <span class="hlt">ice</span> has been recorded, and the causes of which, i.e., natural vs. anthropogenic forcings, and their relevance within the global climate system, are subject of intense scientific and societal debate. In this context, records of past sea-<span class="hlt">ice</span> conditions going beyond instrumental records are of major significance. These records may help to better understand the processes controlling natural sea-<span class="hlt">ice</span> variability and to improve models for forecasts of future climatic conditions. During RV Polarstern Cruise PS92 in summer 2015, a 860 cm long sediment core (PS92/039-2) was recovered from the eastern flank of Yermak Plateau north of the <span class="hlt">Svalbard</span> archipelago (Peeken, 2015). Based on a preliminary age model, this sediment core probably represents the time interval from MIS 6 to MIS 1. This core, located close to the modern summer <span class="hlt">ice</span> edge, has been selected for reconstruction of past Arctic sea-<span class="hlt">ice</span> variability based on specific biomarkers. In this context, we have determined the <span class="hlt">ice</span>-algae-derived sea-<span class="hlt">ice</span> proxy IP25 (Belt et al., 2007), in combination with other biomarkers indicative for open-water conditions (cf., Müller et al., 2009, 2011). Furthermore, organic carbon fluxes were differentiated using specific biomarkers indicative for marine primary production (brassicasterol, dinosterol) and terrigenous input (campesterol, β-sitosterol). In this poster, preliminary results of our organic-geochemical and sedimentological investigations are presented. Distinct fluctuations of these biomarkers indicate several major, partly abrupt changes in sea-<span class="hlt">ice</span> cover in the Yermak Plateau area during the late Quaternary. These changes are probably linked to changes in the inflow of Atlantic Water along the western coastline of <span class="hlt">Svalbard</span> into</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.C43B0802K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.C43B0802K"><span>Towards Quantification of Glacier Dynamic <span class="hlt">Ice</span> Loss through Passive Seismic Monitoring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Köhler, A.; Nuth, C.; Weidle, C.; Schweitzer, J.; Kohler, J.; Buscaino, G.</p> <p>2015-12-01</p> <p>Global glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> loose mass through calving, while existing models are currently not equipped to realistically predict dynamic <span class="hlt">ice</span> loss. This is mainly because long-term continuous calving records, that would help to better understand fine scale processes and key climatic-dynamic feedbacks between calving, climate, terminus evolution and marine conditions, do not exist. Combined passive seismic/acoustic strategies are the only technique able to capture rapid calving events continuously, independent of daylight or meteorological conditions. We have produced such a continuous calving record for Kronebreen, a tidewater glacier in <span class="hlt">Svalbard</span>, using data from permanent seismic stations between 2001 and 2014. However, currently no method has been established in cryo-seismology to quantify the calving <span class="hlt">ice</span> loss directly from seismic data. Independent calibration data is required to derive 1) a realistic estimation of the dynamic <span class="hlt">ice</span> loss unobserved due to seismic noise and 2) a robust scaling of seismic calving signals to <span class="hlt">ice</span> volumes. Here, we analyze the seismic calving record at Kronebreen and independent calving data in a first attempt to quantify <span class="hlt">ice</span> loss directly from seismic records. We make use of a) calving flux data with weekly to monthly resolution obtained from satellite remote sensing and GPS data between 2007 and 2013, and b) direct, visual calving observations in two weeks in 2009 and 2010. Furthermore, the magnitude-scaling property of seismic calving events is analyzed. We derive and discuss an empirical relation between seismic calving events and calving flux which for the first time allows to estimate a time series of calving volumes more than one decade back in time. Improving our model requires to incorporate more precise, high-resolution calibration data. A new field campaign will combine innovative, multi-disciplinary monitoring techniques to measure calving <span class="hlt">ice</span> volumes and dynamic <span class="hlt">ice</span>-ocean interactions simultaneously with terrestrial laser</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70031338','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70031338"><span>Monitoring and modeling <span class="hlt">ice</span>-rock avalanches from <span class="hlt">ice-capped</span> volcanoes: A case study of frequent large avalanches on Iliamna Volcano, Alaska</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Huggel, C.; Caplan-Auerbach, J.; Waythomas, C.F.; Wessels, R.L.</p> <p>2007-01-01</p> <p>Iliamna is an andesitic stratovolcano of the Aleutian arc with regular gas and steam emissions and mantled by several large glaciers. Iliamna Volcano exhibits an unusual combination of frequent and large <span class="hlt">ice</span>-rock avalanches in the order of 1 ?? 106??m3 to 3 ?? 107??m3 with recent return periods of 2-4??years. We have reconstructed an avalanche event record for the past 45??years that indicates Iliamna avalanches occur at higher frequency at a given magnitude than other mass failures in volcanic and alpine environments. Iliamna Volcano is thus an ideal site to study such mass failures and its relation to volcanic activity. In this study, we present different methods that fit into a concept of (1) long-term monitoring, (2) early warning, and (3) event documentation and analysis of <span class="hlt">ice</span>-rock avalanches on <span class="hlt">ice-capped</span> active volcanoes. Long-term monitoring methods include seismic signal analysis, and space-and airborne observations. Landsat and ASTER satellite data was used to study the extent of hydrothermally altered rocks and surface thermal anomalies at the summit region of Iliamna. Subpixel heat source calculation for the summit regions where avalanches initiate yielded temperatures of 307 to 613??K assuming heat source areas of 1000 to 25??m2, respectively, indicating strong convective heat flux processes. Such heat flow causes <span class="hlt">ice</span> melting conditions and is thus likely to reduce the strength at the base of the glacier. We furthermore demonstrate typical seismic records of Iliamna avalanches with rarely observed precursory signals up to two hours prior to failure, and show how such signals could be used for a multi-stage avalanche warning system in the future. For event analysis and documentation, space- and airborne observations and seismic records in combination with SRTM and ASTER derived terrain data allowed us to reconstruct avalanche dynamics and to identify remarkably similar failure and propagation mechanisms of Iliamna avalanches for the past 45??years</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.C33A0663K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.C33A0663K"><span>Evidence for smaller extents of the northwestern Greenland <span class="hlt">Ice</span> Sheet and North <span class="hlt">Ice</span> <span class="hlt">Cap</span> during the Holocene</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelly, M. A.; Osterberg, E. C.; Axford, Y.; Bigl, M.; Birkel, S. D.; Corbett, L. B.; Roy, E. P.; Thompson, J. T.; Whitecloud, S.</p> <p>2013-12-01</p> <p>The Greenland <span class="hlt">Ice</span> Sheet (GrIS) and local glaciers on Greenland are responding dynamically to warming temperatures with widespread retreat. GRACE satellite data (e.g., Kahn et al., 2010) and the Petermann Glacier calving events document the recent expansion of <span class="hlt">ice</span> loss into northwestern Greenland. To improve the ability to estimate future <span class="hlt">ice</span> loss in a warming climate, we are developing records of the response of the northwestern Greenlandic cryosphere to Holocene climatic conditions, with a focus on past warm periods. Our ongoing research includes analyses of glacial geology, sub-fossil vegetation, lake sediment cores, chironomid assemblages and <span class="hlt">ice</span> cores combined with glaciological modeling. To constrain past <span class="hlt">ice</span> extents that were as small as, or smaller than, at present, we recovered sub-fossil vegetation exposed at the receding margins of the GrIS and North <span class="hlt">Ice</span> <span class="hlt">Cap</span> (NIC) in the Nunatarssuaq region (~76.7°N, 67.4°W) and of the GrIS near Thule (~76.5°N, 68.7°W). We present vegetation types and radiocarbon ages of 30 plant samples collected in August 2012. In the Nunatarssuaq region, five ages of in situ (rooted) vegetation including Polytrichum moss, Saxifraga nathorstii and grasses located <5 m outboard of the GrIS margin are ~120-200 cal yr BP (range of medians of the 2-sigma calibrated age ranges). Nine ages of in situ Polytrichum, Saxifraga oppositafolia and grasses from ~1-5 m inboard of the NIC margin (excavated from beneath <span class="hlt">ice</span>) range from ~50 to 310 cal yr BP. The growth of these plants occurred when the GrIS and NIC were at least as small as at present and their ages suggest that <span class="hlt">ice</span> advances occurred in the last 50-120 yrs. In addition to the in situ samples, we collected plants from well-preserved ground material exposed along shear planes in the GrIS margins. In Nunatarssuaq, two Polytrichum mosses rooted in ground material and exposed along a shear plane in the GrIS margin date to 4680 and 4730 cal yr BP. Near Thule, three ages of Salix arctica</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C14A..04T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C14A..04T"><span>Changes of Arctic Marine Glaciers and <span class="hlt">Ice</span> <span class="hlt">Caps</span> from CryoSat Swath Altimetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tepes, P.; Gourmelen, N.; Weissgerber, F.; Escorihuela, M. J.; Wuite, J.; Nagler, T.; Foresta, L.; Brockley, D.; Baker, S.; Roca, M.; Shepherd, A.; Plummer, S.</p> <p>2017-12-01</p> <p>Glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> (GICs) are major contributors to the current budget of global mean sea level change. <span class="hlt">Ice</span> losses from GICs are expected to increase over the next century and beyond (Gardner et al., 2011), particularly in the Arctic where mean annual surface temperatures have recently been increasing twice as fast as the global average (Screen and Simmonds, 2010). Investigating cryospheric changes over GICs from space-based observations has proven to be challenging due in large part to the limited spatial and temporal resolution of present day observation techniques compared to the relatively small size and the steep and complex terrain that often define GICs. As a result, not much is known about modern changes in <span class="hlt">ice</span> mass in most of these smaller glaciated regions of the Arctic (Moholdt et al., 2012; Carr et al., 2014). Radar altimetry is well suited to monitoring elevation changes over land <span class="hlt">ice</span> due to its all-weather year-round capability of observing <span class="hlt">ice</span> surfaces. Since 2010, the Synthetic Interferometric Radar Altimeter (SIRAL) on board the European Space Agency (ESA) radar altimetry CryoSat (CS) mission has been collecting <span class="hlt">ice</span> elevation measurements over GICs. Data from the CS-SARIn mode have been used to infer high resolution elevation and elevation change rates using "swath processing" (Hawley et al., 2009; Gray et al., 2013; Christie et al., 2016; Foresta et al., 2016; Smith et al., 2016). Together with a denser ground track interspacing of the CS mission, swath processing provides measurements at unprecedented spatial coverage and resolution, enabling the study of key processes that underlie current changes of GICs in the Arctic. In this study, we use CS swath observations to identify patterns of change of marine versus land-terminating glaciers across the Arctic. We generate maps of <span class="hlt">ice</span> elevation change rates and present estimates of volumetric changes for GICs outside of Greenland. We then compare marine versus land terminating glaciers in terms of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC11F..01T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC11F..01T"><span>Climate Changes Documented in <span class="hlt">Ice</span> Core Records from Third Pole Glaciers, with Emphasis on the Guliya <span class="hlt">Ice</span> <span class="hlt">Cap</span> in the Western Kunlun Mountains over the Last 100 Years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, L. G.; Yao, T.; Beaudon, E.; Mosley-Thompson, E.; Davis, M. E.; Kenny, D. V.; Lin, P. N.</p> <p>2016-12-01</p> <p>The Third Pole (TP) is a rapidly warming region containing 100,000 km2 of <span class="hlt">ice</span> cover that collectively holds one of Earth's largest stores of freshwater that feeds Asia's largest rivers and helps sustain 1.5 billion people. Information on the accelerating warming in the region, its impact on the glaciers and subsequently on future water resources is urgently needed to guide mitigation and adaptation policies. <span class="hlt">Ice</span> core histories collected over the last three decades across the TP demonstrate its climatic complexity and diversity. Here we present preliminary results from the flagship project of the Third Pole Environment Program, the 2015 Sino-American cooperative <span class="hlt">ice</span> core drilling of the Guliya <span class="hlt">ice</span> <span class="hlt">cap</span> in the Kunlun Mountains in the western TP near the northern limit of the region influenced by the southwest monsoon. Three <span class="hlt">ice</span> cores, each 51 meters in length, were recovered from the summit ( 6700 masl) while two deeper cores, one to bedrock ( 310 meters), were recovered from the plateau ( 6200 masl). Across the <span class="hlt">ice</span> <span class="hlt">cap</span> the net balance (accumulation) has increased annually by 2.3 cm of water equivalent from 1963-1992 to 1992-2015, and average oxygen isotopic ratios (δ18O) have enriched by 2‰. This contrasts with the recent ablation on the Naimona'nyi glacier located 540 km south of Guliya in the western Himalaya. Borehole temperatures in 2015 on the Guliya plateau have warmed substantially in the upper 30 meters of the <span class="hlt">ice</span> compared to temperatures in 1992, when the first deep-drilling of the Guliya plateau was conducted. Compared with glaciers in the northern and western TP, the Himalayan <span class="hlt">ice</span> fields are more sensitive to both fluctuations in the South Asian Monsoon and rising temperatures in the region. We examine the climatic changes of the last century preserved in <span class="hlt">ice</span> core records from sites throughout the TP and compare them with those reconstructed for earlier warm epochs, such as the Medieval Climate Anomaly ( 950-1250 AD), the early Holocene "Hypsithermal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25536177','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25536177"><span>Levels and temporal trends of persistent organic pollutants (POPs) in arctic foxes (Vulpes lagopus) from <span class="hlt">Svalbard</span> in relation to dietary habits and food availability.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Andersen, Martin S; Fuglei, Eva; König, Max; Lipasti, Inka; Pedersen, Åshild Ø; Polder, Anuschka; Yoccoz, Nigel G; Routti, Heli</p> <p>2015-04-01</p> <p>Temporal trends of persistent organic pollutants (POPs) in arctic foxes (Vulpes lagopus) from <span class="hlt">Svalbard</span>, Norway, were investigated in relation to feeding habits and seasonal food availability. Arctic foxes from <span class="hlt">Svalbard</span> forage in both marine and terrestrial ecosystems and the availability of their food items are impacted by climatic variability. Concentrations of polychlorinated biphenyls (PCBs), organochlorinated pesticides (OCPs) and brominated flame retardants (polybrominated diphenyl ethers [PBDEs] and hexabromocyclododecane [HBCDD]) were analyzed in the liver of 141 arctic foxes collected between 1997 and 2013. Stable carbon isotope values (δ13C) were used as a proxy for feeding on marine versus terrestrial prey. The annual number of recovered reindeer carcasses and sea <span class="hlt">ice</span> cover were used as proxies for climate influenced food availability (reindeers, seals). Linear models revealed that concentrations of PCBs, chlordanes, p,p'-DDE, mirex and PBDEs decreased 4-11% per year, while no trends were observed for hexachlorobenzene (HCB) or β-hexachlorocyclohexane (β-HCH). Positive relationships between POP concentrations and δ13C indicate that concentrations of all compounds increase with increasing marine dietary input. Increasing reindeer mortality was related to lower HCB concentrations in the foxes based on the linear models. This suggests that concentrations of HCB in arctic foxes may be influenced by high mortality levels of <span class="hlt">Svalbard</span> reindeer. Further, β-HCH concentrations showed a positive association with sea <span class="hlt">ice</span> cover. These results in addition to the strong effect of δ13C on all POP concentrations suggest that climate-related changes in arctic fox diet are likely to influence contaminant concentrations in arctic foxes from <span class="hlt">Svalbard</span>. Copyright © 2014 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870060018&hterms=marginal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmarginal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870060018&hterms=marginal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmarginal"><span>Variations of mesoscale and large-scale sea <span class="hlt">ice</span> morphology in the 1984 Marginal <span class="hlt">Ice</span> Zone Experiment as observed by microwave remote sensing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Campbell, W. J.; Josberger, E. G.; Gloersen, P.; Johannessen, O. M.; Guest, P. S.</p> <p>1987-01-01</p> <p>The data acquired during the summer 1984 Marginal <span class="hlt">Ice</span> Zone Experiment in the Fram Strait-Greenland Sea marginal <span class="hlt">ice</span> zone, using airborne active and passive microwave sensors and the Nimbus 7 SMMR, were analyzed to compile a sequential description of the mesoscale and large-scale <span class="hlt">ice</span> morphology variations during the period of June 6 - July 16, 1984. Throughout the experiment, the long <span class="hlt">ice</span> edge between northwest <span class="hlt">Svalbard</span> and central Greenland meandered; eddies were repeatedly formed, moved, and disappeared but the <span class="hlt">ice</span> edge remained within a 100-km-wide zone. The <span class="hlt">ice</span> pack behind this alternately diffuse and compact edge underwent rapid and pronounced variations in <span class="hlt">ice</span> concentration over a 200-km-wide zone. The high-resolution <span class="hlt">ice</span> concentration distributions obtained in the aircraft images agree well with the low-resolution distributions of SMMR images.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC23D1175M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC23D1175M"><span>Sea <span class="hlt">ice</span>-induced cold air advection as a mechanism controlling tundra primary productivity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Macias-Fauria, M.; Karlsen, S. R.</p> <p>2015-12-01</p> <p>The recent sharp decline in Arctic sea <span class="hlt">ice</span> extent, concentration, and volume leaves urgent questions regarding its effects on ecological processes. Changes in tundra productivity have been associated with sea <span class="hlt">ice</span> dynamics on the basis that most tundra ecosystems lay close to the sea. Although some studies have addressed the potential effect of sea <span class="hlt">ice</span> decline on the primary productivity of terrestrial arctic ecosystems (Bhatt et al., 2010), a clear picture of the mechanisms and patterns linking both processes remains elusive. We hypothesised that sea <span class="hlt">ice</span> might influence tundra productivity through 1) cold air advection during the growing season (direct/weather effect) or 2) changes in regional climate induced by changes in sea <span class="hlt">ice</span> (indirect/climate effect). We present a test on the direct/weather effect hypothesis: that is, tundra productivity is coupled with sea <span class="hlt">ice</span> when sea <span class="hlt">ice</span> remains close enough from land vegetation during the growing season for cold air advection to limit temperatures locally. We employed weekly MODIS-derived Normalised Difference Vegetation Index (as a proxy for primary productivity) and sea <span class="hlt">ice</span> data at a spatial resolution of 232m for the period 2000-2014 (included), covering the <span class="hlt">Svalbard</span> Archipelago. Our results suggest that sea <span class="hlt">ice</span>-induced cold air advection is a likely mechanism to explain patterns of NDVI trends and heterogeneous spatial dynamics in the <span class="hlt">Svalbard</span> archipelago. The mechanism offers the potential to explain sea <span class="hlt">ice</span>/tundra productivity dynamics in other Arctic areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920024481&hterms=Frost&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DFrost','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920024481&hterms=Frost&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DFrost"><span>Sunlight penetration through the Martian polar <span class="hlt">caps</span>: Effects on the thermal and frost budgets</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lindner, Bernhard Lee</p> <p>1992-01-01</p> <p>An energy balance model of the seasonal polar <span class="hlt">caps</span> on Mars is modified to include penetration of solar radiation into and through the <span class="hlt">ice</span>. Penetration of solar radiation has no effect on subsurface temperature or total frost sublimation if seasonal <span class="hlt">ice</span> overlies a dust surface. An effect is noted for seasonal <span class="hlt">ice</span> which overlies the residual polar <span class="hlt">caps</span>. For the case of an exposed water-<span class="hlt">ice</span> residual polar <span class="hlt">cap</span>, the temperature at depth is calculated to be up to several degrees warmer and the calculated lifetime of seasonal CO2 frost is slightly lower when penetration of sunlight is properly treated in the model. For the case of a residual polar <span class="hlt">cap</span> which is perennially covered by CO2 frost, the calculated lifetime of seasonal CO2 frost is very slightly increased as a result of sunlight penetration through the <span class="hlt">ice</span>. Hence, penetration of sunlight into the <span class="hlt">ice</span> helps to stabilize the observed dichotomy in the residual polar <span class="hlt">caps</span> on Mars, although it is a small effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920071989&hterms=Frost&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DFrost','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920071989&hterms=Frost&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DFrost"><span>Sunlight penetration through the Martian polar <span class="hlt">caps</span> - Effects on the thermal and frost budgets</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lindner, Bernhard L.</p> <p>1992-01-01</p> <p>An energy balance model of the seasonal polar <span class="hlt">caps</span> on Mars is modified to include penetration of solar radiation into and through the <span class="hlt">ice</span>. Penetration of solar radiation has no effect on subsurface temperature or total frost sublimation if seasonal <span class="hlt">ice</span> overlies a dust surface. An effect is noted for seasonal <span class="hlt">ice</span> which overlies the residual polar <span class="hlt">caps</span>. For the case of an exposed water-<span class="hlt">ice</span> residual polar <span class="hlt">cap</span>, the temperature at depth is calculated to be up to several degrees warmer, and the calculated lifetime of seasonal CO2 frost is slightly lower when penetration of sunlight is properly treated in the model. For the case of a residual polar <span class="hlt">cap</span> which is perennially covered by CO2 frost, the calculated lifetime of seasonal CO2 frost is very slightly increased as a result of sunlight penetration through the <span class="hlt">ice</span>. Hence, penetration of sunlight into the <span class="hlt">ice</span> helps to stabilize the observed dichotomy in the residual polar <span class="hlt">caps</span> on Mars, although it is a small effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017TCry...11..191I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017TCry...11..191I"><span>Diagnosing the decline in climatic mass balance of glaciers in <span class="hlt">Svalbard</span> over 1957-2014</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ims Østby, Torbjørn; Vikhamar Schuler, Thomas; Ove Hagen, Jon; Hock, Regine; Kohler, Jack; Reijmer, Carleen H.</p> <p>2017-01-01</p> <p>Estimating the long-term mass balance of the high-Arctic <span class="hlt">Svalbard</span> archipelago is difficult due to the incomplete geodetic and direct glaciological measurements, both in space and time. To close these gaps, we use a coupled surface energy balance and snow pack model to analyse the mass changes of all <span class="hlt">Svalbard</span> glaciers for the period 1957-2014. The model is forced by ERA-40 and ERA-Interim reanalysis data, downscaled to 1 km resolution. The model is validated using snow/firn temperature and density measurements, mass balance from stakes and <span class="hlt">ice</span> cores, meteorological measurements, snow depths from radar profiles and remotely sensed surface albedo and skin temperatures. Overall model performance is good, but it varies regionally. Over the entire period the model yields a climatic mass balance of 8.2 cm w. e. yr-1, which corresponds to a mass input of 175 Gt. Climatic mass balance has a linear trend of -1.4 ± 0.4 cm w. e. yr-2 with a shift from a positive to a negative regime around 1980. Modelled mass balance exhibits large interannual variability, which is controlled by summer temperatures and further amplified by the albedo feedback. For the recent period 2004-2013 climatic mass balance was -21 cm w. e. yr-1, and accounting for frontal ablation estimated by Błaszczyk et al.(2009) yields a total <span class="hlt">Svalbard</span> mass balance of -39 cm w. e. yr-1 for this 10-year period. In terms of eustatic sea level, this corresponds to a rise of 0.037 mm yr-1. Refreezing of water in snow and firn is substantial at 22 cm w. e. yr-1 or 26 % of total annual accumulation. However, as warming leads to reduced firn area over the period, refreezing decreases both absolutely and relative to the total accumulation. Negative mass balance and elevated equilibrium line altitudes (ELAs) resulted in massive reduction of the thick (> 2 m) firn extent and an increase in the superimposed <span class="hlt">ice</span>, thin (< 2 m) firn and bare <span class="hlt">ice</span> extents. Atmospheric warming also leads to a marked change in the thermal regime</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..12210837M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..12210837M"><span>Winter snow conditions on Arctic sea <span class="hlt">ice</span> north of <span class="hlt">Svalbard</span> during the Norwegian young sea <span class="hlt">ICE</span> (N-<span class="hlt">ICE</span>2015) expedition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Merkouriadi, Ioanna; Gallet, Jean-Charles; Graham, Robert M.; Liston, Glen E.; Polashenski, Chris; Rösel, Anja; Gerland, Sebastian</p> <p>2017-10-01</p> <p>Snow is a crucial component of the Arctic sea <span class="hlt">ice</span> system. Its thickness and thermal properties control heat conduction and radiative fluxes across the ocean, <span class="hlt">ice</span>, and atmosphere interfaces. Hence, observations of the evolution of snow depth, density, thermal conductivity, and stratigraphy are crucial for the development of detailed snow numerical models predicting energy transfer through the snow pack. Snow depth is also a major uncertainty in predicting <span class="hlt">ice</span> thickness using remote sensing algorithms. Here we examine the winter spatial and temporal evolution of snow physical properties on first-year (FYI) and second-year <span class="hlt">ice</span> (SYI) in the Atlantic sector of the Arctic Ocean, during the Norwegian young sea <span class="hlt">ICE</span> (N-<span class="hlt">ICE</span>2015) expedition (January to March 2015). During N-<span class="hlt">ICE</span>2015, the snow pack consisted of faceted grains (47%), depth hoar (28%), and wind slab (13%), indicating very different snow stratigraphy compared to what was observed in the Pacific sector of the Arctic Ocean during the SHEBA campaign (1997-1998). Average snow bulk density was 345 kg m-3 and it varied with <span class="hlt">ice</span> type. Snow depth was 41 ± 19 cm in January and 56 ± 17 cm in February, which is significantly greater than earlier suggestions for this region. The snow water equivalent was 14.5 ± 5.3 cm over first-year <span class="hlt">ice</span> and 19 ± 5.4 cm over second-year <span class="hlt">ice</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27811967','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27811967"><span>Differences in Bacterial Diversity and Communities Between Glacial Snow and Glacial Soil on the Chongce <span class="hlt">Ice</span> <span class="hlt">Cap</span>, West Kunlun Mountains.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Guang Li; Hou, Shu Gui; Le Baoge, Ri; Li, Zhi Guo; Xu, Hao; Liu, Ya Ping; Du, Wen Tao; Liu, Yong Qin</p> <p>2016-11-04</p> <p>A detailed understanding of microbial ecology in different supraglacial habitats is important due to the unprecedented speed of glacier retreat. Differences in bacterial diversity and community structure between glacial snow and glacial soil on the Chongce <span class="hlt">Ice</span> <span class="hlt">Cap</span> were assessed using 454 pyrosequencing. Based on rarefaction curves, Chao1, ACE, and Shannon indices, we found that bacterial diversity in glacial snow was lower than that in glacial soil. Principal coordinate analysis (PCoA) and heatmap analysis indicated that there were major differences in bacterial communities between glacial snow and glacial soil. Most bacteria were different between the two habitats; however, there were some common bacteria shared between glacial snow and glacial soil. Some rare or functional bacterial resources were also present in the Chongce <span class="hlt">Ice</span> <span class="hlt">Cap</span>. These findings provide a preliminary understanding of the shifts in bacterial diversity and communities from glacial snow to glacial soil after the melting and inflow of glacial snow into glacial soil.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B21F..01H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B21F..01H"><span>Pedogenesis on <span class="hlt">ice</span> (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hodson, A. J.</p> <p>2010-12-01</p> <p>It is well known from <span class="hlt">ice</span> cores that organic and mineral debris accumulates within glacier <span class="hlt">ice</span> following atmospheric deposition. However, the concentrations of such debris are usually greatest upon the <span class="hlt">ice</span> surface, especially at the margins of continental glaciers and <span class="hlt">ice</span> sheets, where it forms mm-scale aggregate particles called “cryoconite”. According to the literature, cryoconite covers about 2 % of the ablation areas of glaciers outside Greenland and Antarctica, equivalent to a mass loading of ca. 25 g/m2. Of the great <span class="hlt">ice</span> sheets not included in this figure, Greenland is the easiest to estimate, and new observations from the NE and SW sectors indicate mass loadings in the range 17 - 440 g/m2. Studies of cryoconite often report the presence of a significant biomass (usually 10^4 - 10^7 cells/g) that is capable of a wide range of biogeochemical functions. The first part of this presentation will therefore explore the contention that the formation of cryoconite represents the first stages of pedogenesis, resulting in the production of soil-type aggregates that inoculate glacial forefields following glacier retreat. Emphasis will be given to the relevant processes that result in aggregate formation, including rapid cell-mineral attachment within melting snowpacks and the slower, biological processes of cementation within thermodynamically stable habitats such as cryoconite holes. The second part of the presentation will use examples from <span class="hlt">Svalbard</span>, Greenland and Antarctica to consider the carbon balance of the cryoconite during the longest phase of its life cycle: upon the <span class="hlt">ice</span>. It will be demonstrated how the efficacy of photosynthesis is strongly influenced by thermodynamic conditions at or near this surface. Data from the Greenland and Antarctic <span class="hlt">ice</span> sheets will show how thermal equilibration decouples variations in photosynthesis from variations in incident radiation over timescales > 1 d, resulting in an equitable, low-carbon economy for aggregates within</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.7879K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.7879K"><span>Tropospheric characteristics over sea <span class="hlt">ice</span> during N-<span class="hlt">ICE</span>2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kayser, Markus; Maturilli, Marion; Graham, Robert; Hudson, Stephen; Cohen, Lana; Rinke, Annette; Kim, Joo-Hong; Park, Sang-Jong; Moon, Woosok; Granskog, Mats</p> <p>2017-04-01</p> <p>Over recent years, the Arctic Ocean region has shifted towards a younger and thinner sea-<span class="hlt">ice</span> regime. The Norwegian young sea <span class="hlt">ICE</span> (N-<span class="hlt">ICE</span>2015) expedition was designed to investigate the atmosphere-snow-<span class="hlt">ice</span>-ocean interactions in this new <span class="hlt">ice</span> regime north of <span class="hlt">Svalbard</span>. Here we analyze upper-air measurements made by radiosondes launched twice daily together with surface meteorology observations during N-<span class="hlt">ICE</span>2015 from January to June 2015. We study the multiple cyclonic events observed during N-<span class="hlt">ICE</span>2015 with respect to changes in the vertical thermodynamic structure, sudden increases in moisture content and temperature, temperature inversions and boundary layer dynamics. The influence of synoptic cyclones is strongest under polar night conditions, when radiative cooling is most effective and the moisture content is low. We find that transitions between the radiatively clear and opaque state are the largest drivers of changes to temperature inversion and stability characteristics in the boundary layer during winter. In spring radiative fluxes warm the surface leading to lifted temperature inversions and a statically unstable boundary layer. The unique N-<span class="hlt">ICE</span>2015 dataset is used for case studies investigating changes in the vertical structure of the atmosphere under varying synoptic conditions. The goal is to deepen our understanding of synoptic interactions within the Arctic climate system, to improve model performance, as well as to identify gaps in instrumentation, which precludes further investigations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.9829W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.9829W"><span>Mass loss of the Greenland peripheral glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> from satellite altimetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wouters, Bert; Noël, Brice; Moholdt, Geir; Ligtenberg, Stefan; van den Broeke, Michiel</p> <p>2017-04-01</p> <p>At its rapidly warming margins, the Greenland <span class="hlt">Ice</span> Sheet is surrounded by (semi-)detached glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> (GIC). Although they cover only roughly 5% of the total glaciated area in the region, they are estimated to account for 15-20% of the total sea level rise contribution of Greenland. The spatial and temporal evolution of the mass changes of the peripheral GICs, however, remains poorly constrained. In this presentation, we use satellite altimetry from ICESat and Cryosat-2 combined with a high-resolution regional climate model to derive a 14 year time series (2003-2016) of regional elevation and mass changes. The total mass loss has been relatively constant during this period, but regionally, the GICs show marked temporal variations. Whereas thinning was concentrated along the eastern margin during 2003-2009, western GICs became the prime sea level rise contributors in recent years. Mass loss in the northern region has been steadily increasing throughout the record, due to a strong atmospheric warning and a deterioration of the capacity of the firn layer to buffer the resulting melt water.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1014822','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1014822"><span>Using <span class="hlt">Ice</span> Predictions to Guide Submarines</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2016-01-01</p> <p>the Arctic <span class="hlt">Cap</span> Nowcast/ Forecast System (ACNFS) in September 2013. The ACNFS consists of a coupled <span class="hlt">ice</span> -ocean model that assimilates available real...of the <span class="hlt">ice</span> cover. The age of the sea <span class="hlt">ice</span> serves as an indicator of its physical properties including surface roughness, melt pond coverage, and...the Arctic <span class="hlt">Cap</span> Nowcast/Forecast System (ACNFS). <span class="hlt">Ice</span> thickness is in meters for 11 September 2015. Thickness ranges from zero to five meters as shown</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1714301S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1714301S"><span>Validating Cryosat-2 elevation estimates with airborne laser scanner data for the Greenland <span class="hlt">ice</span> sheet, Austfonna and Devon <span class="hlt">ice</span> <span class="hlt">caps</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Simonsen, Sebastian B.; Sandberg Sørensen, Louise; Nilsson, Johan; Helm, Veit; Langley, Kirsty A.; Forsberg, Rene; Hvidegaard, Sine M.; Skourup, Henriette</p> <p>2015-04-01</p> <p>The ESA CryoSat-2 satellite, launched in late 2010, carries a new type of radar altimeter especially designed for monitoring changes of sea and land <span class="hlt">ice</span>. The radar signal might penetrate into the snow pack and the depth of the radar reflecting surface depends on the ratio between the surface and the volume backscatter, which is a function of several different properties such as snow density, crystal structure and surface roughness. In case of large volume scatter, the radar waveforms become broad and the determination of the range (surface elevation) becomes more difficult. Different algorithms (retrackers) are used for the range determination, and estimated surface penetration is highly dependent on the applied retracker. As part of the ESA-CryoVEx/CryoVal-Land <span class="hlt">Ice</span> projects, DTU Space has gathered accurate airborne laser scanner elevation measurements. Sites on the Greenland <span class="hlt">ice</span> sheet, Austfonna and Devon <span class="hlt">ice</span> <span class="hlt">caps</span>, has been surveyed repeatedly, aligned with Cryosat-2 ground tracks and surface experiments. Here, we utilize elevation estimates from available Cryosat-2 retrackers (ESA level-2 retracker, DTU retracker, etc.) and validate the elevation measurements against ESA-CryoVEx campaigns. A difference between laser and radar elevations is expected due to radar penetration issues, however an inter-comparison between retrackers will shed light on individual performances and biases. Additionally, the geo-location of the radar return will also be a determining factor for the precision. Ultimately, the use of multiple retrackers can provide information about subsurface conditions and utilize more of the waveform information than presently used in radar altimetry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015QSRv..126..201V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015QSRv..126..201V"><span>Reconstruction of glacier variability from lake sediments reveals dynamic Holocene climate in <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van der Bilt, Willem G. M.; Bakke, Jostein; Vasskog, Kristian; D'Andrea, William J.; Bradley, Raymond S.; Ólafsdóttir, Sædis</p> <p>2015-10-01</p> <p>The Arctic is warming faster than anywhere else on Earth. Holocene proxy time-series are increasingly used to put this amplified response in perspective by understanding Arctic climate processes beyond the instrumental period. However, available datasets are scarce, unevenly distributed and often of coarse resolution. Glaciers are sensitive recorders of climate shifts and variations in rock-flour production transfer this signal to the lacustrine sediment archives of downstream lakes. Here, we present the first full Holocene record of continuous glacier variability on <span class="hlt">Svalbard</span> from glacier-fed Lake Hajeren. This reconstruction is based on an undisturbed lake sediment core that covers the entire Holocene and resolves variability on centennial scales owing to 26 dating points. A toolbox of physical, geochemical (XRF) and magnetic proxies in combination with multivariate statistics has allowed us to fingerprint glacier activity in addition to other processes affecting the sediment record. Evidence from variations in sediment density, validated by changes in Ti concentrations, reveal glaciers remained present in the catchment following deglaciation prior to 11,300 cal BP, culminating in a Holocene maximum between 9.6 and 9.5 ka cal BP. Correspondence with freshwater pulses from Hudson Strait suggests that Early Holocene glacier advances were driven by the melting Laurentide <span class="hlt">Ice</span> Sheet (LIS). We find that glaciers disappeared from the catchment between 7.4 and 6.7 ka cal BP, following a late Hypsithermal. Glacier reformation around 4250 cal BP marks the onset of the Neoglacial, supporting previous findings. Between 3380 and 3230 cal BP, we find evidence for a previously unreported centennial-scale glacier advance. Both events are concurrent with well-documented episodes of North Atlantic cooling. We argue that this brief forcing created suitable conditions for glaciers to reform in the catchment against a background of gradual orbital cooling. These findings highlight the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JHyd..538..177S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JHyd..538..177S"><span>Chemical denudation and the role of sulfide oxidation at Werenskioldbreen, <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stachnik, Łukasz; Majchrowska, Elżbieta; Yde, Jacob C.; Nawrot, Adam P.; Cichała-Kamrowska, Katarzyna; Ignatiuk, Dariusz; Piechota, Agnieszka</p> <p>2016-07-01</p> <p>This study aims to determine the rate of chemical denudation and the relationships between dominant geochemical reactions operating in the proglacial and subglacial environments of the polythermal glacier Werenskioldbreen (SW <span class="hlt">Svalbard</span>) during an entire ablation season. Water sampling for major ion chemistry was performed at a proglacial hydrometric station and from subglacial outflows from May to September 2011. These data were combined with measurements of discharge and supraglacial ablation rates. The slopes and intercepts in best-fit regressions of [*Ca2+ + *Mg2+ vs. *SO42-] and [HCO3- vs. *SO42-] in meltwater from <span class="hlt">ice</span>-marginal subglacial channels were close to the stoichiometric parameters of sulfide oxidation and simple hydrolysis coupled to carbonate dissolution (*concentrations corrected for input of sea-salt). This shows that these relationships predominates the meltwater chemistry. Our findings also show that sulfide oxidation is a better indicator of the configuration of subglacial drainage systems than, for instance, Na+ and K+. In the proglacial area and in sub-artesian outflows, the ion associations represent sulfide oxidation but other processes such as ion exchange and dissolution of Ca and Mg efflorescent salts may also contribute to the solute variations. These processes may cause enhanced fluxes of Ca2+ and HCO3- from glacierized basins during the early ablation and peak flow seasons as the proglacial salts re-dissolve. The overall chemical denudation rate in the basin for 2011 (ranging from 1601 to 1762 meq m-2 yr-1 (121.9 to 132.2 t km-2 yr-1)) was very high when compared to other <span class="hlt">Svalbard</span> valley glaciers suggesting that the high rate of chemical denudation was mostly caused by the high rates of discharge and ablation. Chemical weathering intensities (876 and 964 meq m-3 yr-1) exceeded previously reported intensities in <span class="hlt">Svalbard</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.C12A..05G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.C12A..05G"><span>Analysis of vanillic acid in polar <span class="hlt">ice</span> cores as a biomass burning proxy - preliminary results from the Akademii Nauk <span class="hlt">Ice</span> <span class="hlt">Cap</span> in Siberia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grieman, M. M.; Jimenez, R.; McConnell, J. R.; Fritzsche, D.; Saltzman, E. S.</p> <p>2013-12-01</p> <p>Biomass burning influences global climate change and the composition of the atmosphere. The drivers, effects, and climate feedbacks related to fire are poorly understood. Many different proxies have been used to reconstruct past fire frequency from lake sediments and polar <span class="hlt">ice</span> cores. Reconstruction of historical trends in biomass burning is challenging because of regional variability and the qualitative nature of various proxies. Vanillic acid (4-hydroxy-3-methoxybenzoic acid) is a product of the combustion of conifer lignin that is known to occur in biomass burning aerosols. Biomass burning is likely the only significant source of vanillic acid in polar <span class="hlt">ice</span>. In this study we describe an analytical method for quantifying vanillic acid in polar <span class="hlt">ice</span> using HPLC with electrospray ionization and tandem mass spectrometric detection. The method has a detection limit of 100 pM and a precision of × 10% at the 100 pM level for analysis of 100 μl of <span class="hlt">ice</span> melt water. The method was used to analyze more than 1000 discrete samples from the Akademii Nauk <span class="hlt">ice</span> <span class="hlt">cap</span> on Severnaya Zemlya in the high Russia Arctic (79°30'N, 97°45'E) (Fritzsche et al., 2002; Fritzsche et al., 2005; Weiler et al., 2005). The samples range in age over the past 2,000 years. The results show a mean vanillic acid concentration of 440 × 710 pM (1σ), with elevated levels during the periods from 300-600 and 1450-1550 C.E.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA03627&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DCAPS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA03627&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DCAPS"><span>South Polar <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2005-01-01</p> <p><p/> 8 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows landforms created by sublimation processes on the south polar residual <span class="hlt">cap</span> of Mars. The bulk of the <span class="hlt">ice</span> in the south polar residual <span class="hlt">cap</span> is frozen carbon dioxide. <p/> <i>Location near</i>: 86.6oS, 342.2oW <i>Image width</i>: width: 3 km (1.9 mi) <i>Illumination from</i>: upper left <i>Season</i>: Southern Summer</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010Icar..210...58P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010Icar..210...58P"><span>MGS TES observations of the water vapor above the seasonal and perennial <span class="hlt">ice</span> <span class="hlt">caps</span> during northern spring and summer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pankine, Alexey A.; Tamppari, Leslie K.; Smith, Michael D.</p> <p>2010-11-01</p> <p>We report on new retrievals of water vapor column abundances from the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) data. The new retrievals are from the TES nadir data taken above the 'cold' surface areas in the North polar region ( Tsurf < 220 K, including seasonal frost and permanent <span class="hlt">ice</span> <span class="hlt">cap</span>) during spring and summer seasons, where retrievals were not performed initially. Retrievals are possible (with some modifications to the original algorithm) over cold surfaces overlaid by sufficiently warm atmosphere. The retrieved water vapor column abundances are compared to the column abundances observed by other spacecrafts in the Northern polar region during spring and summer and good agreement is found. We detect an annulus of water vapor growing above the edge of the retreating seasonal <span class="hlt">cap</span> during spring. The formation of the vapor annulus is consistent with the previously proposed mechanism for water cycling in the polar region, according to which vapor released by frost sublimation during spring re-condenses on the retreating seasonal CO 2 <span class="hlt">cap</span>. The source of the vapor in the vapor annulus, according to this model, is the water frost on the surface of the CO 2 at the retreating edge of the <span class="hlt">cap</span> and the frost on the ground that is exposed by the retreating <span class="hlt">cap</span>. Small contribution from regolith sources is possible too, but cannot be quantified based on the TES vapor data alone. Water vapor annulus exhibits interannual variability, which we attribute to variations in the atmospheric temperature. We propose that during spring and summer the water <span class="hlt">ice</span> sublimation is retarded by high relative humidity of the local atmosphere, and that higher atmospheric temperatures lead to higher vapor column abundances by increasing the water holding capacity of the atmosphere. Since the atmospheric temperatures are strongly influenced by the atmospheric dust content, local dust storms may be controlling the release of vapor into the polar atmosphere. Water vapor</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018QSRv..183..204V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018QSRv..183..204V"><span>Alkenone-based reconstructions reveal four-phase Holocene temperature evolution for High Arctic <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van der Bilt, Willem G. M.; D'Andrea, William J.; Bakke, Jostein; Balascio, Nicholas L.; Werner, Johannes P.; Gjerde, Marthe; Bradley, Raymond S.</p> <p>2018-03-01</p> <p>Situated at the crossroads of major oceanic and atmospheric circulation patterns, the Arctic is a key component of Earth's climate system. Compounded by sea-<span class="hlt">ice</span> feedbacks, even modest shifts in the region's heat budget drive large climate responses. This is highlighted by the observed amplified response of the Arctic to global warming. Assessing the imprint and signature of underlying forcing mechanisms require paleoclimate records, allowing us to expand our knowledge beyond the short instrumental period and contextualize ongoing warming. However, such datasets are scarce and sparse in the Arctic, limiting our ability to address these issues. Here, we present two quantitative Holocene-length paleotemperature records from the High Arctic <span class="hlt">Svalbard</span> archipelago, situated in the climatically sensitive Arctic North Atlantic. Temperature estimates are based on U37K unsaturation ratios from sediment cores of two lakes. Our data reveal a dynamic Holocene temperature evolution, with reconstructed summer lake water temperatures spanning a range of ∼6-8 °C, and characterized by four phases. The Early Holocene was marked by an early onset (∼10.5 ka cal. BP) of insolation-driven Hypsithermal conditions, likely compounded by strengthening oceanic heat transport. This warm interval was interrupted by cooling between ∼10.5-8.3 ka cal. BP that we attribute to cooling effects from the melting Northern Hemisphere <span class="hlt">ice</span> sheets. Temperatures declined throughout the Middle Holocene, following a gradual trend that was accentuated by two cooling steps between ∼7.8-7 ka cal. BP and around ∼4.4-4.3 ka cal. BP. These transitions coincide with a strengthening influence of Arctic water and sea-<span class="hlt">ice</span> in the adjacent Fram Strait. During the Late Holocene (past 4 ka), temperature change decoupled from the still-declining insolation, and fluctuated around comparatively cold mean conditions. By showing that Holocene <span class="hlt">Svalbard</span> temperatures were governed by an alternation of forcings, this study</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911826D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911826D"><span>Multilevel Cloud Structures above <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dörnbrack, Andreas; Pitts, Micheal; Poole, Lamont; Gisinger, Sonja; Maturlli, Marion</p> <p>2017-04-01</p> <p>The presentation focusses on the reslts recently published by the authors under the heading "picture of the month" in Monthly Weather Review. The presented picture of the month is a superposition of space-borne lidar observations and high-resolution temperature fields of the ECMWF integrated forecast system (IFS). It displays complex tropospheric and stratospheric clouds in the Arctic winter 2015/16. Near the end of December 2015, the unusual northeastward propagation of warm and humid subtropical air masses as far north as 80°N lifted the tropopause by more than 3 km in 24 h and cooled the stratosphere on a large scale. A widespread formation of thick cirrus clouds near the tropopause and of synoptic-scale polar stratospheric clouds (PSCs) occurred as the temperature dropped below the thresholds for the existence of cloud particles. Additionally, mountain waves were excited by the strong flow at the western edge of the ridge across <span class="hlt">Svalbard</span>, leading to the formation of mesoscale <span class="hlt">ice</span> PSCs. The most recent IFS cycle using a horizontal resolution of 8 km globally reproduces the large-scale and mesoscale flow features and leads to a remarkable agreement with the wave structure revealed by the space-borne observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70036086','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70036086"><span>Characterization of Mars' seasonal <span class="hlt">caps</span> using neutron spectroscopy</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Prettyman, T.H.; Feldman, W.C.; Titus, T.N.</p> <p>2009-01-01</p> <p>Mars' seasonal <span class="hlt">caps</span> are characterized during Mars years 26 and 27 (April 2002 to January 2006) using data acquired by the 2001 Mars Odyssey Neutron Spectrometer. Time-dependent maps of the column abundance of seasonal CO 2 surface <span class="hlt">ice</span> poleward of 60?? latitude in both hemispheres are determined from spatially deconvolved, epithermal neutron counting data. Sources of systematic error are analyzed, including spatial blurring by the spectrometer's broad footprint and the seasonal variations in the abundance of noncondensable gas at high southern latitudes, which are found to be consistent with results reported by Sprague et al. (2004, 2007). Corrections for spatial blurring are found to be important during the recession, when the column abundance of seasonal CO2 <span class="hlt">ice</span> has the largest latitude gradient. The measured distribution and inventory of seasonal CO2 <span class="hlt">ice</span> is compared to simulations by a general circulation model (GCM) calibrated using Viking lander pressure data, <span class="hlt">cap</span> edge functions determined by thermal emission spectroscopy, and other nuclear spectroscopy data sets. On the basis of the amount of CO2 cycled through the <span class="hlt">caps</span> during years 26 and 27, the gross polar energy balance has not changed significantly since Viking. The distribution of seasonal CO2 <span class="hlt">ice</span> is longitudinally asymmetric: in the north, deposition rates of CO2 <span class="hlt">ice</span> are elevated in Acidalia, which is exposed to katabatic winds from Chasma Borealis; in the south, CO2 deposition is highest near the residual <span class="hlt">cap</span>. During southern recession, CO 2 <span class="hlt">ice</span> is present longer than calculated by the GCM, which has implications for the local polar energy balance. Copyright 2009 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28361871','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28361871"><span>A tipping point in refreezing accelerates mass loss of Greenland's glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Noël, B; van de Berg, W J; Lhermitte, S; Wouters, B; Machguth, H; Howat, I; Citterio, M; Moholdt, G; Lenaerts, J T M; van den Broeke, M R</p> <p>2017-03-31</p> <p>Melting of the Greenland <span class="hlt">ice</span> sheet (GrIS) and its peripheral glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> (GICs) contributes about 43% to contemporary sea level rise. While patterns of GrIS mass loss are well studied, the spatial and temporal evolution of GICs mass loss and the acting processes have remained unclear. Here we use a novel, 1 km surface mass balance product, evaluated against in situ and remote sensing data, to identify 1997 (±5 years) as a tipping point for GICs mass balance. That year marks the onset of a rapid deterioration in the capacity of the GICs firn to refreeze meltwater. Consequently, GICs runoff increases 65% faster than meltwater production, tripling the post-1997 mass loss to 36±16 Gt -1 , or ∼14% of the Greenland total. In sharp contrast, the extensive inland firn of the GrIS retains most of its refreezing capacity for now, buffering 22% of the increased meltwater production. This underlines the very different response of the GICs and GrIS to atmospheric warming.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5380968','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5380968"><span>A tipping point in refreezing accelerates mass loss of Greenland's glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Noël, B.; van de Berg, W. J; Lhermitte, S.; Wouters, B.; Machguth, H.; Howat, I.; Citterio, M.; Moholdt, G.; Lenaerts, J. T. M.; van den Broeke, M. R.</p> <p>2017-01-01</p> <p>Melting of the Greenland <span class="hlt">ice</span> sheet (GrIS) and its peripheral glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> (GICs) contributes about 43% to contemporary sea level rise. While patterns of GrIS mass loss are well studied, the spatial and temporal evolution of GICs mass loss and the acting processes have remained unclear. Here we use a novel, 1 km surface mass balance product, evaluated against in situ and remote sensing data, to identify 1997 (±5 years) as a tipping point for GICs mass balance. That year marks the onset of a rapid deterioration in the capacity of the GICs firn to refreeze meltwater. Consequently, GICs runoff increases 65% faster than meltwater production, tripling the post-1997 mass loss to 36±16 Gt−1, or ∼14% of the Greenland total. In sharp contrast, the extensive inland firn of the GrIS retains most of its refreezing capacity for now, buffering 22% of the increased meltwater production. This underlines the very different response of the GICs and GrIS to atmospheric warming. PMID:28361871</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017NatCo...814730N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017NatCo...814730N"><span>A tipping point in refreezing accelerates mass loss of Greenland's glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noël, B.; van de Berg, W. J.; Lhermitte, S.; Wouters, B.; Machguth, H.; Howat, I.; Citterio, M.; Moholdt, G.; Lenaerts, J. T. M.; van den Broeke, M. R.</p> <p>2017-03-01</p> <p>Melting of the Greenland <span class="hlt">ice</span> sheet (GrIS) and its peripheral glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> (GICs) contributes about 43% to contemporary sea level rise. While patterns of GrIS mass loss are well studied, the spatial and temporal evolution of GICs mass loss and the acting processes have remained unclear. Here we use a novel, 1 km surface mass balance product, evaluated against in situ and remote sensing data, to identify 1997 (+/-5 years) as a tipping point for GICs mass balance. That year marks the onset of a rapid deterioration in the capacity of the GICs firn to refreeze meltwater. Consequently, GICs runoff increases 65% faster than meltwater production, tripling the post-1997 mass loss to 36+/-16 Gt-1, or ~14% of the Greenland total. In sharp contrast, the extensive inland firn of the GrIS retains most of its refreezing capacity for now, buffering 22% of the increased meltwater production. This underlines the very different response of the GICs and GrIS to atmospheric warming.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008epsc.conf..650C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008epsc.conf..650C"><span>Field Studies of Gullies and Pingos on <span class="hlt">Svalbard</span> - a Martian Analog.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carlsson, E.; Johannsson, H. A. B.; Johnsson, A.; Heldmann, J. L.; McKay, C. P.; Olvmo, M.; Johansson, L.; Fredriksson, S.; Schmidt, H. T.; McDaniel, S.; Reiss, D.; Hiesinger, H.; Hauber, E.; Zanetti, M.</p> <p>2008-09-01</p> <p>Introduction: The gully systems on Mars [1] have been found to superpose young geological surfaces such as dunes and thermal contraction polygons [2]. This in combination with the general absence of superimposed impact craters suggest that the gullies are relatively recent geological formations [3]. The observed gullies display a wide set of morphologies ranging from features seemingly formed by fluvial erosion to others pointing to dry landslide processes. A recent discovery [4] suggests that this is an ongoing process, which appears to occur even today. Several formation mechanisms have been proposed for the Martian gullies, such as liquid carbon dioxide reservoirs [5], shallow liquid water aquifer [6], melting ground <span class="hlt">ice</span> [7], dry landslide [8], snow melt [9] and deep liquid water aquifer [10]. However, none of these models can alone explain all the gullies discovered on Mars. So far Martian gullies have been studied only from orbit via remote sensing data. Hydrostatic pingos are perennial <span class="hlt">ice</span>-cored mounds that may reach an elongated or circular radius of approximately 150 m. They are found in periglacial environments where they are formed by freezing processes in the continuous permafrost. The pingos go through different evolutionary stages as they mature, where the final stage leaves an annular rim left by the collapse of the summit. Images from the High Resolution Imaging Science Experiment (HiRISE) show small fractured mounds in the Martian mid-latitudes [11]. Even though some differences are observed, the best terrestrial analogues for the observed mound morphology are pingos [11]. Gullies and pingos found in Arctic climates on Earth could be an analog for the Martian ones. A comparative analysis might help to understand the formation mechanisms of the Martian pingos and gullies and their possible eroding agent. <span class="hlt">Svalbard</span> as a Martian Analog: <span class="hlt">Svalbard</span> is situated at 74°-81°N and 10°-35°E, in the discontinuous zone of permafrost, and is a fairly good</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5475A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5475A"><span><span class="hlt">Ice</span> thickness measurements and volume estimates for glaciers in Norway</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Andreassen, Liss M.; Huss, Matthias; Melvold, Kjetil; Elvehøy, Hallgeir; Winsvold, Solveig H.</p> <p>2014-05-01</p> <p>Whereas glacier areas in many mountain regions around the world now are well surveyed using optical satellite sensors and available in digital inventories, measurements of <span class="hlt">ice</span> thickness are sparse in comparison and a global dataset does not exist. Since the 1980s <span class="hlt">ice</span> thickness measurements have been carried out by ground penetrating radar on many glaciers in Norway, often as part of contract work for hydropower companies with the aim to calculate hydrological divides of <span class="hlt">ice</span> <span class="hlt">caps</span>. Measurements have been conducted on numerous glaciers, covering the largest <span class="hlt">ice</span> <span class="hlt">caps</span> as well as a few smaller mountain glaciers. However, so far no <span class="hlt">ice</span> volume estimate for Norway has been derived from these measurements. Here, we give an overview of <span class="hlt">ice</span> thickness measurements in Norway, and use a distributed model to interpolate and extrapolate the data to provide an <span class="hlt">ice</span> volume estimate of all glaciers in Norway. We also compare the results to various volume-area/thickness-scaling approaches using values from the literature as well as scaling constants we obtained from <span class="hlt">ice</span> thickness measurements in Norway. Glacier outlines from a Landsat-derived inventory from 1999-2006 together with a national digital elevation model were used as input data for the <span class="hlt">ice</span> volume calculations. The inventory covers all glaciers in mainland Norway and consists of 2534 glaciers (3143 glacier units) covering an area of 2692 km2 ± 81 km2. To calculate the <span class="hlt">ice</span> thickness distribution of glaciers in Norway we used a distributed model which estimates surface mass balance distribution, calculates the volumetric balance flux and converts it into thickness using the flow law for <span class="hlt">ice</span>. We calibrated this model with <span class="hlt">ice</span> thickness data for Norway, mainly by adjusting the mass balance gradient. Model results generally agree well with the measured values, however, larger deviations were found for some glaciers. The total <span class="hlt">ice</span> volume of Norway was estimated to be 275 km3 ± 30 km3. From the <span class="hlt">ice</span> thickness data set we selected</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMPP43B1288M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMPP43B1288M"><span>Molecular Markers in the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Peru Describe 20th Century Biomass Burning Variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Makou, M. C.; Thompson, L. G.; Eglinton, T. I.; Montluçon, D. B.</p> <p>2007-12-01</p> <p>Organic geochemical analytical methods were applied to Andean <span class="hlt">ice</span> core samples, resulting in a multi- molecular biomass burning record spanning 1915 to 2001 AD. The Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> in Peru is situated on the eastern flank of the Andes at 14°S and is well situated to receive aeolian inputs of organic matter derived from Amazonian forest fire events. Compounds of interest, which occur in trace quantities in <span class="hlt">ice</span>, were recovered by stir bar sorptive extraction and analyzed by gas chromatography/time-of-flight mass spectrometry coupled with thermal desorption. These methods permitted identification and quantitation of numerous biomarkers in sample volumes of as little as 10 ml. At least one wet and dry season sample was analyzed for every year. Observed biomarkers that may be derived from vegetation fires include several polycyclic aromatic hydrocarbons (PAHs), atraric acid, 2-ethylhexyl p-methoxycinnamate, and a range of other aromatic compounds. Abrupt changes in compound abundances were superimposed on decadal variability. Systematic offsets between wet and dry season abundances were not observed, suggesting that the biomass burning signal is not biased by seasonal depositional effects, such as dust delivery. Inputs likely reflect a combination of sources from anthropogenic burning of the Amazon rainforest as well as natural fires related to aridity, and include both high and low elevation vegetation. These compounds and techniques can be applied to older <span class="hlt">ice</span> in this and other core locations as an independent estimate of aridity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhDT........67W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhDT........67W"><span><span class="hlt">Ice</span>-atmosphere interactions in the Canadian High Arctic: Implications for the thermo-mechanical evolution of terrestrial <span class="hlt">ice</span> masses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wohlleben, Trudy M. H.</p> <p></p> <p>Canadian High Arctic terrestrial <span class="hlt">ice</span> masses and the polar atmosphere evolve codependently, and interactions between the two systems can lead to feedbacks, positive and negative. The two primary positive cryosphere-atmosphere feedbacks are: (1) The snow/<span class="hlt">ice</span>-albedo feedback (where area changes in snow and/or <span class="hlt">ice</span> cause changes in surface albedo and surface air temperatures, leading to further area changes in snow/<span class="hlt">ice</span>); and (2) The elevation - mass balance feedback (where thickness changes in terrestrial <span class="hlt">ice</span> masses cause changes to atmospheric circulation and precipitation patterns, leading to further <span class="hlt">ice</span> thickness changes). In this thesis, numerical experiments are performed to: (1) quantify the magnitudes of the two feedbacks for chosen Canadian High Arctic terrestrial <span class="hlt">ice</span> masses; and (2) to examine the direct and indirect consequences of surface air temperature changes upon englacial temperatures with implications for <span class="hlt">ice</span> flow, mass flux divergence, and topographic evolution. Model results show that: (a) for John Evans Glacier, Ellesmere Island, the magnitude of the terrestrial snow/<span class="hlt">ice</span>-albedo feedback can locally exceed that of sea <span class="hlt">ice</span> on less than decadal timescales, with implications for glacier response times to climate perturbations; (b) although historical air temperature changes might be the direct cause of measured englacial temperature anomalies in various glacier and <span class="hlt">ice</span> <span class="hlt">cap</span> accumulation zones, they can also be the indirect cause of their enhanced diffusive loss; (c) while the direct result of past air temperature changes has been to cool the interior of John Evans Glacier, and its bed, the indirect result has been to create and maintain warm (pressure melting point) basal temperatures in the ablation zone; and (d) for Devon <span class="hlt">Ice</span> <span class="hlt">Cap</span>, observed mass gains in the northwest sector of the <span class="hlt">ice</span> <span class="hlt">cap</span> would be smaller without orographic precipitation and the mass balance---elevation feedback, supporting the hypothesis that this feedback is playing a role in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010TCD.....4..153D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010TCD.....4..153D"><span>Brief communication: ikaite (CaCO3*6H2O) discovered in Arctic sea <span class="hlt">ice</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dieckmann, G. S.; Nehrke, G.; Uhlig, C.; Göttlicher, J.; Gerland, S.; Granskog, M. A.; Thomas, D. N.</p> <p>2010-02-01</p> <p>We report for the first time on the discovery of calcium carbonate crystals as ikaite (CaCO3*6H2O) in sea <span class="hlt">ice</span> from the Arctic (Kongsfjorden, <span class="hlt">Svalbard</span>). This finding demonstrates that the precipitation of calcium carbonate during the freezing of sea <span class="hlt">ice</span> is not restricted to the Antarctic, where it was observed for the first time in 2008. This finding is an important step in the quest to quantify its impact on the sea <span class="hlt">ice</span> driven carbon cycle and should in the future enable improvement parametrization sea <span class="hlt">ice</span> carbon models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016QSRv..147..148C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016QSRv..147..148C"><span>An East Siberian <span class="hlt">ice</span> shelf during the Late Pleistocene glaciations: Numerical reconstructions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Colleoni, Florence; Kirchner, Nina; Niessen, Frank; Quiquet, Aurélien; Liakka, Johan</p> <p>2016-09-01</p> <p>A recent data campaign in the East Siberian Sea has revealed evidence of grounded and floating <span class="hlt">ice</span> dynamics in regions of up to 1000 m water depth, and which are attributed to glaciations older than the Last Glacial Maximum (21 kyrs BP). The main hypothesis based on this evidence is that a small <span class="hlt">ice</span> <span class="hlt">cap</span> developed over Beringia and expanded over the East Siberian continental margin during some of the Late Pleistocene glaciations. Other similar evidence of <span class="hlt">ice</span> dynamics that have been previously collected on the shallow continental shelves of the Arctic Ocean have been attributed to the penultimate glaciation, i.e. Marine Isotopes Stage 6 (≈140 kyrs BP). We use an <span class="hlt">ice</span> sheet model, forced by two previously simulated MIS 6 glacial maximum climates, to carry out a series of sensitivity experiments testing the impact of dynamics and mass-balance related parameters on the geometry of the East Siberian <span class="hlt">ice</span> <span class="hlt">cap</span> and <span class="hlt">ice</span> shelf. Results show that the <span class="hlt">ice</span> <span class="hlt">cap</span> developing over Beringia connects to the Eurasian <span class="hlt">ice</span> sheet in all simulations and that its volume ranges between 6 and 14 m SLE, depending on the climate forcing. This <span class="hlt">ice</span> <span class="hlt">cap</span> generates an <span class="hlt">ice</span> shelf of dimensions comparable with or larger than the present-day Ross <span class="hlt">ice</span> shelf in West Antarctica. Although the <span class="hlt">ice</span> shelf extent strongly depends on the <span class="hlt">ice</span> flux through the grounding line, it is particularly sensitive to the choice of the calving and basal melting parameters. Finally, inhibiting a merging of the Beringia <span class="hlt">ice</span> <span class="hlt">cap</span> with the Eurasian <span class="hlt">ice</span> sheet affects the expansion of the <span class="hlt">ice</span> shelf only in the simulations where the <span class="hlt">ice</span> <span class="hlt">cap</span> fluxes are not large enough to compensate for the fluxes coming from the Eurasian <span class="hlt">ice</span> sheet.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..12210820G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..12210820G"><span>Spring snow conditions on Arctic sea <span class="hlt">ice</span> north of <span class="hlt">Svalbard</span>, during the Norwegian Young Sea <span class="hlt">ICE</span> (N-<span class="hlt">ICE</span>2015) expedition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gallet, Jean-Charles; Merkouriadi, Ioanna; Liston, Glen E.; Polashenski, Chris; Hudson, Stephen; Rösel, Anja; Gerland, Sebastian</p> <p>2017-10-01</p> <p>Snow is crucial over sea <span class="hlt">ice</span> due to its conflicting role in reflecting the incoming solar energy and reducing the heat transfer so that its temporal and spatial variability are important to estimate. During the Norwegian Young Sea <span class="hlt">ICE</span> (N-<span class="hlt">ICE</span>2015) campaign, snow physical properties and variability were examined, and results from April until mid-June 2015 are presented here. Overall, the snow thickness was about 20 cm higher than the climatology for second-year <span class="hlt">ice</span>, with an average of 55 ± 27 cm and 32 ± 20 cm on first-year <span class="hlt">ice</span>. The average density was 350-400 kg m-3 in spring, with higher values in June due to melting. Due to flooding in March, larger variability in snow water equivalent was observed. However, the snow structure was quite homogeneous in spring due to warmer weather and lower amount of storms passing over the field camp. The snow was mostly consisted of wind slab, faceted, and depth hoar type crystals with occasional fresh snow. These observations highlight the more dynamic character of evolution of snow properties over sea <span class="hlt">ice</span> compared to previous observations, due to more variable sea <span class="hlt">ice</span> and weather conditions in this area. The snowpack was isothermal as early as 10 June with the first onset of melt clearly identified in early June. Based on our observations, we estimate than snow could be accurately represented by a three to four layers modeling approach, in order to better consider the high variability of snow thickness and density together with the rapid metamorphose of the snow in springtime.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015TCry....9..197D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015TCry....9..197D"><span>Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dunse, T.; Schellenberger, T.; Hagen, J. O.; Kääb, A.; Schuler, T. V.; Reijmer, C. H.</p> <p>2015-02-01</p> <p>Mass loss from glaciers and <span class="hlt">ice</span> sheets currently accounts for two-thirds of the observed global sea-level rise and has accelerated since the 1990s, coincident with strong atmospheric warming in the polar regions. Here we present continuous GPS measurements and satellite synthetic-aperture-radar-based velocity maps from Basin-3, the largest drainage basin of the Austfonna <span class="hlt">ice</span> <span class="hlt">cap</span>, <span class="hlt">Svalbard</span>. Our observations demonstrate strong links between surface-melt and multiannual <span class="hlt">ice</span>-flow acceleration. We identify a hydro-thermodynamic feedback that successively mobilizes stagnant <span class="hlt">ice</span> regions, initially frozen to their bed, thereby facilitating fast basal motion over an expanding area. By autumn 2012, successive destabilization of the marine terminus escalated in a surge of Basin-3. The resulting iceberg discharge of 4.2±1.6 Gt a-1 over the period April 2012 to May 2013 triples the calving loss from the entire <span class="hlt">ice</span> <span class="hlt">cap</span>. With the seawater displacement by the terminus advance accounted for, the related sea-level rise contribution amounts to 7.2±2.6 Gt a-1. This rate matches the annual <span class="hlt">ice</span>-mass loss from the entire <span class="hlt">Svalbard</span> archipelago over the period 2003-2008, highlighting the importance of dynamic mass loss for glacier mass balance and sea-level rise. The active role of surface melt, i.e. external forcing, contrasts with previous views of glacier surges as purely internal dynamic instabilities. Given sustained climatic warming and rising significance of surface melt, we propose a potential impact of the hydro-thermodynamic feedback on the future stability of <span class="hlt">ice</span>-sheet regions, namely at the presence of a cold-based marginal <span class="hlt">ice</span> plug that restricts fast drainage of inland <span class="hlt">ice</span>. The possibility of large-scale dynamic instabilities such as the partial disintegration of <span class="hlt">ice</span> sheets is acknowledged but not quantified in global projections of sea-level rise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28835469','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28835469"><span>Sea-<span class="hlt">ice</span> induced growth decline in Arctic shrubs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Forchhammer, Mads</p> <p>2017-08-01</p> <p>Measures of increased tundra plant productivity have been associated with the accelerating retreat of the Arctic sea-<span class="hlt">ice</span>. Emerging studies document opposite effects, advocating for a more complex relationship between the shrinking sea-<span class="hlt">ice</span> and terrestrial plant productivity. I introduce an autoregressive plant growth model integrating effects of biological and climatic conditions for analysing individual ring-width growth time series. Using 128 specimens of Salix arctica , S. glauca and Betula nana sampled across Greenland to <span class="hlt">Svalbard</span>, an overall negative effect of the retreating June sea-<span class="hlt">ice</span> extent was found on the annual growth. The negative effect of the retreating June sea-<span class="hlt">ice</span> was observed for younger individuals with large annual growth allocations and with little or no trade-off between previous and current year's growth. © 2017 The Author(s).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016FrEaS...4..102V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016FrEaS...4..102V"><span>The changing impact of snow conditions and refreezing on the mass balance of an idealized <span class="hlt">Svalbard</span> glacier</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Van Pelt, Ward; Pohjola, Veijo; Reijmer, Carleen</p> <p>2016-11-01</p> <p>Glacier surface melt and runoff depend strongly on seasonal and perennial snow (firn) conditions. Not only does the presence of snow and firn directly affect melt rates by reflecting solar radiation, it may also act as a buffer against mass loss by storing melt water in refrozen or liquid form. In <span class="hlt">Svalbard</span>, ongoing and projected amplified climate change with respect to the global mean change has severe implications for the state of snow and firn and its impact on glacier mass loss. Model experiments with a coupled surface energy balance - firn model were done to investigate the surface mass balance and the changing role of snow and firn conditions for an idealized <span class="hlt">Svalbard</span> glacier. A climate forcing for the past, present and future (1984-2104) is constructed, based on observational data from <span class="hlt">Svalbard</span> Airport and a seasonally dependent projection scenario. Results illustrate ongoing and future firn degradation in response to an elevational retreat of the equilibrium line altitude (ELA) of 31 m decade-1. The temperate firn zone is found to retreat and expand, while cold <span class="hlt">ice</span> in the ablation zone warms considerably. In response to pronounced winter warming and an associated increase in winter rainfall, the current prevalence of refreezing during the melt season gradually shifts to the winter season in a future climate. Sensitivity tests reveal that in a present and future climate the density and thermodynamic structure of <span class="hlt">Svalbard</span> glaciers are heavily influenced by refreezing. Refreezing acts as a net buffer against mass loss. However, the net mass balance change after refreezing is substantially smaller than the amount of refreezing itself, which can be ascribed to melt-enhancing effects after refreezing, which partly offset the primary mass-retaining effect of refreezing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.7457N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.7457N"><span>Quantifying the mass loss of peripheral Greenland glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> (1958-2014).</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noël, Brice; van de Berg, Willem Jan; Machguth, Horst; van den Broeke, Michiel</p> <p>2016-04-01</p> <p>Since the 2000s, mass loss from Greenland peripheral glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> (GICs) has accelerated, becoming an important contributor to sea level rise. Under continued warming throughout the 21st century, GICs might yield up to 7.5 to 11 mm sea level rise, with increasing dominance of surface runoff at the expense of <span class="hlt">ice</span> discharge. However, despite multiple observation campaigns, little remains known about the contribution of GICs to total Greenland mass loss. Furthermore, the relatively coarse resolutions in regional climate models, i.e. 5 km to 20 km, fail to represent the small scale patterns of surface mass balance (SMB) components over these topographically complex regions including also narrow valley glaciers. Here, we present a novel approach to quantify the contribution of GICs to surface melt and runoff, based on an elevation dependent downscaling method. GICs daily SMB components at 1 km resolution are obtained by statistically downscaling the outputs of RACMO2.3 at 11 km resolution to a down-sampled version of the GIMP DEM for the period 1958-2014. This method has recently been successfully validated over the Greenland <span class="hlt">ice</span> sheet and is now applied to GICs. In this study, we first evaluate the 1 km daily downscaled GICs SMB against a newly available and comprehensive dataset of ablation stake measurements. Then, we investigate present-day trends of meltwater production and SMB for different regions and estimate GICs contribution to total Greenland mass loss. These data are considered valuable for model evaluation and prediction of future sea level rise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.P23G..07H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.P23G..07H"><span>Results from Field Testing the RIMFAX GPR on <span class="hlt">Svalbard</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hamran, S. E.; Amundsen, H. E. F.; Berger, T.; Carter, L. M.; Dypvik, H.; Ghent, R. R.; Kohler, J.; Mellon, M. T.; Nunes, D. C.; Paige, D. A.; Plettemeier, D.; Russell, P.</p> <p>2017-12-01</p> <p>The Radar Imager for Mars' Subsurface Experiment - RIMFAX is a Ground Penetrating Radar being developed for NASÁs MARS 2020 rover mission. The principal goals of the RIMFAX investigation are to image subsurface structures, provide context for sample sites, derive information regarding subsurface composition, and search for <span class="hlt">ice</span> or brines. In meeting these goals, RIMFAX will provide a view of the stratigraphic section and a window into the geological and environmental history of Mars. To verify the design an Engineering Model (EM) of the radar was tested in the field in the spring 2017. Different sounding modes on the EM were tested in different types of subsurface geology on <span class="hlt">Svalbard</span>. Deep soundings were performed on polythermal glaciers down to a couple of hundred meters. Shallow soundings were used to map a ground water table in the firn area of a glacier. A combination of deep and shallow soundings was used to image buried <span class="hlt">ice</span> under a sedimentary layer of a couple of meters. Subsurface sedimentary layers were imaged down to more than 20 meters in sand stone permafrost. This presentation will give an overview of the RIMFAX investigation, describe the development of the radar system, and show results from field tests of the radar.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1248935','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1248935"><span>Norwegian Young Sea <span class="hlt">Ice</span> Experiment (N-<span class="hlt">ICE</span>) Field Campaign Report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Walden, V. P.; Hudson, S. R.; Cohen, L.</p> <p></p> <p>The Norwegian Young Sea <span class="hlt">Ice</span> (N-<span class="hlt">ICE</span>) experiment was conducted aboard the R/V Lance research vessel from January through June 2015. The primary purpose of the experiment was to better understand thin, first-year sea <span class="hlt">ice</span>. This includes understanding of how different components of the Arctic system affect sea <span class="hlt">ice</span>, but also how changing sea <span class="hlt">ice</span> affects the system. A major part of this effort is to characterize the atmospheric conditions throughout the experiment. A micropulse lidar (MPL) (S/N: 108) was deployed from the U.S. Department of Energy’s (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility as part of the atmospheric suitemore » of instruments. The MPL operated successfully throughout the entire experiment, acquiring data from 21 January 2015 through 23 June 2015. The MPL was the essential instrument for determining the phase (water, <span class="hlt">ice</span> or mixed) of the lower-level clouds over the sea <span class="hlt">ice</span>. Data obtained from the MPL during the N-<span class="hlt">ICE</span> experiment show large cloud fractions over young, thin Arctic sea <span class="hlt">ice</span> from January through June 2015 (north of <span class="hlt">Svalbard</span>). The winter season was characterized by frequent synoptic storms and large fluctuations in the near-surface temperature. There was much less synoptic activity in spring and summer as the near-surface temperature rose to 0 C. The cloud fraction was lower in winter (60%) than in the spring and summer (80%). Supercooled liquid clouds were observed for most of the deployment, appearing first in mid-February. Spring and summer clouds were characterized by low, thick, uniform clouds.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010002506&hterms=Viking&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DViking','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010002506&hterms=Viking&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DViking"><span>Martian North Polar Water-<span class="hlt">Ice</span> Clouds During the Viking Era</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tamppari, L. K.; Bass, D. S.</p> <p>2000-01-01</p> <p>The Viking Orbiters determined that the surface of Mars' northern residual <span class="hlt">cap</span> consists of water <span class="hlt">ice</span>. Observed atmospheric water vapor abundances in the equatorial regions have been related to seasonal exchange between reservoirs such as the polar <span class="hlt">caps</span>, the regolith and between different phases in the atmosphere. Kahn modeled the physical characteristics of <span class="hlt">ice</span> hazes seen in Viking Orbiter imaging limb data, hypothesizing that <span class="hlt">ice</span> hazes provide a method for scavenging water vapor from the atmosphere and accumulating it into <span class="hlt">ice</span> particles. Given that Jakosky found that these particles had sizes such that fallout times were of order one Martian sol, these water-<span class="hlt">ice</span> hazes provided a method for returning more water to the regolith than that provided by adsorption alone. These hazes could also explain the rapid hemispheric decrease in atmospheric water in late northern summer as well as the increase during the following early spring. A similar comparison of water vapor abundance versus polar <span class="hlt">cap</span> brightness has been done for the north polar region. They have shown that water vapor decreases steadily between L(sub s) = 100-150 deg while polar <span class="hlt">cap</span> albedo increases during the same time frame. As a result, they suggested that late summer water-<span class="hlt">ice</span> deposition onto the <span class="hlt">ice</span> <span class="hlt">cap</span> may be the cause of the <span class="hlt">cap</span> brightening. This deposition could be due to adsorption directly onto the <span class="hlt">cap</span> surface or to snowfall. Thus, an examination of north polar waterice clouds could lend insight into the fate of the water vapor during this time period. Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912222G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912222G"><span>Basal friction evolution and crevasse distribution during the surge of Basin 3, Austfonna <span class="hlt">ice-cap</span> - offline coupling between a continuum <span class="hlt">ice</span> dynamic model and a discrete element model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gong, Yongmei; Zwinger, Thomas; Åström, Jan; Gladstone, Rupert; Schellenberger, Thomas; Altena, Bas; Moore, John</p> <p>2017-04-01</p> <p>The outlet glacier at Basin 3, Austfonna <span class="hlt">ice-cap</span> entered its active surge phase in autumn 2012. We assess the evolution of the basal friction during the surge through inverse modelling of basal friction coefficients using recent velocity observation from 2012 to 2014 in a continuum <span class="hlt">ice</span> dynamic model Elmer/<span class="hlt">ice</span>. The obtained basal friction coefficient distributions at different time instances are further used as a boundary condition in a discrete element model (HiDEM) that is capable of computing fracturing of <span class="hlt">ice</span>. The inverted basal friction coefficient evolution shows a gradual 'unplugging' of the stagnant frontal area and northwards and inland expansion of the fast flowing region in the southern basin. The validation between the modeled crevasses distribution and the satellite observation in August 2013 shows a good agreement in shear zones inland and at the frontal area. Crevasse distributions of the summer before and after the glacier reached its maximum velocity in January 2013 (August 2012 and August 2014, respectively) are also evaluated. Previous studies suggest the triggering and development of the surge are linked to surface melt water penetrating through <span class="hlt">ice</span> to form an efficient basal hydrology system thereby triggering a hydro- thermodynamic feedback. This preliminary offline coupling between a continuum <span class="hlt">ice</span> dynamic model and a discrete element model will give a hint on future model development of linking supra-glacial to sub-glacial hydrology system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMGC21D0991S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMGC21D0991S"><span>Lake Sediment Records as an Indicator of Holocene Fluctuations of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Peru and Regional Climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stroup, J. S.; Kelly, M. A.; Lowell, T. V.; Beal, S. A.; Smith, C. A.; Baranes, H. E.</p> <p>2012-12-01</p> <p>The past fluctuations of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>, (QIC; 13°S, 70°W, 5200 m asl) located in the southeastern Peruvian Andes, provide a record of tropical climate since the last glacial-interglacial transition. A detailed surficial geomorphic record of past glacial extents developed over the last several decades (e.g. Mercer and Palacios 1977; Buffen et al. 2009; Kelly et al. 2012 accepted) demonstrates that QIC is a dynamic glacial system. These records show that the <span class="hlt">ice</span> <span class="hlt">cap</span> was larger than present and retreating by ~11,500 yr BP, and smaller than present between ~7,000 and ~4,600 yr BP. The most recent advance occurred during the late Holocene (Little <span class="hlt">Ice</span> Age;LIA), dated with 10Be surface exposure ages (510±90 yrs (n = 8)) (Stroup et al. in prep.). This overrode earlier deposits obscuring a complete Holocene record; we aim to address the gaps in glacial chronology using the sedimentary record archived in lakes. We retrieved two sets cores (8 and 5 m-long) from Laguna Challpacocha (13.91°S, 70.86°W, 5040 m asl), a lake that currently receives meltwater from QIC. Four radiocarbon ages from the cores suggest a continuous record dating to at least ~10,500 cal. yr BP. Variations in magnetic susceptibility, percent organic and inorganic carbon, bulk density, grayscale and X-ray fluorescence chemistry indicate changes in the amount of clastic sediment deposition. We interpret clastic sediments to have been deposited from <span class="hlt">ice</span> <span class="hlt">cap</span> meltwater, thus indicating more extensive <span class="hlt">ice</span>. Clastic sediments compose the top of the core from 4 to 30 cm depth, below there is a sharp transition to organic sediments radiocarbon dated to (500±30 and 550±20 cal. yr BP). The radiocarbon ages are similar to the 10Be dated (LIA) glacial position. At least three other clastic units exist in the core; dating to ~2600-4300, ~4800-7300 and older then ~10,500 cal. yr BP based on a linear age model with four radiocarbon dates. We obtained two, ~4 m long, cores from Laguna Yanacocha (13.95°S,70.87</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820006693&hterms=marginal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmarginal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820006693&hterms=marginal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmarginal"><span>The Norwegian remote sensing experiment (Norsex) in a marginal <span class="hlt">ice</span> zone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farrelly, B.; Johannessen, J.; Johannessen, O. M.; Svendson, E.; Kloster, K.; Horjen, I.; Campbell, W. J.; Crawford, J.; Harrington, R.; Jones, L.</p> <p>1981-01-01</p> <p>Passive and active microwave measurements from surface based, airborne, and satellite instruments were obtained together with surface observations northwest of <span class="hlt">Svalbard</span>. Emissivities of different <span class="hlt">ice</span> patches in the <span class="hlt">ice</span> edge region over the spectral range from 4.9 to 94 GHz are presented. The combination of a 6.6 GHz microwave radiometer with a 14.6 GHz scatterometer demonstrates the usefulness of an active/passive system in <span class="hlt">ice</span> classification. A variety of mesoscale features under different meteorological conditions is revealed by a 1.36 GHz synthetic aperture radar. <span class="hlt">Ice</span> edge location by Nimbus 7 scanning multifrequency microwave radiometer is shown accurate to 10 km when the 37 GHz horizontal polarized channel is used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP21B1327O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP21B1327O"><span><span class="hlt">Ice</span> Core Records of Recent Northwest Greenland Climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Osterberg, E. C.; Wong, G. J.; Ferris, D.; Lutz, E.; Howley, J. A.; Kelly, M. A.; Axford, Y.; Hawley, R. L.</p> <p>2014-12-01</p> <p>Meteorological station data from NW Greenland indicate a 3oC temperature rise since 1990, with most of the warming occurring in fall and winter. According to remote sensing data, the NW Greenland <span class="hlt">ice</span> sheet (GIS) and coastal <span class="hlt">ice</span> <span class="hlt">caps</span> are responding with <span class="hlt">ice</span> mass loss and margin retreat, but the cryosphere's response to previous climate variability is poorly constrained in this region. We are developing multi-proxy records (lake sediment cores, <span class="hlt">ice</span> cores, glacial geologic data, glaciological models) of Holocene climate change and cryospheric response in NW Greenland to improve projections of future <span class="hlt">ice</span> loss and sea level rise in a warming climate. As part of our efforts to develop a millennial-length <span class="hlt">ice</span> core paleoclimate record from the Thule region, we collected and analyzed snow pit samples and short firn cores (up to 21 m) from the coastal region of the GIS (2Barrel site; 76.9317o N, 63.1467o W, 1685 m el.) and the summit of North <span class="hlt">Ice</span> <span class="hlt">Cap</span> (76.938o N, 67.671o W, 1273 m el.) in 2011, 2012 and 2014. The 2Barrel <span class="hlt">ice</span> core record has statistically significant relationships with regional spring and fall Baffin Bay sea <span class="hlt">ice</span> extent, summertime temperature, and annual precipitation. Here we evaluate relationships between the 2014 North <span class="hlt">Ice</span> <span class="hlt">Cap</span> firn core glaciochemical record and climate variability from regional instrumental stations and reanalysis datasets. We compare the coastal North <span class="hlt">Ice</span> <span class="hlt">Cap</span> record to more inland records from 2Barrel, Camp Century and NEEM to evaluate spatial and elevational gradients in recent NW Greenland climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160011105','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160011105"><span>Investigating Mars South Residual CO2 <span class="hlt">Cap</span> with a Global Climate Model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kahre, M. A.; Dequaire, J.; Hollingsworth, J. L.; Haberle, R. M.</p> <p>2016-01-01</p> <p>The CO2 cycle is one of the three controlling climate cycles on Mars. One aspect of the CO2 cycle that is not yet fully understood is the existence of a residual CO2 <span class="hlt">ice</span> <span class="hlt">cap</span> that is offset from the south pole. Previous investigations suggest that the atmosphere may control the placement of the south residual <span class="hlt">cap</span> (e.g., Colaprete et al., 2005). These investigations show that topographically forced stationary eddies in the south during southern hemisphere winter produce colder atmospheric temperatures and increased CO2 snowfall over the hemisphere where the residual <span class="hlt">cap</span> resides. Since precipitated CO2 <span class="hlt">ice</span> produces higher surface albedos than directly deposited CO2 <span class="hlt">ice</span>, it is plausible that CO2 snowfall resulting from the zonally asymmetric atmospheric circulation produces surface <span class="hlt">ice</span> albedos high enough to maintain a residual <span class="hlt">cap</span> only in one hemisphere. The goal of the current work is to further evaluate Colaprete et al.'s hypothesis by investigating model-predicted seasonally varying snowfall patterns in the southern polar region and the atmospheric circulation components that control them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Geomo.293..433E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Geomo.293..433E"><span>Freeze/thaw conditions at periglacial landforms in Kapp Linné, <span class="hlt">Svalbard</span>, investigated using field observations, in situ, and radar satellite monitoring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eckerstorfer, M.; Malnes, E.; Christiansen, H. H.</p> <p>2017-09-01</p> <p>In periglacial landscapes, snow dynamics and microtopography have profound implications of freeze-thaw conditions and thermal regime of the ground. We mapped periglacial landforms at Kapp Linné, central <span class="hlt">Svalbard</span>, where we chose six widespread landforms (solifluction sheet, nivation hollow, palsa and peat in beach ridge depressions, raised marine beach ridge, and exposed bedrock ridge) as study sites. At these six landforms, we studied ground thermal conditions, freeze-thaw cycles, and snow dynamics using a combination of in situ monitoring and C-band radar satellite data in the period 2005-2012. Based on these physical parameters, the six studied landforms can be classified into raised, dry landforms with minor ground <span class="hlt">ice</span> content and a thin, discontinuous snow cover and into wet landforms with high <span class="hlt">ice</span> content located in the topographical depressions in-between with medium to thick snow cover. This results in a differential snow-melting period inferred from the C-band radar satellite data, causing the interseasonal and interlandform variability in the onset of ground surface thawing once the ground becomes snow free. Therefore, variability also exists in the period of thawed ground surface conditions. However, the length of the season with thawed ground surface conditions does not determine the mean annual ground surface temperature, it only correlates well with the active layer depths. From the C-band radar satellite data series, measured relative backscatter trends hint toward a decrease in snow cover through time and a more frequent presence of <span class="hlt">ice</span> layers from mid-winter rain on snow events at Kapp Linné, <span class="hlt">Svalbard</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA05742&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DCAPS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA05742&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DCAPS"><span>Summer South Polar <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2004-01-01</p> <p><p/>13 April 2004 The martian south polar residual <span class="hlt">ice</span> <span class="hlt">cap</span> is composed mainly of frozen carbon dioxide. Each summer, a little bit of this carbon dioxide sublimes away. Pits grow larger, and mesas get smaller, as this process continues from year to year. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a view of a small portion of the south polar <span class="hlt">cap</span> as it appeared in mid-summer in January 2004. The dark areas may be places where the frozen carbon dioxide contains impurities, such as dust, or places where sublimation of <span class="hlt">ice</span> has roughened the surface so that it appears darker because of small shadows cast by irregularities in the roughened surface. The image is located near 86.9oS, 7.6oW. The image covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the upper left.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17731883','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17731883"><span><span class="hlt">Ice</span> core evidence for extensive melting of the greenland <span class="hlt">ice</span> sheet in the last interglacial.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Koerner, R M</p> <p>1989-05-26</p> <p>Evidence from <span class="hlt">ice</span> at the bottom of <span class="hlt">ice</span> cores from the Canadian Arctic Islands and Camp Century and Dye-3 in Greenland suggests that the Greenland <span class="hlt">ice</span> sheet melted extensively or completely during the last interglacial period more than 100 ka (thousand years ago), in contrast to earlier interpretations. The presence of dirt particles in the basal <span class="hlt">ice</span> has previously been thought to indicate that the base of the <span class="hlt">ice</span> sheets had melted and that the evidence for the time of original growth of these <span class="hlt">ice</span> masses had been destroyed. However, the particles most likely blew onto the <span class="hlt">ice</span> when the dimensions of the <span class="hlt">ice</span> <span class="hlt">caps</span> and <span class="hlt">ice</span> sheets were much smaller. <span class="hlt">Ice</span> texture, gas content, and other evidence also suggest that the basal <span class="hlt">ice</span> at each drill site is superimposed <span class="hlt">ice</span>, a type of <span class="hlt">ice</span> typical of the early growth stages of an <span class="hlt">ice</span> <span class="hlt">cap</span> or <span class="hlt">ice</span> sheet. If the present-day <span class="hlt">ice</span> masses began their growth during the last interglacial, the <span class="hlt">ice</span> sheet from the earlier (Illinoian) glacial period must have competely or largely melted during the early part of the same interglacial period. If such melting did occur, the 6-meter higher-than-present sea level during the Sangamon cannot be attributed to disintegration of the West Antarctic <span class="hlt">ice</span> sheet, as has been suggested.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C41A0644M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C41A0644M"><span>Modelling of Sea <span class="hlt">Ice</span> Thermodynamics and Biogeochemistry during the N-<span class="hlt">ICE</span>2015 Expedition in the Arctic Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meyer, A.; Duarte, P.; Mork Olsen, L.; Kauko, H.; Assmy, P.; Rösel, A.; Itkin, P.; Hudson, S. R.; Granskog, M. A.; Gerland, S.; Sundfjord, A.; Steen, H.; Jeffery, N.; Hunke, E. C.; Elliott, S.; Turner, A. K.</p> <p>2016-12-01</p> <p>Changes in the sea <span class="hlt">ice</span> regime of the Arctic Ocean over the last decades from a thick perennial multiyear <span class="hlt">ice</span> to a first year <span class="hlt">ice</span> have been well documented. These changes in the sea <span class="hlt">ice</span> regime will affect feedback mechanisms between the sea <span class="hlt">ice</span>, atmosphere and ocean. Here we evaluate the performance of the Los Alamos Sea <span class="hlt">Ice</span> Model (CICE), a state of the art sea <span class="hlt">ice</span> model, to predict sea <span class="hlt">ice</span> physical and biogeochemical properties at time scales of a few weeks. We also identify the most problematic prognostic variables and what is necessary to improve their forecast. The availability of a complete data set of forcing collected during the Norwegian Young sea <span class="hlt">Ice</span> (N-<span class="hlt">ICE</span>-2015) expedition north of <span class="hlt">Svalbard</span> opens the possibility to properly test CICE. Oceanographic, atmospheric, sea <span class="hlt">ice</span>, snow, and biological data were collected above, on, and below the <span class="hlt">ice</span> using R/V Lance as the base for the <span class="hlt">ice</span> camps that were drifting south towards the Fram Strait. Over six months, four different drifts took place, from the Nansen Basin, through the marginal <span class="hlt">ice</span> zone, to the open ocean. Obtained results from the model show a good performance regarding <span class="hlt">ice</span> thickness, salinity and temperature. Nutrients and sea <span class="hlt">ice</span> algae are however not modelled as accurately. We hypothesize that improvements in biogeochemical modeling may be achieved by complementing brine drainage with a diffusion parameterization and biogeochemical modeling with the introduction of an explicit formulation to forecast chlorophyll and regulate photosynthetic efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A13A2036H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A13A2036H"><span><span class="hlt">Ice</span> nucleating particles in the high Arctic at the beginning of the melt season</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hartmann, M.; Gong, X.; Van Pinxteren, M.; Welti, A.; Zeppenfeld, S.; Herrmann, H.; Stratmann, F.</p> <p>2017-12-01</p> <p><span class="hlt">Ice</span> nucleating particles (INPs) initiate the <span class="hlt">ice</span> crystal formation in persistent Arctic mixed-phase clouds and are important for the formation of precipitation, which affects the radiative properties of the Arctic pack <span class="hlt">ice</span> as well as the radiative properties of clouds. Sources of Arctic INP have been suggested to be local emissions from the marine boundary and long-range transport. To what extent local marine sources contribute to the INP population or if the majority of INPs originate from long-range transport is not yet known. Ship-based INP measurements in the PASCAL framework are reported. The field campaign took place from May 24 to July 20 2017 around and north of <span class="hlt">Svalbard</span> (up to 84°N, between 0° and 35°E) onboard the RV Polarstern. INP concentrations were determined applying in-situ measurements (DMT Spectrometer for <span class="hlt">Ice</span> Nuclei, SPIN) and offline filter techniques (filter sampling on both quartz fiber and polycarbonate filters with subsequent analysis of filter pieces and water suspension from particles collected on filters by means of immersion freezing experiments on cold stage setups). Additionally the compartments sea-surface micro layer (SML), bulk sea water, snow, sea <span class="hlt">ice</span> and fog water were sampled and their <span class="hlt">ice</span> nucleation potential quantified, also utilizing cold stages. The measurements yield comprehensive picture of the spatial and temporal distribution of INPs around <span class="hlt">Svalbard</span> for the different compartments. The dependence of the INP concentration on meteorological conditions (e.g. wind speed) and the geographical situation (sea <span class="hlt">ice</span> cover, distance to the <span class="hlt">ice</span> edge) are investigated. Potential sources of INP are identified by the comparison of INP concentrations in the compartments and by back trajectory analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3554413','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3554413"><span>Microbial communities in the subglacial waters of the Vatnajökull <span class="hlt">ice</span> <span class="hlt">cap</span>, Iceland</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Thór Marteinsson, Viggó; Rúnarsson, Árni; Stefánsson, Andri; Thorsteinsson, Thorsteinn; Jóhannesson, Tómas; Magnússon, Sveinn H; Reynisson, Eyjólfur; Einarsson, Bergur; Wade, Nicole; Morrison, Hilary G; Gaidos, Eric</p> <p>2013-01-01</p> <p>Subglacial lakes beneath the Vatnajökull <span class="hlt">ice</span> <span class="hlt">cap</span> in Iceland host endemic communities of microorganisms adapted to cold, dark and nutrient-poor waters, but the mechanisms by which these microbes disseminate under the <span class="hlt">ice</span> and colonize these lakes are unknown. We present new data on this subglacial microbiome generated from samples of two subglacial lakes, a subglacial flood and a lake that was formerly subglacial but now partly exposed to the atmosphere. These data include parallel 16S rRNA gene amplicon libraries constructed using novel primers that span the v3–v5 and v4–v6 hypervariable regions. Archaea were not detected in either subglacial lake, and the communities are dominated by only five bacterial taxa. Our paired libraries are highly concordant for the most abundant taxa, but estimates of diversity (abundance-based coverage estimator) in the v4–v6 libraries are 3–8 times higher than in corresponding v3–v5 libraries. The dominant taxa are closely related to cultivated anaerobes and microaerobes, and may occupy unique metabolic niches in a chemoautolithotrophic ecosystem. The populations of the major taxa in the subglacial lakes are indistinguishable (>99% sequence identity), despite separation by 6 km and an <span class="hlt">ice</span> divide; one taxon is ubiquitous in our Vatnajökull samples. We propose that the glacial bed is connected through an aquifer in the underlying permeable basalt, and these subglacial lakes are colonized from a deeper, subterranean microbiome. PMID:22975882</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRG..122.1486K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRG..122.1486K"><span>Windows in Arctic sea <span class="hlt">ice</span>: Light transmission and <span class="hlt">ice</span> algae in a refrozen lead</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kauko, Hanna M.; Taskjelle, Torbjørn; Assmy, Philipp; Pavlov, Alexey K.; Mundy, C. J.; Duarte, Pedro; Fernández-Méndez, Mar; Olsen, Lasse M.; Hudson, Stephen R.; Johnsen, Geir; Elliott, Ashley; Wang, Feiyue; Granskog, Mats A.</p> <p>2017-06-01</p> <p>The Arctic Ocean is rapidly changing from thicker multiyear to thinner first-year <span class="hlt">ice</span> cover, with significant consequences for radiative transfer through the <span class="hlt">ice</span> pack and light availability for algal growth. A thinner, more dynamic <span class="hlt">ice</span> cover will possibly result in more frequent leads, covered by newly formed <span class="hlt">ice</span> with little snow cover. We studied a refrozen lead (≤0.27 m <span class="hlt">ice</span>) in drifting pack <span class="hlt">ice</span> north of <span class="hlt">Svalbard</span> (80.5-81.8°N) in May-June 2015 during the Norwegian young sea <span class="hlt">ICE</span> expedition (N-<span class="hlt">ICE</span>2015). We measured downwelling incident and <span class="hlt">ice</span>-transmitted spectral irradiance, and colored dissolved organic matter (CDOM), particle absorption, ultraviolet (UV)-protecting mycosporine-like amino acids (MAAs), and chlorophyll a (Chl a) in melted sea <span class="hlt">ice</span> samples. We found occasionally very high MAA concentrations (up to 39 mg m-3, mean 4.5 ± 7.8 mg m-3) and MAA to Chl a ratios (up to 6.3, mean 1.2 ± 1.3). Disagreement in modeled and observed transmittance in the UV range let us conclude that MAA signatures in CDOM absorption spectra may be artifacts due to osmotic shock during <span class="hlt">ice</span> melting. Although observed PAR (photosynthetically active radiation) transmittance through the thin <span class="hlt">ice</span> was significantly higher than that of the adjacent thicker <span class="hlt">ice</span> with deep snow cover, <span class="hlt">ice</span> algal standing stocks were low (≤2.31 mg Chl a m-2) and similar to the adjacent <span class="hlt">ice</span>. <span class="hlt">Ice</span> algal accumulation in the lead was possibly delayed by the low inoculum and the time needed for photoacclimation to the high-light environment. However, leads are important for phytoplankton growth by acting like windows into the water column.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1811691C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1811691C"><span><span class="hlt">Ice</span> <span class="hlt">cap</span> melting and low viscosity crustal root explain narrow geodetic uplift of the Western Alps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chery, Jean; Genti, Manon; Vernant, Philippe</p> <p>2016-04-01</p> <p>More than 10 years of geodetic measurements demonstrate an uplift rate of 1-3 mm/yr of the high topography region of the Western Alps. By contrast, no significant horizontal motion has been detected. Three uplift mechanisms have been proposed so far: (1) the isostatic response to denudation. However this process is responsible for only a fraction of the observed uplift and (2) the rebound induced by the Wurmian <span class="hlt">ice</span> <span class="hlt">cap</span> melting. This process leads to a broader uplifting region than the one evidenced by geodetic observations. (3) a deep source motion associated with slab motion or some deep isostatic unbalance. Using a numerical model accounting for crustal and mantle rheology of the Alps and its foreland, we model the response to Wurmian <span class="hlt">ice</span> <span class="hlt">cap</span> melting. We show that a crustal viscosity contrast between the foreland and the central part of the Alps, the later being weaker with a viscosity of 1021 Pa.s, is needed to produce a narrow uplift. The vertical rates are enhanced if the strong uppermost mantle beneath the Moho is interrupted across the Alps, therefore allowing a weak vertical rheological anomaly thanks to the continuity between the low viscosity parts of the crust and mantle. References: Champagnac, J.-D., F. Schlunegger, K. Norton, F. von Blanckenburg, L. M. Abbühl, and M. Schwab (2009), Erosion-driven uplift of the modern Central Alps, Tectonophysics, 474(1-2), 236-249. Vernant, P., F. Hivert, J. Chéry, P. Steer, R. Cattin, and A. Rigo (2013), Erosion-induced isostatic rebound triggers extension in low convergent mountain ranges, geology, 41(4), 467-470.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C51C0997M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C51C0997M"><span>Glacial Boundary Features Delineated Using Enhanced-resolution Passive-microwave Data to Determine Melt Season Variation of the Vatnajokull <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Iceland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marzillier, D. M.; Ramage, J. M.</p> <p>2017-12-01</p> <p>Temperate glaciers such as those seen in Iceland experience high annual mass flux, thereby responding to small scale changes in Earth's climate. Decadal changes in the glacial margins of Iceland's <span class="hlt">ice</span> <span class="hlt">caps</span> are observable in the Landsat record, however twice daily AMSR-E Calibrated Enhanced-Resolution Passive Microwave Daily EASE-Grid 2.0 Brightness Temperature (CETB) Earth System Data Record (ESDR) allow for observation on a daily temporal scale and a 3.125 km spatial scale, which can in turn be connected to patterns seen over longer periods of time. Passive microwave data allow for careful observation of melt onset and duration in Iceland's glacial regions by recording changes in emissivity of the <span class="hlt">ice</span> surface, known as brightness temperature (TB), which is sensitive to fluctuations in the liquid water content of snow and <span class="hlt">ice</span> seen during melting in glaciated regions. Enhanced resolution of this data set allows for a determination of a threshold that defines the melting season. The XPGR snowmelt algorithm originally presented by Abdalati and Steffen (1995) is used as a comparison with the diurnal amplitude variation (DAV) values on Iceland's Vatnajokull <span class="hlt">ice</span> <span class="hlt">cap</span> located at 64.4N, -16.8W. Ground-based air temperature data in this region, digital elevation models (DEMs), and river discharge dominated by glacial runoff are used to confirm the glacial response to changes in global climate. Results show that Iceland glaciers have a bimodal distribution of brightness temperature delineating when the snow/<span class="hlt">ice</span> is melting and refreezing. Ground based temperatures have increased on a decadal trend. Clear glacial boundaries are visible on the passive microwave delineating strong features, and we are working to understand their variability and contribution to glacier evolution. The passive microwave data set allows connections to be made between observations seen on a daily scale and the long term glacier changes observed by the Landsat satellite record that integrates the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26104673','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26104673"><span>Microbial community development on the surface of Hans and Werenskiold Glaciers (<span class="hlt">Svalbard</span>, Arctic): a comparison.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Grzesiak, Jakub; Górniak, Dorota; Świątecki, Aleksander; Aleksandrzak-Piekarczyk, Tamara; Szatraj, Katarzyna; Zdanowski, Marek K</p> <p>2015-09-01</p> <p>Surface <span class="hlt">ice</span> and cryoconite holes of two types of polythermal <span class="hlt">Svalbard</span> Glaciers (Hans Glacier--grounded tidewater glacier and Werenskiold Glacier-land-based valley glacier) were investigated in terms of chemical composition, microbial abundance and diversity. Gathered data served to describe supraglacial habitats and to compare microbe-environment interactions on those different type glaciers. Hans Glacier samples displayed elevated nutrient levels (DOC, nitrogen and seston) compared to Werenskiold Glacier. Adjacent tundra formations, bird nesting sites and marine aerosol were candidates for allochtonic enrichment sources. Microbial numbers were comparable on both glaciers, with surface <span class="hlt">ice</span> containing cells in the range of 10(4) mL(-1) and cryoconite sediment 10(8) g(-1) dry weight. Denaturating gradient gel electrophoresis band-based clustering revealed differences between glaciers in terms of dominant bacterial taxa structure. Microbial community on Werenskiold Glacier benefited from the snow-released substances. On Hans Glacier, this effect was not as pronounced, affecting mainly the photoautotrophs. Over-fertilization of Hans Glacier surface was proposed as the major factor, desensitizing the microbial community to the snow melt event. Nitrogen emerged as a limiting factor in surface <span class="hlt">ice</span> habitats, especially to Eukaryotic algae.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994JGR....9921143C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994JGR....9921143C"><span>Spatial variability in the seasonal south polar <span class="hlt">CAP</span> of Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Calvin, Wendy M.; Martin, Terry Z.</p> <p>1994-10-01</p> <p>The first comprehensive discussion of the south seasonal polar <span class="hlt">cap</span> spectra obtained by the Mariner 7 infrared spectrometer in the short-wavelength region (2-4 microns) is presented. The infrared spectra is correlated with images acquired by the wide-angle camera. Significant spectral variation is noted in the <span class="hlt">cap</span> interior and regions of varying water frost abundance, CO2 <span class="hlt">ice</span>/frost cover, and CO2-<span class="hlt">ice</span> path length can be distinguished. Many of these spectral variations correlate with heterogeneity noted in the camera images, but certain significant infrared spectral variations are not discernible in the visible. Simple reflectance models are used to classify the observed spectral variations into four regions. Region I is at the <span class="hlt">cap</span> edge, where there is enhanced absorption beyond 3 microns inferred to be caused by an increased abundance of water frost. The increase in water abundance over that in the interior is on the level of a few parts per thousand or less. Region II is the typical <span class="hlt">cap</span> interior characterized by spectral features of CO2 <span class="hlt">ice</span> at grain sizes of several millimeters to centimeters. These spectra also indicate the presence of water frost at the parts per thousand level. A third, unusual region (III), is defined by three spectra in which weak CO2 absorption features are as much as twice as strong as in the average <span class="hlt">cap</span> spectra and are assumed to be caused by an increased path length in the CO2. Such large paths are inconsistent with the high reflectance in the visible and at 2.2 microns and suggest layered structures or deposition conditions that are not accounted for in current reflectance models. The final region (IV) is an area of thinning frost coverage or transparent <span class="hlt">ice</span> well in the interior of the seasonal <span class="hlt">cap</span>. These spectra are a combination of CO2 and ground signatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950037998&hterms=image+heterogeneity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dimage%2Bheterogeneity','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950037998&hterms=image+heterogeneity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dimage%2Bheterogeneity"><span>Spatial variability in the seasonal south polar <span class="hlt">cap</span> of Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Calvin, Wendy M.; Martin, Terry Z.</p> <p>1994-01-01</p> <p>The first comprehensive discussion of the south seasonal polar <span class="hlt">cap</span> spectra obtained by the Mariner 7 infrared spectrometer in the short-wavelength region (2-4 microns) is presented. The infrared spectra is correlated with images acquired by the wide-angle camera. Significant spectral variation is noted in the <span class="hlt">cap</span> interior and regions of varying water frost abundance, CO2 <span class="hlt">ice</span>/frost cover, and CO2-<span class="hlt">ice</span> path length can be distinguished. Many of these spectral variations correlate with heterogeneity noted in the camera images, but certain significant infrared spectral variations are not discernible in the visible. Simple reflectance models are used to classify the observed spectral variations into four regions. Region I is at the <span class="hlt">cap</span> edge, where there is enhanced absorption beyond 3 microns inferred to be caused by an increased abundance of water frost. The increase in water abundance over that in the interior is on the level of a few parts per thousand or less. Region II is the typical <span class="hlt">cap</span> interior characterized by spectral features of CO2 <span class="hlt">ice</span> at grain sizes of several millimeters to centimeters. These spectra also indicate the presence of water frost at the parts per thousand level. A third, unusual region (III), is defined by three spectra in which weak CO2 absorption features are as much as twice as strong as in the average <span class="hlt">cap</span> spectra and are assumed to be caused by an increased path length in the CO2. Such large paths are inconsistent with the high reflectance in the visible and at 2.2 microns and suggest layered structures or deposition conditions that are not accounted for in current reflectance models. The final region (IV) is an area of thinning frost coverage or transparent <span class="hlt">ice</span> well in the interior of the seasonal <span class="hlt">cap</span>. These spectra are a combination of CO2 and ground signatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.P24A..10F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.P24A..10F"><span>Variability of Seasonal CO2 <span class="hlt">Ice</span> <span class="hlt">Caps</span> on Mars for Mars Years 26 through 29</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feldman, W. C.; Maurice, S.; Prettyman, T. H.</p> <p>2011-12-01</p> <p>We have developed an improved thermal, epithermal, and fast neutron counting-rate time series data of the Mars Odyssey Neutron Spectrometer (MONS), optimized to greatly reduce both statistical and systematic uncertainties. This new data set was applied to study temporal and spatial distributions of the growth, decay, and maximum amount of precipitated CO2 <span class="hlt">ice</span> during Martian years (MY) 26, 27, 28, and 29. For this study, we concentrate on the epithermal counting rate detected using the down-looking prism (P1) of MONS, and a combination of the epithermal and thermal counting rate detected by the forward-looking sensor (P2) of MONS. Although the energy range of neutrons detected by P2 covers both the thermal and epithermal range, it is heavily weighted to the thermal range. We find that the variance of the maximum epithermal counting rate is remarkably small over both north and south seasonal <span class="hlt">caps</span>, varying by less than 3% over the four-year period. In contrast, although the maximum P2 counting rate over both poles is sensibly the same within error bars (about 2%) during the first three years, it drops by 18% over the north pole and 8% over the south pole during MY 29. The most-likely explanation of this drop is that abundances of the non-condensable gases N2 and Ar, are unusually enhanced during MY 29. Movies were also made of maps of the growth and decay of P2 counting rates summed over the first three years of these data. Careful inspection shows that both the growth and decay in the north were cylindrically symmetric, centered near the geographic north pole. In contrast, both the growth and decay of CO2 buildup in the south were skewed off the geographic pole to the center of the CO2 residual <span class="hlt">cap</span>, and contained a small, but definitely distinct ring-like annular enhancement centered at a latitude of about 83.5° S spread over a longitude range that extends between about -35° and +35° E. This arc runs parallel to, and overlays, the very steep drop in altitude from</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeoRL..45..789I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeoRL..45..789I"><span>Contribution of Deformation to Sea <span class="hlt">Ice</span> Mass Balance: A Case Study From an N-<span class="hlt">ICE</span>2015 Storm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Itkin, Polona; Spreen, Gunnar; Hvidegaard, Sine Munk; Skourup, Henriette; Wilkinson, Jeremy; Gerland, Sebastian; Granskog, Mats A.</p> <p>2018-01-01</p> <p>The fastest and most efficient process of gaining sea <span class="hlt">ice</span> volume is through the mechanical redistribution of mass as a consequence of deformation events. During the <span class="hlt">ice</span> growth season divergent motion produces leads where new <span class="hlt">ice</span> grows thermodynamically, while convergent motion fractures the <span class="hlt">ice</span> and either piles the resultant <span class="hlt">ice</span> blocks into ridges or rafts one floe under the other. Here we present an exceptionally detailed airborne data set from a 9 km2 area of first year and second year <span class="hlt">ice</span> in the Transpolar Drift north of <span class="hlt">Svalbard</span> that allowed us to estimate the redistribution of mass from an observed deformation event. To achieve this level of detail we analyzed changes in sea <span class="hlt">ice</span> freeboard acquired from two airborne laser scanner surveys just before and right after a deformation event brought on by a passing low-pressure system. A linear regression model based on divergence during this storm can explain 64% of freeboard variability. Over the survey region we estimated that about 1.3% of level sea <span class="hlt">ice</span> volume was pressed together into deformed <span class="hlt">ice</span> and the new <span class="hlt">ice</span> formed in leads in a week after the deformation event would increase the sea <span class="hlt">ice</span> volume by 0.5%. As the region is impacted by about 15 storms each winter, a simple linear extrapolation would result in about 7% volume increase and 20% deformed <span class="hlt">ice</span> fraction at the end of the season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009LPI....40.2281F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009LPI....40.2281F"><span>Perchlorate Found by Phoenix Could Provide a Mobile Brine Sludge at the Bed of Mars Northern <span class="hlt">Ice</span> <span class="hlt">Cap</span> that Would Allow Flow with Very Low Basal Temperatures: Possible Mechanism for Water Table Re-Charge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fisher, D. A.; Hecht, M.; Kounaves, S.; Catling, D.</p> <p>2009-03-01</p> <p>The north <span class="hlt">cap</span> of Mars has basal temperature that precludes the flow of <span class="hlt">ice</span>. Phoenix discovered polar soils contain perchlorate salts. These salts depress the melting point so it could form a sludge that provides a mobile bed that moves the <span class="hlt">ice</span> outwards.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070017882','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070017882"><span>Exposure of Water <span class="hlt">Ice</span> in the Northern Mid-lattitudes of Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Allen, Carlton C.; Kanner, Lisa C.</p> <p>2007-01-01</p> <p>Water <span class="hlt">ice</span> is exposed in the martian north polar <span class="hlt">cap</span>, and is occasionally exposed beyond the <span class="hlt">cap</span> boundary. Orbital gamma ray spectrometry data strongly imply the presence of water <span class="hlt">ice</span> within meters of the surface at latitudes north of approximately 60 deg. We have examined midlatitude areas of the northern plains displaying evidence of residual <span class="hlt">ice</span>-rich layers, and report possible present-day exposures of <span class="hlt">ice</span>. These exposures, if confirmed, could constrain the latitudinal and temporal stability of surface <span class="hlt">ice</span> on Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.5147Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.5147Y"><span>Esr Observations of Tid In The Polar Cusp/<span class="hlt">cap</span> Ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yin, F.; Ma, S. Y.; Schlegel, K.</p> <p></p> <p>EISCAT-<span class="hlt">Svalbard</span> radar provides new opportunity to study TIDs in the polar cusp/<span class="hlt">cap</span> ionosphere. Propagation characteristics of AGW-caused TIDs in quiet days are stud- ied by means of maximum entropy cross-spectral analysis of ESR CP1 and CP2 data. Apparent vertical wave-number of the TIDs as a function of height and the horizontal wave-number vector are obtained for main period of disturbances. It is observed as the first time that some of TIDs in the polar <span class="hlt">cap</span>/cusp ionosphere can propagate vertically from the height lower than 200 km up to as high as about 700 km with little attenu- ation. In the auroral ionosphere, however, they usually fade away below 500 km. In the region from about 100 to 180 km height, downward propagating mode is seen ob- viously. The possible relations of the TIDs with cusp particle precipitation and upper E-region heating are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.3339R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.3339R"><span><span class="hlt">Ice</span> loading model for Glacial Isostatic Adjustment in the Barents Sea constrained by GRACE gravity observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Root, Bart; Tarasov, Lev; van der Wal, Wouter</p> <p>2014-05-01</p> <p>The global <span class="hlt">ice</span> budget is still under discussion because the observed 120-130 m eustatic sea level equivalent since the Last Glacial Maximum (LGM) can not be explained by the current knowledge of land-<span class="hlt">ice</span> melt after the LGM. One possible location for the missing <span class="hlt">ice</span> is the Barents Sea Region, which was completely covered with <span class="hlt">ice</span> during the LGM. This is deduced from relative sea level observations on <span class="hlt">Svalbard</span>, Novaya Zemlya and the North coast of Scandinavia. However, there are no observations in the middle of the Barents Sea that capture the post-glacial uplift. With increased precision and longer time series of monthly gravity observations of the GRACE satellite mission it is possible to constrain Glacial Isostatic Adjustment in the center of the Barents Sea. This study investigates the extra constraint provided by GRACE data for modeling the past <span class="hlt">ice</span> geometry in the Barents Sea. We use CSR release 5 data from February 2003 to July 2013. The GRACE data is corrected for the past 10 years of secular decline of glacier <span class="hlt">ice</span> on <span class="hlt">Svalbard</span>, Novaya Zemlya and Frans Joseph Land. With numerical GIA models for a radially symmetric Earth, we model the expected gravity changes and compare these with the GRACE observations after smoothing with a 250 km Gaussian filter. The comparisons show that for the viscosity profile VM5a, <span class="hlt">ICE</span>-5G has too strong a gravity signal compared to GRACE. The regional calibrated <span class="hlt">ice</span> sheet model (GLAC) of Tarasov appears to fit the amplitude of the GRACE signal. However, the GRACE data are very sensitive to the <span class="hlt">ice</span>-melt correction, especially for Novaya Zemlya. Furthermore, the <span class="hlt">ice</span> mass should be more concentrated to the middle of the Barents Sea. Alternative viscosity models confirm these conclusions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.5209S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.5209S"><span>Cool episodes in Early Tertiary Arctic climate: Evidence from <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spielhagen, R. F.; Tripati, A.</p> <p>2009-04-01</p> <p>The Arctic is a climatically sensitive and important region. However, very little is known about the climatic and oceanographic evolution of the area, particularly prior to the Neogene. Until recently, the Arctic was assumed to be characterized by relatively warm conditions during the early Cenozoic. The Early Tertiary sedimentary sequence on <span class="hlt">Svalbard</span> contains several layers with coal seams and broad-leaved plants which were commonly accepted as indicators of a generally temperate-warm climate. Here we report on the intermittent occurrence of certain temperature indicators in the succession, which may represent the first northern high-latitude record of near-freezing temperatures for the early Cenozoic. Besides the findings of probably <span class="hlt">ice</span>-rafted erratic clasts in the Paleocene and Eocene sandstones and shales, we note especially the occurrence of glendonites which are pseudomorphs of calcite after ikaite (calcium carbonate hexahydrate). We measured the chemical composition of <span class="hlt">Svalbard</span> glendonites which is almost identical to that of similar pseudomorphs from the Lower Cretaceaous of Northern Canada. Mass spectrometric analyses of the glendonite calcite gave very low carbon isotope values. These values suggest a provenance of the calcium carbonate from marine organic carbon and connect our glendonites to the precursor mineral ikaite which has similar low values. Since a variety of studies has demonstrated that ikaite is stable only at temperatures close to freezing point, we have to infer low temperatures also for the deepositional environment of which the sediments were deposited that now hold glendonites. These results imply the occurrence of cooling phases episodically during the warm background climate of the Paleocene and Eocene, suggesting that temperature variability was much greater than previously recognized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040085689','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040085689"><span>Evolving Technologies for In-Situ Studies of Mars <span class="hlt">Ice</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Carsey, F. D.; Hecht, M. H.</p> <p>2003-01-01</p> <p>Icy sites on Mars continue to be of high scientific importance. These sites include the polar <span class="hlt">caps</span>, the southern mid-latitude subsurface permafrost, and the seasonal frost. These sites have interest due to their roles in climate processes, past climates, surface and near-surface water, astrobiology, geomorphology, and other topics. As is the case for many planetary features, remote sensing, while of great value, cannot answer all questions; in-situ examination is essential, and the motivation for in-situ observations generally leads to the subsurface, which, fortunately, is accessible on Mars. It is clear in fact that a Mars polar <span class="hlt">cap</span> subsurface mission is both scientifically compelling and practical. Recent data from orbiting platforms has provided a remarkable level of information about the Mars <span class="hlt">ice</span> <span class="hlt">caps</span>; we know, for example, the size, shape and annual cycle of the <span class="hlt">cap</span> topography as well as we know that of Earth, and we have more information on stratification that we have of, for example, the <span class="hlt">ice</span> of East Antarctica. To understand the roles that the Mars polar <span class="hlt">caps</span> play, it is necessary to gather information on the <span class="hlt">ice</span> <span class="hlt">cap</span> surface, strata, composition and bed. In this talk the status of in-situ operations and observations will be summarized, and, since we have conveniently at hand another planet with polar <span class="hlt">caps</span>, permafrost and <span class="hlt">ice</span>, the role of testing and validation of experimental procedures on Earth will be addressed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP33C1338B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP33C1338B"><span>Inception of the Laurentide <span class="hlt">Ice</span> Sheet using asynchronous coupling of a regional atmospheric model and an <span class="hlt">ice</span> model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Birch, L.; Cronin, T.; Tziperman, E.</p> <p>2017-12-01</p> <p>The climate over the past 0.8 million years has been dominated by <span class="hlt">ice</span> ages. <span class="hlt">Ice</span> sheets have grown about every 100 kyrs, starting from warm interglacials, until they spanned continents. State-of-the-art global climate models (GCMs) have difficulty simulating glacial inception, or the transition of Earth's climate from an interglacial to a glacial state. It has been suggested that this failure may be related to their poorly resolved local mountain topography, due to their coarse spatial resolution. We examine this idea as well as the possible role of <span class="hlt">ice</span> flow dynamics missing in GCMs. We investigate the growth of the Laurentide <span class="hlt">Ice</span> Sheet at 115 kya by focusing on the mountain glaciers of Canada's Baffin Island, where geologic evidence indicates the last inception occurred. We use the Weather Research and Forecasting model (WRF) in a regional, cloud-resolving configuration with resolved mountain terrain to explore how quickly Baffin Island could become glaciated with the favorable yet realizable conditions of 115 kya insolation, cool summers, and wet winters. Using the model-derived mountain glacier mass balance, we force an <span class="hlt">ice</span> sheet model based on the shallow-<span class="hlt">ice</span> approximation, capturing the <span class="hlt">ice</span> flow that may be critical to the spread of <span class="hlt">ice</span> sheets away from mountain <span class="hlt">ice</span> <span class="hlt">caps</span>. The <span class="hlt">ice</span> sheet model calculates the surface area newly covered by <span class="hlt">ice</span> and the change in the <span class="hlt">ice</span> surface elevation, which we then use to run WRF again. Through this type of iterated asynchronous coupling, we investigate how the regional climate responds to both larger areas of <span class="hlt">ice</span> cover and changes in <span class="hlt">ice</span> surface elevation. In addition, we use the NOAH-MP Land model to characterize the importance of land processes, like refreezing. We find that initial <span class="hlt">ice</span> growth on the Penny <span class="hlt">Ice</span> <span class="hlt">Cap</span> causes regional cooling that increases the accumulation on the Barnes <span class="hlt">Ice</span> <span class="hlt">Cap</span>. We investigate how <span class="hlt">ice</span> and topography changes on Baffin Island may impact both the regional climate and the large-scale circulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018TCry...12..609V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018TCry...12..609V"><span>Effects of undercutting and sliding on calving: a global approach applied to Kronebreen, <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vallot, Dorothée; Åström, Jan; Zwinger, Thomas; Pettersson, Rickard; Everett, Alistair; Benn, Douglas I.; Luckman, Adrian; van Pelt, Ward J. J.; Nick, Faezeh; Kohler, Jack</p> <p>2018-02-01</p> <p>In this paper, we study the effects of basal friction, sub-aqueous undercutting and glacier geometry on the calving process by combining six different models in an offline-coupled workflow: a continuum-mechanical <span class="hlt">ice</span> flow model (Elmer/<span class="hlt">Ice</span>), a climatic mass balance model, a simple subglacial hydrology model, a plume model, an undercutting model and a discrete particle model to investigate fracture dynamics (Helsinki Discrete Element Model, HiDEM). We demonstrate the feasibility of reproducing the observed calving retreat at the front of Kronebreen, a tidewater glacier in <span class="hlt">Svalbard</span>, during a melt season by using the output from the first five models as input to HiDEM. Basal sliding and glacier motion are addressed using Elmer/<span class="hlt">Ice</span>, while calving is modelled by HiDEM. A hydrology model calculates subglacial drainage paths and indicates two main outlets with different discharges. Depending on the discharge, the plume model computes frontal melt rates, which are iteratively projected to the actual front of the glacier at subglacial discharge locations. This produces undercutting of different sizes, as melt is concentrated close to the surface for high discharge and is more diffuse for low discharge. By testing different configurations, we show that undercutting plays a key role in glacier retreat and is necessary to reproduce observed retreat in the vicinity of the discharge locations during the melting season. Calving rates are also influenced by basal friction, through its effects on near-terminus strain rates and <span class="hlt">ice</span> velocity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.C31C..05L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.C31C..05L"><span>A comparison of Holocene fluctuations of the eastern and western margins of the Greenland <span class="hlt">Ice</span> Sheet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Levy, L.; Kelly, M. A.; Lowell, T. V.; Hall, B. L.; Applegate, P. J.; Howley, J.; Axford, Y.</p> <p>2013-12-01</p> <p>Determining how the Greenland <span class="hlt">Ice</span> Sheet (GrIS) responded to past temperature fluctuations is important for assessing its future stability in a changing climate. We present a record of the Holocene extents of the western GrIS margin near Kangerlussuaq (67.0°N, 50.7°W) and compare this with the past fluctuations of Bregne <span class="hlt">ice</span> <span class="hlt">cap</span> (71°N, 25.6° W), a small <span class="hlt">ice</span> <span class="hlt">cap</span> in the Scoresby Sund region 90 km from the eastern GrIS margin, to examine the mechanisms that influenced past <span class="hlt">ice</span> margin fluctuations. The past extents of the Bregne <span class="hlt">ice</span> <span class="hlt">cap</span> are a proxy for the climatic conditions that influenced the nearby GrIS margin. We used glacial geomorphic mapping, 10Be dating of boulders and bedrock, and sediment cores from proglacial and non-glacial lakes. In western Greenland, 10Be ages on the Keglen moraines, 13 km west of the current GrIS margin and the Ørkendalen moraines, ≤2 km west of the current <span class="hlt">ice</span> margin date to 7.3 × 0.1 ka (n=6) and 6.8 × 0.3 ka (n=9), respectively. Fresh moraines, ≤50 m from the current <span class="hlt">ice</span> margin date to AD 1830-1950 and are likely associated with advances during the Little <span class="hlt">Ice</span> Age (LIA). In some areas, the LIA moraines lie stratigraphically above the Ørkendalen moraines, indicating the GrIS was inboard of the Ørkendalen limit from 6.8 ka to the 20th century. In eastern Greenland, 10Be ages show that Bregne <span class="hlt">ice</span> <span class="hlt">cap</span> retreated within its late Holocene limit by 10.7 ka. A lack of clastic sediment in a proglacial lake suggests the <span class="hlt">ice</span> <span class="hlt">cap</span> was smaller or completely absent from ~10-2.6 ka. A snowline analysis indicates that temperatures ~0.5°C warmer than present would render the entire <span class="hlt">ice</span> <span class="hlt">cap</span> into an ablation zone. Glacial silts in the proglacial lake at ~2.6 and ~1.9 cal kyr BP to present indicate advances of Bregne <span class="hlt">ice</span> <span class="hlt">cap</span>. Fresh moraines ≤200 m of Bregne <span class="hlt">ice</span> <span class="hlt">cap</span> were deposited ≤2.6 cal kyr BP and mark the largest advance of the Holocene. Both the western GrIS margin and Bregne <span class="hlt">ice</span> <span class="hlt">cap</span> were influenced by Northern Hemisphere summer</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AtmEn.176...91S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AtmEn.176...91S"><span>Atmospheric depositions of natural and anthropogenic trace elements on the Guliya <span class="hlt">ice</span> <span class="hlt">cap</span> (northwestern Tibetan Plateau) during the last 340 years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sierra-Hernández, M. Roxana; Gabrielli, Paolo; Beaudon, Emilie; Wegner, Anna; Thompson, Lonnie G.</p> <p>2018-03-01</p> <p>A continuous record of 29 trace elements (TEs) has been constructed between 1650 and 1991 CE (Common Era) from an <span class="hlt">ice</span> core retrieved in 1992 from the Guliya <span class="hlt">ice</span> <span class="hlt">cap</span>, on the northwestern Tibetan Plateau. Enrichments of Pb, Cd, Zn and Sb were detected during the second half of the 19th century and the first half of the 20th century (∼1850-1950) while enrichments of Sn (1965-1991), Cd and Pb (1975-1991) were detected during the second half of the 20th century. The EFs increased significantly by 20% for Cd and Sb, and by 10% for Pb and Zn during 1850-1950 relative to the pre-1850s. Comparisons of the Guliya TEs data with other <span class="hlt">ice</span> core-derived and production/consumption data suggest that Northern Hemisphere coal combustion (primarily in Western Europe) is the likely source of Pb, Cd, Zn, and Sb during the 1850-1950 period. Coal combustion in Europe declined as oil replaced coal as the primary energy source. The European shift from coal to oil may have contributed to the observed Sn enrichment in ∼1965 (60% EF increase in 1975-1991), although regional fossil fuel combustion (coal and leaded gasoline) from western China, Central Asia, and South Asia (India, Nepal), as well as Sn mining/smelting in Central Asia, may also be possible sources. The post-1975 Cd and Pb enrichments (40% and 20% EF increase respectively in 1975-1991) may reflect emissions from phosphate fertilizers, fossil fuel combustion, and/or non-ferrous metal production, from western China, Central Asia, and/or South Asia. Leaded gasoline is likely to have also contributed to the post-1975 Pb enrichment observed in this record. The results strongly suggest that the Guliya <span class="hlt">ice</span> <span class="hlt">cap</span> has recorded long-distance emissions from coal combustion since the 1850s with more recent contributions from regional agriculture, mining, and/or fossil fuel combustion. This new Guliya <span class="hlt">ice</span> core record of TEs fills a geographical gap in the reconstruction of the pollution history of this region that extends well beyond modern</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010TCry....4..227D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010TCry....4..227D"><span>Brief Communication: Ikaite (CaCO3·6H2O) discovered in Arctic sea <span class="hlt">ice</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dieckmann, G. S.; Nehrke, G.; Uhlig, C.; Göttlicher, J.; Gerland, S.; Granskog, M. A.; Thomas, D. N.</p> <p>2010-05-01</p> <p>We report for the first time on the discovery of calcium carbonate crystals as ikaite (CaCO3·6H2O) in sea <span class="hlt">ice</span> from the Arctic (Kongsfjorden, <span class="hlt">Svalbard</span>) as confirmed by morphology and indirectly by X-ray diffraction as well as XANES spectroscopy of its amorophous decomposition product. This finding demonstrates that the precipitation of calcium carbonate during the freezing of sea <span class="hlt">ice</span> is not restricted to the Antarctic, where it was observed for the first time in 2008. This observation is an important step in the quest to quantify its impact on the sea <span class="hlt">ice</span> driven carbon cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009IJAsB...8..117W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009IJAsB...8..117W"><span>Mars polar <span class="hlt">cap</span>: a habitat for elementary life1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wallis, M. K.; Wickramasinghe, N. C.</p> <p>2009-04-01</p> <p><span class="hlt">Ices</span> in the Martian polar <span class="hlt">caps</span> are potential habitats for various species of microorganisms. Salts in the <span class="hlt">ice</span> and biological anti-freeze polymers maintain liquid in cracks in the <span class="hlt">ices</span> far below 0°C, possibly down to the mean 220-240 K. Sub-surface microbial life is shielded from ultraviolet (UV) radiation, but could potentially be activated on south-facing slopes under the midday, midsummer Sun. Such life would be limited by low levels of vapour, little transport of nutrients, low light levels below a protective dirt-crust, frost accumulation at night and in shadows, and little if any active translocation of organisms. As in the Antarctic and in permafrost, movement to new habitats depends on geo-climatic changes, which for Mars's north polar <span class="hlt">cap</span> occur on a 50 000 year scale, except for rare meteorite impacts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C33B0805G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C33B0805G"><span>In situ validation of segmented SAR satellite scenes of young Arctic thin landfast sea <span class="hlt">ice</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gerland, S.; Negrel, J.; Doulgeris, A. P.; Akbari, V.; Lauknes, T. R.; Rouyet, L.; Storvold, R.</p> <p>2016-12-01</p> <p>The use of satellite remote sensing techniques for the observation and monitoring of the polar regions has increased in recent years due to the ability to cover larger areas than can be covered by ground measurements, However, in situ data remain mandatory for the validation of such data. In April 2016 an Arctic fieldwork campaign was conducted at Kongsfjorden, <span class="hlt">Svalbard</span>. Ground measurements from this campaign are used together with satellite data acquisitions to improve identification of young sea <span class="hlt">ice</span> types from satellite data. This work was carried out in combination with Norwegian Polar Institute's long-term monitoring of <span class="hlt">Svalbard</span> fast <span class="hlt">ice</span>, and with partner institutes in the Center for Integrated Remote Sensing and Forecasting for Arctic operations (CIRFA). Thin <span class="hlt">ice</span> types are generally more difficult to investigate than thicker <span class="hlt">ice</span>, because <span class="hlt">ice</span> of only a few centimetres thickness does not allow scientists to stand and work on it. Identifying it on radar scenes will make it easier to study and monitor. Four high resolution 25 km x 25 km Radarsat-2 quad-pol scenes were obtained, coincident in space and time with the in situ measurements. The field teams used a variety of methods, including <span class="hlt">ice</span> thickness transects, <span class="hlt">ice</span> salinity measurements, ground-based radar imaging from the coast and UAV-based photography, to identify the different thin <span class="hlt">ice</span> types, their location and evolution in time. Sampling of the thinnest <span class="hlt">ice</span> types was managed from a small boat. In addition, iceberg positions were recorded with GPS and photographed to enable us to quantify their contribution to the radar response. Thin <span class="hlt">ice</span> from 0.02 to 0.18 m thickness was sampled on in a total nine <span class="hlt">ice</span> stations. The <span class="hlt">ice</span> had no or only a thin snow layer. The GPS positions and tracks and <span class="hlt">ice</span> characteristics are then compared to the Radarsat-2 scenes, and the radar responses of the different thin <span class="hlt">ice</span> types in the quad-pol scenes are identified. The first segmentation results of the scenes present a good</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930051807&hterms=water+cycles&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwater%2Bcycles','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930051807&hterms=water+cycles&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwater%2Bcycles"><span>The Mars water cycle at other epochs - Recent history of the polar <span class="hlt">caps</span> and layered terrain</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jakosky, Bruce M.; Henderson, Bradley G.; Mellon, Michael T.</p> <p>1993-01-01</p> <p>A numerical model is presented of the integrated role of seasonal water cycle on the evolution of polar deposits on Mars over the last 10 million years. From the model, it is concluded that the only major difference between the polar <span class="hlt">caps</span> which affects their long-term behavior is ultimately the difference in their elevations. Because of that difference, there is a preference for CO2 frost to stay longer on the northern polar <span class="hlt">cap</span>. The average difference in sublimation at the <span class="hlt">caps</span> results in a net south-to-north transport of water <span class="hlt">ice</span> over long time scales. Superimposed on any long-term behavior is a transfer of water <span class="hlt">ice</span> between the <span class="hlt">caps</span> on the 10 exp 5 - 10 exp 6 yr time scales. The amount of water exchanged is small compared to the total <span class="hlt">ice</span> content of the polar deposits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993Icar..102..286J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993Icar..102..286J"><span>The Mars water cycle at other epochs - Recent history of the polar <span class="hlt">caps</span> and layered terrain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jakosky, B. M.; Henderson, B. G.; Mellon, M. T.</p> <p>1993-04-01</p> <p>A numerical model is presented of the integrated role of seasonal water cycle on the evolution of polar deposits on Mars over the last 10 million years. From the model, it is concluded that the only major difference between the polar <span class="hlt">caps</span> which affects their long-term behavior is ultimately the difference in their elevations. Because of that difference, there is a preference for CO2 frost to stay longer on the northern polar <span class="hlt">cap</span>. The average difference in sublimation at the <span class="hlt">caps</span> results in a net south-to-north transport of water <span class="hlt">ice</span> over long time scales. Superimposed on any long-term behavior is a transfer of water <span class="hlt">ice</span> between the <span class="hlt">caps</span> on the 10 exp 5 - 10 exp 6 yr time scales. The amount of water exchanged is small compared to the total <span class="hlt">ice</span> content of the polar deposits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1412698F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1412698F"><span>Surface energy balance measurements and modeling on the <span class="hlt">ice</span> <span class="hlt">cap</span> of King George Island, West Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Falk, U.; Braun, M.; Sala, H.; Menz, G.</p> <p>2012-04-01</p> <p>The Antarctic Peninsula is amongst the fastest warming places on Earth and further temperature increase is to be expected. It has undergone rapid environmental changes in the past decades. Exceptional rates of surface air temperature increases (2.5K in 50 years) are concurrent with retreating glacier fronts, an increase in melt areas, surface lowering and rapid retreat, break-up and disintegration of <span class="hlt">ice</span> shelves. The South Shetland Islands are located on the northern tip of the Peninsula and are especially vulnerable to climate change due to their maritime climate. For King George Island we have compiled a unique data set comprising direct measurements of evaporation and sensible heat flux by eddy covariance on the Warszawa Icefield for the austral summers November 2010 to March 2011 and January to February 2012 in combination with a fully equipped automated weather station measuring long- and short-wave radiation components, profiles of temperature, humidity and wind velocities as well as glacier <span class="hlt">ice</span> temperatures in profile. The combination with the eddy covariance data allows for analysis of variability and seasonality of surface energy balance components on a glacier for an entire year. Repeat measurements of surface lowering at different locations on King George Island are used for analysis of multi-sensor satellite data to identify melt patterns and bare <span class="hlt">ice</span> areas during summer. In combination with long-term time series of weather data, these data give indication of the sensitivity of the inland <span class="hlt">ice</span> <span class="hlt">cap</span> to the ongoing changes. This research is part of the ESF project IMCOAST funded by BMBF. Field work was carried out at the Dallmann laboratory (Jubany, King George Island) in cooperation of the Instituto Antartico Argentino (Argentina) and the Alfred-Wegener Institute (German).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800042192&hterms=melting+ice+caps&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmelting%2Bice%2Bcaps','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800042192&hterms=melting+ice+caps&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmelting%2Bice%2Bcaps"><span>Volcano-<span class="hlt">ice</span> interactions on Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Allen, C. C.</p> <p>1979-01-01</p> <p>Central volcanic eruptions beneath terrestrial glaciers have built steep-sided, flat-topped mountains composed of pillow lava, glassy tuff, <span class="hlt">capping</span> flows, and cones of basalt. Subglacial fissure eruptions produced ridges of similar composition. In some places the products from a number of subglacial vents have combined to form widespread deposits. The morphologies of these subglacial volcanoes are distinctive enough to allow their recognition at the resolutions characteristic of Viking orbiter imagery. Analogs to terrestrial subglacial volcanoes have been identified on the northern plains and near the south polar <span class="hlt">cap</span> of Mars. The polar feature provides probable evidence of volcanic eruptions beneath polar <span class="hlt">ice</span>. A mixed unit of rock and <span class="hlt">ice</span> is postulated to have overlain portions of the northern plains, with eruptions into this ground <span class="hlt">ice</span> having produced mountains and ridges analogous to those in Iceland. Subsequent breakdown of this unit due to <span class="hlt">ice</span> melting revealed the volcanic features. Estimated heights of these landforms indicate that the <span class="hlt">ice</span>-rich unit once ranged from approximately 100 to 1200 m thick.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.P23A1706T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.P23A1706T"><span>Comparison of Mars Northern <span class="hlt">Cap</span> Edge Advance and Recession Rates over the Last 6 Mars Years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Titus, T. N.; Cushing, G. E.; Langevin, Y.; Brown, A. J.; Themis Science Team; CRISM Science Team</p> <p>2011-12-01</p> <p>The most observable parameter that describes the Mars polar seasonal <span class="hlt">caps</span> is their size, which has been measured since the days of Herschel. The advance and retreat of the polar <span class="hlt">cap</span> from year to year may exhibit many clues to help elucidate little understood physical processes. For example, summertime heat storage in the regolith could delay the onset of seasonal CO2 <span class="hlt">cap</span> formation. The evolution of the seasonal <span class="hlt">cap</span> could also be directly affected by the thermal inertia of the near-surface regolith and place constraints on the depth of the <span class="hlt">ice</span> table. Parameterizations of the seasonal <span class="hlt">cap</span> edges provide useful constraints on atmospheric GCMs and mesoscale models. Longitudinally resolving the <span class="hlt">cap</span> edges as they advance and retreat constrains the times when zonal means are appropriate and when longitudinal asymmetries make zonal means invalid. These same kinds of parameterizations can also be used when modeling other data that have low spatial resolutions, such as Gamma Ray Spectrometer (GRS )and Neutron Spectrometer (NS) data. By knowing where the <span class="hlt">cap</span> edge should be, coarse spatial data can correct for subpixel mixing caused by large point-spread functions including both frosted and frost-free areas. The northern <span class="hlt">cap</span> exhibits a near symmetric retreat, which has been well characterized at visible wavelengths by both telescopic and spacecraft observations. However, the advance of the <span class="hlt">cap</span> has not been well characterized until the 21st century. Kieffer and Titus (2001) have used zonal means to observe surface temperature and visible bolometric albedo variations with season using MGS/TES. The TES thermal observations show an almost perfectly symmetrical advance; i.e., condensation at consistent latitude across all longitudes, with the most northern edge of the seasonal <span class="hlt">cap</span> occurring between longitudes 245°E to 265°E and the most southern edge of the seasonal <span class="hlt">cap</span> occurring between 280°E and 30°E. The advance of the northern <span class="hlt">cap</span> typically leads the advance of the edge of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1614647H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1614647H"><span>A detailed Holocene glacial-periglacial reconstruction based on multidisciplinary studies of a 60 m permafrost core from central <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hvidtfeldt Christiansen, Hanne; Elberling, Bo; Gilbert, Graham L.; Thiel, Christine; Murray, Andrew; Buylaert, Jan-Pieter; Dypvik, Henning; Lomstein, Bente; Hovgaard, Jonas; Christensen, Anne T.; Mørkved, Pål T.; Reigstad, Laila J.; Fromreide, Siren; Seidenkrantz, Marit-Solveig</p> <p>2014-05-01</p> <p>During summer 2012, a 60 m sedimentary permafrost core was retrieved from the lower part of the Adventdalen Valley, central <span class="hlt">Svalbard</span>, as part of the Longyearbyen CO2 project. The core was taken in 3 m long sections, with 20 % core loss, and reached the sedimentary bedrock (Lower Cretaceous). Thus our samples had the potential to represent the entire Quaternary and reflect changes in the sedimentary environments through time. The stratigraphy and sedimentology of the core was first investigated, to establish an overall geological model for the sampling site. The general stratigraphy encompasses a layer of basal till at the bottom of the core. This is overlain by marine sediments documenting a transition from glacial-proximal to open-marine conditions. Subsequently, a thick package of deltaic sediments records the progradation of the local river system. Finally, aeolian sediments, characterizing the modern environment, form the top few meters of the core. The <span class="hlt">ice</span> content of the permafrost is generally low. Gravimetric water content generally ranges between 20% and 40%, but is considerably higher in some <span class="hlt">ice</span>-rich layers. High resolution optically stimulated luminescence dating of the core sediment shows that deposition was very fast and took place primarily during the mid Holocene, with very rapid sedimentation of around 4 m/ka. With the onset of aeolian deposition (around 3-4 ka) the sedimentation rate decreased significantly to 1m/ka. The microbial diversity and activity of the core are being studied displaying decreasing activity with depth. Microbial community and functional gene numbers indicate variations with depth and geochemistry. Incubation studies have been performed primarily on the upper 30 m, and indicate a potential CO2 production from all depth intervals being studied. The potential for using foraminifer studies for both dating and palaeoenvironmental reconstructions are evaluated with the intension of comparison with previous studies of marine</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP31C1302J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP31C1302J"><span>Holocene environmental changes recorded in Dicksonfjorden and Woodfjorden, <span class="hlt">Svalbard</span>: impacts of global climate changes in a glacial-marine system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Joo, Y. J.; Nam, S. I.; Son, Y. J.; Forwick, M.</p> <p>2017-12-01</p> <p>Fjords in the <span class="hlt">Svalbard</span> archipelago are characterized by an extreme environmental gradient between 1) the glacial system affected by tidewater glaciers and seasonal sea <span class="hlt">ice</span> inside the fjords and 2) the warm Atlantic Water intrusion by the West Spitsbergen Current from open ocean. As sediment is largely supplied from the terrestrial source area exposed along the steep slopes of the fjords, the changes in the surface processes affected by glaciers are likely preserved in the sediments in the inner fjords. On the other hand, variations in the influence of the warm Atlantic Water in the marine realm (e.g. marine productivity) can be archived in the sediment deposited in the vicinity of the entrance to the fjords. Since the last deglaciation of the <span class="hlt">Svalbard</span>-Barents <span class="hlt">ice</span> sheet ( 13000 yrs BP), the <span class="hlt">Svalbard</span> fjords have faced dramatic climate changes including the early Holocene Climate Optimum (HCO) and subsequent cooling that eventually led to the current cold and dry climate. We investigate the Holocene environmental changes in both terrestrial and marine realms based on stable isotopic and inorganic geochemical analyses of sediments deposited in Dicksonfjorden and Woodfjorden in the western and northern Spitsbergen, respectively. The two fjords are expected to provide intriguing information regarding how terrestrial and marine realms of the Arctic fjords system responded to regional and global climate changes. Being a branch of the larger Isfjorden, Dicksonfjorden penetrates deeply to the land, whereas Woodfjorden is rather directly connected to the open ocean. Accordingly, the results suggest that the Dicksonfjorden sediment records mainly terrestrial signals with marked fluctuations in sediment composition that coincide with major climate changes (e.g. HCO). On the contrary, the two Woodfjorden cores collected from different parts of the fjord exhibit contrasting results, likely illustrating differing response of terrestrial and marine realms to the climate changes in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012TCry....6.1483R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012TCry....6.1483R"><span>The first complete inventory of the local glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> on Greenland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rastner, P.; Bolch, T.; Mölg, N.; Machguth, H.; Le Bris, R.; Paul, F.</p> <p>2012-12-01</p> <p>Glacier inventories provide essential baseline information for the determination of water resources, glacier-specific changes in area and volume, climate change impacts as well as past, potential and future contribution of glaciers to sea-level rise. Although Greenland is heavily glacierised and thus highly relevant for all of the above points, a complete inventory of its glaciers was not available so far. Here we present the results and details of a new and complete inventory that has been compiled from more than 70 Landsat scenes (mostly acquired between 1999 and 2002) using semi-automated glacier mapping techniques. A digital elevation model (DEM) was used to derive drainage divides from watershed analysis and topographic attributes for each glacier entity. To serve the needs of different user communities, we assigned to each glacier one of three connectivity levels with the <span class="hlt">ice</span> sheet (CL0, CL1, CL2; i.e. no, weak, and strong connection) to clearly, but still flexibly, distinguish the local glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> (GIC) from the <span class="hlt">ice</span> sheet and its outlet glaciers. In total, we mapped ~ 20 300 glaciers larger than 0.05 km2 (of which ~ 900 are marine terminating), covering an area of 130 076 ± 4032 km2, or 89 720 ± 2781 km2 without the CL2 GIC. The latter value is about 50% higher than the mean value of more recent previous estimates. Glaciers smaller than 0.5 km2 contribute only 1.5% to the total area but more than 50% (11 000) to the total number. In contrast, the 25 largest GIC (> 500 km2) contribute 28% to the total area, but only 0.1% to the total number. The mean elevation of the GIC is 1700 m in the eastern sector and around 1000 m otherwise. The median elevation increases with distance from the coast, but has only a weak dependence on mean glacier aspect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMED32A..06R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMED32A..06R"><span>The <span class="hlt">Svalbard</span> REU Program: Undergraduates Pursuing Arctic Climate Change Research on <span class="hlt">Svalbard</span>, Norway</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roof, S.; Werner, A.</p> <p>2007-12-01</p> <p>The <span class="hlt">Svalbard</span> Research Experiences for Undergraduates (REU) program sponsored by the Arctic Natural Sciences Program of the National Science Foundation has been successfully providing international field research experiences since 2004. Each year, 7-9 undergraduate students have participated in 4-5 weeks of glacial geology and climate change fieldwork on Spitsbergen in the <span class="hlt">Svalbard</span> archipelago in the North Atlantic (76- 80° N lat.). While we continue to learn new and better ways to run our program, we have learned specific management and pedagogical strategies that allow us to streamline our logistics and to provide genuine, meaningful research opportunities to undergraduate students. We select student participants after extensive nationwide advertising and recruiting. Even before applying to the program, students understand that they will be doing meaningful climate change science, will take charge of their own project, and will be expected to continue their research at their home institution. We look for a strong commitment of support from a student's advisor at their home institution before accepting students into our program. We present clear information, including participant responsibilities, potential risks and hazards, application procedures, equipment needed, etc on our program website. The website also provides relevant research papers and data and results from previous years, so potential participants can see how their efforts will contribute to growing body of knowledge. New participants meet with the previous years' participants at a professional meeting (our "REUnion") before they start their field experience. During fieldwork, students are expected to develop research questions and test their own hypotheses while providing and responding to peer feedback. Professional assessment by an independent expert provides us with feedback that helps us improve logistical procedures and shape our educational strategies. The assessment also shows us how</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15975634','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15975634"><span>Levels of toxaphene congeners in white whales (Delphinapterus leucas) from <span class="hlt">Svalbard</span>, Norway.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Andersen, G; Føreid, S; Skaare, J U; Jenssen, B M; Lydersen, C; Kovacs, K M</p> <p>2006-03-15</p> <p>This study reports concentrations of three pesticide toxaphene congeners (CHBs; CHB-26, -50 and -62) from the blubber of ten adult, male white whales (Delphinapterus leucas) from <span class="hlt">Svalbard</span>, Norway. The CHB congeners that occurred at the highest levels in the blubber of the white whales were, as expected, CHB-26 (4636+/-1992 (SD) ng/g l.w.) and CHB-50 (6579+/-2214 ng/g l.w.); CHB-62 (232+/-231 ng/g l.w.) was also present, but at much lower concentrations. The mean level of the sum of the three CHBs (SigmaCHBs = 11,447+/-4208 ng/g l.w.) in this study is more than twice the mean concentrations of the well-known organochlorine (OC) pollutants SigmaDDTs (sum of pp'-DDT, pp'-DDE, pp'-DDD) and SigmaPCBs (sum of 27 PCB congeners) previously reported from the same individual white whales. The concentrations of CHBs in white whales from <span class="hlt">Svalbard</span> are at the high end of the range for concentrations of these compounds compared to other Arctic white whale populations. Additionally, the contribution of CHBs to the overall OC burden is larger in white whales from <span class="hlt">Svalbard</span> compared with their counterparts from other areas in the Arctic. Male white whales from <span class="hlt">Svalbard</span> have several orders of magnitude higher concentrations of SigmaCHBs compared to seals and polar bears (Ursus maritimus) from the same area. The high levels of CHBs in these whales, and their dominance in the OC pattern, suggests that white whales in <span class="hlt">Svalbard</span> are exposed to high levels of this group of contaminants. Further studies are needed to investigate possible effects of CHBs and other OC contaminants on the white whale population in <span class="hlt">Svalbard</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19840052166&hterms=gardening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgardening','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19840052166&hterms=gardening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgardening"><span>Polar <span class="hlt">cap</span> formation on Ganymede</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shaya, E. J.; Pilcher, C. B.</p> <p>1984-01-01</p> <p>It is argued that Ganymede's polar <span class="hlt">caps</span> are the remnants of a more extensive covering of water <span class="hlt">ice</span> that formed during a period in which the satellite was geologically active. It is inferred that the initial thickness of this covering was a significant fraction of the gardening depth since the covering formed. This suggests an initial thickness of at least a few meters over heavily cratered regions such as the south polar grooved terrain. The absence of similar polar <span class="hlt">caps</span> on Callisto apparently reflects the absence of comparable geologic activity in the history of this satellite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70025908','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70025908"><span>Exposed water <span class="hlt">ice</span> discovered near the south pole of Mars</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Titus, T.N.; Kieffer, H.H.; Christensen, P.R.</p> <p>2003-01-01</p> <p>The Mars Odyssey Thermal Emission Imaging System (THEMIS) has discovered water <span class="hlt">ice</span> exposed near the edge of Mars' southern perennial polar <span class="hlt">cap</span>. The surface H2O <span class="hlt">ice</span> was first observed by THEMIS as a region that was cooler than expected for dry soil at that latitude during the summer season. Diurnal and seasonal temperature trends derived from Mars Global Surveyor Thermal Emission Spectrometer observations indicate that there is H2O <span class="hlt">ice</span> at the surface. Viking observations, and the few other relevant THEMIS observations, indicate that surface H2O <span class="hlt">ice</span> may be widespread around and under the perennial CO2 <span class="hlt">cap</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070006554','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070006554"><span>Present-day Exposures of Water <span class="hlt">Ice</span> in the Northern Mid-latitudes of Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Allen, Carlton C.; Kanner, Lisa C.</p> <p>2007-01-01</p> <p>Water <span class="hlt">ice</span> is exposed in the martian north polar <span class="hlt">cap</span>, but is rarely exposed beyond the <span class="hlt">cap</span> boundary. Orbital gamma ray spectrometry data strongly imply the presence of water <span class="hlt">ice</span> within meters of the surface at latitudes north of approximately 60deg. We have examined mid-latitude areas of the northern plains displaying residual <span class="hlt">ice</span>-rich layers, and report evidence of present-day surface exposures of water <span class="hlt">ice</span>. These exposures, if confirmed, could con-strain the latitudinal and temporal stability of surface <span class="hlt">ice</span> on Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.P54B..04C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.P54B..04C"><span>Radar Detection of Layering in <span class="hlt">Ice</span>: Experiments on a Constructed Layered <span class="hlt">Ice</span> Sheet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carter, L. M.; Koenig, L.; Courville, Z.; Ghent, R. R.; Koutnik, M. R.</p> <p>2016-12-01</p> <p>The polar <span class="hlt">caps</span> and glaciers of both Earth and Mars display internal layering that preserves a record of past climate. These layers are apparent both in optical datasets (high resolution images, core samples) and in ground penetrating radar (GPR) data. On Mars, the SHARAD (Shallow Radar) radar on the Mars Reconnaissance Orbiter shows fine layering that changes spatially and with depth across the polar <span class="hlt">caps</span>. This internal layering has been attributed to changes in fractional dust contamination due to obliquity-induced climate variations, but there are other processes that can lead to internal layers visible in radar data. In particular, terrestrial sounding of <span class="hlt">ice</span> sheets compared with core samples have revealed that <span class="hlt">ice</span> density and composition differences account for the majority of the radar reflectors. The large cold rooms and <span class="hlt">ice</span> laboratory facility at the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) provide us a unique opportunity to construct experimental <span class="hlt">ice</span> sheets in a controlled setting and measure them with radar. In a CRREL laboratory, we constructed a layered <span class="hlt">ice</span> sheet that is 3-m deep with a various snow and <span class="hlt">ice</span> layers with known dust concentrations (using JSC Mars-1 basaltic simulant) and density differences. These <span class="hlt">ice</span> sheets were profiled using a commercial GPR, at frequencies of 200, 400 and 900 MHz, to determine how the radar profile changes due to systematic and known changes in snow and <span class="hlt">ice</span> layers, including layers with sub-wavelength spacing. We will report results from these experiments and implications for interpreting radar-detected layering in <span class="hlt">ice</span> on Earth and Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.C31A..01G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.C31A..01G"><span>Seasonal Changes of Arctic Sea <span class="hlt">Ice</span> Physical Properties Observed During N-<span class="hlt">ICE</span>2015: An Overview</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gerland, S.; Spreen, G.; Granskog, M. A.; Divine, D.; Ehn, J. K.; Eltoft, T.; Gallet, J. C.; Haapala, J. J.; Hudson, S. R.; Hughes, N. E.; Itkin, P.; King, J.; Krumpen, T.; Kustov, V. Y.; Liston, G. E.; Mundy, C. J.; Nicolaus, M.; Pavlov, A.; Polashenski, C.; Provost, C.; Richter-Menge, J.; Rösel, A.; Sennechael, N.; Shestov, A.; Taskjelle, T.; Wilkinson, J.; Steen, H.</p> <p>2015-12-01</p> <p>Arctic sea <span class="hlt">ice</span> is changing, and for improving the understanding of the cryosphere, data is needed to describe the status and processes controlling current seasonal sea <span class="hlt">ice</span> growth, change and decay. We present preliminary results from in-situ observations on sea <span class="hlt">ice</span> in the Arctic Basin north of <span class="hlt">Svalbard</span> from January to June 2015. Over that time, the Norwegian research vessel «Lance» was moored to in total four <span class="hlt">ice</span> floes, drifting with the sea <span class="hlt">ice</span> and allowing an international group of scientists to conduct detailed research. Each drift lasted until the ship reached the marginal <span class="hlt">ice</span> zone and <span class="hlt">ice</span> started to break up, before moving further north and starting the next drift. The ship stayed within the area approximately 80°-83° N and 5°-25° E. While the expedition covered measurements in the atmosphere, the snow and sea <span class="hlt">ice</span> system, and in the ocean, as well as biological studies, in this presentation we focus on physics of snow and sea <span class="hlt">ice</span>. Different <span class="hlt">ice</span> types could be investigated: young <span class="hlt">ice</span> in refrozen leads, first year <span class="hlt">ice</span>, and old <span class="hlt">ice</span>. Snow surveys included regular snow pits with standardized measurements of physical properties and sampling. Snow and <span class="hlt">ice</span> thickness were measured at stake fields, along transects with electromagnetics, and in drillholes. For quantifying <span class="hlt">ice</span> physical properties and texture, <span class="hlt">ice</span> cores were obtained regularly and analyzed. Optical properties of snow and <span class="hlt">ice</span> were measured both with fixed installed radiometers, and from mobile systems, a sledge and an ROV. For six weeks, the surface topography was scanned with a ground LIDAR system. Spatial scales of surveys ranged from spot measurements to regional surveys from helicopter (<span class="hlt">ice</span> thickness, photography) during two months of the expedition, and by means of an array of autonomous buoys in the region. Other regional information was obtained from SAR satellite imagery and from satellite based radar altimetry. The analysis of the data collected has started, and first results will be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19191538','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19191538"><span>Short- and long-term olivine weathering in <span class="hlt">Svalbard</span>: implications for Mars.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hausrath, E M; Treiman, A H; Vicenzi, E; Bish, D L; Blake, D; Sarrazin, P; Hoehler, T; Midtkandal, I; Steele, A; Brantley, S L</p> <p>2008-12-01</p> <p>Liquid water is essential to life as we know it on Earth; therefore, the search for water on Mars is a critical component of the search for life. Olivine, a mineral identified as present on Mars, has been proposed as an indicator of the duration and characteristics of water because it dissolves quickly, particularly under low-pH conditions. The duration of olivine persistence relative to glass under conditions of aqueous alteration reflects the pH and temperature of the reacting fluids. In this paper, we investigate the utility of 3 methodologies to detect silicate weathering in a Mars analog environment (Sverrefjell volcano, <span class="hlt">Svalbard</span>). CheMin, a miniature X-ray diffraction instrument developed for flight on NASA's upcoming Mars Science Laboratory, was deployed on <span class="hlt">Svalbard</span> and was successful in detecting olivine and weathering products. The persistence of olivine and glass in <span class="hlt">Svalbard</span> rocks was also investigated via laboratory observations of weathered hand samples as well as an in situ burial experiment. Observations of hand samples are consistent with the inference that olivine persists longer than glass at near-zero temperatures in the presence of solutions at pH approximately 7-9 on <span class="hlt">Svalbard</span>, whereas in hydrothermally altered zones, glass has persisted longer than olivine in the presence of fluids at similar pH at approximately 50 degrees C. Analysis of the surfaces of olivine and glass samples, which were buried on Sverrefjell for 1 year and then retrieved, documented only minor incipient weathering, though these results suggest the importance of biological impacts. The 3 types of observations (CheMin, laboratory observations of hand samples, burial experiments) of weathering of olivine and glass at <span class="hlt">Svalbard</span> show promise for interpretation of weathering on Mars. Furthermore, the weathering relationships observed on <span class="hlt">Svalbard</span> are consistent with laboratory-measured dissolution rates, which suggests that relative mineral dissolution rates in the laboratory, in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992Metic..27R.257M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992Metic..27R.257M"><span>Cosmic Dust in ~50 KG Blocks of Blue <span class="hlt">Ice</span> from <span class="hlt">Cap</span>-Prudhomme and Queen Alexandra Range, Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maurette, M.; Cragin, J.; Taylor, S.</p> <p>1992-07-01</p> <p>Favorable Antarctic blue <span class="hlt">ice</span> fields have produced a large number of meteorite finds because of the <span class="hlt">ice</span> ablation concentration process (Cassidy et al., 1982). Such <span class="hlt">ice</span> fields should also concentrate cosmic dust grains including both spherules and unmelted micrometeorites. Here we present preliminary results of concentrations of cosmic dust grains in <span class="hlt">ice</span> from two very different Antarctic blue <span class="hlt">ice</span> fields. The first sample (~60 kg) was collected in January 1987 from the surface of the blue <span class="hlt">ice</span> field at <span class="hlt">Cap</span>-Prudhomme (CP), near the French station of Dumont d'Urville, by a team from the "Laboratoire de Glaciologie du CNRS" (A. Barnola). The second sample (~50 kg), was retrieved from a meteorite stranding surface near the Queen Alexandra range (QUE) by a team (M. Burger, W. Cassidy, and R.Walker) of the ANSMET 1990 field expedition in Antarctica. Both samples were transported frozen to the laboratory where they were subdivided and processed. The CP sample was cut with a stainless steel saw into 4 pieces while the QUE sample, which had the top surface identified, was cut into three equal (~15 cm) horizontal layers to provide constituent variability with depth. All subsequent work on both samples was performed in a class 100 clean room using procedures developed by M. de Angelis and M. Maurette aimed at minimizing the loss of extraterrestrial particles. Pieces of both samples were cleaned by rinsing thoroughly with ultrapure water (Milli-O) and then melted in polyethylene containers in a microwave oven. Aliquots were decanted for chemical analysis and the remaining meltwater was filtered through stainless steel sieves for collection of large (>30 micrometers) particles. Using a 30X binocular microscope particles were hand picked for subsequent SEM/EDX analyses. Our initial objective was to compare the cosmic dust concentration in <span class="hlt">ice</span> from the two locations. But this comparison was only partial because in the CP-<span class="hlt">ice</span>, only magnetic spherules of >50 micrometers were studied</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11814041','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11814041"><span>Echinococcus multilocularis on <span class="hlt">Svalbard</span>: introduction of an intermediate host has enabled the local life-cycle.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Henttonen, H; Fuglei, E; Gower, C N; Haukisalmi, V; Ims, R A; Niemimaa, J; Yoccoz, N G</p> <p>2001-12-01</p> <p>The taeniid tapeworm Echinococcus multilocularis is here reported for the first time at the <span class="hlt">Svalbard</span> Archipelago in the Norwegian Arctic. This new finding is interesting because the establishment of E. multilocularis is due to a recent anthropogenic introduction of its intermediate host--the sibling vole Microtus rossiaemeridionalis at <span class="hlt">Svalbard</span>. The parasite itself has probably become naturally transferred to <span class="hlt">Svalbard</span> due to migratory movements of its final host--the arctic fox Alopex lagopus between source areas for E. multilocularis in Siberia and <span class="hlt">Svalbard</span>. We report macroscopically determined prevalence of E. multilocularis from a sample of 224 voles trapped in August in 1999 and 2000. The prevalence was among the highest ever recorded in intermediate hosts and was dependent on age and sex of the hosts approaching 100% in overwintered males. The high prevalence and the simplicity of the vole-arctic fox-E. multilocularis system at <span class="hlt">Svalbard</span> makes it an eminent model system for further epidemiological studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20171208_Archive_e000121.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20171208_Archive_e000121.html"><span>NASA’s Aerial Survey of Polar <span class="hlt">Ice</span> Expands Its Arctic Reach</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-12-08</p> <p>For the past eight years, Operation <span class="hlt">Ice</span>Bridge, a NASA mission that conducts aerial surveys of polar <span class="hlt">ice</span>, has produced unprecedented three-dimensional views of Arctic and Antarctic <span class="hlt">ice</span> sheets, providing scientists with valuable data on how polar <span class="hlt">ice</span> is changing in a warming world. Now, for the first time, the campaign will expand its reach to explore the Arctic’s Eurasian Basin through two research flights based out of <span class="hlt">Svalbard</span>, a Norwegian archipelago in the northern Atlantic Ocean. More: go.nasa.gov/2ngAxX2 Credits: NASA/Nathan Kurtz NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900038314&hterms=water+cycle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwater%2Bcycle','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900038314&hterms=water+cycle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwater%2Bcycle"><span>The role of water <span class="hlt">ice</span> clouds in the Martian hydrologic cycle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>James, Philip B.</p> <p>1990-01-01</p> <p>A one-dimensional model for the seasonal cycle of water on Mars has been used to investigate the direction of the net annual transport of water on the planet and to study the possible role of water <span class="hlt">ice</span> clouds, which are included as an independent phase in addition to ground <span class="hlt">ice</span> and water vapor, in the cycle. The calculated seasonal and spatial patterns of occurrence of water <span class="hlt">ice</span> clouds are qualitatively similar to the observed polar hoods, suggesting that these polar clouds are, in fact, an important component of water cycle. A residual dry <span class="hlt">ice</span> in the south acts as a cold trap which, in the absence of sources other than the <span class="hlt">caps</span>, will ultimately attract the water <span class="hlt">ice</span> from the north <span class="hlt">cap</span>; however, in the presence of a source of water in northern midlatitudes during spring, it is possible that the observed distribution of vapor and <span class="hlt">ice</span> can be in a steady state even if a residual CO2 <span class="hlt">cap</span> is a permanent feature of the system.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E1879L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1879L"><span>Possible contemporary evaporites formation at the Martian Northern Polar <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Losiak, Anna; Czechowski, Leszek</p> <p></p> <p>Evaporitic minerals are abundant on the surface of Mars (e.g., Wentworth et al. 2005, Velbel 2012, Clark and Van Hart 1981, Wang et al. 2006, Kuzmin et al. 2009), especially within the Circumpolar Dune Field and on the Northern <span class="hlt">Ice</span> <span class="hlt">Cap</span> itself (e.g., Langevin et al., 2005, Roach et al. 2007, Horgan et al. 2009, Masse et al. 2010, 2012). Most of their proposed formation mechanisms require significant amounts of liquid water and are thus not possible under current Martian conditions (Arvidson et al. 2006, Andrews-Hanna et al. 2007, Fishbaugh et al. 2007, Szynkiewicz et al. 2010). Some authors have considered the potential role of <span class="hlt">ice</span> and <span class="hlt">ice</span>- or snowmelt-related alteration in the weathering of Martian materials (e.g., Catling et al. 2006, Zolotov and Mironenko 2007, Niles and Michalski 2009, Masse et al. 2010). However, none of those studies discussed details of the process leading to the formation of the evaporites or the timing of the processes. The aim of this paper is to model numerically if the current radiant heating is sufficient to melt a thin layer of <span class="hlt">ice</span> surrounding a single dust grain exposed within the south facing side of the Martian North Polar <span class="hlt">Cap</span> trench. The results of our initial study suggest that for dust grains with basaltic properties and <span class="hlt">ice</span> with low values of coefficient of heat conduction, and solar constant = 492 W/m2 liquid water may exist below a dust grain for up to 4 hours a sol. This suggest that contemporary evaporites formation on Martian Polar <span class="hlt">Cap</span> is possible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMPP23A1388K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMPP23A1388K"><span>10Be dating of late-glacial moraines near the Cordillera Vilcanota and the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Peru</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelly, M. A.; Thompson, L. G.</p> <p>2004-12-01</p> <p>The surface exposure method, based on the measurement of cosmogenic 10Be produced in quartz, is applied to determine the age of deposition of glacial moraines near the Cordillera Vilcanota and the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> (about 13° S, 70° W) in southeastern Peru. These data are useful for examining the timing of past glaciation in the tropical Andes and for comparison with chronologies of glaciation at higher latitudes. The preliminary data set consists of more than ten surface exposure ages. Samples used for dating are from the surfaces of boulders on a set of prominent moraines about four kilometers away from the present <span class="hlt">ice</span> margins. The age of the moraine set was previously bracketed by radiocarbon dating of peat associated with the glacial deposits. Based on radiocarbon ages, these moraines were formed during the late-glacial period, just prior to the last glacial-interglacial transition. The surface exposure dating method enables the direct dating of the moraines. Surface exposure dates are cross-checked with the previously existing radiocarbon dates and provide a means to improve the chronology of past glaciation in the tropical Andes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17767407','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17767407"><span>Phylogenetic comparison of rabies viruses from disease outbreaks on the <span class="hlt">Svalbard</span> Islands.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Johnson, N; Dicker, A; Mork, T; Marston, D A; Fooks, A R; Tryland, M; Fuglei, E; Müller, T</p> <p>2007-01-01</p> <p>Periodic wildlife rabies epizootics occur in Arctic regions. The original sources of these outbreaks are rarely identified. In 1980, a wildlife epizootic of rabies occurred on the previously rabies-free <span class="hlt">Svalbard</span> Islands, Norway. After this outbreak of rabies in the arctic fox population (Alopex lagopus), only single cases have been reported from the Islands over the following two decades. Phylogenetic characterization of four viruses isolated from infected arctic foxes from <span class="hlt">Svalbard</span> from three different time periods suggest that the source of these epizootics could have been migration of this species from the Russian mainland. Arctic fox migration has likely contributed to the establishment of another zoonotic disease, Echinococcus multilocularis, on <span class="hlt">Svalbard</span> in recent years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..12210855K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..12210855K"><span>Vertical thermodynamic structure of the troposphere during the Norwegian young sea <span class="hlt">ICE</span> expedition (N-<span class="hlt">ICE</span>2015)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kayser, Markus; Maturilli, Marion; Graham, Robert M.; Hudson, Stephen R.; Rinke, Annette; Cohen, Lana; Kim, Joo-Hong; Park, Sang-Jong; Moon, Woosok; Granskog, Mats A.</p> <p>2017-10-01</p> <p>The Norwegian young sea <span class="hlt">ICE</span> (N-<span class="hlt">ICE</span>2015) expedition was designed to investigate the atmosphere-snow-<span class="hlt">ice</span>-ocean interactions in the young and thin sea <span class="hlt">ice</span> regime north of <span class="hlt">Svalbard</span>. Radiosondes were launched twice daily during the expedition from January to June 2015. Here we use these upper air measurements to study the multiple cyclonic events observed during N-<span class="hlt">ICE</span>2015 with respect to changes in the vertical thermodynamic structure, moisture content, and boundary layer characteristics. We provide statistics of temperature inversion characteristics, static stability, and boundary layer extent. During winter, when radiative cooling is most effective, we find the strongest impact of synoptic cyclones. Changes to thermodynamic characteristics of the boundary layer are associated with transitions between the radiatively "clear" and "opaque" atmospheric states. In spring, radiative fluxes warm the surface leading to lifted temperature inversions and a statically unstable boundary layer. Further, we compare the N-<span class="hlt">ICE</span>2015 static stability distributions to corresponding profiles from ERA-Interim reanalysis, from the closest land station in the Arctic North Atlantic sector, Ny-Ålesund, and to soundings from the SHEBA expedition (1997/1998). We find similar stability characteristics for N-<span class="hlt">ICE</span>2015 and SHEBA throughout the troposphere, despite differences in location, sea <span class="hlt">ice</span> thickness, and snow cover. For Ny-Ålesund, we observe similar characteristics above 1000 m, while the topography and <span class="hlt">ice</span>-free fjord surrounding Ny-Ålesund generate great differences below. The long-term radiosonde record (1993-2014) from Ny-Ålesund indicates that during the N-<span class="hlt">ICE</span>2015 spring period, temperatures were close to the climatological mean, while the lowest 3000 m were 1-3°C warmer than the climatology during winter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1812196K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1812196K"><span>First evidence of the Ellesmerian metamorphism on <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kośmińska, Karolina; Majka, Jarosław; Manecki, Maciej; Schneider, David A.</p> <p>2016-04-01</p> <p>The Ellesmerian fold-and-thrust belt is exposed in the High Arctic from Ellesmere Island in the east, through North Greenland, to <span class="hlt">Svalbard</span> in the west (e.g. Piepjohn et al., 2015). It developed during Late Devonian - Early Carboniferous, and overprinted older (mainly Caledonian) structures. It is thought that this fold-and-thrust belt was formed due to collision of the Pearya Terrane and <span class="hlt">Svalbard</span> with the Franklinian Basin of Laurentia. Traditionally, the Ellesmerian fold-and-thrust belt comprises a passive continental margin affected by foreland deformation processes, but the exact larger scale tectonic context of this belt is disputable. It is partly because the Eocene Eurekan deformation superimposed significantly the Ellesmerian structures, thus making the reconstruction of the pre-Eurekan history very difficult. Here we present for the first time evidence for Ellesmerian metamorphism within the crystalline basement of <span class="hlt">Svalbard</span>. These rocks are exposed in the Pinkie unit on Prins Karls Forland (W-<span class="hlt">Svalbard</span>), which exhibits tectonic contacts with the overlying sequences. The Pinkie unit is mainly composed of strongly deformed lithologies such as laminated quartzites, siliciclastic rocks and garnet-bearing mica schists. Detrital zircon dating yielded ages as young as Neoproterozoic (0.95-1.05 Ga), thus the Pinkie unit is considered to be Neoproterozoic (Kośmińska et al., 2015a). The M1 assemblages and D1 structures are affected by D2 mylonitization (cf. Faehnrich et al., 2016, this meeting). Petrological characterization and Th-U-total Pb chemical monazite dating have been performed on the Pinkie metapelites. These rocks exhibit an apparent inverted Barrovian metamorphic sequence, within which three metamorphic zones have been distinguished: garnet+staurolite+muscovite+biotite, garnet+staurolite+kyanite+muscovite+biotite, garnet+kyanite+muscovite+biotite. The P-T estimates using the QuiG barometry coupled with thermodynamic modelling revealed that the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.P53F..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.P53F..07L"><span>Can the Solid State Greenhouse Effect Produce ~100 Year Cycles in the Mars South Polar Residual CO2 <span class="hlt">Ice</span> <span class="hlt">Cap</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Line, M. R.; Ingersoll, A. P.</p> <p>2010-12-01</p> <p>Malin et al. (2001) reported that the south perennial <span class="hlt">cap</span> consists of quasi-circular pits ~8 meters deep, with a flat surface in between. The walls of the pits are retreating at a rate of 1 to 3 meters per year. Byrne and Ingersoll (2003a, 2003b) showed evidence that the floors of the pits are water <span class="hlt">ice</span> and the upper layer is CO2. This layer will be gone in a few Martian centuries, if the observations are taken at face value. This raises some difficult questions: How likely is it that mankind would be witnessing the final few hundred years of the residual CO2 frost on Mars? Can one imagine extreme weather events that could recharge the residual CO2 frost once it is gone? Both seem unlikely, and we propose a different mechanism. Kieffer et al. (2000) showed that sunlight can penetrate several meters through the seasonal CO2 frost, where it warms the surface below. We have observational evidence that the same is happening in the perennial CO2 frost. Further, we have a model that shows how this "solid-state greenhouse" can lead to cyclic behavior, in which layers of CO2 build up on a water <span class="hlt">ice</span> substrate, are heated internally by sunlight and lose mass from within. Eventually the layer becomes too weak to support itself, and it collapses to form pits. Then a new CO2 layer accumulates and the process repeats. Our study addresses fundamental questions of long-term stability of the Martian polar <span class="hlt">caps</span> and how the <span class="hlt">caps</span> control the atmospheric pressure. Instead of invoking extreme climate events to explain the data, we propose that processes within the frost itself can lead to cyclic growth and collapse of the pits. Our model implies that there is no long-term change in the ~8 meter layer of CO2 and no extreme weather events to make it change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900038317&hterms=fine+dust&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dfine%2Bdust','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900038317&hterms=fine+dust&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dfine%2Bdust"><span>H2O grain size and the amount of dust in Mars' residual north polar <span class="hlt">cap</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kieffer, Hugh H.</p> <p>1990-01-01</p> <p>In Mars' north polar <span class="hlt">cap</span>, the probable composition of material residual from the annual condensation cycle is a mixture of fine dust and H2O grains of comparable size and abundance. However, metamorphism of such material will gradually lower its albedo by increasing the size of the H2O grains only. If the <span class="hlt">cap</span> is undergoing net annual sublimation (as inferred from water vapor observations), late summer observations should be of old <span class="hlt">ice</span> with H2O grain sizes of 100 microns or more. <span class="hlt">Ice</span> of this granularity containing 30 percent fine dust has a reflectivity similar to that of dust alone; the observed albedo and computed <span class="hlt">ice</span> grain size imply dust concentrations of 1 part per 1000 or less. The brightness of the icy areas conflicts with what would be expected for a residual <span class="hlt">cap</span> deposited by an annual cycle similar to that observed by Viking and aged for thousands of years. The residual <span class="hlt">cap</span> surface cannot be 'old dirty' <span class="hlt">ice</span>. It could be old, coarse, and clean; or it could be young, fine, and dirty. This brings into question both the source of the late summer water vapor and the formation rate of laminated terrain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70016320','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70016320"><span>H2O grain size and the amount of dust in Mars' residual North polar <span class="hlt">cap</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kieffer, H.H.</p> <p>1990-01-01</p> <p>In Mars' north polar <span class="hlt">cap</span> the probable composition of material residual from the annual condensation cycle is a mixture of fine dust and H2O grains of comparable size and abundance. However, metamorphism of such material will gradually lower its albedo by increasing the size of the H2O grains only. If the <span class="hlt">cap</span> is undergoing net annual sublimation (as inferred from water vapor observations), late summer observations should be of old <span class="hlt">ice</span> with H2O grain sizes of 100 ??m or more. <span class="hlt">Ice</span> of this granularity containing 30% fine dust has a reflectivity similar to that of dust alone; the observed albedo and computed <span class="hlt">ice</span> grain size imply dust concentrations of 1 part per 1000 or less. The brightness of the icy areas conflicts with what would be expected for a residual <span class="hlt">cap</span> deposited by an annual cycle similar to that observed by Viking and aged for thousands of years. The residual <span class="hlt">cap</span> surface cannot be "old dirty' <span class="hlt">ice</span>. It could be old, coarse, and clean; or it could be young, fine, and dirty. This brings into question both the source of the late summer water vapor and the formation rate of laminated terrain. -Author</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5179960','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5179960"><span>The influence of closed brine pockets and permeable brine channels on the thermo-elastic properties of saline <span class="hlt">ice</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lishman, Ben</p> <p>2017-01-01</p> <p>A model of the thermo-elastic behaviour of saline <span class="hlt">ice</span> is formulated, and model solutions describing thermo-elastic waves (TEW) propagating into a half-space of the <span class="hlt">ice</span> are investigated. The model is based on a proposal that saline <span class="hlt">ice</span> is a matrix, which encompasses both closed brine pockets and permeable channels filled with brine. Experiments on the thermal expansion of saline <span class="hlt">ice</span> samples, and on TEW in saline <span class="hlt">ice</span>, have been performed in the cold laboratories of the University Centre in <span class="hlt">Svalbard</span> and in University College London. The experimental data are compared with theoretical conclusions. The experimental data support our hypothesis that the brine in saline <span class="hlt">ice</span> is divided between closed pockets and open, permeable channels. This article is part of the themed issue ‘Microdynamics of ice’. PMID:28025299</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150023051','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150023051"><span>Results from Three Years of Ka-Band Propagation Characterization at <span class="hlt">Svalbard</span>, Norway</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nessel, James; Zemba, Michael; Morse, Jacquelynne</p> <p>2015-01-01</p> <p>Over the next several years, NASA plans to launch several earth science missions which are expected to achieve data throughputs of 5-40 terabits per day transmitted from low earth orbiting spacecraft to ground stations. The current S-band and X-band frequency allocations in use by NASA, however, are incapable of supporting the data rates required to meet this demand. As such, NASA is in the planning stages to upgrade its existing Near Earth Network (NEN) polar ground stations to support Ka-band (25.5-27 GHz) operations. Consequently, it installed and operated a Ka-band radiometer at the <span class="hlt">Svalbard</span> site. <span class="hlt">Svalbard</span> was chosen as the appropriate site for two primary reasons: (1) <span class="hlt">Svalbard</span> will be the first site to be upgraded to Ka-band operations within the NEN Polar Network enhancement plan, and (2) there exists a complete lack of Ka-band propagation data at this site (as opposed to the Fairbanks, AK NEN site, which has 5 years of characterization collected during the Advanced Communications Technology becomes imperative that characterization of propagation effects at these NEN sites is conducted to determine expected system Satellite (ACTS) campaign). processing and provide the Herein, we discuss the data three-year measurement results performance, particularly at low elevation angles ((is) less than 10 deg) from the ongoing Ka-band propagation characterization where spacecraft signal acquisition typically occurs. Since May 2011, NASA Glenn Research Center has installed and operated a Ka-band radiometer at the NEN site located in <span class="hlt">Svalbard</span>, Norway. The Ka-band radiometer monitors the water vapor line, as well as 4 frequencies around 26.5 GHz at a fixed 10 deg elevation angle. Three-year data collection results indicate good campaign at <span class="hlt">Svalbard</span>, Norway. Comparison of these results with the ITU models and existing ERA profile data indicates very good agreement when the 2010 rain maps and cloud statistics are used. Finally, the <span class="hlt">Svalbard</span> data is used to derive the expected</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150009385','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150009385"><span>Results from Three Years of Ka-band Propagation Characterization at <span class="hlt">Svalbard</span>, Norway</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nessel, James A.; Zemba, Michael; Morse, Jacquelynne</p> <p>2015-01-01</p> <p>Over the next several years, NASA plans to launch several earth science missions which are expected to achieve data throughputs of 5-40 terabits per day transmitted from low earth orbiting spacecraft to ground stations. The current S-band and X-band frequency allocations in use by NASA, however, are incapable of supporting the data rates required to meet this demand. As such, NASA is in the planning stages to upgrade its existing Near Earth Network (NEN) polar ground stations to support Ka-band (25.5-27 GHz) operations. Consequently, it installed and operated a Ka-band radiometer at the <span class="hlt">Svalbard</span> site. <span class="hlt">Svalbard</span> was chosen as the appropriate site for two primary reasons: (1) <span class="hlt">Svalbard</span> will be the first site to be upgraded to Ka-band operations within the NEN Polar Network enhancement plan, and (2) there exists a complete lack of Ka-band propagation data at this site (as opposed to the Fairbanks, AK NEN site, which has 5 years of characterization collected during the Advanced Communications Technology becomes imperative that characterization of propagation effects at these NEN sites is conducted to determine expected system Satellite (ACTS) campaign). processing and provide the Herein, we discuss the data three-year measurement results performance, particularly at low elevation angles ((is) less than 10 deg) from the ongoing Ka-band propagation characterization where spacecraft signal acquisition typically occurs. Since May 2011, NASA Glenn Research Center has installed and operated a Ka-band radiometer at the NEN site located in <span class="hlt">Svalbard</span>, Norway. The Ka-band radiometer monitors the water vapor line, as well as 4 frequencies around 26.5 GHz at a fixed 10 deg elevation angle. Three-year data collection results indicate good campaign at <span class="hlt">Svalbard</span>, Norway. Comparison of these results with the ITU models and existing ERA profile data indicates very good agreement when the 2010 rain maps and cloud statistics are used. Finally, the <span class="hlt">Svalbard</span> data is used to derive the expected</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050170989','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050170989"><span>A GCM Recent History of Northern Martian Polar Layered Deposits: Contribution from Past Equatorial <span class="hlt">Ice</span> Reservoirs</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Levrard, B.; Laskar, J.; Montmessin, F.; Forget, F.</p> <p>2005-01-01</p> <p>Polar layered deposits are exposed in the walls of the troughs cutting the north polar <span class="hlt">cap</span> of Mars. They consist of alternating <span class="hlt">ice</span> and dust layers or layers of an <span class="hlt">ice</span>-dust mixture with varying proportions and are found throughout the <span class="hlt">cap</span>. Layers thickness ranges from meters to several tens of meters with an approximately 30 meter dominant wavelength. Although their formation processes is not known, they are presumed to reflect changes in <span class="hlt">ice</span> and dust stability over orbital and axial variations. Intensive 3-D LMD GCM simulations of the martian water cycle have been thus performed to determine the annual rates of exchange of surface <span class="hlt">ice</span> between the northern <span class="hlt">cap</span> and tropical areas for a wide range of obliquity and orbital parameters values.These rates have been employed to reconstruct an history of the northern <span class="hlt">cap</span> and test simple models of dust-<span class="hlt">ice</span> layers formation over the last 10 Ma orbital variations. We use the 3-D water cycle model simulated by the 3-D LMD GCM with an intermediate grid resolution (7.5 longitude x 5.625 latitude) and 25 vertical levels. The dust opacity is constant and set to 0,15. No exchange of <span class="hlt">ice</span> with regolith is allowed. The evolution of the northern <span class="hlt">cap</span> over obliquity and orbital changes (eccentricity, Longitude of perihelion) has been recently described with this model. High summer insolation favors transfer of <span class="hlt">ice</span> from the northern pole to the Tharsis and Olympus Montes, while at low obliquity, unstable equatorial <span class="hlt">ice</span> is redeposited in high-latitude and polar areas of both hemisphere. The disappearance of the equatorial <span class="hlt">ice</span> reservoir leads to a poleward recession of icy high latitude reservoirs, providing an additional source for the <span class="hlt">cap</span> accumulation during each obliquity or orbital cycle. Furthering the efforts, a quantitative evolution of <span class="hlt">ice</span> reservoirs is here investigated for various astronomical conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18..268M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18..268M"><span>Bottom melting of Arctic Sea <span class="hlt">Ice</span> in the Nansen Basin due to Atlantic Water influence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muilwijk, Morven; Smedsrud, Lars H.; Meyer, Amelie</p> <p>2016-04-01</p> <p>Our global climate is warming, and a shrinking Arctic sea <span class="hlt">ice</span> cover remains one of the most visible signs of this warming. Sea <span class="hlt">Ice</span> loss is now visible for all months in all regions of the Arctic. Hydrographic and current observations from a region north of <span class="hlt">Svalbard</span> collected during the Norwegian Young Sea <span class="hlt">Ice</span> Cruise (N-<span class="hlt">ICE</span>2015) are presented here. Comparison with historical data shows that the new observations from January through June fill major gaps in available observations, and help describing important processes linking changes in regional Atlantic Water (AW) heat transport and sea <span class="hlt">ice</span>. Warm and salty AW originating in the North Atlantic enters the Arctic Ocean through the Fram Strait and is present below the Arctic Sea <span class="hlt">Ice</span> cover throughout the Arctic. However, the depth of AW varies by region and over time. In the region north of <span class="hlt">Svalbard</span>, we assume that depth could be governed primarily by local processes, by upstream conditions of the <span class="hlt">ice</span> cover (Northwards), or by upstream conditions of the AW (Southwards). AW carries heat corresponding to the volume transport of approximately 9 SV through Fram Strait, varying seasonally from 28 TW in winter to 46 TW in summer. Some heat is recirculated, but the net annual heat flux into the Arctic Ocean from AW is estimated to be around 40 TW. The Atlantic Water layer temperature at intermediate depths (150-900m) has increased in recent years. Until recently, maximum temperatures have been found to be 2-3 C in the Nansen Basin. Studies have shown that for example, in the West Spitsbergen Current the upper 50-200m shows an overall AW warming of 1.1 C since 1979. In general we expect efficient melting when AW is close to the surface. Previously the AW entering through Fram Strait has been considered as less important because changes in the sea <span class="hlt">ice</span> cover have been connected to greater inflow of Pacific Water through Bering Strait and atmospheric forcing. Conversely it is now suggested that AW has direct impact on melting of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMPP33B1555S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMPP33B1555S"><span>Evidence From <span class="hlt">Svalbard</span> for Cool Episodes in Early Tertiary Arctic Climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spielhagen, R. F.; Tripati, A.; Mac Niocaill, C.</p> <p>2008-12-01</p> <p>The Arctic is a climatically sensitive and important region. However, very little is known about the climatic and oceanographic evolution of the area, particularly prior to the Neogene. Until recently, the Arctic was assumed to be characterized by relatively warm conditions during the early Cenozoic. The Early Tertiary sedimentary sequence on <span class="hlt">Svalbard</span> contains several layers with coal seams and broad-leaved plants which were commonly accepted as indicators of a generally temperate-warm climate. Here we report on the intermittent occurrence of certain temperature indicators in the succession, which may represent the first northern high- latitude record of near-freezing temperatures for the early Cenozoic. Besides the findings of probably <span class="hlt">ice</span>- rafted erratic clasts in the Paleocene and Eocene sandstones and shales, we note especially the occurrence of glendonites which are pseudomorphs of calcite after ikaite (calcium carbonate hexahydrate). Stratigraphic control for the most important glendonite layers was improved by paleomagnetic investigations on the host sediment. We measured the chemical composition of <span class="hlt">Svalbard</span> glendonites which is almost identical to that of similar pseudomorphs from the Lower Cretaceaous of Northern Canada. Mass spectrometric analyses of the glendonite calcite gave very low carbon isotope values. These values suggest a provenance of the calcium carbonate from marine organic carbon and connect our glendonites to the precursor mineral ikaite which has similar low values. Since a variety of studies has demonstrated that ikaite is stable only at temperatures close to freezing point, we have to infer low temperatures also for the deepositional environment of which the sediments were deposited that now hold glendonites. These results imply the occurrence of cooling phases episodically during the warm background climate of the Paleocene and Eocene, suggesting that temperature variability was much greater than previously recognized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21344255','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21344255"><span>Pulses of movement across the sea <span class="hlt">ice</span>: population connectivity and temporal genetic structure in the arctic fox.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Norén, Karin; Carmichael, Lindsey; Fuglei, Eva; Eide, Nina E; Hersteinsson, Pall; Angerbjörn, Anders</p> <p>2011-08-01</p> <p>Lemmings are involved in several important functions in the Arctic ecosystem. The Arctic fox (Vulpes lagopus) can be divided into two discrete ecotypes: "lemming foxes" and "coastal foxes". Crashes in lemming abundance can result in pulses of "lemming fox" movement across the Arctic sea <span class="hlt">ice</span> and immigration into coastal habitats in search for food. These pulses can influence the genetic structure of the receiving population. We have tested the impact of immigration on the genetic structure of the "coastal fox" population in <span class="hlt">Svalbard</span> by recording microsatellite variation in seven loci for 162 Arctic foxes sampled during the summer and winter over a 5-year period. Genetic heterogeneity and temporal genetic shifts, as inferred by STRUCTURE simulations and deviations from Hardy-Weinberg proportions, respectively, were recorded. Maximum likelihood estimates of movement as well as STRUCTURE simulations suggested that both immigration and genetic mixture are higher in <span class="hlt">Svalbard</span> than in the neighbouring "lemming fox" populations. The STRUCTURE simulations and AMOVA revealed there are differences in genetic composition of the population between summer and winter seasons, indicating that immigrants are not present in the reproductive portion of the <span class="hlt">Svalbard</span> population. Based on these results, we conclude that Arctic fox population structure varies with time and is influenced by immigration from neighbouring populations. The lemming cycle is likely an important factor shaping Arctic fox movement across sea <span class="hlt">ice</span> and the subsequent population genetic structure, but is also likely to influence local adaptation to the coastal habitat and the prevalence of diseases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017TCry...11.2137T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017TCry...11.2137T"><span>Modelling radiative transfer through ponded first-year Arctic sea <span class="hlt">ice</span> with a plane-parallel model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Taskjelle, Torbjørn; Hudson, Stephen R.; Granskog, Mats A.; Hamre, Børge</p> <p>2017-09-01</p> <p>Under-<span class="hlt">ice</span> irradiance measurements were done on ponded first-year pack <span class="hlt">ice</span> along three transects during the <span class="hlt">ICE</span>12 expedition north of <span class="hlt">Svalbard</span>. Bulk transmittances (400-900 nm) were found to be on average 0.15-0.20 under bare <span class="hlt">ice</span>, and 0.39-0.46 under ponded <span class="hlt">ice</span>. Radiative transfer modelling was done with a plane-parallel model. While simulated transmittances deviate significantly from measured transmittances close to the edge of ponds, spatially averaged bulk transmittances agree well. That is, transect-average bulk transmittances, calculated using typical simulated transmittances for ponded and bare <span class="hlt">ice</span> weighted by the fractional coverage of the two surface types, are in good agreement with the measured values. Radiative heating rates calculated from model output indicates that about 20 % of the incident solar energy is absorbed in bare <span class="hlt">ice</span>, and 50 % in ponded <span class="hlt">ice</span> (35 % in pond itself, 15 % in the underlying <span class="hlt">ice</span>). This large difference is due to the highly scattering surface scattering layer (SSL) increasing the albedo of the bare <span class="hlt">ice</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.9118R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.9118R"><span>New deglacial and Holocene micropaleontological and geochemical records from the southern margin of the <span class="hlt">Svalbard</span> Archipelago (Arctic Ocean)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rigual-Hernández, Andrés.</p> <p>2010-05-01</p> <p>This study is presented in the context of the Spanish research project "The development of an Arctic <span class="hlt">ice</span> stream-dominated sedimentary system: The southern <span class="hlt">Svalbard</span> continental margin" (SVAIS), developed within the framework of the International Polar Year (IPY) Activity N. 367 (NICE STREAMS). Its main goal is to understand the evolution of glacial continental margins and their relationship with the changes in <span class="hlt">ice</span> sheet dynamics induced by natural climatic changes, combining the geophysical data with the sediment record both collected during an oceanographic cruise in the Storfjorden area (SW <span class="hlt">Svalbard</span> margin) in August 2007. This marine depositional system, dominated by an <span class="hlt">ice</span> stream during the last glacial period, was selected due to its small size inducing a rapid response to climatic changes, and for the oceanographic relevance of the area for global ocean circulation. The results obtained aim to define the sedimentary architecture and morphology, and to provide more insight into the paleoceanographic and paleoclimatic evolution of the region. We specifically report on new micropaleontological and geochemical data obtained from the sediment cores. A preliminary age model indicates that the sediment sequences cover approximately the Last Deglaciation and the Holocene. Microfossils are generally well preserved, although the abundances of the different groups show marked shifts along the record. Low concentrations of coccolithophores, diatoms, planktic foraminifers and cysts of organic-walled dinoflagellates (dinocysts) are found at the lower half of the sequence (IRD-rich, coarser-grained sediments), and increase towards the Late Holocene (fine-grained bioturbated sediments). The Climatic Optimum is characterized by the warmest sea surface temperatures as estimated from the fossil assemblage, diverse transfer functions and biogeochemical proxies, and by high nutrient contents in the bottom waters shown by light carbon isotope values and high Cd/Ca ratios in benthic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004EOSTr..85..378N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004EOSTr..85..378N"><span>Cratering in Marine Environments and on <span class="hlt">Ice</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newsom, Horton E.</p> <p>2004-09-01</p> <p>Since the discovery of plate tectonics, impact cratering is arguably the most significant geologic process now recognized as an important process on Earth. Impacts into <span class="hlt">ice</span>, another main topic covered in this book, may be important on other worlds. Large numbers of impact craters that formed in marine environments on Earth have only been discovered in the last 10 years. Twenty-five craters that formed in marine environments have been documented, according to the first chapter of this book, although none are known that excavated oceanic crust. The papers in Cratering in Marine Environments and on <span class="hlt">Ice</span> will whet your appetite for the exciting and ambitious range of topics implied by the title, which stems from a conference in <span class="hlt">Svalbard</span>, Norway, in September 2001. This book provides a flavor of the rapidly advancing and diverse field of impact cratering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5485476','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5485476"><span>Characterisation of Arctic Bacterial Communities in the Air above <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cuthbertson, Lewis; Amores-Arrocha, Herminia; Malard, Lucie A.; Els, Nora; Sattler, Birgit; Pearce, David A.</p> <p>2017-01-01</p> <p>Atmospheric dispersal of bacteria is increasingly acknowledged as an important factor influencing bacterial community biodiversity, biogeography and bacteria–human interactions, including those linked to human health. However, knowledge about patterns in microbial aerobiology is still relatively scarce, and this can be attributed, in part, to a lack of consensus on appropriate sampling and analytical methodology. In this study, three different methods were used to investigate aerial biodiversity over <span class="hlt">Svalbard</span>: impaction, membrane filtration and drop plates. Sites around <span class="hlt">Svalbard</span> were selected due to their relatively remote location, low human population, geographical location with respect to air movement and the tradition and history of scientific investigation on the archipelago, ensuring the presence of existing research infrastructure. The aerial bacterial biodiversity found was similar to that described in other aerobiological studies from both polar and non-polar environments, with Proteobacteria, Actinobacteria, and Firmicutes being the predominant groups. Twelve different phyla were detected in the air collected above <span class="hlt">Svalbard</span>, although the diversity was considerably lower than in urban environments elsewhere. However, only 58 of 196 bacterial genera detected were consistently present, suggesting potentially higher levels of heterogeneity. Viable bacteria were present at all sampling locations, showing that living bacteria are ubiquitous in the air around <span class="hlt">Svalbard</span>. Sampling location influenced the results obtained, as did sampling method. Specifically, impaction with a Sartorius MD8 produced a significantly higher number of viable colony forming units (CFUs) than drop plates alone. PMID:28481257</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.P23B2127J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.P23B2127J"><span>Albedo of Carbon Dioxide <span class="hlt">Ice</span> in Mars' Residual South Polar <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>James, P. B.; Wolff, M. J.; Bonev, B.</p> <p>2015-12-01</p> <p>The albedo of surface CO2 deposits in the Residual South Polar <span class="hlt">Cap</span> (RSPC) of Mars controls their net condensation / sublimation over a martian year and is therefore a crucial parameter in determining RSPC stability. The albedo used in previous analyses is obtained by dividing I/F, determined from radiometrically calibrated imaging data, by the cosine of the incidence angle. Because of atmospheric aerosols, the albedo calculated from I/F above the atmosphere is not the surface albedo that enters into stability considerations. In order to determine the surface albedo, we interpolate optical depths determined from CRISM EPF measurements to provide estimates of the dust and <span class="hlt">ice</span> opacities over the RSPC (Wolff et al., 2009) and use these to determine the actual surface albedos from MARCI images using the radiative transport program DISORT (Stamnes et al., 1988). Assuming that dust is the only contributor to atmospheric opacity, the retrieved surface albedos for the longer wavelength MARCI filters in MY 28 and 29 are found to be consistent despite very different dust opacities in the two years (James et al., 2014). However, this model fails to reproduce the short wavelength behavior in early summer and suggests either an additional opacity source or modification of the CRISM dust opacity or the dust phase function. The consequences of these changes will be discussed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.9654S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.9654S"><span>Micromechanics of sea <span class="hlt">ice</span> gouge in shear zones</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sammonds, Peter; Scourfield, Sally; Lishman, Ben</p> <p>2015-04-01</p> <p>The deformation of sea <span class="hlt">ice</span> is a key control on the Arctic Ocean dynamics. Shear displacement on all scales is an important deformation process in the sea cover. Shear deformation is a dominant mechanism from the scale of basin-scale shear lineaments, through floe-floe interaction and block sliding in <span class="hlt">ice</span> ridges through to the micro-scale mechanics. Shear deformation will not only depend on the speed of movement of <span class="hlt">ice</span> surfaces but also the degree that the surfaces have bonded during thermal consolidation and compaction. Recent observations made during fieldwork in the Barents Sea show that shear produces a gouge similar to a fault gouge in a shear zone in the crust. A range of sizes of gouge are exhibited. The consolidation of these fragments has a profound influence on the shear strength and the rate of the processes involved. We review experimental results in sea <span class="hlt">ice</span> mechanics from mid-scale experiments, conducted in the Hamburg model ship <span class="hlt">ice</span> tank, simulating sea <span class="hlt">ice</span> floe motion and interaction and compare these with laboratory experiments on <span class="hlt">ice</span> friction done in direct shear, and upscale to field measurement of sea <span class="hlt">ice</span> friction and gouge deformation made during experiments off <span class="hlt">Svalbard</span>. We find that consolidation, fragmentation and bridging play important roles in the overall dynamics and fit the model of Sammis and Ben-Zion, developed for understanding the micro-mechanics of rock fault gouge, to the sea <span class="hlt">ice</span> problem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C21E..02I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C21E..02I"><span>Measurements of sea <span class="hlt">ice</span> mass redistribution during <span class="hlt">ice</span> deformation event in Arctic winter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Itkin, P.; Spreen, G.; King, J.; Rösel, A.; Skourup, H.; Munk Hvidegaard, S.; Wilkinson, J.; Oikkonen, A.; Granskog, M. A.; Gerland, S.</p> <p>2016-12-01</p> <p>Sea-<span class="hlt">ice</span> growth during high winter is governed by <span class="hlt">ice</span> dynamics. The highest growth rates are found in leads that open under divergent conditions, where exposure to the cold atmosphere promotes thermodynamic growth. Additionally <span class="hlt">ice</span> thickens dynamically, where convergence causes rafting and ridging. We present a local study of sea-<span class="hlt">ice</span> growth and mass redistribution between two consecutive airborne measurements, on 19 and 24 April 2015, during the N-<span class="hlt">ICE</span>2015 expedition in the area north of <span class="hlt">Svalbard</span>. Between the two overflights an <span class="hlt">ice</span> deformation event was observed. Airborne laser scanner (ALS) measurements revisited the same sea-<span class="hlt">ice</span> area of approximately 3x3 km. By identifying the sea surface within the ALS measurements as a reference the sea <span class="hlt">ice</span> plus snow freeboard was obtained with a spatial resolution of 5 m. By assuming isostatic equilibrium of level floes, the freeboard heights can be converted to <span class="hlt">ice</span> thickness. The snow depth is estimated from in-situ measurements. Sea <span class="hlt">ice</span> thickness measurements were made in the same area as the ALS measurements by electromagnetic sounding from a helicopter (HEM), and with a ground-based device (EM31), which allows for cross-validation of the sea-<span class="hlt">ice</span> thickness estimated from all 3 procedures. Comparison of the ALS snow freeboard distributions between the first and second overflight shows a decrease in the thin <span class="hlt">ice</span> classes and an increase of the thick <span class="hlt">ice</span> classes. While there was no observable snowfall and a very low sea-<span class="hlt">ice</span> growth of older level <span class="hlt">ice</span> during this period, an autonomous buoy array deployed in the surroundings of the area measured by the ALS shows first divergence followed by convergence associated with shear. To quantify and link the sea <span class="hlt">ice</span> deformation with the associated sea-<span class="hlt">ice</span> thickness change and mass redistribution we identify over 100 virtual buoys in the ALS data from both overflights. We triangulate the area between the buoys and calculate the strain rates and freeboard change for each individual triangle</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ACP....17.6153H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ACP....17.6153H"><span>New particle formation in the <span class="hlt">Svalbard</span> region 2006-2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heintzenberg, Jost; Tunved, Peter; Galí, Martí; Leck, Caroline</p> <p>2017-05-01</p> <p>Events of new particle formation (NPF) were analyzed in a 10-year data set of hourly particle size distributions recorded on Mt. Zeppelin, Spitsbergen, <span class="hlt">Svalbard</span>. Three different types of NPF events were identified through objective search algorithms. The first and simplest algorithm utilizes short-term increases in particle concentrations below 25 nm (PCT (percentiles) events). The second one builds on the growth of the sub-50 nm diameter median (DGR (diameter growth) events) and is most closely related to the classical <q>banana type</q> of event. The third and most complex, multiple-size approach to identifying NPF events builds on a hypothesis suggesting the concurrent production of polymer gel particles at several sizes below ca. 60 nm (MEV (multi-size growth) events). As a first and general conclusion, we can state that NPF events are a summer phenomenon and not related to Arctic haze, which is a late winter to early spring feature. The occurrence of NPF events appears to be somewhat sensitive to the available data on precipitation. The seasonal distribution of solar flux suggests some photochemical control that may affect marine biological processes generating particle precursors and/or atmospheric photochemical processes that generate condensable vapors from precursor gases. Notably, the seasonal distribution of the biogenic methanesulfonate (MSA) follows that of the solar flux although it peaks before the maxima in NPF occurrence. A host of ancillary data and findings point to varying and rather complex marine biological source processes. The potential source regions for all types of new particle formation appear to be restricted to the marginal-<span class="hlt">ice</span> and open-water areas between northeastern Greenland and eastern <span class="hlt">Svalbard</span>. Depending on conditions, yet to be clarified new particle formation may become visible as short bursts of particles around 20 nm (PCT events), longer events involving condensation growth (DGR events), or extended events with elevated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AnGeo..27...65D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AnGeo..27...65D"><span>Aspect sensitive E- and F-region SPEAR-enhanced incoherent backscatter observed by the EISCAT <span class="hlt">Svalbard</span> radar</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dhillon, R. S.; Robinson, T. R.; Yeoman, T. K.</p> <p>2009-01-01</p> <p>Previous studies of the aspect sensitivity of heater-enhanced incoherent radar backscatter in the high-latitude ionosphere have demonstrated the directional dependence of incoherent scatter signatures corresponding to artificially excited electrostatic waves, together with consistent field-aligned signatures that may be related to the presence of artificial field-aligned irregularities. These earlier high-latitude results have provided motivation for repeating the investigation in the different geophysical conditions that obtain in the polar <span class="hlt">cap</span> ionosphere. The Space Plasma Exploration by Active Radar (SPEAR) facility is located within the polar <span class="hlt">cap</span> and has provided observations of RF-enhanced ion and plasma line spectra recorded by the EISCAT <span class="hlt">Svalbard</span> UHF incoherent scatter radar system (ESR), which is collocated with SPEAR. In this paper, we present observations of aspect sensitive E- and F-region SPEAR-induced ion and plasma line enhancements that indicate excitation of both the purely growing mode and the parametric decay instability, together with sporadic E-layer results that may indicate the presence of cavitons. We note consistent enhancements from field-aligned, vertical and also from 5° south of field-aligned. We attribute the prevalence of vertical scatter to the importance of the Spitze region, and of that from field-aligned to possible wave/irregularity coupling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1817852E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1817852E"><span>Recent transformations in the high-Arctic glacier landsystem Hørbyebreen, <span class="hlt">Svalbard</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ewertowski, Marek; Evans, David; Roberts, David; Tomczyk, Aleksandra</p> <p>2016-04-01</p> <p>The Hørbyebreen is a polythermal valley glacier in the Petuniabukta area, central part of Spitsbergen. Since the end of the Little <span class="hlt">Ice</span> Age, a debris-free glacier margin retreated by more than 3 km exposing complex landform assemblages including <span class="hlt">ice</span>-cored moraines, flutes, eskers and geometric ridge networks. Glacier recession and landforms' development in the terrestrial parts of the foreland were quantified using time-series of orthophotos and digital elevation models (generated based on 1961, 1990, 2009 aerial photographs) and high resolution satellite images from 2013. Additionally, detailed analyses of a case study area were performed based on unmanned aerial vehicle (UAV) imagery (3 cm resolution) captured in 2014. A time-series of 1:5,000 geomorphological maps of the whole foreland, together with 1:300 map of a sample area of complex geometric ridge networks and results of sedimentological analysis, enable us to assess the evolution of glacial landform assemblages. The two main areas of the Hørbyebreen foreland were identified as: (1) the outer moraine ridge and (2) the inner zone between the contemporary <span class="hlt">ice</span> edge and the outer moraine ridge. The outer moraine ridge was relatively stable and subject to mainly vertical transformation between 1960 and 2009. The most prominent changes were observed within the inner zone. In 1960 it was covered by glacier <span class="hlt">ice</span>, whereas in 2009 this area exhibited a wide range of subglacial and englacial landforms, including a network of rectilinear ridges which we interpret as crevasse infills created by the injection of pressurized englacial meltwater. Other prominent features in this zone include controlled moraine, indicative of sub-marginal debris entrainment by the polythermal snout, and complex esker network. This landform assemblage is diagnostic of a variable process-form regime in which the glacial geomorphology of polythermal conditions is supplemented with surge signatures and therefore is likely to be the most</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740004942','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740004942"><span>Evaluation of glacier mass balance by observing variations in transient snowline positions. [Jostedalsbreen <span class="hlt">ice</span> <span class="hlt">cap</span>, Norway</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oestrem, G. (Principal Investigator)</p> <p>1973-01-01</p> <p>The author has identified the following significant results. The transient snowline on five outlet glaciers from the Jostedalsbreen <span class="hlt">ice-cap</span> in Southwestern Norway could be determined from ERTS-1 image 1336-10260, when bands MSS 5, 6, and 7 were combined in an additive color viewer. The snowline was situated at a very low altitude at the time of imagery (24 June 1973) indicating that glacier melt was behind normal schedule, a fact that has a hydrologic bearing: one could expect less melt water in the streams. The idea to use ERTS-1 imagery in snowline determinations proved realistic and relatively easy to apply in practice. The method will be useful to estimate the glaciers' mass balance for large areas, provided some ground truth observations are made. Images from the end of the melt season are of course vital in this work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013Icar..225..869H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013Icar..225..869H"><span>An examination of Mars' north seasonal polar <span class="hlt">cap</span> using MGS: Composition and infrared radiation balance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hansen, Gary B.</p> <p>2013-08-01</p> <p>A detailed analysis of data from one revolution of the Mars Global Surveyor (MGS) is presented. Approximately 80% of this revolution observes the mid-winter northern seasonal polar <span class="hlt">cap</span>, which covers the surface to <60°N, and which is predominantly within polar night. The surface composition and temperature are determined through analysis of 6-50 μm infrared spectra from the Thermal Emission Spectrometer (TES). The infrared radiative balance, which is the entire heat balance in the polar night except for small subsurface and atmospheric advection terms, is calculated for the surface and atmospheric column. The primary constituent, CO2 <span class="hlt">ice</span>, also dominates the infrared spectral properties by variations in its grain size and by admixtures of dust and water <span class="hlt">ice</span>, which cause large variations in the 20-50 μm emissivity. This is modified by incomplete areal coverage, and clouds or hazes. This quantitative analysis reveals CO2 grain radii ranging from ˜100 μm in isolated areas, to 1-5 mm in more widespread regions. The water <span class="hlt">ice</span> content varies from none to about one part per thousand by mass, with a clear increase towards the periphery of the polar <span class="hlt">cap</span>. The dust content is typically a few parts per thousand by mass, but is as much as an order of magnitude less abundant in "cold spot" regions, where the low emissivity of pure CO2 <span class="hlt">ice</span> is revealed. This is the first quantitative analysis of thermal spectra of the seasonal polar <span class="hlt">cap</span> and the first to estimate water <span class="hlt">ice</span> content. Our models show that the cold spots represent cleaner, dust-free <span class="hlt">ice</span> rather than finer grained <span class="hlt">ice</span> than the background. Our guess is that the dust in cold spots is hidden in the center of the CO2 frost particles rather than not present. The fringes of the <span class="hlt">cap</span> have more dust and water <span class="hlt">ice</span>, and become patchy, with warmer water snow filling the gaps on the night side, and warmer bare soil on the day side. A low optical depth (<1 in the visible) water <span class="hlt">ice</span> atmospheric haze is apparent on the night side</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050167018','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050167018"><span>Effects of Atmospheric Dust on Residual South Polar <span class="hlt">Cap</span> Stability</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bonrv, B. P.; Bjorkman, J. E.; Hansen, G. B.; James, P. B.; Wolff, M. J.</p> <p>2005-01-01</p> <p>The Martian polar <span class="hlt">caps</span> have been studied from the time of Herschel. Neither polar <span class="hlt">cap</span> normally disappears in summer. The Residual North Polar <span class="hlt">Cap</span> (portion that remains through summer) is composed of a mixture of water <span class="hlt">ice</span> and dust, and its interannual stability is due to its low sublimation rate at the summer temperatures in the North Polar Region. The Residual South Polar <span class="hlt">Cap</span> (RSPC) is more enigmatic, surviving the relatively hot perihelic summer season despite being composed of much more volatile CO2. It is able to do so because of its unusually high albedo, which is larger than that of other bright regions in the seasonal <span class="hlt">cap</span> (e.g. Mountains of Mitchel). The proximity of the albedo of the RSPC to the critical albedo for stability raises the question of whether the RSPC exists in every Martian year. The ground based record is somewhat ambivalent. Douglass and Lowell reported that RSPC suddenly vanished at Ls=297deg in 1894 and did not reappear until Ls=0deg [1], and Kuiper reported that it disappeared in 1956 [2]; but both observations were questioned by contemporaries, who tended to attribute them to obscuring dust. Barker [3] reported a large amount of water vapor over the south polar <span class="hlt">cap</span> in 1969 that could be attributed to exposure of near surface water <span class="hlt">ice</span> during partial removal of the CO2 in the RSPC in 1969.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20171208_Archive_e000122.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20171208_Archive_e000122.html"><span>NASA’s Aerial Survey of Polar <span class="hlt">Ice</span> Expands Its Arctic Reach</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-12-08</p> <p>For the past eight years, Operation <span class="hlt">Ice</span>Bridge, a NASA mission that conducts aerial surveys of polar <span class="hlt">ice</span>, has produced unprecedented three-dimensional views of Arctic and Antarctic <span class="hlt">ice</span> sheets, providing scientists with valuable data on how polar <span class="hlt">ice</span> is changing in a warming world. Now, for the first time, the campaign will expand its reach to explore the Arctic’s Eurasian Basin through two research flights based out of <span class="hlt">Svalbard</span>, a Norwegian archipelago in the northern Atlantic Ocean. More: go.nasa.gov/2ngAxX2 Caption: Ellesmere Island mountain tops bathed in light as the sun began to peak over the horizon during Operation <span class="hlt">Ice</span>Bridge’s first flight of its 2017 Arctic campaign, on March 9, 2017. Credits: NASA/Nathan Kurtz NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMEP32A..05L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMEP32A..05L"><span>Timing of Expansions of the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Peru, and Implications for Cosmogenic Nuclide Production Rate Calibration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lowell, T. V.; Kelly, M. A.; Applegate, P. J.; Smith, C. A.; Phillips, F. M.; Hudson, A. M.</p> <p>2010-12-01</p> <p>We calibrate the production rate of the cosmogenic nuclide beryllium-10 (10Be) at a low-latitude, high-elevation site, using nuclide concentrations measured in moraine boulders and an independent chronology determined with bracketing radiocarbon dates. The measurement of terrestrial cosmogenic nuclide (TCN) concentrations in earth surface materials has been an important development for understanding a host of earth surface processes. Uncertainty in cosmogenic nuclide production rates has hampered application of this method. Here, we contribute to the estimation of 10Be production rates by reporting both preliminary 10Be concentrations and independent radiocarbon dates from a low latitude, high elevation site. Our study site in the southeastern Peruvian Andes (~13.9°S, 70.9°W, 4850 m asl) is centered on a moraine set, known as the Huancané II moraines, that represents a ~4 km expansion of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> during late glacial time. At this location, organic material situated both stratigraphically below and above moraines in two adjacent valleys provide material for radiocarbon dating. Based on geomorphic arguments, we correlate results from the two valleys. The timing of <span class="hlt">ice</span> <span class="hlt">cap</span> margin advance is bracketed by 13 radiocarbon ages on organic material within the outermost Huancané II moraines that range from 13.6 to 12.5 ka. Two stratigraphic sections upvalley from the moraines yield 6 radiocarbon ages from 11.3 to 12.4 ka, indicating the time of retreat . We computed the probability density function that lies between these two sets of dates, and assign an age of 12.4 ka (+/-???) for the formation of the Huancané II moraines. Calculating beryllium-10 exposure dates from the measured concentrations yield exposure dates that significantly underestimate the independently determined age of the moraine (~8-30%), if existing production rate estimates are used. We suggest that the radiocarbon age for the moraines can be used as a robust independent calibration for 10Be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17950534','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17950534"><span>Serosurvey for Toxoplasma gondii in arctic foxes and possible sources of infection in the high Arctic of <span class="hlt">Svalbard</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Prestrud, Kristin Wear; Asbakk, Kjetil; Fuglei, Eva; Mørk, Torill; Stien, Audun; Ropstad, Erik; Tryland, Morten; Gabrielsen, Geir Wing; Lydersen, Christian; Kovacs, Kit M; Loonen, Maarten J J E; Sagerup, Kjetil; Oksanen, Antti</p> <p>2007-11-30</p> <p>Samples (blood or tissue fluid) from 594 arctic foxes (Alopex lagopus), 390 <span class="hlt">Svalbard</span> reindeer (Rangifer tarandus platyrhynchus), 361 sibling voles (Microtus rossiaemeridionalis), 17 walruses (Odobenus rosmarus), 149 barnacle geese (Branta leucopsis), 58 kittiwakes (Rissa tridactyla), and 27 glaucous gulls (Larus hyperboreus) from <span class="hlt">Svalbard</span> and nearby waters were assayed for antibodies against Toxoplasma gondii using a direct agglutination test. The proportion of seropositive animals was 43% in arctic foxes, 7% in barnacle geese, and 6% (1 of 17) in walruses. There were no seropositive <span class="hlt">Svalbard</span> reindeer, sibling voles, glaucous gulls, or kittiwakes. The prevalence in the arctic fox was relatively high compared to previous reports from canid populations. There are no wild felids in <span class="hlt">Svalbard</span> and domestic cats are prohibited, and the absence of antibodies against T. gondii among the herbivorous <span class="hlt">Svalbard</span> reindeer and voles indicates that transmission of the parasite by oocysts is not likely to be an important mechanism in the <span class="hlt">Svalbard</span> ecosystem. Our results suggest that migratory birds, such as the barnacle goose, may be the most important vectors bringing the parasite to <span class="hlt">Svalbard</span>. In addition to transmission through infected prey and carrion, the age-seroprevalence profile in the fox population suggests that their infection levels are enhanced by vertical transmission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910011738','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910011738"><span>The hemispherical asymmetry of the residual polar <span class="hlt">caps</span> on Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lindner, Bernhard Lee</p> <p>1991-01-01</p> <p>A model of the polar <span class="hlt">caps</span> of Mars was created which allows: (1) for light penetration into the <span class="hlt">cap</span>; (2) <span class="hlt">ice</span> albedo to vary with age, latitude, hemisphere, dust content, and solar zenith angle; and (3) for diurnal variability. The model includes the radiative effects of clouds and dust, and heat transport as represented by a thermal wind. The model reproduces polar <span class="hlt">cap</span> regression data very well, including the survival of CO2 frost at the south pole and reproduces the general trend in the Viking Lander pressure data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A51E2115L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A51E2115L"><span>High resolution present climate and surface mass balance (SMB) of <span class="hlt">Svalbard</span> modelled by MAR and implementation of a new online SMB downscaling method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lang, C.; Fettweis, X.; Kittel, C.; Erpicum, M.</p> <p>2017-12-01</p> <p>We present the results of high resolution simulations of the climate and SMB of <span class="hlt">Svalbard</span> with the regional climate model MAR forced by ERA-40 then ERA-Interim, as well as an online downscaling method allowing us to model the SMB and its components at a resolution twice as high (2.5 vs 5 km here) using only about 25% more CPU time. Spitsbergen, the largest island in <span class="hlt">Svalbard</span>, has a very hilly topography and a high spatial resolution is needed to correctly represent the local topography and the complex pattern of <span class="hlt">ice</span> distribution and precipitation. However, high resolution runs with an RCM fully coupled to an energy balance module like MAR require a huge amount of computation time. The hydrostatic equilibrium hypothesis used in MAR also becomes less valid as the spatial resolution increases. We therefore developed in MAR a method to run the snow module at a resolution twice as high as the atmospheric module. Near-surface temperature and humidity are corrected on a grid with a resolution twice as high, as a function of their local gradients and the elevation difference between the corresponding pixels in the 2 grids. We compared the results of our runs at 5 km and with SMB downscaled at 2.5 km over 1960 — 2016 and compared those to previous 10 km runs. On Austfonna, where the slopes are gentle, the agreement between observations and the 5 km SMB is better than with the 10 km SMB. It is again improved at 2.5 km but the gain is relatively small, showing the interest of our method rather than running a time consuming classic 2.5 km resolution simulation. On Spitsbergen, we show that a spatial resolution of 2.5 km is still not enough to represent the complex pattern of topography, precipitation and SMB. Due to a change in the summer atmospheric circulation, from a westerly flow over <span class="hlt">Svalbard</span> to a northwesterly flow bringing colder air, the SMB of <span class="hlt">Svalbard</span> was stable between 2006 and 2012, while several melt records were broken in Greenland, due to conditions more</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUSM.U51A..05H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUSM.U51A..05H"><span>Falsifying the Sikussak-Oasis Hypothesis for the Tillite Group, East Greenland: Implications for Trezona-like Carbon Isotope Excursions Beneath Neoproterozoic Glacials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoffman, P. F.; Domack, E. W.; Maloof, A. C.; Halverson, G. P.</p> <p>2006-05-01</p> <p>In Neoproterozoic time, East Greenland and East <span class="hlt">Svalbard</span> (EGES) occupied landward and seaward positions, respectively, on the southern subtropical margin of Laurentia. In both areas, thick clastic-to-carbonate successions are overlain by two discrete glacial and/or periglacial formations, separated by fine basinal clastics. In <span class="hlt">Svalbard</span>, the younger glacial has a characteristic Marinoan (basal Ediacaran) <span class="hlt">cap</span> dolostone, but the older glacial is underlain by a 10-permil negative carbon isotope excursion that is indistinguishable from excursions observed exclusively beneath Marinoan glacials in Australia, Namibia and western Laurentia. This led us to propose (Basin Research 16, 297-324, 2004) that the paired glacials in EGES represent the onset and climax of a single, long-lived, Marinoan glaciation. The intervening fine clastics, which contain ikaite pseudomorphs, presumptively accumulated beneath permanent shorefast sea <span class="hlt">ice</span> (sikussak), analogous to East Greenland fjords during the Younger Dryas and Little <span class="hlt">Ice</span> Age. In this model, the top of the older glacial signals the start of Snowball Earth. We conducted a preliminary field test of the sikussak hypothesis in Strindberg Land (SL), Andrée Land (AL) and Ella O (EO), East Greenland. We confirmed the correlation of the paired glacials and the Marinoan <span class="hlt">cap</span> dolostone (missing on EO). In SL, the older glacial (Ulveso Fm) is a thin diamictite overlain by conglomerate lag and a set of megavarves composed of alternating siltstone and <span class="hlt">ice</span>-rafted debris. In AL and EO, the Ulveso is a sub-glacial diamictite overlain by aeolian and/or marine sandstone. In Bastion Bugt on EO, it is a transgressive shoreface sandstone. This proves that glacial recession occurred under open-water conditions and did not result from permanent sea-<span class="hlt">ice</span> formation, as stipulated in the sikussak model. There is no evidence that the fine clastic sequence between the glacials formed under an <span class="hlt">ice</span> cover, or for a single glacial period. This brings us back to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C33G..08B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C33G..08B"><span>Characterizing the Chemical and Physical Signature of the 2015-16 El Niño in the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> Snow and <span class="hlt">Ice</span> to Calibrate Past ENSO Reconstructions.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beaudon, E.; Barker, J. D.; Kenny, D. V.; Thompson, L. G.</p> <p>2017-12-01</p> <p>Pacific Sea Surface Temperature (SST) anomalies have reached +3°C in the Niño 3.4 region in November 2015 making this one of the strongest El Niños in 100 years. This warm phase of the El Niño - Southern Oscillation (ENSO) has pronounced differential impacts across the tropical Pacific as well as in South America. Peru statistically experienced flooding in the northern and central regions and drought conditions in the south on the Altiplano. However, the 2015-16 El Nino event led to drought throughout the Peruvian Andes. El Niño is a warm and dry episode, phase locked with the accumulation season on the Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> (QIC) so that this strong event create conditions favorable for enhanced surface ablation and dry deposition of soluble and insoluble aerosols. Here we present new glaciochemical (major and organic ions, dust, black carbon, oxygen isotopes) results from two consecutive snow and <span class="hlt">ice</span> sampling campaign on QIC framing the climax of the 2015/2016 El Niño episode in Peru. We allocate the ionic and black carbon sources and describe the biogenic and evaporitic contributions to Quelccaya snow chemistry under El Niño atmospheric conditions. Elution factors and ionic budgets are compared to those of the snow and <span class="hlt">ice</span> samples collected prior to the El Niño initiation and thereby assess the magnitude of the impact of El Niño-induced post-depositional processes. Our results provide the database needed to verify that: 1) melt and percolation induced by El Niño is identifiable in the prior year's snow layer and thus might be calibrated to the El Niño's strength; and 2) the concentration and co-association of biogenic (e.g., NH4, black carbon) and evaporitic (salts) species is enhanced and detectable deeper in the <span class="hlt">ice</span> and thereby might serve as a proxy for documenting past El Niño frequency. By capturing the chemical signature of a modern El Niño event occurring in a warming world, these results shed light on past ENSO variability preserved in <span class="hlt">ice</span> core</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24820354','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24820354"><span><span class="hlt">Ice</span> crystallization in ultrafine water-salt aerosols: nucleation, <span class="hlt">ice</span>-solution equilibrium, and internal structure.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hudait, Arpa; Molinero, Valeria</p> <p>2014-06-04</p> <p>Atmospheric aerosols have a strong influence on Earth's climate. Elucidating the physical state and internal structure of atmospheric aqueous aerosols is essential to predict their gas and water uptake, and the locus and rate of atmospherically important heterogeneous reactions. Ultrafine aerosols with sizes between 3 and 15 nm have been detected in large numbers in the troposphere and tropopause. Nanoscopic aerosols arising from bubble bursting of natural and artificial seawater have been identified in laboratory and field experiments. The internal structure and phase state of these aerosols, however, cannot yet be determined in experiments. Here we use molecular simulations to investigate the phase behavior and internal structure of liquid, vitrified, and crystallized water-salt ultrafine aerosols with radii from 2.5 to 9.5 nm and with up to 10% moles of ions. We find that both <span class="hlt">ice</span> crystallization and vitrification of the nanodroplets lead to demixing of pure water from the solutions. Vitrification of aqueous nanodroplets yields nanodomains of pure low-density amorphous <span class="hlt">ice</span> in coexistence with vitrified solute rich aqueous glass. The melting temperature of <span class="hlt">ice</span> in the aerosols decreases monotonically with an increase of solute fraction and decrease of radius. The simulations reveal that nucleation of <span class="hlt">ice</span> occurs homogeneously at the subsurface of the water-salt nanoparticles. Subsequent <span class="hlt">ice</span> growth yields phase-segregated, internally mixed, aerosols with two phases in equilibrium: a concentrated water-salt amorphous mixture and a spherical <span class="hlt">cap</span>-like <span class="hlt">ice</span> nanophase. The surface of the crystallized aerosols is heterogeneous, with <span class="hlt">ice</span> and solution exposed to the vapor. Free energy calculations indicate that as the concentration of salt in the particles, the advance of the crystallization, or the size of the particles increase, the stability of the spherical <span class="hlt">cap</span> structure increases with respect to the alternative structure in which a core of <span class="hlt">ice</span> is fully surrounded by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007Geo....35..739G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007Geo....35..739G"><span>Pacing the post-Last Glacial Maximum demise of the Animas Valley glacier and the San Juan Mountain <span class="hlt">ice</span> <span class="hlt">cap</span>, Colorado</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guido, Zackry S.; Ward, Dylan J.; Anderson, Robert S.</p> <p>2007-08-01</p> <p>During the Last Glacial Maximum (LGM), a 5000 km2 <span class="hlt">ice</span> <span class="hlt">cap</span> covered the San Juan Mountains of southwest Colorado. The largest valley glacier draining this <span class="hlt">ice</span> <span class="hlt">cap</span> occupied the Animas Valley and flowed 91 km to the south. To characterize the post-LGM demise of the Animas Valley glacier, we employ cosmogenic 10Be to date the LGM terrace outside the terminal moraines and a suite of seven glacially polished bedrock samples. The 10Be depth profile within the terrace sediments suggests abandonment at 19.4 ± 1.5 ka. As deglaciation began, the ponding of Glacial Lake Durango behind the terminal moraines shut off fluvial sediment supply and caused terrace abandonment. The age of the terrace therefore records the initiation of LGM retreat. Negligible 10Be inheritance in the terrace profile suggests that glacial erosion of the bedrock valley floor from which sediments were derived erased all cosmogenic inventory. Glacial polish exposure ages monotonically decrease up-valley from 17.1 to 12.3 ka, with the single exception of a sample collected from a quartzite rib, yielding an average retreat rate of 15.4 m/yr. This trend and the lack of inherited cosmogenic nuclides in the terrace sediments imply that polish ages accurately record the glacial retreat history. Retreat of the Animas lobe began at a time of regional drying recorded in sediments and shoreline elevations of large lakes. Deglaciation lasted for ˜7.2 k.y., and was complete by 12.3 ± 1.0 ka. The retreat history followed the pattern of increasing insolation and was perhaps fastest during a time of regional drying.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..122.7235C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..122.7235C"><span>Meteorological conditions in a thinner Arctic sea <span class="hlt">ice</span> regime from winter to summer during the Norwegian Young Sea <span class="hlt">Ice</span> expedition (N-<span class="hlt">ICE</span>2015)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cohen, Lana; Hudson, Stephen R.; Walden, Von P.; Graham, Robert M.; Granskog, Mats A.</p> <p>2017-07-01</p> <p>Atmospheric measurements were made over Arctic sea <span class="hlt">ice</span> north of <span class="hlt">Svalbard</span> from winter to early summer (January-June) 2015 during the Norwegian Young Sea <span class="hlt">Ice</span> (N-<span class="hlt">ICE</span>2015) expedition. These measurements, which are available publicly, represent a comprehensive meteorological data set covering the seasonal transition in the Arctic Basin over the new, thinner sea <span class="hlt">ice</span> regime. Winter was characterized by a succession of storms that produced short-lived (less than 48 h) temperature increases of 20 to 30 K at the surface. These storms were driven by the hemispheric scale circulation pattern with a large meridional component of the polar jet stream steering North Atlantic storms into the high Arctic. Nonstorm periods during winter were characterized by strong surface temperature inversions due to strong radiative cooling ("radiatively clear state"). The strength and depth of these inversions were similar to those during the Surface Heat Budget of the Arctic Ocean (SHEBA) campaign. In contrast, atmospheric profiles during the "opaquely cloudy state" were different to those from SHEBA due to differences in the synoptic conditions and location within the <span class="hlt">ice</span> pack. Storm events observed during spring/summer were the result of synoptic systems located in the Barents Sea and the Arctic Basin rather than passing directly over N-<span class="hlt">ICE</span>2015. These synoptic systems were driven by a large-scale circulation pattern typical of recent years, with an Arctic Dipole pattern developing during June. Surface temperatures became near-constant 0°C on 1 June marking the beginning of summer. Atmospheric profiles during the spring and early summer show persistent lifted temperature and moisture inversions that are indicative of clouds and cloud processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030001036','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030001036"><span><span class="hlt">Ice</span> Accretion Formations on a NACA 0012 Swept Wing Tip in Natural <span class="hlt">Icing</span> Conditions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vargas, Mario; Giriunas, Julius A.; Ratvasky, Thomas P.</p> <p>2002-01-01</p> <p>An experiment was conducted in the DeHavilland DHC-6 Twin Otter <span class="hlt">Icing</span> Research Aircraft at NASA Glenn Research Center to study the formation of <span class="hlt">ice</span> accretions on swept wings in natural <span class="hlt">icing</span> conditions. The experiment was designed to obtain <span class="hlt">ice</span> accretion data to help determine if the mechanisms of <span class="hlt">ice</span> accretion formation observed in the <span class="hlt">Icing</span> Research Tunnel are present in natural <span class="hlt">icing</span> conditions. The experiment in the Twin Otter was conducted using a NACA 0012 swept wing tip. The model enabled data acquisition at 0 deg, 15 deg, 25 deg, 30 deg, and 45 deg sweep angles. Casting data, <span class="hlt">ice</span> shape tracings, and close-up photographic data were obtained. The results showed that the mechanisms of <span class="hlt">ice</span> accretion formation observed in-flight agree well with the ones observed in the <span class="hlt">Icing</span> Research Tunnel. Observations on the end <span class="hlt">cap</span> of the airfoil showed the same strong effect of the local sweep angle on the formation of scallops as observed in the tunnel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19..187K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19..187K"><span>Last Glacial-Interglacial Transition <span class="hlt">ice</span> dynamics in the Wicklow Mountains, Ireland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Knight, Lauren; Boston, Clare; Lovell, Harold; Pepin, Nick</p> <p>2017-04-01</p> <p>Understanding of the extent and dynamics of former <span class="hlt">ice</span> masses in the Wicklow Mountains, Ireland, during the Last Glacial-Interglacial Transition (LGIT; 15-10 ka BP) is currently unresolved. Whilst it is acknowledged that the region hosted a local <span class="hlt">ice</span> <span class="hlt">cap</span> within the larger British-Irish <span class="hlt">Ice</span> Sheet at the Last Glacial Maximum (LGM; 27 ka BP), there has been little consideration of <span class="hlt">ice</span> <span class="hlt">cap</span> disintegration to a topographically constrained <span class="hlt">ice</span> mass during the LGIT. This research has produced the first regional glacial geomorphological map, through remote sensing (aerial photograph and digital terrain model interrogation) and field mapping. This has allowed both the style and extent of mountain glaciation and <span class="hlt">ice</span> recession dynamics during the LGIT to be established. This geomorphological mapping has highlighted that evidence for local glaciation in the Wicklow Mountains is more extensive than previously recognised, and that small icefields and associated outlet valley glaciers existed during the LGIT following disintegration of the Wicklow <span class="hlt">Ice</span> <span class="hlt">Cap</span>. A relative chronology based on morphostratigraphic principles is developed, which indicates complex patterns of <span class="hlt">ice</span> mass oscillation characterised by periods of both sustained retreat and minor readvance. Variations in the pattern of recession across the Wicklow Mountains are evident and appear to be influenced, in part, by topographic controls (e.g. slope, aspect, glacier hypsometry). In summary, this research establishes a relative chronology of glacial events in the region during the LGIT and presents constraints on <span class="hlt">ice</span> mass extent, dynamics and retreat patterns, offering an insight into small <span class="hlt">ice</span> mass behaviour in a warming climate.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26567474','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26567474"><span>Taxonomic characterization and the bio-potential of bacteria isolated from glacier <span class="hlt">ice</span> cores in the High Arctic.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Singh, Purnima; Singh, Shiv Mohan; Roy, Utpal</p> <p>2016-03-01</p> <p>Glacier <span class="hlt">ice</span> and firn cores have ecological and biotechnological importance. The present study is aimed at characterizing bacteria in crustal <span class="hlt">ice</span> cores from <span class="hlt">Svalbard</span>, the Arctic. Counts of viable isolates ranged from 10 to 7000 CFU/ml (mean 803 CFU/ml) while the total bacterial numbers ranged from 7.20 × 10(4) to 2.59 × 10(7)  cells ml(-1) (mean 3.12 × 10(6)  cells ml(-1) ). Based on 16S rDNA sequence data, the identified species belonged to seven species, namely Bacillus barbaricus, Pseudomonas orientalis, Pseudomonas oryzihabitans, Pseudomonas fluorescens, Pseudomonas syncyanea, Sphingomonas dokdonensis, and Sphingomonas phyllosphaerae, with a sequence similarity ranging between 93.5 and 99.9% with taxa present in the database. The isolates exhibited unique phenotypic properties, and three isolates (MLB-2, MLB-5, and MLB-9) are novel species, yet to be described. To the best of our knowledge, this is the first report on characterization of cultured bacterial communities from <span class="hlt">Svalbard</span> <span class="hlt">ice</span> cores. We conclude that high lipase, protease, cellulase, amylase, and urease activities expressed by most of the isolates provide a clue to the potential industrial applications of these organisms. These microbes, producing cold-adapted enzymes may provide an opportunity for biotechnological research. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18258082','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18258082"><span>Spatial distribution of Echinococcus multilocularis, <span class="hlt">Svalbard</span>, Norway.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fuglei, Eva; Stien, Audun; Yoccoz, Nigel G; Ims, Rolf A; Eide, Nina E; Prestrud, Pål; Deplazes, Peter; Oksanen, Antti</p> <p>2008-01-01</p> <p>In <span class="hlt">Svalbard</span>, Norway, the only intermediate host for Echinococcus multilocularis, the sibling vole, has restricted spatial distribution. A survey of feces from the main host, the arctic fox, showed that only the area occupied by the intermediate host is associated with increased risk for human infection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110008112','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110008112"><span>Cryogenic Origin for Mars Analog Carbonates in the Bockfjord Volcanic Complex <span class="hlt">Svalbard</span> (Norway)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Amundsen, H. E. F.; Benning, L.; Blake, D. F.; Fogel, M.; Ming, D.; Skidmore, M.; Steele, A.</p> <p>2011-01-01</p> <p>The Sverrefjell and Sigurdfjell eruptive centers in the Bockfjord Volcanic Complex (BVC) on <span class="hlt">Svalbard</span> (Norway) formed by subglacial eruptions ca. 1 Ma ago. These eruptive centers carry ubiquitous magnesian carbonate deposits including dolomitemagnesite globules similar to those in the Martian meteorite ALH84001. Carbonates in mantle xenoliths are dominated by ALH84001 type carbonate globules that formed during quenching of CO2-rich mantle fluids. Lava hosted carbonates include ALH84001 type carbonate globules occurring throughout lava vesicles and microfractures and massive carbonate deposits associated with vertical volcanic vents. Massive carbonates include < or equal 5 cm thick magnesite deposits protruding downwards into clear blue <span class="hlt">ice</span> within volcanic vents and carbonate cemented lava breccias associated with volcanic vents. Carbonate cements comprise layered deposits of calcite, dolomite, huntite, magnesite and aragonite associated with ALH84001 type carbonate globules lining lava vesicles. Combined Mossbauer, XRD and VNIR data show that breccia carbonate cements at Sverrefjell are analog to Comanche carbonates at Gusev crater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050167126','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050167126"><span>Palmer Quest: A Feasible Nuclear Fission "Vision Mission" to the Mars Polar <span class="hlt">Caps</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Carsey, F. D.; Beegle, L. W.; Nakagawa, R.; Elliott, J. O.; Matthews, J. B.; Coleman, M. L.; Hecht, M. H.; Ivaniov, A. B.; Head, J. W.; Milkovich, S.</p> <p>2005-01-01</p> <p>We are engaged in a NASA Vision Mission study, called Palmer Quest after the American Antarctic explorer Nathaniel Palmer, to assess the presence of life and evaluate the habitability of the basal domain of the Mars polar <span class="hlt">caps</span>. We address this goal through four objectives: 1. Determine the presence of amino acids, nutrients, and geochemical heterogeneity in the <span class="hlt">ice</span> sheet. 2. Quantify and characterize the provenance of the amino acids in Mars <span class="hlt">ice</span>. 3. Assess the stratification of outcropped units for indications of habitable zones. 4. Determine the accumulation of <span class="hlt">ice</span>, mineralogic material, and amino acids in Mars <span class="hlt">ice</span> <span class="hlt">caps</span> over the present epoch. Because of the defined scientific goal for the vision mission, the Palmer Quest focus is astrobiological; however, the results of the study make us optimistic that aggressive multi-platform in-situ missions that address a wide range of objectives, such as climate change, can be supported by variations of the approach used on this mission. Mission Overview: The Palmer Quest baseline</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.3163L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.3163L"><span>On the possibility of <span class="hlt">ice</span> on Greenland during the Eocene-Oligocene transition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Langebroek, Petra M.; Nisancioglu, Kerim H.; Lunt, Daniel J.; Kathrine Pedersen, Vivi; Nele Meckler, A.; Gasson, Edward</p> <p>2017-04-01</p> <p>The Eocene-Oligocene transition ( 34 Ma) is one of the major climate transitions of the Cenozoic era. Atmospheric CO2 decreased from the high levels of the Greenhouse world (>1000 ppm) to values of about 600-700 ppm in the early Oligocene. High latitude temperatures dropped by several degrees, causing a large-scale expansion of the Antarctic <span class="hlt">ice</span> sheet. Concurrently, in the Northern Hemisphere, the inception of <span class="hlt">ice</span> <span class="hlt">caps</span> on Greenland is suggested by indirect evidence from <span class="hlt">ice</span>-rafted debris and changes in erosional regime. However, <span class="hlt">ice</span> sheet models have not been able to simulate extensive <span class="hlt">ice</span> on Greenland under the warm climate of the Eocene-Oligocene transition. We show that elevated bedrock topography is key in solving this inconsistency. During the late Eocene / early Oligocene, East Greenland bedrock elevations were likely higher than today due to tectonic and deep-Earth processes related to the break-up of the North Atlantic and the position of the Icelandic plume. When allowing for higher initial bedrock topography, we do simulate a large <span class="hlt">ice</span> <span class="hlt">cap</span> on Greenland under the still relatively warm climate of the early Oligocene. <span class="hlt">Ice</span> inception takes place at high elevations in the colder regions of North and Northeast Greenland; with the size of the <span class="hlt">ice</span> <span class="hlt">cap</span> being strongly dependent on the climate forcing and the bedrock topography applied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70047201','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70047201"><span>Observations of the northern seasonal polar <span class="hlt">cap</span> on Mars: I. Spring sublimation activity and processes</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hansen, C.J.; Byrne, S.; Portyankina, G.; Bourke, M.; Dundas, C.; McEwen, A.; Mellon, M.; Pommerol, A.; Thomas, N.</p> <p>2013-01-01</p> <p>Spring sublimation of the seasonal CO2 northern polar <span class="hlt">cap</span> is a dynamic process in the current Mars climate. Phenomena include dark fans of dune material propelled out onto the seasonal <span class="hlt">ice</span> layer, polygonal cracks in the seasonal <span class="hlt">ice</span>, sand flow down slipfaces, and outbreaks of gas and sand around the dune margins. These phenomena are concentrated on the north polar erg that encircles the northern residual polar <span class="hlt">cap</span>. The Mars Reconnaissance Orbiter has been in orbit for three Mars years, allowing us to observe three northern spring seasons. Activity is consistent with and well described by the Kieffer model of basal sublimation of the seasonal layer of <span class="hlt">ice</span> applied originally in the southern hemisphere. Three typical weak spots have been identified on the dunes for escape of gas sublimed from the bottom of the seasonal <span class="hlt">ice</span> layer: the crest of the dune, the interface of the dune with the interdune substrate, and through polygonal cracks in the <span class="hlt">ice</span>. Pressurized gas flows through these vents and carries out material entrained from the dune. Furrows in the dunes channel gas to outbreak points and may be the northern equivalent of southern radially-organized channels (“araneiform” terrain), albeit not permanent. Properties of the seasonal CO2 <span class="hlt">ice</span> layer are derived from timing of seasonal events such as when final sublimation occurs. Modification of dune morphology shows that landscape evolution is occurring on Mars today, driven by seasonal activity associated with sublimation of the seasonal CO2 polar <span class="hlt">cap</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C53A0279G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C53A0279G"><span>Rapid Access <span class="hlt">Ice</span> Drill: A New Tool for Exploration of the Deep Antarctic <span class="hlt">Ice</span> Sheets and Subglacial Geology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goodge, J. W.; Severinghaus, J. P.</p> <p>2014-12-01</p> <p>The Rapid Access <span class="hlt">Ice</span> Drill (RAID) will penetrate the Antarctic <span class="hlt">ice</span> sheets in order to core through deep <span class="hlt">ice</span>, the glacial bed, and into bedrock below. This new technology will provide a critical first look at the interface between major <span class="hlt">ice</span> <span class="hlt">caps</span> and their subglacial geology. Currently in construction, RAID is a mobile drilling system capable of making several long boreholes in a single field season in Antarctica. RAID is interdisciplinary and will allow access to polar paleoclimate records in <span class="hlt">ice</span> >1 Ma, direct observation at the base of the <span class="hlt">ice</span> sheets, and recovery of rock cores from the <span class="hlt">ice</span>-covered East Antarctic craton. RAID uses a diamond rock-coring system as in mineral exploration. Threaded drill-pipe with hardened metal bits will cut through <span class="hlt">ice</span> using reverse circulation of Estisol for pressure-compensation, maintenance of temperature, and removal of <span class="hlt">ice</span> cuttings. Near the bottom of the <span class="hlt">ice</span> sheet, a wireline bottom-hole assembly will enable diamond coring of <span class="hlt">ice</span>, the glacial bed, and bedrock below. Once complete, boreholes will be kept open with fluid, <span class="hlt">capped</span>, and made available for future down-hole measurement of thermal gradient, heat flow, <span class="hlt">ice</span> chronology, and <span class="hlt">ice</span> deformation. RAID will also sample for extremophile microorganisms. RAID is designed to penetrate up to 3,300 meters of <span class="hlt">ice</span> and take sample cores in less than 200 hours. This rapid performance will allow completion of a borehole in about 10 days before moving to the next drilling site. RAID is unique because it can provide fast borehole access through thick <span class="hlt">ice</span>; take short <span class="hlt">ice</span> cores for paleoclimate study; sample the glacial bed to determine <span class="hlt">ice</span>-flow conditions; take cores of subglacial bedrock for age dating and crustal history; and create boreholes for use as an observatory in the <span class="hlt">ice</span> sheets. Together, the rapid drilling capability and mobility of the drilling system, along with <span class="hlt">ice</span>-penetrating imaging methods, will provide a unique 3D picture of the interior Antarctic <span class="hlt">ice</span> sheets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011EOSTr..92R..88S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011EOSTr..92R..88S"><span>Research Spotlight: No tipping point for Arctic Ocean <span class="hlt">ice</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schultz, Colin</p> <p>2011-03-01</p> <p>Declines in the summer sea <span class="hlt">ice</span> extent have led to concerns within the scientific community that the Arctic Ocean may be nearing a tipping point, beyond which the sea <span class="hlt">ice</span> <span class="hlt">cap</span> could not recover. In such a scenario, greenhouse gases in the atmosphere trap outgoing radiation, and as the Sun beats down 24 hours a day during the Arctic summer, temperatures rise and melt what remains of the polar sea <span class="hlt">ice</span> <span class="hlt">cap</span>. The Arctic Ocean, now less reflective, would absorb more of the Sun’s warmth, a feedback loop that would keep the ocean <span class="hlt">ice</span> free. However, new research by Tietsche et al. suggests that even if the Arctic Ocean sees an <span class="hlt">ice</span>-free summer, it would not lead to catastrophic runaway <span class="hlt">ice</span> melt. The researchers, using a general circulation model of the global ocean and the atmosphere, found that Arctic sea <span class="hlt">ice</span> recovers within 2 years of an imposed <span class="hlt">ice</span>-free summer to the conditions dictated by general climate conditions during that time. Furthermore, they found that this quick recovery occurs whether the <span class="hlt">ice</span>-free summer is triggered in 2000 or in 2060, when global temperatures are predicted to be 2°C warmer. (Geophysical Research Letters, doi:10.1029/2010GL045698, 2011)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24264767','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24264767"><span>Pink marine sediments reveal rapid <span class="hlt">ice</span> melt and Arctic meltwater discharge during Dansgaard-Oeschger warmings.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rasmussen, Tine L; Thomsen, Erik</p> <p>2013-01-01</p> <p>The climate of the last glaciation was interrupted by numerous abrupt temperature fluctuations, referred to as Greenland interstadials and stadials. During warm interstadials the meridional overturning circulation was active transferring heat to the north, whereas during cold stadials the Nordic Seas were <span class="hlt">ice</span>-covered and the overturning circulation was disrupted. Meltwater discharge, from <span class="hlt">ice</span> sheets surrounding the Nordic Seas, is implicated as a cause of this ocean instability, yet very little is known regarding this proposed discharge during warmings. Here we show that, during warmings, pink clay from Devonian Red Beds is transported in suspension by meltwater from the surrounding <span class="hlt">ice</span> sheet and replaces the greenish silt that is normally deposited on the north-western slope of <span class="hlt">Svalbard</span> during interstadials. The magnitude of the outpourings is comparable to the size of the outbursts during the deglaciation. Decreasing concentrations of <span class="hlt">ice</span>-rafted debris during the interstadials signify that the <span class="hlt">ice</span> sheet retreats as the meltwater production increases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5046916','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5046916"><span>The role of sea <span class="hlt">ice</span> for vascular plant dispersal in the Arctic</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ehrich, Dorothee; Bennike, Ole; Geirsdottir, Aslaug</p> <p>2016-01-01</p> <p>Sea <span class="hlt">ice</span> has been suggested to be an important factor for dispersal of vascular plants in the Arctic. To assess its role for postglacial colonization in the North Atlantic region, we compiled data on the first Late Glacial to Holocene occurrence of vascular plant species in East Greenland, Iceland, the Faroe Islands and <span class="hlt">Svalbard</span>. For each record, we reconstructed likely past dispersal events using data on species distributions and genetics. We compared these data to sea-<span class="hlt">ice</span> reconstructions to evaluate the potential role of sea <span class="hlt">ice</span> in these past colonization events and finally evaluated these results using a compilation of driftwood records as an independent source of evidence that sea <span class="hlt">ice</span> can disperse biological material. Our results show that sea <span class="hlt">ice</span> was, in general, more prevalent along the most likely dispersal routes at times of assumed first colonization than along other possible routes. Also, driftwood is frequently dispersed in regions that have sea <span class="hlt">ice</span> today. Thus, sea <span class="hlt">ice</span> may act as an important dispersal agent. Melting sea <span class="hlt">ice</span> may hamper future dispersal of Arctic plants and thereby cause more genetic differentiation. It may also limit the northwards expansion of competing boreal species, and hence favour the persistence of Arctic species. PMID:27651529</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..1113700S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..1113700S"><span>Nature and History of Cenozoic Polar <span class="hlt">Ice</span> Covers: The Case of the Greenland <span class="hlt">Ice</span> Sheet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spielhagen, R.; Thiede, J.</p> <p>2009-04-01</p> <p>The nature of the modern climate System is characterized by steep temperature gradients between the tropical and polar climatic zones and finds its most spectacular expression in the formation of <span class="hlt">ice</span> <span class="hlt">caps</span> in high Northern and Southern latitudes. While polar regions of Planet Earth have been glaciated repeatedly in the long course of their geological history, the Cenozoic transition from a „greenhouse" to an „icehouse" has in fact produced a unique climatic scenario with bipolar glacation, different from all previous glacial events. The Greenland <span class="hlt">ice</span> sheet is a remainder of the Northern Hemisphere last glacial maximum <span class="hlt">ice</span> sheets and represents hence a spectacular anomaly. Geological records from Tertiary and Quaternary terrestrial and oceanic sections have documented the presence of <span class="hlt">ice</span> <span class="hlt">caps</span> and sea <span class="hlt">ice</span> covers both on the Southern as well on the Northern hemisphere since Eocene times, aqpprox. 45 Mio. years ago. While this was well known in the case of Antarctica already for some time, previous ideas about the origin of Northern hemisphere glaciation during Pliocene times (approx. 2-3 Mio. years ago) have been superceded by the dramatic findings of coarse, terrigenous <span class="hlt">ice</span> rafted detritus in Eocene sediments from Lomonosov Ridge (close to the North Pole) apparently slightly older than the oldest Antarctic records of <span class="hlt">ice</span> rafting.The histories of the onset of Cenozoic glaciation in high Northern and Southern latitudes remain enigmatic and are presently subjects of international geological drilling projects, with prospects to reveal some of their secrets over the coming decades. By virtue of the physical porperties of <span class="hlt">ice</span> and the processes controlling the dynamics of the turn-over of the <span class="hlt">ice</span>-sheets only young records of glacial <span class="hlt">ice</span> <span class="hlt">caps</span> on Antarctica and on Greemnland have been preserved, on Greenland with <span class="hlt">ice</span> probably not older than a few hundred thousand years, on Antarctica potentially as old as 1.5-2 Mio. years. Deep-sea cores with their records od <span class="hlt">ice</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5791158','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5791158"><span>3-D Imaging of Mars’ Polar <span class="hlt">Ice</span> <span class="hlt">Caps</span> Using Orbital Radar Data</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Foss, Frederick J.; Putzig, Nathaniel E.; Campbell, Bruce A.; Phillips, Roger J.</p> <p>2018-01-01</p> <p>Since its arrival in early 2006, various instruments aboard NASA’s Mars Reconnaissance Orbiter (MRO) have been collecting a variety of scientific and engineering data from orbit around Mars. Among these is the SHAllow RADar (SHARAD) instrument, supplied by Agenzia Spaziale Italiana (ASI) and designed for subsurface sounding in the 15–25 MHz frequency band. As of this writing, MRO has completed over 46,000 nearly polar orbits of Mars, 30% of which have included active SHARAD data collection. By 2009, a sufficient density of SHARAD coverage had been obtained over the polar regions to support 3-D processing and analysis of the data. Using tools and techniques commonly employed in terrestrial seismic data processing, we have processed subsets of the resulting collection of SHARAD observations covering the north and south polar regions as SHARAD 3-D volumes, imaging the interiors of the north and south polar <span class="hlt">ice</span> <span class="hlt">caps</span> known, respectively, as Planum Boreum and Planum Australe. After overcoming a series of challenges revealed during the 3-D processing and analysis, a completed Planum Boreum 3-D volume is currently being used for scientific research. Lessons learned in the northern work fed forward into our 3-D processing and analysis of the Planum Australe 3-D volume, currently under way. We discuss our experiences with these projects and present results and scientific insights stemming from these efforts. PMID:29400351</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.8973H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.8973H"><span>Capturing total chronological and spatial uncertainties in palaeo-<span class="hlt">ice</span> sheet reconstructions: the DATED example</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hughes, Anna; Gyllencreutz, Richard; Mangerud, Jan; Svendsen, John Inge</p> <p>2017-04-01</p> <p>Glacial geologists generate empirical reconstructions of former <span class="hlt">ice</span>-sheet dynamics by combining evidence from the preserved record of glacial landforms (e.g. end moraines, lineations) and sediments with chronological evidence (mainly numerical dates derived predominantly from radiocarbon, exposure and luminescence techniques). However the geomorphological and sedimentological footprints and chronological data are both incomplete records in both space and time, and all have multiple types of uncertainty associated with them. To understand <span class="hlt">ice</span> sheets' response to climate we need numerical models of <span class="hlt">ice</span>-sheet dynamics based on physical principles. To test and/or constrain such models, empirical reconstructions of past <span class="hlt">ice</span> sheets that capture and acknowledge all uncertainties are required. In 2005 we started a project (Database of the Eurasian Deglaciation, DATED) to produce an empirical reconstruction of the evolution of the last Eurasian <span class="hlt">ice</span> sheets, (including the British-Irish, Scandinavian and <span class="hlt">Svalbard</span>-Barents-Kara Seas <span class="hlt">ice</span> sheets) that is fully documented, specified in time, and includes uncertainty estimates. Over 5000 dates relevant to constraining <span class="hlt">ice</span> build-up and retreat were assessed for reliability and used together with published <span class="hlt">ice</span>-sheet margin positions based on glacial geomorphology to reconstruct time-slice maps of the <span class="hlt">ice</span> sheets' extent. The DATED maps show synchronous <span class="hlt">ice</span> margins with maximum-minimum uncertainty bounds for every 1000 years between 25-10 kyr ago. In the first version of results (DATED-1; Hughes et al. 2016) all uncertainties (both quantitative and qualitative, e.g. precision and accuracy of numerical dates, correlation of moraines, stratigraphic interpretations) were combined based on our best glaciological-geological assessment and expressed in terms of distance as a 'fuzzy' margin. Large uncertainties (>100 km) exist; predominantly across marine sectors and other locations where there are spatial gaps in the dating record (e.g. the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20120012561&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCAPS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20120012561&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCAPS"><span>24/7 Solar Minimum Polar <span class="hlt">Cap</span> and Auroral Ion Temperature Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sojka, Jan J.; Nicolls, Michael; van Eyken, Anthony; Heinselman, Craig; Bilitza, Dieter</p> <p>2011-01-01</p> <p>During the International Polar Year (IPY) two Incoherent Scatter Radars (ISRs) achieved close to 24/7 continuous observations. This presentation describes their data sets and specifically how they can provide the International Reference Ionosphere (IRI) a fiduciary E- and F-region ionosphere description for solar minimum conditions in both the auroral and polar <span class="hlt">cap</span> regions. The ionospheric description being electron density, ion temperature and electron temperature profiles from as low as 90 km extending to several scale heights above the F-layer peak. The auroral location is Poker Flat in Alaska at 65.1 N latitude, 212.5 E longitude where the NSF s new Poker Flat Incoherent Scatter Radar (PFISR) is located. This location during solar minimum conditions is in the auroral region for most of the day but is at midlatitudes, equator ward of the cusp, for about 4-8 h per day dependent upon geomagnetic activity. In contrast the polar location is <span class="hlt">Svalbard</span>, at 78.2 N latitude, 16.0 E longitude where the EISCAT <span class="hlt">Svalbard</span> Radar (ESR) is located. For most of the day the ESR is in the Northern Polar <span class="hlt">Cap</span> with a noon sector passage often through the dayside cusp. Of unique relevance to IRI is that these extended observations have enabled the ionospheric morphology to be distinguished between quiet and disturbed geomagnetic conditions. During the IPY year, 1 March 2007 - 29 February 2008, about 50 solar wind Corotating Interaction Regions (CIRs) impacted geospace. Each CIR has a two to five day geomagnetic disturbance that is observed in the ESR and PFISR observations. Hence, this data set also enables the quiet-background ionospheric climatology to be established as a function of season and local time. These two separate climatologies for the ion temperature at an altitude of 300 km are presented and compared with IRI ion temperatures. The IRI ion temperatures are about 200-300 K hotter than the observed values. However, the MSIS neutral temperature at 300 km compares favorably</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20050170951&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DCAPS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20050170951&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DCAPS"><span>High LMD GCM Resolution Modeling of the Seasonal Evolution of the Martian Northern Permanent <span class="hlt">Cap</span>: Comparison with Mars Express OMEGA Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Levrard, B.; Forget, F.; Montmessin, F.; Schmitt, B.; Doute, S.; Langevin, Y.; Poulet, F.; Bibring, J. P.; Gondet, B.</p> <p>2005-01-01</p> <p>Analyses of imaging data from Mariner, Viking and MGS have shown that surface properties (albedo, temperature) of the northern <span class="hlt">cap</span> present significant differences within the summer season and between Mars years. These observations include differential brightening and/or darkening between polar areas from the end of the spring to midsummer. These differences are attributed to changes in grain size or dust content of surface <span class="hlt">ice</span>. To better understand the summer behavior of the permanent northern polar <span class="hlt">cap</span>, we perfomed a high resolution modeling (approximately 1 deg x 1 deg.) of northern <span class="hlt">cap</span> in the Martian Climate/water cycle as simulated by the Laboratoire de Meteorologie Dynamique (LMD) global climate model. We compare the predicted properties of the surface <span class="hlt">ice</span> (<span class="hlt">ice</span> thickness, temperature) with the Mars Express Omega summer observations of the northern <span class="hlt">cap</span>. albedo and thermal inertia svariations model. In particular, albedo variations could be constrained by OMEGA data. Meteorological predictions of the LMD GCM wil be presented at the conference to interpret the unprecedently resolved OMEGA observations. The specific evolution of regions of interest (<span class="hlt">cap</span> center, Chasma Boreal...) and the possibility of late summer global <span class="hlt">cap</span> brightening will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28704670','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28704670"><span>Cryo-conditioned rocky coast systems: A case study from Wilczekodden, <span class="hlt">Svalbard</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Strzelecki, M C; Kasprzak, M; Lim, M; Swirad, Z M; Jaskólski, M; Pawłowski, Ł; Modzel, P</p> <p>2017-12-31</p> <p>This paper presents the results of an investigation into the processes controlling development of a cryo-conditioned rock coast system in Hornsund, <span class="hlt">Svalbard</span>. A suite of nested geomorphological and geophysical methods have been applied to characterise the functioning of rock cliffs and shore platforms influenced by lithological control and geomorphic processes driven by polar coast environments. Electrical resistivity tomography (ERT) surveys have been used to investigate permafrost control on rock coast dynamics and reveal the strong interaction with marine processes in High Arctic coastal settings. Schmidt hammer rock tests, demonstrated strong spatial control on the degree of rock weathering (rock strength) along High Arctic rock coasts. Elevation controlled geomorphic zones are identified and linked to distinct processes and mechanisms, transitioning from peak hardness values at the <span class="hlt">ice</span> foot through the wave and storm dominated scour zones to the lowest values on the cliff tops, where the effects of periglacial weathering dominate. Observations of rock surface change using a traversing micro-erosion meter (TMEM) indicate that significant changes in erosion rates occur at the junction between the shore platform and the cliff toe, where rock erosion is facilitated by frequent wetting and drying and operation of nivation and sea <span class="hlt">ice</span> processes (formation and melting of snow patches and icefoot complexes). The results are synthesised to propose a new conceptual model of High Arctic rock coast systems, with the aim of contributing towards a unifying concept of cold region landscape evolution and providing direction for future research regarding the state of polar rock coasts. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP33A2279P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP33A2279P"><span>Initial Insights into the Quaternary Evolution of the Laurentide <span class="hlt">Ice</span> Sheet on Southeastern Baffin Island</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pendleton, S.; Anderson, R. S.; Miller, G. H.; Refsnider, K. A.</p> <p>2015-12-01</p> <p>Increasing Arctic summer temperatures in recent decades and shrinking cold-based <span class="hlt">ice</span> <span class="hlt">caps</span> on Cumberland Peninsula, Baffin Island, are exposing ancient landscapes complete with uneroded bedrock surfaces. Previous work has indicated that these upland surfaces covered with cold-based <span class="hlt">ice</span> experience negligible erosion compared with the valleys and fjords systems that contain fast-flowing <span class="hlt">ice</span>. Given the appearance of highly weathered bedrock, it is argued that these landscapes have remained largely unchanged since at least the last interglaciation (~120 ka), and have likely experienced multiple cycles of <span class="hlt">ice</span> expansion and retraction with little erosion throughout the Quaternary. To explore this hypothesis, we use multiple cosmogenic radionuclides (26Al and 10Be) to investigate and provide insight into longer-term cryosphere activity and landscape evolution. 26Al/10Be in surfaces recently exposed exhibit a wide range of exposure-burial histories. Total exposure-burial times range from ~0.3 - 1.5 My and estimated erosion rates from 0.5 - 6.2 m Ma-1. The upland surfaces of the Penny <span class="hlt">Ice</span> <span class="hlt">cap</span> generally experienced higher erosion rates (~0.45 cm ka-1) than those covered by smaller <span class="hlt">ice</span> <span class="hlt">caps</span> (~0.2 cm ka-1). The cumulative burial/exposure histories in high, fjord-edge locations indicate that significant erosion north of the Penny <span class="hlt">Ice</span> <span class="hlt">Cap</span> ceased between ~600 and 800 ka, suggesting that Laurentide <span class="hlt">Ice</span> Sheet (LIS) organization and fjord inception was underway by at least this time. Additionally, 26Al/10Be ratios near production values despite high inventories from a coastal summit 50 km east of the Penny <span class="hlt">Ice</span> Cape suggest that that area has not experienced appreciable burial by <span class="hlt">ice</span>, suggesting that it was never inundated by the LIS. Moreover, these initial data suggest a variable and dynamic cryosphere in the region and provide insight into how large <span class="hlt">ice</span> sheets evolved and organized themselves during the Quaternary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18578588','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18578588"><span>Prevalence of antibodies against Toxoplasma gondii in polar bears (Ursus maritimus) from <span class="hlt">Svalbard</span> and East Greenland.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Oksanen, A; Asbakk, K; Prestrud, K W; Aars, J; Derocher, A E; Tryland, M; Wiig, O; Dubey, J P; Sonne, C; Dietz, R; Andersen, M; Born, E W</p> <p>2009-02-01</p> <p>Serum samples from 419 polar bears (Ursus maritimus) from <span class="hlt">Svalbard</span> and the Barents Sea (collected 1990-2000) and 108 polar bears from East Greenland (collected 1999-2004) were assayed for antibodies against Toxoplasma gondii using the modified agglutination test. Antibody prevalences were 3.6% among cubs dependent on their mothers and 21.4% among subadults and adults. Among subadults and adults there was an interaction between population and sex, with similar prevalences among females (<span class="hlt">Svalbard</span> = 19.5%, Greenland = 18.0%), but a high frequency among <span class="hlt">Svalbard</span> males (28.7%) as compared to Greenland males (5.8%). The pattern was also significant after correcting for differences in age distribution. The sex-population interaction term is believed to be connected to area- and sex-specific feeding ecology. The prevalences of antibodies against T. gondii in <span class="hlt">Svalbard</span> and Greenland were high compared to previously reported findings in polar bears from Russian and Alaskan areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911611S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911611S"><span><span class="hlt">Ice</span> crystals classification using airborne measurements in mixing phase</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sorin Vajaiac, Nicolae; Boscornea, Andreea</p> <p>2017-04-01</p> <p>This paper presents a case study of <span class="hlt">ice</span> crystals classification from airborne measurements in mixed-phase clouds. <span class="hlt">Ice</span> crystal shadow is recorded with CIP (Cloud Imaging Probe) component of <span class="hlt">CAPS</span> (Cloud, Aerosol, and Precipitation Spectrometer) system. The analyzed flight was performed in the south-western part of Romania (between Pietrosani, Ramnicu Valcea, Craiova and Targu Jiu), with a Beechcraft C90 GTX which was specially equipped with a <span class="hlt">CAPS</span> system. The temperature, during the fly, reached the lowest value at -35 °C. These low temperatures allow the formation of <span class="hlt">ice</span> crystals and influence their form. For the here presented <span class="hlt">ice</span> crystals classification a special software, OASIS (Optical Array Shadow Imaging Software), developed by DMT (Droplet Measurement Technologies), was used. The obtained results, as expected are influenced by the atmospheric and microphysical parameters. The particles recorded where classified in four groups: edge, irregular, round and small.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1612286F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1612286F"><span>Geomicrobial characterization of a 60 m long permafrost core from <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fromreide, Siren; Tore Mørkved, Pål; Gilbert, Graham Lewis; Christiansen, Hanne H.; Reigstad, Laila</p> <p>2014-05-01</p> <p>In connection with a planned CO2 storage pilot project in the Arctic, a 60 m long permafrost core was drilled in Adventdalen, <span class="hlt">Svalbard</span>. The on-shore drilling was performed through mainly marine and deltafront sediments, ending at the bedrock. The core has undergone detailed analyses of sedimentary stratigraphy, age, as well as the permafrost <span class="hlt">ice</span> and carbon content at The University Centre in <span class="hlt">Svalbard</span> (UNIS), and at the Center for Permafrost (CENPERM), Copenhagen. The main aim of the study presented here is to link the geochemical properties of the permafrost to the microbial community structure and its potential functions. As little is known about microbial life in permafrost at such depths this study will contribute to the understanding of these inaccessible ecosystems. A baseline geomicrobial description of 7 different depths in the 3 - 60 m interval of the permafrost core was done by culture independent methods such as 16S rRNA amplicon 454 pyrosequencing and functional and ribosomal gene quantifications. Additionally, geochemical analyses of the extracted pore water have been performed, as well as measurements of carbon content and major elements. The enumeration of the total prokaryotic community indicated similar numbers of bacteria and archaea down to approximately 50 m depth, while below this depth there was a dominance of archaeal cells. The bacterial 16S rRNA copy numbers ranged between 108 copies per gram sediment at 3 m depth to 104 copies per gram at the bedrock. Concerning the archaeal cells, the 16S rRNA copy numbers per gram sediment were in the range of 107 at the top of the core, ending at 105in the top of the bedrock. Detection and quantification of selected functional marker genes indicated high numbers of sulphate reducing bacteria at certain sediment depths, and a significant potential for microbial methanogenic activity throughout the core. Correlations studies between geochemical data and microbial community composition are currently ongoing.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMGC11B..01I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMGC11B..01I"><span>Fossil Find on <span class="hlt">Svalbard</span> Highlights the Natural History of the Polar Bear (Ursus maritimus)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ingolfsson, O.; Wiig, O.</p> <p>2007-12-01</p> <p>During recent fieldwork on <span class="hlt">Svalbard</span> a well preserved subfossil left ramus of a polar bear (Ursus maritimus) mandible was discovered. A 14C age determination shows that it is older than 45 ka (kilo-years), and an OSL (Optical Stimulated Luminescence) age determination together with the stratigraphic position of the bone suggests that it is of Eemian-Early Weichselian/Wisconsinan age, 150-80 ka old. This puts the find among the oldest fossil remains of a polar bear ever discovered. Osteological study of the mandible suggests that it comes from a fully grown female. The fossil record suggests that polar bears may have developed from brown bears during the early part of the last glacial cycle, some 100 ka ago. The present interglacial might be the first such that the species has to endure. This underlines the potential status of the polar bears as an endangered species if the current warming trend and diminishing of sea <span class="hlt">ice</span> cover in the Arctic continues.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70033550','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70033550"><span>Observations of the north polar water <span class="hlt">ice</span> annulus on Mars using THEMIS and TES</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wagstaff, K.L.; Titus, T.N.; Ivanov, A.B.; Castano, R.; Bandfield, J.L.</p> <p>2008-01-01</p> <p>The Martian seasonal CO2 <span class="hlt">ice</span> <span class="hlt">caps</span> advance and retreat each year. In the spring, as the CO2 <span class="hlt">cap</span> gradually retreats, it leaves behind an extensive defrosting zone from the solid CO2 <span class="hlt">cap</span> to the location where all CO2 frost has sublimated. We have been studying this phenomenon in the north polar region using data from the THermal EMission Imaging System (THEMIS), a visible and infra-red (IR) camera on the Mars Odyssey spacecraft, and the Thermal Emission Spectrometer (TES) on Mars Global Surveyor. Recently, we discovered that some THEMIS images of the CO2 defrosting zone contain evidence for a distinct defrosting phenomenon: some areas just south of the CO2 <span class="hlt">cap</span> edge are too bright in visible wavelengths to be defrosted terrain, but too warm in the IR to be CO2 <span class="hlt">ice</span>. We hypothesize that we are seeing evidence for a seasonal annulus of water <span class="hlt">ice</span> (frost) that recedes with the seasonal CO2 <span class="hlt">cap</span>, as predicted by previous workers. In this paper, we describe our observations with THEMIS and compare them to simultaneous observations by TES and OMEGA. All three instruments find that this phenomenon is distinct from the CO2 <span class="hlt">cap</span> and most likely composed of water <span class="hlt">ice</span>. We also find strong evidence that the annulus widens as it recedes. Finally, we show that this annulus can be detected in the raw THEMIS data as it is collected, enabling future long-term onboard monitoring. ?? 2007.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22073783','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22073783"><span>Climate, <span class="hlt">icing</span>, and wild arctic reindeer: past relationships and future prospects.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hansen, Brage Bremset; Aanes, Ronny; Herfindal, Ivar; Kohler, Jack; Saether, Bernt-Erik</p> <p>2011-10-01</p> <p>Across the Arctic, heavy rain-on-snow (ROS) is an "extreme" climatic event that is expected to become increasingly frequent with global warming. This has potentially large ecosystem implications through changes in snowpack properties and ground-<span class="hlt">icing</span>, which can block the access to herbivores' winter food and thereby suppress their population growth rates. However, the supporting empirical evidence for this is still limited. We monitored late winter snowpack properties to examine the causes and consequences of ground-<span class="hlt">icing</span> in a <span class="hlt">Svalbard</span> reindeer (Rangifer tarandus platyrhynchus) metapopulation. In this high-arctic area, heavy ROS occurred annually, and ground-<span class="hlt">ice</span> covered from 25% to 96% of low-altitude habitat in the sampling period (2000-2010). The extent of ground-<span class="hlt">icing</span> increased with the annual number of days with heavy ROS (> or = 10 mm) and had a strong negative effect on reindeer population growth rates. Our results have important implications as a downscaled climate projection (2021-2050) suggests a substantial future increase in ROS and <span class="hlt">icing</span>. The present study is the first to demonstrate empirically that warmer and wetter winter climate influences large herbivore population dynamics by generating <span class="hlt">ice</span>-locked pastures. This may serve as an early warning of the importance of changes in winter climate and extreme weather events in arctic ecosystems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.3193C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.3193C"><span><span class="hlt">Ice</span> <span class="hlt">cap</span> melting and low-viscosity crustal root explain the narrow geodetic uplift of the Western Alps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chéry, J.; Genti, M.; Vernant, P.</p> <p>2016-04-01</p> <p>More than 10 years of geodetic measurements demonstrate an uplift rate of 1-3 mm/yr of the high topography region of the Western Alps. By contrast, no significant horizontal motion has been detected. Two uplift mechanisms have been proposed: (1) the isostatic response to denudation responsible for only a fraction of the observed uplift and (2) the rebound induced by the Wurmian <span class="hlt">ice</span> <span class="hlt">cap</span> melting which predicts a broader uplifting region than the one evidenced by geodetic observations. Using a numerical model to fit the geodetic data, we show that a crustal viscosity contrast between the foreland and the central part of the Alps, the latter being weaker with a viscosity of 1021 Pa s, is needed. The vertical rates are enhanced if the strong uppermost mantle beneath the Moho is interrupted across the Alps, therefore allowing a weak vertical rheological anomaly over the entire lithosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1916979U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1916979U"><span>Chemical and geochemical composition of spring-summer Arctic aerosol collected at Ny Alesund, <span class="hlt">Svalbard</span> Islands.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Udisti, Roberto; Becagli, Silvia; Caiazzo, Laura; Cappelletti, David; Giardi, Fabio; Grotti, Marco; Lucarelli, Franco; Moroni, Beatrice; Nava, Silvia; Severi, Mirko; Traversi, Rita</p> <p>2017-04-01</p> <p>Since March 2010, spring-summer (usually March - September) campaigns were continuously carried out at the Italian Gruvebadet Observatory, Ny Alesund, <span class="hlt">Svalbard</span> Island. Aerosol was sampled by PM10 (daily) and 4-stage (4-day resolution) collector devices and size distribution was evaluated at 10 min resolution in the range 10 nm - 20 um (106 size classes by a TSI SMPS-APS integrated system). Six-year (2010-2015) PM10 and size-segregated (>10, 10-2.5, 2.5-1, < 1 um) filters were analyzed for ion composition (inorganic anions and cations, and selected organic anions by Ion Chromatography), metal content (major and trace metals, including Rare Earth Elements - REEs, by PIXE and ICP-MS), Pb isotopic composition (by ICP-MS) and Elemental and Organic Carbon (EC-OC) concentrations. The data set was elaborated by multi-parametric statistical analysis (Positive Matrix Factorization - PMF), in order to identifying and quantifying the contribution of the main anthropic and natural aerosol sources. Particular attention was spent in evaluating the anthropic contribution of nss-sulphate, nitrate, EC and heavy metals during the Arctic Haze in spring. The isotopic composition of Pb was used in identifying the source areas (North America, Greenland, North Europe, Siberia, Iceland) of anthropic emissions as a function of seasonality (different atmospheric circulation pathway). Crustal metals and, especially, REEs anomalies (with respect to the Chondrite-normalized profile) allowed characterizing the dust emissions from their Potential Source Areas (PSA). Biogenic markers (especially methane sulfonic acid - MSA - and bio-nss-sulphate) was used to obtain relevant information about the relationship between marine biogenic activity (primary productivity) and sea <span class="hlt">ice</span> coverage and atmospheric conditions (irradiance, temperature, circulation pathways). The seasonal pattern of the nitrate deposition was also investigated. Chemical and geochemical measurements were compared with high</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006DPS....38.6704G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006DPS....38.6704G"><span>The Residual South Polar <span class="hlt">Cap</span> of Mars: Stable or Transitory?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glenar, David A.; Bonev, B. P.; Hansen, G. B.; James, P. B.; Bjorkman, J. E.</p> <p>2006-09-01</p> <p>It remains uncertain whether the CO2 residual south polar <span class="hlt">cap</span> (RSPC) is a permanent feature of the present Mars climate, or whether it occasionally sublimes completely during years marked by dramatic dust storm activity. While there is no firm evidence for complete disappearance of the <span class="hlt">cap</span> in the past, observations show that the residual <span class="hlt">cap</span> lost significant CO2 material in the spring / summer season prior to the Mariner 9 encounter. On the other hand, little interannual change has been observed in the RSPC during the MGS mission [1], despite the massive early-spring dust storm which occurred in 2001. We discuss whether a global dust storm beginning near perihelion could enhance the net CO2 sublimation sufficiently to completely remove the RSPC. We utilize a surface-plus-aerosol radiative transfer model under conditions of both modest and heavy atmospheric dust loading. The sublimination behavior depends critically on the extended (visible to thermal IR) albedo spectrum of the polar CO2 <span class="hlt">ice</span>, which we have strongly constrained [2] from a combination of HST photometric imaging, ground based near-IR imaging spectroscopy and spectroscopic measurements by the Mars Express PFS. The extension of the <span class="hlt">cap</span> spectrum to thermal IR wavelengths was accomplished by forward modeling using a semi-infinite grid of scattering grains. Results of this analysis depend on the strength of possible feedback mechanisms (increased surface dust content; exposure of water <span class="hlt">ice</span>) as well as on the possibility of dust confinement by the polar vortex; but the general conclusion is that it would require multiple, intense dust storms in a given year in order to completely remove the CO2 <span class="hlt">ice</span> veneer layer. This work has been supported by the NASA Planetary Astronomy and Mars Data Analysis Programs. [1] Benson and James, Icarus 174, 513, 2005; [2] Bonev et al., Planet Space Sci. 2006 (accepted).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMPP13D1850R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMPP13D1850R"><span>Snowball Earth: Skating on Thin <span class="hlt">Ice</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roberson, A. L.; Stout, A. M.; Pollard, D.; Kasting, J. F.</p> <p>2011-12-01</p> <p>There is evidence of at least two intervals of widespread glaciation during the late Neoproterozoic (600-800 Myr ago), which are commonly referred to as "Snowball Earth" episodes. The global nature of these events is indicated by the fact that glacial deposits are found at low paleolatitudes during this time. Models of a global glacial event have produced a variety of solutions at low latitudes: thick <span class="hlt">ice</span>, thin <span class="hlt">ice</span>, slushball, and open ocean . The latter two models are similar, except that the slushball model has its <span class="hlt">ice</span>-line at higher latitudes. To be viable, a model has to be able to account for the survival of life through the glaciations and also explain the existence of <span class="hlt">cap</span> carbonates and other glacial debris deposited at low latitudes. The "thick-<span class="hlt">ice</span>" model is not viable because kilometers of <span class="hlt">ice</span> prevent the penetration of light necessary for the photosynthetic biota below. The "slushball" model is also not viable as it does not allow the formation of <span class="hlt">cap</span> carbonates. The "thin-<span class="hlt">ice</span>" model has been discussed previously and can account for continuation of photosynthetic life and glacial deposits at low paleolatitudes. The recently proposed "open-ocean" or "Jormungand" model also satisfies these requirements. What is it, though, that causes some models to produce thin <span class="hlt">ice</span> near the equator and others to have open water there? We examine this question using a zonally symmetric energy balance climate model (EBM) with flowing sea glaciers to determine what parameter ranges produce each type of solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010002409&hterms=water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D50%26Ntt%3Dwater','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010002409&hterms=water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D50%26Ntt%3Dwater"><span>The Contribution of Water <span class="hlt">Ice</span> Clouds to the Water Cycle in the North Polar Region of Mars: Preliminary Analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bass, D. S.; Tamppari, L. K.</p> <p>2000-01-01</p> <p>While it has long been known that Mars' north residual polar <span class="hlt">cap</span> and the Martian regolith are significant sources of atmospheric water vapor, the amount of water vapor observed in the northern spring season by the Viking Mars Atmospheric Water Detector instrument (MAWD) cannot be attributed to <span class="hlt">cap</span> and regolith sources alone. Kahn suggested that <span class="hlt">ice</span> hazes may be the mechanism by which additional water is supplied to the Martian atmosphere. Additionally, a significant decrease in atmospheric water vapor was observed in the late northern summer that could not be correlated with the return of the cold seasonal C02 <span class="hlt">ice</span>. While the detection of water <span class="hlt">ice</span> clouds on Mars indicate that water exists in Mars' atmosphere in several different phases, the extent to which water <span class="hlt">ice</span> clouds play a role in moving water through the Martian atmosphere remains uncertain. Work by Bass et. al. suggested that the time dependence of water <span class="hlt">ice</span> <span class="hlt">cap</span> seasonal variability and the increase in atmospheric water vapor depended on the polar <span class="hlt">cap</span> center reaching 200K, the night time saturation temperature. Additionally, they demonstrated that a decrease in atmospheric water vapor may be attributed to deposition of water <span class="hlt">ice</span> onto the surface of the polar <span class="hlt">cap</span>; temperatures were still too warm at this time in the summer for the deposition of carbon dioxide. However, whether water <span class="hlt">ice</span> clouds contribute significantly to this variability is unknown. Additional information is contained in original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008P%26SS...56..181B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008P%26SS...56..181B"><span>Albedo models for the residual south polar <span class="hlt">cap</span> on Mars: Implications for the stability of the <span class="hlt">cap</span> under near-perihelion global dust storm conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bonev, Boncho P.; Hansen, Gary B.; Glenar, David A.; James, Philip B.; Bjorkman, Jon E.</p> <p>2008-02-01</p> <p>It is uncertain whether the residual (perennial) south polar <span class="hlt">cap</span> on Mars is a transitory or a permanent feature in the current Martian climate. While there is no firm evidence for complete disappearance of the <span class="hlt">cap</span> in the past, clearly observable changes have been documented. Observations suggest that the perennial <span class="hlt">cap</span> lost more CO 2 material in the spring/summer season prior to the Mariner 9 mission than in those same seasons monitored by Viking and Mars Global Surveyor. In this paper we examine one process that may contribute to these changes - the radiative effects of a planet encircling dust storm that starts during late Martian southern spring on the stability of the perennial south polar <span class="hlt">cap</span>. To approach this, we model the radiative transfer through a dusty planetary atmosphere bounded by a sublimating CO 2 surface. A critical parameter for this modeling is the surface albedo spectrum from the near-UV to the thermal-IR, which was determined from both space-craft and Earth-based observations covering multiple wavelength regimes. Such a multi-wavelength approach is highly desirable since one spectral band by itself cannot tightly constrain the three-parameter space for polar surface albedo models, namely photon "scattering length" in the CO 2 <span class="hlt">ice</span> and the amounts of intermixed water and dust. Our results suggest that a planet-encircling dust storm with onset near solstice can affect the perennial <span class="hlt">cap</span>'s stability, leading to advanced sublimation in a "dusty" year. Since the total amount of solid CO 2 removed by a single storm may be less than the total CO 2 thickness, a series of dust storms would be required to remove the entire residual CO 2 <span class="hlt">ice</span> layer from the south perennial <span class="hlt">cap</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1814340V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1814340V"><span>Holocene record of glacier variability from lake sediments reveals tripartite climate history for <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van der Bilt, Willem; Bakke, Jostein; Vasskog, Kristian; D`Andrea, William; Bradley, Raymond; Olafsdottir, Sædis</p> <p>2016-04-01</p> <p> progressively lowered. The forcing behind these advances remains elusive, but their agreement with other glacier reconstructions from the region indicates a North Atlantic signature. Prolonged glacier activity commenced after 0.7 ka BP during the Little <span class="hlt">Ice</span> Age, in agreement with other evidence from <span class="hlt">Svalbard</span>. Comparatively high reconstructed temperatures during this timeframe suggest that glacier growth was precipitation-driven. Our findings highlight the sensitivity of small glaciers to climate shifts, demonstrating their potential to resolve centennial-scale perturbations. Moreover, this study underlines the value of lake sediments from glacier-fed lakes in understanding Holocene climate in the Arctic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28607400','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28607400"><span>Arctic sea <span class="hlt">ice</span> melt leads to atmospheric new particle formation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dall Osto, M; Beddows, D C S; Tunved, P; Krejci, R; Ström, J; Hansson, H-C; Yoon, Y J; Park, Ki-Tae; Becagli, S; Udisti, R; Onasch, T; O Dowd, C D; Simó, R; Harrison, Roy M</p> <p>2017-06-12</p> <p>Atmospheric new particle formation (NPF) and growth significantly influences climate by supplying new seeds for cloud condensation and brightness. Currently, there is a lack of understanding of whether and how marine biota emissions affect aerosol-cloud-climate interactions in the Arctic. Here, the aerosol population was categorised via cluster analysis of aerosol size distributions taken at Mt Zeppelin (<span class="hlt">Svalbard</span>) during a 11 year record. The daily temporal occurrence of NPF events likely caused by nucleation in the polar marine boundary layer was quantified annually as 18%, with a peak of 51% during summer months. Air mass trajectory analysis and atmospheric nitrogen and sulphur tracers link these frequent nucleation events to biogenic precursors released by open water and melting sea <span class="hlt">ice</span> regions. The occurrence of such events across a full decade was anti-correlated with sea <span class="hlt">ice</span> extent. New particles originating from open water and open pack <span class="hlt">ice</span> increased the cloud condensation nuclei concentration background by at least ca. 20%, supporting a marine biosphere-climate link through sea <span class="hlt">ice</span> melt and low altitude clouds that may have contributed to accelerate Arctic warming. Our results prompt a better representation of biogenic aerosol sources in Arctic climate models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12676595','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12676595"><span>Polychlorinated biphenyls and reproductive hormones in female polar bears at <span class="hlt">Svalbard</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Haave, Marte; Ropstad, Erik; Derocher, Andrew E; Lie, Elisabeth; Dahl, Ellen; Wiig, Øystein; Skaare, Janneche U; Jenssen, Bjørn Munro</p> <p>2003-04-01</p> <p>High concentrations of polychlorinated biphenyls (PCBs) in polar bears from <span class="hlt">Svalbard</span> have increased concern for that population's reproductive health. We examined whether there were associations between the plasma concentrations of PCBs and reproductive hormones [progesterone (P4)] and 17 beta-estradiol (E2)] in free-living female polar bears from <span class="hlt">Svalbard</span>. Concentrations of P4 depended on reproductive status, and concentrations were lowest in females with offspring--females with cubs and females with yearlings. In these females, the P4 concentrations were positively correlated with plasma sigma PCBs (sum of all analyzed polychlorinated biphenyl congeners) concentrations. The sigma PCBs concentrations explained 27% of the variation in the P4 concentrations. There were no correlations between sigma PCBs and E2 and cortisol in any of the groups of polar bears, or between sigma PCBs and P4 in single polar bears. Although the sigma PCBs-P4 relationship in female polar bears with offspring is not evidence per se of a direct cause-effect association, the results indicate that PCBs may affect levels of P4 in polar bear females. There is a clear need to further assess the hormone balance and population health of polar bears at <span class="hlt">Svalbard</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A13O..05S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A13O..05S"><span>Atmospheric Depositions of Natural and Anthropogenic Aerosols on the Guliya <span class="hlt">Ice</span> <span class="hlt">Cap</span> (Northwestern Tibetan Plateau) during the last 340 years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sierra Hernandez, R.; Gabrielli, P.; Beaudon, E.; Thompson, L. G.; Wegner, A.</p> <p>2017-12-01</p> <p>Anthropogenic emissions (e.g., greenhouse gases, trace elements (TE) including toxic metals) to the atmosphere have dramatically increased since the Industrial Revolution in the 19th century. High temperature processes such as fossil fuel combustion and pyrometallurgy generate fumes and fine particles (< 0.1µm - 10 µm) containing toxic metals (e.g., Cd, Zn, Pb) that if not captured by emission controls can be transported over long distances by air masses and subsequently deposited far from their emission sources. Atmospheric TE monitoring programs, along with emission inventories, have been conducted in recent decades. However, they lack pre-1900 information which is necessary to contextualize current atmospheric changes. Thus, it is necessary to use natural archives (e.g., <span class="hlt">ice</span> cores, lake sediments) to reconstruct atmospheric pollution trends. Glaciers and <span class="hlt">ice</span> sheets preserve atmospheric species that are deposited as snow accumulates over time, creating valuable records of past climatic/environmental conditions. Polar <span class="hlt">ice</span> cores have been used to obtain TE records. However, only a few non-polar <span class="hlt">ice</span> core records provide continuous information back to pre-industrial times. Thus, <span class="hlt">ice</span> core records of TEs from mid- and low-latitudes are needed to assess the spatial and temporal extent and levels of pollution in the environment. Here we present records of 29 TEs spanning the period 1650-1991 CE from the Guliya <span class="hlt">ice</span> <span class="hlt">cap</span> in the western Kunlun Mountains, northwest Tibetan Plateau to assess their natural and anthropogenic sources. The Guliya TEs records show two distinct periods with only crustal contributions prior to the 1850s and non-crustal contributions (Pb, Cd, Sb, Zn, Sn) after the 1850s. Enrichments of Pb, Cd, Sb, and Zn in Guliya between 1850 and 1950 can be attributed primarily to coal combustion emissions from western countries (Europe) while regional emissions (fossil fuel combustion, mining/smelting, fertilizers) from Central Asia, and probably from Kashgar in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11858273','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11858273"><span>Self-sustaining Mars colonies utilizing the North Polar <span class="hlt">Cap</span> and the Martian atmosphere.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Powell, J; Maise, G; Paniagua, J</p> <p>2001-01-01</p> <p>A revolutionary new concept for the early establishment of robust, self-sustaining Martian colonies is described. The colonies would be located on the North Polar <span class="hlt">Cap</span> of Mars and utilize readily available water <span class="hlt">ice</span> and the CO2 Martian atmosphere as raw materials to produce all of the propellants, fuel, air, water, plastics, food, and other supplies needed by the colony. The colonists would live in thermally insulated large, comfortable habitats under the <span class="hlt">ice</span> surface, fully shielded from cosmic rays. The habitats and supplies would be produced by a compact, lightweight (~4 metric tons) nuclear powered robotic unit termed ALPH (Atomic Liberation of Propellant and Habitat), which would land 2 years before the colonists arrived. Using a compact, lightweight 5 MW (th) nuclear reactor/steam turbine (1 MW(e)) power source and small process units (e.g., H2O electrolyzer, H2 and O2 liquefiers, methanator, plastic polymerizer, food producer, etc.) ALPH would stockpile many hundreds of tons of supplies in melt cavities under the <span class="hlt">ice</span>, plus insulated habitats, to be in place and ready for use when the colonists landed. With the stockpiled supplies, the colonists would construct and operate rovers and flyers to explore the surface of Mars. ALPH greatly reduces the amount of Earth supplied material needed and enables large permanent colonies on Mars. It also greatly reduces human and mission risks and vastly increases the capability not only for exploration of the surrounding Martian surface, but also the <span class="hlt">ice</span> <span class="hlt">cap</span> itself. The North Polar <span class="hlt">Cap</span> is at the center of the vast ancient ocean that covered much of the Martian Northern Hemisphere. Small, nuclear heated robotic probes would travel deep (1 km or more) inside the <span class="hlt">ice</span> <span class="hlt">cap</span>, collecting data on its internal structure, the composition and properties of the ancient Martian atmosphere, and possible evidence of ancient life forms (microfossils, traces of DNA, etc.) that were deposited either by wind or as remnants of the ancient ocean</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.P41A1913B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.P41A1913B"><span>Dust-Driven Halos on the Martian South Polar Residual <span class="hlt">CAP</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Becerra, P.; Byrne, S.; Brown, A. J.</p> <p>2013-12-01</p> <p>The CO2 <span class="hlt">ice</span> South Polar Residual <span class="hlt">Cap</span> (SPRC) on Mars may be a sensitive indicator of inter-annual planetary climate variability. Imaging by HiRISE [1], and CTX [2] found that many scarps and pits in the 'Swiss cheese terrain' [3] of the SPRC exhibited a bright 'halo' around their edges. These halos appeared during Martian southern summer in Mars Year 28 (MY28, [4]), and have been observed in only one of eight mars years for which observations at high enough resolution exist. We hypothesize that the formation of these features is linked to the late-summer global dust storm of MY28 and report on observations and formation models. We surveyed HiRISE, CTX, and CRISM [5] data to constrain the optical properties and composition of the halos, as well as their time of appearance and location within the SPRC. The halos appeared throughout most of the surface area of the SPRC between Ls 280° and 330° in MY28. The widest portions of the halos occurred adjacent to north-facing walls, and the brightest parts adjacent to sun-facing walls, which points to a connection between insolation and halo appearance. CRISM spectral products rule out the presence of water <span class="hlt">ice</span> as a factor in the halos' appearance. These data also imply larger CO2 <span class="hlt">ice</span> grain sizes where the bright halos were seen, which are normally associated with lower, rather than higher, albedos [6]. Thus, we also ruled out CO2 <span class="hlt">ice</span> grain size differences as the main cause for the halos. The remaining possibility is that the halos appeared due to differences in dust content between the terrain adjacent to the pit walls and the surrounding <span class="hlt">ice</span>. To investigate this we made a Hapke [7] surface reflectance model in which the CO2 <span class="hlt">ice</span> grain size, dust volumetric content and dust particle size were free parameters. We used the HiRISE and CRISM bandpass coefficients to simulate HiRISE I/F values and CRISM spectra, and attempted to match the HiRISE RED I/F, HiRISE BG/RED color ratio, and the CRISM 1.43 μm band depths. A self</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC23D1174G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC23D1174G"><span>The Role of Sea <span class="hlt">Ice</span> for Vascular Plant Dispersal in the Arctic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geirsdottir, A.; Alsos, I. G.; Seidenkrantz, M. S.; Bennike, O.; Kirchhefer, A.; Ehrich, D.</p> <p>2015-12-01</p> <p>Plant species adapted to arctic environments are expected to go extinct at their southern margins due to climate warming whereas they may find suitable habitats on arctic islands if they are able to disperse there. Analyses of species distribution and phylogenetic data indicate both that the frequency of dispersal events is higher in the arctic than in other regions, and that the dispersal routes often follow the routes of sea surface currents. Thus, it has been hypothesised that sea <span class="hlt">ice</span> has played a central role in Holocene colonisation of arctic islands. Here we compile data on the first Holocene occurrence of species in East Greenland, Iceland, the Faroe Islands, and <span class="hlt">Svalbard</span>. We then combine these records with interpretations of dispersal routes inferred from genetic data and data on geographical distributions, reconstructions of Holocene sea <span class="hlt">ice</span> extent, and records of driftwood to evaluate the potential role sea <span class="hlt">ice</span> has played in past colonisation events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.2986K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.2986K"><span>First continuous flow analysis results from the Greenland Re<span class="hlt">CAP</span> project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kjær, Helle Astrid</p> <p>2016-04-01</p> <p>The new Renland <span class="hlt">ice</span> core was drilled in summer 2015 in Greenland and measured by means of Continuous flow analysis during the last 3 months of 2015. The Renland <span class="hlt">ice</span> core was obtained as part of the Re<span class="hlt">CAP</span> project, extending 584.11 meters to the bottom of the Renland <span class="hlt">ice</span> <span class="hlt">cap</span> located in east Greenland. The unique position on a mountain saddle above 2000 meters altitude, but close to the coast, ensures that the Renland <span class="hlt">ice</span> core offers high accumulation, but also reaches far back in time. Preliminary results show that the record holds <span class="hlt">ice</span> from the past warm interglacial period, the Eemian. The record was analyzed for multiple elements including the forest fire tracers NH4+ and black carbon, insoluble dust particles by means of Abakus laser particle counter and the dust ion Ca2+, sea salt Na and acidity useful for finding volcanic layers to date the core. Further H2O2, and the nutrients Fe and dissolved reactive phosphorus was analyzed as well as the temperature indicator δ18O all by means of continuous flow analysis (CFA). The core was melted at a rate of 3 cm/min providing a temporal resolution for most components determined sufficient to resolve annual layers through the Holocene. The glacial section is strongly thinned, but nonetheless due to the high resolution of the measurements all DO events could be identified. Below the glacial section another ˜20 meters of warm Eemian <span class="hlt">ice</span> have been analysed. Here we present the first chemistry results as obtained by continuous flow analysis (CFA).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C13C0846P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C13C0846P"><span>3D Imaging and Automated <span class="hlt">Ice</span> Bottom Tracking of Canadian Arctic Archipelago <span class="hlt">Ice</span> Sounding Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Paden, J. D.; Xu, M.; Sprick, J.; Athinarapu, S.; Crandall, D.; Burgess, D. O.; Sharp, M. J.; Fox, G. C.; Leuschen, C.; Stumpf, T. M.</p> <p>2016-12-01</p> <p>The basal topography of the Canadian Arctic Archipelago <span class="hlt">ice</span> <span class="hlt">caps</span> is unknown for a number of the glaciers which drain the <span class="hlt">ice</span> <span class="hlt">caps</span>. The basal topography is needed for calculating present sea level contribution using the surface mass balance and discharge method and to understand future sea level contributions using <span class="hlt">ice</span> flow model studies. During the NASA Operation <span class="hlt">Ice</span>Bridge 2014 arctic campaign, the Multichannel Coherent Radar Depth Sounder (MCoRDS) used a three transmit beam setting (left beam, nadir beam, right beam) to illuminate a wide swath across the <span class="hlt">ice</span> glacier in a single pass during three flights over the archipelago. In post processing we have used a combination of 3D imaging methods to produce images for each of the three beams which are then merged to produce a single digitally formed wide swath beam. Because of the high volume of data produced by 3D imaging, manual tracking of the <span class="hlt">ice</span> bottom is impractical on a large scale. To solve this problem, we propose an automated technique for extracting <span class="hlt">ice</span> bottom surfaces by viewing the task as an inference problem on a probabilistic graphical model. We first estimate layer boundaries to generate a seed surface, and then incorporate additional sources of evidence, such as <span class="hlt">ice</span> masks, surface digital elevation models, and feedback from human users, to refine the surface in a discrete energy minimization formulation. We investigate the performance of the imaging and tracking algorithms using flight crossovers since crossing lines should produce consistent maps of the terrain beneath the <span class="hlt">ice</span> surface and compare manually tracked "ground truth" to the automated tracking algorithms. We found the swath width at the nominal flight altitude of 1000 m to be approximately 3 km. Since many of the glaciers in the archipelago are narrower than this, the radar imaging, in these instances, was able to measure the full glacier cavity in a single pass.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20074323','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20074323"><span>Bacterial diversity in faeces from polar bear (Ursus maritimus) in Arctic <span class="hlt">Svalbard</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Glad, Trine; Bernhardsen, Pål; Nielsen, Kaare M; Brusetti, Lorenzo; Andersen, Magnus; Aars, Jon; Sundset, Monica A</p> <p>2010-01-14</p> <p>Polar bears (Ursus maritimus) are major predators in the Arctic marine ecosystem, feeding mainly on seals, and living closely associated with sea <span class="hlt">ice</span>. Little is known of their gut microbial ecology and the main purpose of this study was to investigate the microbial diversity in faeces of polar bears in <span class="hlt">Svalbard</span>, Norway (74-81 degrees N, 10-33 degrees E). In addition the level of blaTEM alleles, encoding ampicillin resistance (ampr) were determined. In total, ten samples were collected from ten individual bears, rectum swabs from five individuals in 2004 and faeces samples from five individuals in 2006. A 16S rRNA gene clone library was constructed, and all sequences obtained from 161 clones showed affiliation with the phylum Firmicutes, with 160 sequences identified as Clostridiales and one sequence identified as unclassified Firmicutes. The majority of the sequences (70%) were affiliated with the genus Clostridium. Aerobic heterotrophic cell counts on chocolate agar ranged between 5.0 x 10(4) to 1.6 x 10(6) colony forming units (cfu)/ml for the rectum swabs and 4.0 x 10(3) to 1.0 x 10(5) cfu/g for the faeces samples. The proportion of ampr bacteria ranged from 0% to 44%. All of 144 randomly selected ampr isolates tested positive for enzymatic beta-lactamase activity. Three % of the ampr isolates from the rectal samples yielded positive results when screened for the presence of blaTEM genes by PCR. BlaTEM alleles were also detected by PCR in two out of three total faecal DNA samples from polar bears. The bacterial diversity in faeces from polar bears in their natural environment in <span class="hlt">Svalbard</span> is low compared to other animal species, with all obtained clones affiliating to Firmicutes. Furthermore, only low levels of blaTEM alleles were detected in contrast to their increasing prevalence in some clinical and commensal bacterial populations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2822771','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2822771"><span>Bacterial diversity in faeces from polar bear (Ursus maritimus) in Arctic <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2010-01-01</p> <p>Background Polar bears (Ursus maritimus) are major predators in the Arctic marine ecosystem, feeding mainly on seals, and living closely associated with sea <span class="hlt">ice</span>. Little is known of their gut microbial ecology and the main purpose of this study was to investigate the microbial diversity in faeces of polar bears in <span class="hlt">Svalbard</span>, Norway (74-81°N, 10-33°E). In addition the level of blaTEM alleles, encoding ampicillin resistance (ampr) were determined. In total, ten samples were collected from ten individual bears, rectum swabs from five individuals in 2004 and faeces samples from five individuals in 2006. Results A 16S rRNA gene clone library was constructed, and all sequences obtained from 161 clones showed affiliation with the phylum Firmicutes, with 160 sequences identified as Clostridiales and one sequence identified as unclassified Firmicutes. The majority of the sequences (70%) were affiliated with the genus Clostridium. Aerobic heterotrophic cell counts on chocolate agar ranged between 5.0 × 104 to 1.6 × 106 colony forming units (cfu)/ml for the rectum swabs and 4.0 × 103 to 1.0 × 105 cfu/g for the faeces samples. The proportion of ampr bacteria ranged from 0% to 44%. All of 144 randomly selected ampr isolates tested positive for enzymatic β-lactamase activity. Three % of the ampr isolates from the rectal samples yielded positive results when screened for the presence of blaTEM genes by PCR. BlaTEM alleles were also detected by PCR in two out of three total faecal DNA samples from polar bears. Conclusion The bacterial diversity in faeces from polar bears in their natural environment in <span class="hlt">Svalbard</span> is low compared to other animal species, with all obtained clones affiliating to Firmicutes. Furthermore, only low levels of blaTEM alleles were detected in contrast to their increasing prevalence in some clinical and commensal bacterial populations. PMID:20074323</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70022909','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70022909"><span>North-south geological differences between the residual polar <span class="hlt">caps</span> on Mars</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Thomas, P.C.; Malin, M.C.; Edgett, K.S.; Carr, M.H.; Hartmann, W.K.; Ingersoll, A.P.; James, P.B.; Soderblom, L.A.; Veverka, J.; Sullivan, R.</p> <p>2000-01-01</p> <p>Polar processes can be sensitive indicators of global climate, and the geological features associated with polar <span class="hlt">ice</span> <span class="hlt">caps</span> can therefore indicate evolution of climate with time. The polar regions on Mars have distinctive morphologic and climatologic features: thick layered deposits, seasonal CO2 frost <span class="hlt">caps</span> extending to mid latitudes, and near-polar residual frost deposits that survive the summer. The relationship of the seasonal and residual frost <span class="hlt">caps</span> to the layered deposits has been poorly constrained, mainly by the limited spatial resolution of the available data. In particular, it has not been known if the residual <span class="hlt">caps</span> represent simple thin frost cover or substantial geologic features. Here we show that the residual <span class="hlt">cap</span> on the south pole is a distinct geologic unit with striking collapse and erosional topography; this is very different from the residual <span class="hlt">cap</span> on the north pole, which grades into the underlying layered materials. These findings indicate that the differences between the <span class="hlt">caps</span> are substantial (rather than reflecting short-lived differences in frost cover), and so support the idea of long-term asymmetry in the polar climates of Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005Icar..174..535T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005Icar..174..535T"><span>South polar residual <span class="hlt">cap</span> of Mars: Features, stratigraphy, and changes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thomas, P. C.; Malin, M. C.; James, P. B.; Cantor, B. A.; Williams, R. M. E.; Gierasch, P.</p> <p>2005-04-01</p> <p>The south residual polar <span class="hlt">cap</span> of Mars, rich in CO 2 <span class="hlt">ice</span>, is compositionally distinct from the north residual <span class="hlt">cap</span> which is dominantly H 2O <span class="hlt">ice</span>. The south <span class="hlt">cap</span> is also morphologically distinct, displaying a bewildering variety of depressions formed in thin layered deposits, which have been observed to change by scarp retreat over an interval of one Mars year (Malin et al., 2001, Science 294, 2146-2148). The climatically sensitive locale of the residual <span class="hlt">caps</span> suggests that their behavior may help in the interpretation of recent fluctuations or repeatability of the Mars climate. We have used Mars Global Surveyor Mars Orbiter Camera (MOC) images obtained in three southern summers to map the variety of features in the south residual <span class="hlt">cap</span> and to evaluate changes over two Mars years (Mars y). The images show that there are two distinct layered units which were deposited at different times separated by a period of degradation. The older unit, ˜10 m thick, has layers approximately 2 m thick. The younger unit has variable numbers of layers, each ˜1 m thick. The older unit is eroding by scarp retreat averaging 3.6 m/Mars y, a rate greater than the retreat of 2.2 m/Mars y observed for the younger unit. The rates of scarp retreat and sizes of the different types of depressions indicate that the history of the residual <span class="hlt">cap</span> has been short periods of deposition interspersed with longer erosional periods. Erosion of the older unit probably occupied ˜100-150 Mars y. One layer may have been deposited after the Mariner 9 observations in 1972. Residual <span class="hlt">cap</span> layers appear to differ from normal annual winter deposits by having a higher albedo and perhaps by having higher porosities. These properties might be produced by differences in the depositional meteorology that affect the fraction of high porosity snow included in the winter deposition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPP43B2319S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPP43B2319S"><span>Interpreting the Holocene fluctuations of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span>, Peru: using a combination of glacial and non-glacial lake records</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stroup, J. S.; Kelly, M. A.; Lowell, T. V.; Smith, C.; Beal, S. A., Jr.; Tapia, P. M.</p> <p>2016-12-01</p> <p>The past fluctuations of Quelccaya <span class="hlt">Ice</span> <span class="hlt">Cap</span> (QIC) are an indicator of tropical paleoclimate. At QIC, <span class="hlt">ice</span> core and glacial geological records provide late Holocene climate constraints. However, early and middle Holocene QIC fluctuations are less well-known. To interpret past QIC fluctuations, we present Holocene-long lake sediment records from Challpacocha, a lake fed by QIC meltwater, and Yanacocha, a lake that has not received meltwater during the Holocene. To assess the clastic sediment delivered to Challpacocha by QIC meltwater, we compare visual stratigraphy, X-ray fluorescence chemistry, grainsize, loss on ignition and clastic flux records from both lakes (additional Yanacocha proxies are presented by Axford et al. (this meeting, abstract 157985)). We compare the meltwater derived clastic sediment record from Challpacocha with moraine and stratigraphic records of past <span class="hlt">ice</span> extents during the late Holocene. This comparison indicates that clastic sediment flux in Challpacocha increased during QIC recession and decreased during QIC advance, or significantly reduced QIC extent. We then use the Challpacocha clastic sediment record to interpret early and middle Holocene QIC fluctuations. Based on the Challpacocha sediment record, combined with prior work, we suggest that from 11 to 6.5 ka QIC was similar to or smaller than its late Holocene extent. From 6.9 to 6.5 ka QIC may have been absent from the landscape. At 3-2.4 and 0.62-0.31 ka QIC experienced the most extensive Holocene fluctuations. We compare the clastic sediment fluxes from Challpacocha and Pacococha (a nearby lake fed by QIC; Rodbell et al., 2008) to infer QIC expansion between 6.5-5 ka. This is supported by 14C ages of in-situ subfossil plants which indicate <span class="hlt">ice</span> advance at 6.3-4.7 ka (Thompson et al., 2006, 2013; Buffen et al., 2009). Our study highlights the value of using multiple datasets to improve lake sediment record interpretations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28605854','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28605854"><span>Central Tibetan Plateau atmospheric trace metals contamination: A 500-year record from the Puruogangri <span class="hlt">ice</span> core.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Beaudon, Emilie; Gabrielli, Paolo; Sierra-Hernández, M Roxana; Wegner, Anna; Thompson, Lonnie G</p> <p>2017-12-01</p> <p>A ~500-year section of <span class="hlt">ice</span> core (1497-1992) from the Puruogangri <span class="hlt">ice</span> <span class="hlt">cap</span> has been analyzed at high resolution for 28 trace elements (TEs: Ag, Al, As, Ba, Bi, Cd, Co, Cr, Cs, Cu, Fe, Ga, Li, Mg, Mn, Na, Nb, Ni, Pb, Rb, Sb, Sn, Sr, Ti, Tl, U, V and Zn) to assess different atmospheric contributions to the <span class="hlt">ice</span> and provide a temporal perspective on the diverse atmospheric influences over the central Tibetan Plateau (TP). At least two volcanic depositions have significantly impacted the central TP over the past 500years, possibly originating from the Billy Mitchell (1580, Papua New Guinea) and the Parker Peak (1641, Philippines) eruptions. A decreasing aeolian dust input to the <span class="hlt">ice</span> <span class="hlt">cap</span> allowed the detection of an atmospheric pollution signal. The anthropogenic pollution contribution emerges in the record since the early 1900s (for Sb and Cd) and increases substantially after 1935 (for Ag, Zn, Pb, Cd and Sb). The metallurgy (Zn, Pb and steel smelting) emission products (Cd, Zn, Pb and Ag) from the former Soviet Union and especially from central Asia (e.g., Kyrgyzstan, Kazakhstan) likely enhanced the anthropogenic deposition to the Puruogangri <span class="hlt">ice</span> <span class="hlt">cap</span> between 1935 and 1980, suggesting that the westerlies served as a conveyor of atmospheric pollution to central Tibet. The impact of this industrial pollution cumulated with that of the hemispheric coal and gasoline combustion which are respectively traced by Sb and Pb enrichment in the <span class="hlt">ice</span>. The Chinese steel production accompanying the Great Leap Forward (1958-1961) and the Chinese Cultural Revolution (1966-1976) is proposed as a secondary but proximal source of Pb pollution affecting the <span class="hlt">ice</span> <span class="hlt">cap</span> between 1958 and 1976. The most recent decade (1980-1992) of the enrichment time series suggests that Puruogangri <span class="hlt">ice</span> <span class="hlt">cap</span> recorded the early Sb, Cd, Zn, Pb and Ag pollution originating from developing countries of South (i.e., India) and East (i.e., China) Asia and transported by the summer monsoonal circulation. Published by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26582841','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26582841"><span>Predictions replaced by facts: a keystone species' behavioural responses to declining arctic sea-<span class="hlt">ice</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hamilton, Charmain D; Lydersen, Christian; Ims, Rolf A; Kovacs, Kit M</p> <p>2015-11-01</p> <p>Since the first documentation of climate-warming induced declines in arctic sea-<span class="hlt">ice</span>, predictions have been made regarding the expected negative consequences for endemic marine mammals. But, several decades later, little hard evidence exists regarding the responses of these animals to the ongoing environmental changes. Herein, we report the first empirical evidence of a dramatic shift in movement patterns and foraging behaviour of the arctic endemic ringed seal (Pusa hispida), before and after a major collapse in sea-<span class="hlt">ice</span> in <span class="hlt">Svalbard</span>, Norway. Among other changes to the <span class="hlt">ice</span>-regime, this collapse shifted the summer position of the marginal <span class="hlt">ice</span> zone from over the continental shelf, northward to the deep Arctic Ocean Basin. Following this change, which is thought to be a 'tipping point', subadult ringed seals swam greater distances, showed less area-restricted search behaviour, dived for longer periods, exhibited shorter surface intervals, rested less on sea-<span class="hlt">ice</span> and did less diving directly beneath the <span class="hlt">ice</span> during post-moulting foraging excursions. In combination, these behavioural changes suggest increased foraging effort and thus also likely increases in the energetic costs of finding food. Continued declines in sea-<span class="hlt">ice</span> are likely to result in distributional changes, range reductions and population declines in this keystone arctic species. © 2015 The Author(s).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA02373.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA02373.html"><span>Mars South Polar <span class="hlt">Cap</span> "Fingerprint" Terrain</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2000-04-24</p> <p>This picture is illuminated by sunlight from the upper left. Some portions of the martian south polar residual <span class="hlt">cap</span> have long, somewhat curved troughs instead of circular pits. These appear to form in a layer of material that may be different than that in which "swiss cheese" circles and pits form, and none of these features has any analog in the north polar <span class="hlt">cap</span> or elsewhere on Mars. This picture shows the "fingerprint" terrain as a series of long, narrow depressions considered to have formed by collapse and widening by sublimation of <span class="hlt">ice</span>. Unlike the north polar <span class="hlt">cap</span>, the south polar region stays cold enough in summer to retain frozen carbon dioxide. Viking Orbiter observations during the late 1970s showed that very little water vapor comes off the south polar <span class="hlt">cap</span> during summer, indicating that any frozen water that might be there remains solid throughout the year. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image was obtained in early southern spring on August 4, 1999. It shows an area 3 x 5 kilometers (1.9 x 3.1 miles) at a resolution of about 7.3 meters (24 ft) per pixel. Located near 86.0°S, 53.9°W. http://photojournal.jpl.nasa.gov/catalog/PIA02373</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007828','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007828"><span>Carbonate Cements from the Sverrefjell and Sigurdfjell Volcanoes, <span class="hlt">Svalbard</span> Norway: Analogs for Martian Carbonates</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Blake, D. F.; Treiman, A. H.; Morris, R.; Bish, D.; Amundsen, H.E.F.; Steele, A.</p> <p>2011-01-01</p> <p>The Sverrefjell and Sigurdfjell volcanic complexes erupted at 1Ma on <span class="hlt">Svalbard</span>, Norway. Sverrefjell is a cone of cinders, pillow lavas and dikes; Sigurdfjell is elongate in outcrop and may represent a fissure eruption [1]. The lavas of both volcanos were volatile rich. The volcanos erupted under <span class="hlt">ice</span> and were subsequently dissected by glaciation (glacial eratics are present on most of Sverrefjell, even on its summit). Eruption beneath an <span class="hlt">ice</span> sheet is inferred, based on the presence of pillow lavas from near sea level to 1000 m above sea level. Sverrefjell contains the largest fraction of ultramafic xenoliths of any volcanic complex in the world, in places accounting for as much as 50% of the volume of the outcrop. The Sverrefjell and Sigurdfell volcanos contain carbonate cements of several varieties: (1) Amundsen [2] reported Mg-Fe-rich carbonate in sub-mm globules in basalts and ultramafic xenoliths from the volcanos. These globules are the best terrestrial analogs to the carbonate globules in the Mars meteorite ALH84001 [3]. (2) Thick (1-3 cm) coatings of carbonate cement drape the walls of vertical volcanic pipes or conduits on the flanks and near the present summit of Sverrefjell. Similar occurrences are found on Sigurdfjell. (3) Breccia-filled pipes or vents occur on Sverrefjell and Siggurdfjell in which the breccia fragments are cemented by carbonate. The fragments themselves commonly contain carbonate globules similar to those found in the basalts and ultramafic xenoliths.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18096319','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18096319"><span>First isolate of Toxoplasma gondii from arctic fox (Vulpes lagopus) from <span class="hlt">Svalbard</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Prestrud, Kristin Wear; Dubey, J P; Asbakk, Kjetil; Fuglei, Eva; Su, C</p> <p>2008-02-14</p> <p>Cats are considered essential for the maintenance of Toxoplasma gondii in nature. However, T. gondii infection has been reported in arctic fox (Vulpes lagopus) from the <span class="hlt">Svalbard</span> high arctic archipelago where felids are virtually absent. To identify the potential source of T. gondii, we attempted to isolate and genetically characterize the parasite from arctic foxes in <span class="hlt">Svalbard</span>. Eleven foxes were trapped live in Grumant (78 degrees 11'N, 15 degrees 09'E), <span class="hlt">Svalbard</span>, in September 2005 and 2006. One of the foxes was found to be seropositive to T. gondii by the modified agglutination test (MAT). The fox was euthanized and its heart and brain were bioassayed in mice for the isolation of T. gondii. All 10 mice inoculated with brain tissue and one of the five inoculated with heart developed MAT antibodies, and tissue cysts were found in the brains of seropositive mice. Two cats fed tissues from infected mice shed T. gondii oocysts. Genotyping using 10 PCR-RFLP markers and DNA sequencing of gene loci BSR4, GRA6, UPRT1 and UPRT2 determined the isolate to be Type II strain, the predominant T. gondii lineage in the world.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A41H0154Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A41H0154Y"><span>10-Year Observations of Cloud and Surface Longwave Radiation at Ny-Ålesund, <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yeo, H.; Kim, S. W.; Kim, B. M.; Kim, J. H.; Shiobara, M.; Choi, T. J.; Son, S. W.; Kim, M. H.; Jeong, J. H.; Kim, S. J.</p> <p>2015-12-01</p> <p>Arctic clouds play a key role in surface radiation budget and may influence sea <span class="hlt">ice</span> and snow melting. In this study, 10-year (2004-2013) observations of cloud from Micro-Pulse Lidar (MPL) and surface longwave (LW) radiation at Ny-Ålesund, <span class="hlt">Svalbard</span> are analyzed to investigate cloud radiative effect. The cloud fraction (CF) derived from MPL shows distinct monthly variation, having higher CF (0.90) in summer and lower CF (0.79) in winter. Downward longwave radiation (DLW) during wintertime (Nov., Dec., Jan., and Feb.) decreases as cloud base height (CBH) increases. The DLW for CBH < 1km (264.7±35.4 W m-2) is approximately 1.46 times larger than that for cloud-free (181.8±25.8 W m-2) conditions. The temperature difference (ΔT) and DLW difference (ΔDLW), which are calculated as the difference of monthly mean temperature and DLW between all-sky and cloud-free conditions, are positively correlated (R2 = 0.83). This implies that an increase of DLW may influence surface warming, which can result in snow and sea <span class="hlt">ice</span> melting. However, dramatic changes in surface temperature, cloud and DLW are observed with a time scale of a few days. The averaged surface temperature on the presence of low-level clouds (CBH < 2km) and under cloud-free conditions are estimated to be -6.9±6.1°C and -14.5±5.7°C, respectively. The duration of low-level clouds, showing relatively high DLW and high surface temperature, is about 2.5 days. This suggests that DLW induced by low-level clouds may not have a critical effect on surface temperature rising and sea <span class="hlt">ice</span> melting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20171208_Archive_e001483.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20171208_Archive_e001483.html"><span>Glaciers and Sea Level Rise</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-12-08</p> <p>Summit camp on top of the Austfonna <span class="hlt">Ice</span> <span class="hlt">Cap</span> in <span class="hlt">Svalbard</span> (Norwegian Arctic). To learn about the contributions of glaciers to sea level rise, visit: www.nasa.gov/topics/earth/features/glacier-sea-rise.html Credit: Thorben Dunse, University of Oslo NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C33B0825F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C33B0825F"><span>Detecting Near-Surface <span class="hlt">Ice</span> Formation Over Time Using the Kennaugh Elements Approach From TerraSAR-X</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernandes, L.</p> <p>2016-12-01</p> <p>The summer melting has increased substantially at higher elevations on the Canadian Arctic <span class="hlt">ice</span> <span class="hlt">caps</span>. The resulting meltwater percolates into the upper layers of snow and firn and then refreeze, building massive <span class="hlt">ice</span> bodies. It seems likely that these within-firn <span class="hlt">ice</span> bodies now limit meltwater penetration into the firn and may be creating a feedback whereby the fraction of melt that runs off to the ocean is increasing. Although changes in firn structure as presence of <span class="hlt">ice</span> layers and <span class="hlt">ice</span> bodies are well documented over the Devon <span class="hlt">ice</span> <span class="hlt">cap</span>, the firm has shown that it exerts a crucial role to predict more accurately the contribution of small <span class="hlt">ice</span> <span class="hlt">caps</span> to the sea level rise. However it is still challenging to assess the extent of these features within the shallow subsurface using <span class="hlt">ice</span> cores and GPR (Ground Penetrating Radar) data collected along a limited number of linear transects. Studying changes in the distribution of <span class="hlt">ice</span> bodies' formation over time has the potential to provide information about how the growth of <span class="hlt">ice</span> bodies in the firn is affecting the pattern of water flow in the firn layer. The objective is investigate the potential of Kennaugh Elements (KE) derived from x-band SAR (Synthetic Aperture Radar) for mapping the distribution and growth of large <span class="hlt">ice</span> bodies within the firn and the evolution of their distribution over time. The evaluation of this method could reveal a new approach suitable for other glacierized regions that would reduce the costs and amount of field work for studying such properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMED11A0761P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMED11A0761P"><span>Modern Process Studies in Kongsfjord, <span class="hlt">Svalbard</span>: Arctic Geoscience Research Experience for U.S. Undergraduates (<span class="hlt">Svalbard</span> REU)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Powell, R. D.; Brigham-Grette, J.</p> <p>2011-12-01</p> <p>The <span class="hlt">Svalbard</span> REU (Research Experience for Undergraduates) program focuses on understanding how high latitude glaciers, meltwater streams, and sedimentation in lakes and fjords respond to changing climate. Since summer of 2004, six under-graduate students have been selected to participate in the summer field program. Students work on individual projects and in close conjunction with faculty advisors and other student researchers. They formulate their own research questions, develop their project, and complete their field research during a five-week program on <span class="hlt">Svalbard</span>, Norway. Following the summer program, students complete their projects at their home institution during the following academic year as a senior thesis. A spring symposium brings all participants back together again with their final results. The most recent field season was completed in Kongsfjord (79N) showing that the contemporary studies of tidewater glacier margins provide an unparalleled opportunity for introducing motivated third year undergraduate students to the challenges and rewards of polar geoscientific field research. Rates of rapid change in this high-latitude Arctic environment emphasize the complexity of the Earth System at the interface of the ocean, atmosphere and cryosphere. Given background information in glacial and marine geology, glaciology, hydrology, climatology and fjord oceanography not routinely offered in undergraduate curricula, students develop the science questions to be addressed and establish a field plan for instrumentation and sampling. Working together in small boats in one of the most challenging natural environments, the students expand their leadership skills, learn the value of teamwork and collaborative data sharing while maintaining a strong sense of ownership over their individual science projects. The rigors of studying an actively calving tidewater glacier also builds on their outdoor skills, especially when it is necessary to improvise and become</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930010623','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930010623"><span>Possible recent and ancient glacial <span class="hlt">ice</span> flow in the south polar region of Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kargel, J. S.</p> <p>1992-01-01</p> <p>Martian polar science began almost as soon as small telescopes were trained on the planet. The seasonal expansion and contraction of the polar <span class="hlt">caps</span> and their high albedoes led most astronomers to think that water <span class="hlt">ice</span> is the dominant constituent. In 1911 Lowell perceived a bluish band around the retreating edge of the polar <span class="hlt">caps</span>, and interpreted it as water from melting polar <span class="hlt">ice</span> and seasonal snow. An alternative idea in his time was that the polar <span class="hlt">caps</span> consist of frozen carbonic acid. Lowell rejected the carbonic acid hypothesis on account of his blue band. He also pointed out that carbonic acid would sublimate rather than melt at confining pressures near and below one bar, hence, carbonic acid could not account for the blue band. In comparing Lowell's theories with today's knowledge, it is recognized that (1) sublimation is mainly responsible for the growth and contraction of Mars' polar <span class="hlt">caps</span>, (2) carbon dioxide is a major component of the southern polar <span class="hlt">cap</span>, and (3) Lowell's blue band was probably seasonal dust and/or clouds. Geomorphic evidence that glacial <span class="hlt">ice</span> and glacial melt waters once flowed over broad areas of the southern polar region. Two aspects of the south polar region suggest possible glacial processes during two distinct eras in Mars' history.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70015972','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70015972"><span>Evidence against a late Wisconsinan <span class="hlt">ice</span> shelf in the Gulf of Maine</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Oldale, R.N.; Williams, R.S.; Colman, Steven M.</p> <p>1990-01-01</p> <p>Proposals for the formation of a late Wisconsinan <span class="hlt">ice</span> shelf in the Gulf of Maine during the retreat of the Laurentide <span class="hlt">Ice</span> Sheet are considered to be inappropriate. An Antarctic-type <span class="hlt">ice</span> shelf does not fit the field data that indicate temperate glacial, terrestrial, and marine climates for the region between 18 ka and 12 ka. A temperate <span class="hlt">ice</span> shelf has no modern analogues and may be physically impossible. The preponderance of stratified drift in the Gulf of Maine region supports temperate climates during late Wisconsinan time. It also indicates that glacial meltwater, rather than <span class="hlt">ice</span> in either an <span class="hlt">ice</span> sheet or <span class="hlt">ice</span> shelf, was the primary transport mechanism of glacial sediment and the source for the glaciomarine mud. For these reasons we have proposed glacial analogues for the deglaciation of the Gulf of Maine that consist of temperate or subpolar marine-based glaciers, characterized by depositional environments dominated by meltwater discharge directly to the sea or the sea by way of subaerial meltwater streams. These analogues include Alaskan fjord glaciers, glaciers on the Alaskan continental shelf that discharged meltwater directly into the sea in the not too distant past, and Austfonna (Nordaustandet, <span class="hlt">Svalbard</span>, Norway) that is presently discharging meltwater in the sea along a grounded <span class="hlt">ice</span> wall. This last example is the best modern-day analogue for the depositional environment for most of the glaciomarine mud in the Gulf of Maine and deglaciation of the Gulf. </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ISPAr41B8..481B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ISPAr41B8..481B"><span>Mass Balance Changes and <span class="hlt">Ice</span> Dynamics of Greenland and Antarctic <span class="hlt">Ice</span> Sheets from Laser Altimetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Babonis, G. S.; Csatho, B.; Schenk, T.</p> <p>2016-06-01</p> <p>During the past few decades the Greenland and Antarctic <span class="hlt">ice</span> sheets have lost <span class="hlt">ice</span> at accelerating rates, caused by increasing surface temperature. The melting of the two big <span class="hlt">ice</span> sheets has a big impact on global sea level rise. If the <span class="hlt">ice</span> sheets would melt down entirely, the sea level would rise more than 60 m. Even a much smaller rise would cause dramatic damage along coastal regions. In this paper we report about a major upgrade of surface elevation changes derived from laser altimetry data, acquired by NASA's <span class="hlt">Ice</span>, Cloud and land Elevation Satellite mission (ICESat) and airborne laser campaigns, such as Airborne Topographic Mapper (ATM) and Land, Vegetation and <span class="hlt">Ice</span> Sensor (LVIS). For detecting changes in <span class="hlt">ice</span> sheet elevations we have developed the Surface Elevation Reconstruction And Change detection (SERAC) method. It computes elevation changes of small surface patches by keeping the surface shape constant and considering the absolute values as surface elevations. We report about important upgrades of earlier results, for example the inclusion of local <span class="hlt">ice</span> <span class="hlt">caps</span> and the temporal extension from 1993 to 2014 for the Greenland <span class="hlt">Ice</span> Sheet and for a comprehensive reconstruction of <span class="hlt">ice</span> thickness and mass changes for the Antarctic <span class="hlt">Ice</span> Sheets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20090034380&hterms=europa+glacier&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Deuropa%2Bglacier','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20090034380&hterms=europa+glacier&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Deuropa%2Bglacier"><span>Life in <span class="hlt">Ice</span>: Implications to Astrobiology</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hoover, Richard B.</p> <p>2009-01-01</p> <p>During the 2008 Tawani International Expedition Schirmacher Oasis/Lake Untersee Antarctica Expedition, living and instantly motile bacteria were found in freshly thawed meltwater from <span class="hlt">ice</span> of the Schirmacher Oasis Lakes, the Anuchin Glacier <span class="hlt">ice</span> and samples of the that perennial <span class="hlt">ice</span> sheet above Lake Untersee. This phenomenon of living bacteria encased in <span class="hlt">ice</span> had previously been observed in the 32,000 year old <span class="hlt">ice</span> of the Fox Tunnel. The bacteria found in this <span class="hlt">ice</span> included the strain FTR1T which was isolated and published as valid new species (Carnobacterium pleistocenium) the first validly published living Pleistocene organism still alive today. Living bacteria were also extracted from ancient <span class="hlt">ice</span> cores from Vostok, Antarctica. The discovery that many strains of bacteria are able to survive and remain alive while frozen in <span class="hlt">ice</span> sheets for long periods of time may have direct relevance to Astrobiology. The abundance of viable bacteria in the <span class="hlt">ice</span> sheets of Antarctica suggests that the presence of live bacteria in <span class="hlt">ice</span> is common, rather than an isolated phenomenon. This paper will discuss the results of recent studies at NSSTC of bacteria cryopreserved in <span class="hlt">ice</span>. This paper advances the hypothesis that cryopreserved cells, and perhaps even viable bacterial cells, may exist today--frozen in the water-<span class="hlt">ice</span> of lunar craters, the Polar <span class="hlt">Caps</span> or craters of Mars; or in the permafrost of Mars; <span class="hlt">ice</span> and rocks of comets or water bearing asteroids; or in the frozen crusts of the icy moons of Jupiter and Saturn. The existence of bacterial life in <span class="hlt">ice</span> suggests that it may not be necessary to drill through a thick <span class="hlt">ice</span> crust to reach liquid water seas deep beneath the icy crusts of Europa, Ganymede and Enceladus. The presence of viable bacteria in the <span class="hlt">ice</span> of the Earth s Polar <span class="hlt">Caps</span> suggests that the possibility that cryo-panspermia (i.e., the trans-planetary transfer of microbial life by impact ejection/spallation of bacteria-rich polar <span class="hlt">ice</span> masses) deserves serious consideration and study as a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRC..122..669J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRC..122..669J"><span>Combined observations of Arctic sea <span class="hlt">ice</span> with near-coincident colocated X-band, C-band, and L-band SAR satellite remote sensing and helicopter-borne measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johansson, A. M.; King, J. A.; Doulgeris, A. P.; Gerland, S.; Singha, S.; Spreen, G.; Busche, T.</p> <p>2017-01-01</p> <p>In this study, we compare colocated near-coincident X-, C-, and L-band fully polarimetry SAR satellite images with helicopter-borne <span class="hlt">ice</span> thickness measurements acquired during the Norwegian Young sea <span class="hlt">ICE</span> 2015 (N-<span class="hlt">ICE</span>2015) expedition in the region of the Arctic Ocean north of <span class="hlt">Svalbard</span> in April 2015. The air-borne surveys provide near-coincident snow plus <span class="hlt">ice</span> thickness, surface roughness data, and photographs. This unique data set allows us to investigate how the different frequencies can complement one another for sea <span class="hlt">ice</span> studies, but also to raise awareness of limitations. X-band and L-band satellite scenes were shown to be a useful complement to the standard SAR frequency for sea <span class="hlt">ice</span> monitoring (C-band) for lead <span class="hlt">ice</span> and newly formed sea <span class="hlt">ice</span> identification. This may be in part be due to the frequency but also the high spatial resolution of these sensors. We found a relatively low correlation between snow plus <span class="hlt">ice</span> thickness and surface roughness. Therefore, in our dataset <span class="hlt">ice</span> thickness cannot directly be observed by SAR which has important implications for operational <span class="hlt">ice</span> charting based on automatic segmentation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6370K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6370K"><span>Freezing and hungry? Hydrocarbon degrading microbial communities in Barents Sea sediments around <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krueger, Martin; Straaten, Nontje</p> <p>2017-04-01</p> <p>The Polar Regions are characterised by varying temperatures and changing <span class="hlt">ice</span> coverage, so most of the primary production take place in the warmer season. Consequently, sedimentation rates and nutrient input are low. The diversity and metabolic potentials of the microbial communities inhabiting these sediments in the Northern Barents Sea are largely unknown. Recent reports on natural methane seeps as well as the increase in hydrocarbon exploration activities in the Arctic initiated our studies on the potential of indigenous microbial communities to degrade methane and higher hydrocarbons under in situ pressure and temperature conditions. Furthermore, the subseafloor geochemistry in these areas was studied, together with important microbial groups, like methanotrophs, methanogens, metal and sulfate reducers, which may drive seafloor ecosystems in the Northern Barents Sea. Sediment samples were collected in several areas around <span class="hlt">Svalbard</span> in the years 2013-2016 ranging from shallow (200m) areas on the <span class="hlt">Svalbard</span> shelf to deep sea areas on the eastern Yermak Plateau (3200m water depths). Shelf sediments showed the highest organic carbon content which decreased with increasing depths. Iron and manganese as potential electron acceptors were found in the porewater especially in the top 50 cm of the cores, while sulfate was always present in substantial amounts in porewater samples down to the end of the up to two metre long cores. Concentrations of dissolved methane and carbon dioxide were low. The potential of the indigenous microorganisms to degrade methane and higher hydrocarbons as well as different oils under in situ temperatures and pressures was widespread in surface sediments. Degradation rates were higher under aerobic than under anaerobic conditions, and decreased with increasing sediment as well as water depths. Similar pattern were found for other metabolic processes, including sulfate, Fe and Mn reduction as well as carbon dioxide and methane production rates</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26932187','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26932187"><span>Colonization of maritime glacier <span class="hlt">ice</span> by bdelloid Rotifera.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shain, Daniel H; Halldórsdóttir, Katrín; Pálsson, Finnur; Aðalgeirsdóttir, Guðfinna; Gunnarsson, Andri; Jónsson, Þorsteinn; Lang, Shirley A; Pálsson, Hlynur Skagfjörð; Steinþórssson, Sveinbjörn; Arnason, Einar</p> <p>2016-05-01</p> <p>Very few animal taxa are known to reside permanently in glacier <span class="hlt">ice</span>/snow. Here we report the widespread colonization of Icelandic glaciers and <span class="hlt">ice</span> fields by species of bdelloid Rotifera. Specimens were collected within the accumulation zones of Langjökull and Vatnajökull <span class="hlt">ice</span> <span class="hlt">caps</span>, among the largest European <span class="hlt">ice</span> masses. Rotifers reached densities up to ∼100 individuals per liter-equivalent of glacier <span class="hlt">ice</span>/snow, and were freeze-tolerant. Phylogenetic analyses indicate that glacier rotifers are polyphyletic, with independent ancestries occurring within the Pleistocene. Collectively, these data identify a previously undescribed environmental niche for bdelloid rotifers and suggest their presence in comparable habitats worldwide. Copyright © 2016 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.C21A0719B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.C21A0719B"><span>Freshwater fluxes into the subpolar North Atlantic from secular trends in Arctic land <span class="hlt">ice</span> mass balance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bamber, J. L.; Enderlin, E. M.; Howat, I. M.; Wouters, B.; van den Broeke, M.</p> <p>2015-12-01</p> <p>Freshwater fluxes (FWF) from river runoff and precipitation minus evaporation for the pan Arctic seas are relatively well documented and prescribed in ocean GCMs. Fluxes from Greenland and Arctic glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> on the other hand are generally ignored, despite their potential impacts on ocean circulation and marine biology and growing evidence for changes to the hydrography of parts of the subpolar North Atlantic. In a previous study we determined the FWF from Greenland for the period 1958-2010 using a combination of observations and regional climate modeling. Here, we update the analysis with data from new satellite observations to extend the record both in space and time. The new FWF estimates cover the period 1958-2014 and include the Canadian, Russian and Norwegian Arctic (<span class="hlt">Svalbard</span>) in addition to the contributions from Greenland. We combine satellite altimetry (including CryoSat 2) with grounding line flux data, regional climate modeling of surface mass balance and gravimetry to produce consistent estimates of solid <span class="hlt">ice</span> and liquid FWF into the Arctic and North Atlantic Oceans. The total cumulative FWF anomaly from land <span class="hlt">ice</span> mass loss started to increase significantly in the mid 1990s and now exceeds 5000 km^3, a value that is about half of the Great Salinity Anomaly of the 1970s. The majority of the anomaly is entering two key areas of deep water overturning in the Labrador and Irminger Seas, at a rate that has been increasing steadily over the last ~20 years. Since the mid 2000s, however, the Canadian Arctic archipelago has been making a significant contribution to the FW anomaly entering Baffin Bay. Tracer experiments with eddy-permitting ocean GCMs suggest that the FW input from southern Greenland and the Canadian Arctic should accumulate in Baffin Bay with the potential to affect geostrophic circulation, stratification in the region and possibly the strength of the Atlantic Meridional Overturning Circulation. We also examine the trajectory of</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70023682','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70023682"><span>Pleistocene reduction of polar <span class="hlt">ice</span> <span class="hlt">caps</span>: Evidence from Cariaco Basin marine sediments</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Poore, R.Z.; Dowsett, H.J.</p> <p>2001-01-01</p> <p>Sea level is projected to rise between 13 and 94 cm over the next 100 yr due to continued climate warming. The sea-level projections assume that polar <span class="hlt">ice</span> sheets will remain stable or even increase on time scales of centuries, but controversial geologic evidence suggests that current polar <span class="hlt">ice</span> sheets have been eliminated or greatly reduced during previous Pleistocene interglacials indicating that modern polar <span class="hlt">ice</span> sheets have become unstable within the natural range of interglacial climates. Sea level may have been more than 20 m higher than today during a presumably very warm interglacial about 400 ka during marine isotope stage 11. Because of the implications for future sea level rise, additional study of the conflicting evidence for warmer conditions and higher sea level during marine isotope stage 11 is needed. Here we present microfossil and isotopic data from marine sediments of the Cariaco Basin supporting the interpretation that global sea level was 10-20 m higher than today during marine isotope stage 11. The increased sea level requires reduction in modern polar <span class="hlt">ice</span> sheets and is consistent with the interpretation that the West Antarctic <span class="hlt">ice</span> sheet and the Greenland <span class="hlt">ice</span> sheet were absent or greatly reduced during marine isotope stage 11. Our results show a warm marine isotope stage 11 interglacial climate with sea level as high as or above modern sea level that lasted for 25 to 30 k.y. Variations in Earth's orbit around the sun (Milankovitch cycles) are considered to be a primary external force driving glacial-interglacial cycles. Current and marine isotope stage 11 Milankovitch forcing are very similar, suggesting that the present interglacial (Holocene) that began ca. 10 ka will continue for another 15 to 20 k.y. Therefore any anthropogenic climate warming will accelerate the natural process toward reduction in polar <span class="hlt">ice</span> sheets. The potential for increased rates of sea level rise related to polar <span class="hlt">ice</span> sheet decay should be considered as a potential natural</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100033799','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100033799"><span>Proposal for a Joint NASA/KSAT Ka-band RF Propagation Terminal at <span class="hlt">Svalbard</span>, Norway</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Volosin, Jeffrey; Acosta, Roberto; Nessel, James; McCarthy, Kevin; Caroglanian, Armen</p> <p>2010-01-01</p> <p>This slide presentation discusses the placement of a Ka-band RF Propagation Terminal at <span class="hlt">Svalbard</span>, Norway. The Near Earth Network (NEN) station would be managed by Kongsberg Satellite Services (KSAT) and would benefit NASA and KSAT. There are details of the proposed NASA/KSAT campaign, and the responsibilities each would agree to. There are several reasons for the placement, a primary reason is comparison with the Alaska site, Based on climatological similarities/differences with Alaska, <span class="hlt">Svalbard</span> site expected to have good radiometer/beacon agreement approximately 99% of time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008epsc.conf..540W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008epsc.conf..540W"><span>North-Polar Martian <span class="hlt">Cap</span> as Habitat for Elementary Life</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wallis, M. K.; Wickramasinghe, J. T.; Wickramasinghe, N. C.</p> <p>2008-09-01</p> <p>North-polar <span class="hlt">cap</span> over millenia Atmospheric water in Mars tends currently as for the past millenia to distil onto the polar <span class="hlt">caps</span> and be buried under dust deposits. Diffusive release from ground-<span class="hlt">ice</span> (and its excavation in meteorite impacts [1]) replenishes atmospheric water, allowing the gradual build up of polar <span class="hlt">ice</span>-dust deposits. When sunlit, this warmed and sublimating <span class="hlt">ice</span>-dust mix has interest as a potential habitat for micro-organisms. Modelling shows precipitable vapour at 10-50μm/yr, varying sensitively with small changes in orbitable obliquity around the present 25° [2]. The modelling applies to a globe with regionally uniform albedo, unlike the steep topography and dark layering of the north polar <span class="hlt">cap</span> whose upper 300m have accumulated over the last 500 kyr [3]. The cliffs and ravines of the north-polar <span class="hlt">cap</span> are thought to form through south-facing slopes sublimating and gaining a dirt-encrusted surface, while horizontal surfaces brighten through frost deposits. The two-phase surface derives from the dust and frost feedback on surface albedo [4] and the resulting terrain develops over diurnal cycles of frosting and sublimation, and over annual seasonal cycles. The steep south-facing sides of observed ravines when unshadowed would see for a few hours the full intensity of sunlight at near normal incidence, without the atmospheric dimming at similar inclinations on Earth. As exposed <span class="hlt">ice</span> sublimates at T > 200K (partial pressure exceeds typical martian 0.1 Pa), a crust of dirt develops to maintain quasi-stability. The dirt crust's main function is to buffer the <span class="hlt">ice</span> against diurnal temperature fluctuations, but it also slows down vapour diffusion - analogous to south polar <span class="hlt">ice</span> sublimation [5] and the growth of ground-<span class="hlt">ice</span> [6]. We envisage 1-10 mm/yr as the net sublimation rate, compatible with the 100 kyr life and scales of the north polar ravines. Modelling of icy-dirt crusts in the polar <span class="hlt">cap</span> Plane-parallel layers have been used to model the changing temperature</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA535295','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA535295"><span>Polar <span class="hlt">Cap</span> and Polar <span class="hlt">Cap</span> Boundary Phenomena</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2009-06-25</p> <p>of the high-latitude ionospheric plasma. Incoherent scatter radar and radio tomography measurements were used to directly observe the remnants of...On the relationship between thin Birkeland current arcs and reversed flow channels in the winter cusp/cleft ionosphere Moen J., Y. Rinne, H...current arcs in the winter cusp ionosphere above <span class="hlt">Svalbard</span>. An RFE is a longitudinally elongated, 100–200 km wide channel, in which the flow direction is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.C41A0692S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.C41A0692S"><span>A Newly Updated Database of Elevation-changes of the Greenand <span class="hlt">Ice</span> Sheet to Study Surface Processes and <span class="hlt">Ice</span> Dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schenk, A. F.; Csatho, B. M.; van den Broeke, M.; Kuipers Munneke, P.</p> <p>2015-12-01</p> <p>This paper reports about important upgrades of the Greenland <span class="hlt">Ice</span> Sheet (GrIS) surface elevation and elevation-change database obtained with our Surface Elevation And Change detection (SERAC) software suite. We have developed SERAC to derive information from laser altimetry data, particularly time series of elevation changes and their partitioning into changes caused by <span class="hlt">ice</span> dynamics. This allows direct investigation of <span class="hlt">ice</span> dynamic processes that is much needed for improving the predictive power of <span class="hlt">ice</span> sheet models. SERAC is different from most other change detection methods. It is based on detecting changes of surface patches, about 1 km by 1 km in size, rather than deriving elevation changes from individual laser points. The current database consists of ~100,000 time series with satellite laser altimetry data from ICESat, airborne laser observations obtained by NASA's Airborne Topographic Mapper (ATM) and the Land, Vegetation and <span class="hlt">Ice</span> Sensor (LVIS). The upgrade is significant, because not only new observations from 2013 and 2014 have been added but also a number of improvements lead to a more comprehensive and consistent record of elevation-changes. First, we used the model that gives in addition to <span class="hlt">ice</span> sheet also information about <span class="hlt">ice</span> <span class="hlt">caps</span> and glaciers (Rastner et al., 2012) for deciding if a laser point is on the <span class="hlt">ice</span> sheet or <span class="hlt">ice</span> <span class="hlt">cap</span>. Then we added small gaps that exist in the ICESat GLA12 data set because the <span class="hlt">ice</span> sheet mask is not wide enough. The new database is now more complete and will facilitate more accurate comparisons of mass balance studies obtained from the Gravity Recovery and Climate Experiment system (GRACE). For determining the part of a time series caused by <span class="hlt">ice</span> dynamics we used the new firn compaction model and Surface Mass Balance (SMB) estimates from RACMO2.3. The new database spans the time period from 1993 to 2014. Adding new observations amounts to a spatial densification of the old record and at the same time extends the time domain by two</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120000737','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120000737"><span>Ka-Band Site Characterization of the NASA Near Earth Network in <span class="hlt">Svalbard</span>, Norway</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Acosta, R.; Morse, J.; Nessel, J.; Zemba, M.; Tuttle, K.; Caroglanian, A.; Younes, B.; Pedersen, Sten-Chirstian</p> <p>2011-01-01</p> <p>Critical to NASA s rapid migration toward Ka-Band is the comprehensive characterization of the communication channels at NASA's ground sites to determine the effects of the atmosphere on signal propagation and the network's ability to support various classes of users in different orbits. Accordingly, NASA has initiated a number of studies involving the ground sites of its Near Earth and Deep Space Networks. Recently, NASA concluded a memorandum of agreement (MOA) with the Norwegian Space Centre of the Kingdom of Norway and began a joint site characterization study to determine the atmospheric effects on Ka-Band links at the <span class="hlt">Svalbard</span> Satellite Station in Norway, which remains a critical component of NASA s Near Earth Communication Network (NEN). System planning and design for Ka-band links at the <span class="hlt">Svalbard</span> site cannot be optimally achieved unless measured attenuation statistics (e.g. cumulative distribution functions (CDF)) are obtained. In general, the CDF will determine the necessary system margin and overall system availability due to the atmospheric effects. To statistically characterize the attenuation statistics at the <span class="hlt">Svalbard</span> site, NASA has constructed a ground-based monitoring station consisting of a multi-channel total power radiometer (25.5 - 26.5 GHz) and a weather monitoring station to continuously measure (at 1 second intervals) attenuation and excess noise (brightness temperature). These instruments have been tested in a laboratory environment as well as in an analogous outdoor climate (i.e. winter in Northeast Ohio), and the station was deployed in <span class="hlt">Svalbard</span>, Norway in May 2011. The measurement campaign is planned to last a minimum of 3 years but not exceeding a maximum of 5 years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMEP41D..07N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMEP41D..07N"><span>Boundary Waves on the <span class="hlt">Ice</span> Surface Created by Currents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Naito, K.; Izumi, N.; Yokokawa, M.; Yamada, T.; de Lima, A. C.</p> <p>2013-12-01</p> <p>The formation of periodic boundary waves, e.g. antidunes and cyclic steps (Parker & Izumi 2000) has been known to be caused by instabilities between flow and bed (e.g. Engelund 1970), and are observed not only on river beds or ocean floors but also on <span class="hlt">ice</span> surfaces, such as the surface of glaciers and underside of river <span class="hlt">ice</span> (Carey 1966). In addition, owing to recent advancements of remote sensing technology, it has been found that the surfaces of the polar <span class="hlt">ice</span> <span class="hlt">caps</span> on Mars as well as on the Earth have step-like formations (Smith & Holt 2010) which are assumed to be boundary waves, because they are generated perpendicularly to the direction of the currents. These currents acting on the polar <span class="hlt">ice</span> <span class="hlt">caps</span> are density airflow, i.e. katabatic wind (Howard et al 2000). The comprehension of the formation process of the Martian polar <span class="hlt">ice</span> <span class="hlt">caps</span> may reveal climate changes which have occurred on Mars. Although the formation of boundary waves on river beds or ocean floors has been studied by a number of researchers, there are few works on their formation on <span class="hlt">ice</span> surfaces. Yokokawa et al (2013) suggested that the temperature distribution of the ambient air, fluid and <span class="hlt">ice</span> is a factor which determines the direction of migration of boundary waves formed on <span class="hlt">ice</span> surfaces through their experiments. In this study, we propose a mathematical model in order to describe the formation process of the boundary waves and the direction of their migration. We consider that a liquid is flowing through a flume filled with a flat <span class="hlt">ice</span> layer on the bottom. The flow is assumed to be turbulent and its temperature is assumed to merge with the ambient temperature at the flow surface and with the melting point of <span class="hlt">ice</span> at the bottom (<span class="hlt">ice</span> surface). The <span class="hlt">ice</span> surface evolution is dependent on the unbalance between the interfacial heat flux of the liquid and <span class="hlt">ice</span>, and we employ the Reynolds-averaged Navier-Stokes equation, the continuity equation, heat transfer equations for the liquid and <span class="hlt">ice</span>, and a heat balance</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70027417','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70027417"><span>Thermal infrared and visual observations of a water <span class="hlt">ice</span> lag in the Mars southern summer</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Titus, T.N.</p> <p>2005-01-01</p> <p>We present thermal infrared and visual evidence for the existence of water <span class="hlt">ice</span> lags in the early southern summer. The observed H2O-<span class="hlt">ice</span> lags lay in and near a chasma and appears to survive between 6-8 sols past the sublimation of the CO2. Possible sources of the H2O that compose the lag are (1) atmospheric H2O that is incorporated into the seasonal <span class="hlt">cap</span> during condensation, (2) cold trapping of atmospheric water vapor onto the surface of the <span class="hlt">cap</span> in the spring, or (3) a combination of the 2 processes where water is released from the sublimating <span class="hlt">cap</span> only to be transported back over the <span class="hlt">cap</span> edge and cold trapped. We refer to this later process as the "Houben" effect which may enrich the amount of water contained in the seasonal <span class="hlt">cap</span> at 85??S by as much as a factor of 15. This phenomenon, which has already been identified for the northern retreating <span class="hlt">cap</span>, may present an important water transport mechanism in the Southern Hemisphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ERL....12h4011A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ERL....12h4011A"><span>Warming in the Nordic Seas, North Atlantic storms and thinning Arctic sea <span class="hlt">ice</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alexeev, Vladimir A.; Walsh, John E.; Ivanov, Vladimir V.; Semenov, Vladimir A.; Smirnov, Alexander V.</p> <p>2017-08-01</p> <p>Arctic sea <span class="hlt">ice</span> over the last few decades has experienced a significant decline in coverage both in summer and winter. The currently warming Atlantic Water layer has a pronounced impact on sea <span class="hlt">ice</span> in the Nordic Seas (including the Barents Sea). More open water combined with the prevailing atmospheric pattern of airflow from the southeast, and persistent North Atlantic storms such as the recent extremely strong Storm Frank in December 2015, lead to increased energy transport to the high Arctic. Each of these storms brings sizeable anomalies of heat to the high Arctic, resulting in significant warming and slowing down of sea <span class="hlt">ice</span> growth or even melting. Our analysis indicates that the recently observed sea <span class="hlt">ice</span> decline in the Nordic Seas during the cold season around <span class="hlt">Svalbard</span>, Franz Joseph Land and Novaya Zemlya, and the associated heat release from open water into the atmosphere, contributed significantly to the increase in the downward longwave radiation throughout the entire Arctic. Added to other changes in the surface energy budget, this increase since the 1960s to the present is estimated to be at least 10 W m-2, which can result in thinner (up to at least 15-20 cm) Arctic <span class="hlt">ice</span> at the end of the winter. This change in the surface budget is an important contributing factor accelerating the thinning of Arctic sea <span class="hlt">ice</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.C21D..04F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.C21D..04F"><span>Airborne surveys in the Arctic and Antarctic for geophysics, sea-<span class="hlt">ice</span> thickness, and CryoSat validation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Forsberg, R.; Olesen, A. V.; Hvidegaard, S.; Skourup, H.</p> <p>2010-12-01</p> <p>Airborne laser and radar measurements over the Greenland <span class="hlt">ice</span> sheet, <span class="hlt">Svalbard</span>, and adjacent parts of the Arctic Ocean have been carried out by DTU-Space in a number of recent Danish/Greenlandic and European project campaigns, with the purpose to monitor <span class="hlt">ice</span> sheet and sea-<span class="hlt">ice</span> changes, support of Greenland societal needs (oil exploration and hydropower), and support of CryoSat pre-launch calibration and validation campaigns. The Arctic campaigns have been done using a Twin-Otter aircraft, carrying laser scanners and various radars. Since 2009 a new program of long-range gravity and magnetic surveys have been initiated using a Basler DC3 aircraft for large-scale surveys in the Arctic Ocean and Antarctica, with the 2010 cooperative Danish-Argentinean-Chilean-US ICEGRAV survey of the Antarctic Peninsula additionally including a UTIG 60 MHz <span class="hlt">ice</span>-penetrating radar. In the paper we outline the recent and upcoming airborne survey activities, outline the usefulness of the airborne data for satellite validation (CryoSat and GOCE), and give examples of measurements and comparisons to satellite and in-situ data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C32B..03N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C32B..03N"><span>Seasonality of light transmittance through Arctic sea <span class="hlt">ice</span> during spring and summe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nicolaus, M.; Hudson, S. R.; Granskog, M. A.; Pavlov, A.; Taskjelle, T.; Kauko, H.; Katlein, C.; Geland, S.; Perovich, D. K.</p> <p>2017-12-01</p> <p>The energy budget of sea <span class="hlt">ice</span> and the upper ocean during spring, summer, and autumn is strongly affected by the transfer of solar shortwave radiation through sea <span class="hlt">ice</span> and into the upper ocean. Previous studies highlighted the great importance of the spring-summer transition, when incoming fluxes are highest and even small changes in surface albedo and transmittance have strong impacts on the annual budgets. The timing of melt onset and changes in snow and <span class="hlt">ice</span> conditions are also crucial for primary productivity and biogeochemical processes. Here we present results from time series measurements of radiation fluxes through seasonal Arctic sea <span class="hlt">ice</span>, as it may be expected to play a key role in the future Arctic. Our observations were performed during the Norwegian N-<span class="hlt">ICE</span> drift experiment in 2015 and the Polarstern expedition PS106 in 2017, both studying sea <span class="hlt">ice</span> north of <span class="hlt">Svalbard</span>. Autonomous stations were installed to monitor spectral radiation fluxes above and under sea <span class="hlt">ice</span>. The observation periods cover the spring-summer transition, including snow melt and early melt pond formation. The results show the direct relation of optical properties to under <span class="hlt">ice</span> algae blooms and their influence on the energy budget. Beyond these results, we will discuss the latest plans and implementation of radiation measurements during the MOSAiC drift in 2019/2020. Then, a full annual cycle of radiation fluxes may be studied from manned and autonomous (buoys) measurements as well as using a remotely operated vehicle (ROV) as measurement platform. These measurements will be performed in direct relation with numerical simulations on different scales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRC..123.1123K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRC..123.1123K"><span>Comparison of Freeboard Retrieval and <span class="hlt">Ice</span> Thickness Calculation From ALS, ASIRAS, and CryoSat-2 in the Norwegian Arctic to Field Measurements Made During the N-<span class="hlt">ICE</span>2015 Expedition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>King, Jennifer; Skourup, Henriette; Hvidegaard, Sine M.; Rösel, Anja; Gerland, Sebastian; Spreen, Gunnar; Polashenski, Chris; Helm, Veit; Liston, Glen E.</p> <p>2018-02-01</p> <p>We present freeboard measurements from airborne laser scanner (ALS), the Airborne Synthetic Aperture and Interferometric Radar Altimeter System (ASIRAS), and CryoSat-2 SIRAL radar altimeter; <span class="hlt">ice</span> thickness measurements from both helicopter-borne and ground-based electromagnetic-sounding; and point measurements of <span class="hlt">ice</span> properties. This case study was carried out in April 2015 during the N-<span class="hlt">ICE</span>2015 expedition in the area of the Arctic Ocean north of <span class="hlt">Svalbard</span>. The region is represented by deep snow up to 1.12 m and a widespread presence of negative freeboards. The main scattering surfaces from both CryoSat-2 and ASIRAS are shown to be closer to the snow freeboard obtained by ALS than to the <span class="hlt">ice</span> freeboard measured in situ. This case study documents the complexity of freeboard retrievals from radar altimetry. We show that even under cold (below -15°C) conditions the radar freeboard can be close to the snow freeboard on a regional scale of tens of kilometers. We derived a modal sea-<span class="hlt">ice</span> thickness for the study region from CryoSat-2 of 3.9 m compared to measured total thickness 1.7 m, resulting in an overestimation of sea-<span class="hlt">ice</span> thickness on the order of a factor 2. Our results also highlight the importance of year-to-year regional scale information about the depth and density of the snowpack, as this influences the sea-<span class="hlt">ice</span> freeboard, the radar penetration, and is a key component of the hydrostatic balance equations used to convert radar freeboard to sea-<span class="hlt">ice</span> thickness.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040085625','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040085625"><span>Constraints on the Within Season and Between Year Variability of the North Residual <span class="hlt">Cap</span> from MGS-TES</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Calvin, W. M.; Titus, T. N.; Mahoney, S. A.</p> <p>2003-01-01</p> <p>There is a long history of telescopic and spacecraft observations of the polar regions of Mars. The finely laminated <span class="hlt">ice</span> deposits and surrounding layered terrains are commonly thought to contain a record of past climate conditions and change. Understanding the basic nature of the deposits and their mineral and <span class="hlt">ice</span> constituents is a continued focus of current and future orbited missions. Unresolved issues in Martian polar science include a) the unusual nature of the CO2 <span class="hlt">ice</span> deposits ("Swiss Cheese", "slab <span class="hlt">ice</span>" etc.) b) the relationship of the <span class="hlt">ice</span> deposits to underlying layered units (which differs from the north to the south), c) understanding the seasonal variations and their connections to the finely laminated units observed in high-resolution images and d) the relationship of dark materials in the wind-swept lanes and reentrant valleys to the surrounding dark dune and surface materials. Our work focuses on understanding these issues in relationship to the north residual <span class="hlt">ice</span> <span class="hlt">cap</span>. Recent work using Mars Global Surveyor (MGS) data sets have described evolution of the seasonal CO2 frost deposits. In addition, the north polar residual <span class="hlt">ice</span> <span class="hlt">cap</span> exhibits albedo variations between Mars years and within the summer season. The Thermal Emission Spectrometer (TES) data set can augment these observations providing additional constraints such as temperature evolution and spectral properties associated with <span class="hlt">ice</span> and rocky materials. Exploration of these properties is the subject of our current study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA21022.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA21022.html"><span>North Polar <span class="hlt">Cap</span> Layers and Ledges</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2016-08-24</p> <p>At the edge of Mars' permanent North Polar <span class="hlt">cap</span>, we see an exposure of the internal layers, each with a different mix of water <span class="hlt">ice</span>, dust and dirt. These layers are believed to correspond to different climate conditions over the past tens of thousands of years. When we zoom in closer, we see that the distinct layers erode differently. Some are stronger and more resistant to erosion, others only weakly cemented. The strong layers form ledges. http://photojournal.jpl.nasa.gov/catalog/PIA21022</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018TCry...12.1563G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018TCry...12.1563G"><span>Simulating the roles of crevasse routing of surface water and basal friction on the surge evolution of Basin 3, Austfonna <span class="hlt">ice</span> <span class="hlt">cap</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gong, Yongmei; Zwinger, Thomas; Åström, Jan; Altena, Bas; Schellenberger, Thomas; Gladstone, Rupert; Moore, John C.</p> <p>2018-05-01</p> <p>The marine-terminating outlet in Basin 3, Austfonna <span class="hlt">ice</span> <span class="hlt">cap</span>, has been accelerating since the mid-1990s. Stepwise multi-annual acceleration associated with seasonal summer speed-up events was observed before the outlet entered the basin-wide surge in autumn 2012. We used multiple numerical models to explore hydrologic activation mechanisms for the surge behaviour. A continuum <span class="hlt">ice</span> dynamic model was used to invert basal friction coefficient distributions using the control method and observed surface velocity data between April 2012 and July 2014. This has provided input to a discrete element model capable of simulating individual crevasses, with the aim of finding locations where meltwater entered the glacier during the summer and reached the bed. The possible flow paths of surface meltwater reaching the glacier bed as well as those of meltwater produced at the bed were calculated according to the gradient of the hydraulic potential. The inverted friction coefficients show the <q>unplugging</q> of the stagnant <span class="hlt">ice</span> front and expansion of low-friction regions before the surge reached its peak velocity in January 2013. Crevasse distribution reflects the basal friction pattern to a high degree. The meltwater reaches the bed through the crevasses located above the margins of the subglacial valley and the basal melt that is generated mainly by frictional heating flows either to the fast-flowing units or potentially accumulates in an overdeepened region. Based on these results, the mechanisms facilitated by basal meltwater production, crevasse opening and the routing of meltwater to the bed are discussed for the surge in Basin 3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22465539','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22465539"><span>Echinococcus multilocularis in <span class="hlt">Svalbard</span>, Norway: microsatellite genotyping to investigate the origin of a highly focal contamination.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Knapp, J; Staebler, S; Bart, J M; Stien, A; Yoccoz, N G; Drögemüller, C; Gottstein, B; Deplazes, P</p> <p>2012-08-01</p> <p>Echinococcus multilocularis is a threatening cestode involved in the human alveolar echinococcosis. The parasite, mainly described in temperate regions of the Northern hemisphere was described for the first time in 1999 in the High Arctic <span class="hlt">Svalbard</span> archipelago, Norway. The origin of this contamination could be due to an anthropogenic introduction from mainland Europe by domestic dogs or with the introduction of the sibling vole, perhaps from mainland Russia (St. Petersburg area), or with roaming Arctic foxes, known as the main definitive host of the parasite in Arctic regions. The genetic diversity of E. multilocularis in <span class="hlt">Svalbard</span> was investigated here for the first time by genotyping using EmsB microsatellite and compared to other genotyped populations in the main worldwide endemic areas. We found low polymorphism amongst the 27 metacestode isolates from sibling voles trapped in the core of the distribution area of the vole on <span class="hlt">Svalbard</span>. E. mutilocularis Arctic populations, using the Arctic fox as the definitive host, were genetically separated from European temperate populations that use the red fox, but closely related to St. Lawrence Island samples from Alaska. The result is inconsistent with the hypothesis of an anthropogenic introduction from mainland Europe, but can be seen as consistent with the hypothesis that Arctic foxes introduced E. multilocularis to <span class="hlt">Svalbard</span>. Copyright © 2012 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Icar..251..164P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Icar..251..164P"><span>Variability of the martian seasonal CO2 <span class="hlt">cap</span> extent over eight Mars Years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piqueux, Sylvain; Kleinböhl, Armin; Hayne, Paul O.; Kass, David M.; Schofield, John T.; McCleese, Daniel J.</p> <p>2015-05-01</p> <p>We present eight Mars Years of nearly continuous tracking of the CO2 seasonal <span class="hlt">cap</span> edges from Mars Year (MY) 24 to 31 using Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) and Mars Reconnaissance Orbiter (MRO) Mars Climate Sounder (MCS) thermal infrared data. Spatial and temporal resolutions are 1 pixel per degree and 10°Ls (aerocentric longitude of the Sun). The seasonal <span class="hlt">caps</span> are defined as the regions where the diurnal radiometric temperature variations at ∼32 μm wavelength do not exceed 5 K. With this definition, terrains with small areal fraction of defrosted regolith able to experience measurable diurnal temperature cycles are not mapped as part of the <span class="hlt">cap</span>. This technique is adequate to distinguish CO2 from H2O <span class="hlt">ices</span>, and effective during the polar night or under low illumination conditions. The present analysis answers outstanding questions stemming from fragmented observations at visible wavelengths: (1) the previously sparsely documented growth of the North seasonal <span class="hlt">caps</span> (160° < Ls < 270°) is shown to be repeatable within 1-2° equivalent latitude, and monotonic over the MY 24-31 time period; high repeatability is observed during the retreat of the <span class="hlt">caps</span> in non-dusty years (∼1° or less equivalent latitude); (2) the MY 25 storm does not seem to have impacted the growth rate, maximal extents, or recession rate of the North seasonal <span class="hlt">caps</span>, whereas the MY 28 dust storm clearly sped up the recession of the <span class="hlt">cap</span> (∼2° smaller on average after the storm, during the recession, compared to other years); (3) during non-dusty years, the growth of the South seasonal <span class="hlt">cap</span> (350° < Ls < 100°) presents noticeable variability (up to ∼4° equivalent latitude near Ls = 20°) with a maximum extent reached near Ls = 90°; (4) the retreat of the Southern seasonal <span class="hlt">cap</span> (100° < Ls < 310°) exhibits large inter-annual variability, especially near 190° < Ls < 220°; (5) the recession of the MY 25 South seasonal <span class="hlt">cap</span> is significantly accelerated during the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008DSRII..55.2225S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008DSRII..55.2225S"><span>Seasonal feeding strategies of Calanus in the high-Arctic <span class="hlt">Svalbard</span> region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Søreide, Janne E.; Falk-Petersen, Stig; Hegseth, Else Nøst; Hop, Haakon; Carroll, Michael L.; Hobson, Keith A.; Blachowiak-Samolyk, Katarzyna</p> <p>2008-10-01</p> <p>The feeding strategies of Calanus hyperboreus, C. glacialis, and C. finmarchicus were investigated in the high-Arctic <span class="hlt">Svalbard</span> region (77-81 °N) in May, August, and December, including seasons with algal blooms, late- to post-bloom situations, and unproductive winter periods. Stable isotope and fatty acid trophic marker (FATM) techniques were employed together to assess trophic level (TL), carbon sources (phytoplankton vs. <span class="hlt">ice</span> algae), and diet of the three Calanus species. In addition, population development, distribution, and nutritional state (i.e. storage lipids) were examined to estimate their population status at the time of sampling. In May and August, the vertical distribution of the three Calanus species usually coincided with the maximum algal biomass. Their stable isotope and fatty acid (FA) composition indicated that they all were essentially herbivores in May, when the algal biomass was highest. Their FA composition, however, revealed different food preferences. C. hyperboreus had high proportions of 18:4n3, suggesting that it fed mainly on Phaeocystis, whereas C. glacialis and C. finmarchicus had high proportions of 16:4n1, 16:1n7, and 20:5n3, suggesting diatoms as their major food source. Carbon sources (i.e. phytoplankton vs. <span class="hlt">ice</span> algae) were not possible to determine solely from FATM techniques since <span class="hlt">ice</span>-diatoms and pelagic-diatoms were characterised by the same FA. However, the enriched δ13C values of C. glacialis and C. finmarchicus in May indicated that they fed both on pelagic- and <span class="hlt">ice</span>-diatoms. Patterns in absolute FA and fatty alcohol composition revealed that diatoms were the most important food for C. hyperboreus and C. glacialis, followed by Phaeocystis, whereas diatoms, Phaeocystis and other small autotrophic flagellates were equally important food for C. finmarchicus. During periods of lower algal biomass, only C. glacialis exhibited evidence of significant dietary switch, with a TL indicative of omnivory (mean TL=2.4). Large spatial</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C31C0322H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C31C0322H"><span>Sedimentation Waves on the Martian North Polar <span class="hlt">Cap</span>: Analogy with Megadunes in Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Herny, C.; Masse, M.; Bourgeois, O.; Carpy, S.; Le Mouelic, S.; Appéré, T.; Smith, I. B.; Spiga, A.; Perret, L.; Rodriguez, S.; Piquet, T.; Gaudin, D.; Le Menn, E.</p> <p>2014-12-01</p> <p>Complex feedbacks between katabatic winds and the cryosphere may lead to the development of sedimentation waves at the surface of <span class="hlt">ice</span> sheets. These have been first described and named megadunes in Antarctica. Here we use topographic data, optical images, spectroscopic data and radar soundings, acquired by Mars orbiters, to show that the surface of the Martian North Polar <span class="hlt">Cap</span> displays two superimposed sets of sedimentation waves with differing wavelengths. These sedimentation waves grow and migrate upwind in response to the development of periodic accumulation/ablation patterns controlled by katabatic winds. They have similarities with Antarctic megadunes regarding their surface morphology, texture, grain size, and internal stratigraphic architecture. Based on this analogy, we are currently developing a model of <span class="hlt">ice</span>/wind interaction at the surface of <span class="hlt">ice</span> sheets. In Antarctica the accumulation processes on megadunes fields is generally attributed to the wind-blown snow transport while on sedimentation waves of the North Polar <span class="hlt">Cap</span> of Mars the accumulation seems to be dominated by sublimation/condensation processes at the surface. The model is designed to explore the implication of the water vapor mass transfer and heat transfer on the development of sedimentation waves both on Mars and Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRC..122.9332K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRC..122.9332K"><span>The Yermak Pass Branch: A Major Pathway for the Atlantic Water North of <span class="hlt">Svalbard</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koenig, Zoé; Provost, Christine; Sennéchael, Nathalie; Garric, Gilles; Gascard, Jean-Claude</p> <p>2017-12-01</p> <p>An upward-looking Acoustic Doppler Current Profiler deployed from July 2007 to September 2008 in the Yermak Pass, north of <span class="hlt">Svalbard</span>, gathered velocity data from 570 m up to 90 m at a location covered by sea <span class="hlt">ice</span> 10 months out of 12. Barotropic diurnal and semidiurnal tides are the dominant signals in the velocity (more than 70% of the velocity variance). In winter, baroclinic eddies at periods between 5 and 15 days and pulses of 1-2 month periodicity are observed in the Atlantic Water layer and are associated with a shoaling of the pycnocline. Mercator-Ocean global operational model with daily and 1/12° spatial resolution is shown to have skills in representing low-frequency velocity variations (>1 month) in the West Spitsbergen Current and in the Yermak Pass. Model outputs suggest that the Yermak Pass Branch has had a robust winter pattern over the last 10 years, carrying on average 31% of the Atlantic Water volume transport of the West Spitsbergen Current (36% in autumn/winter). However, those figures have to be considered with caution as the model neither simulates tides nor fully resolves eddies and ignores residual mean currents that could be significant.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.V12B..01G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.V12B..01G"><span><span class="hlt">Ice</span> Thickness, Melting Rates and Styles of Activity in <span class="hlt">Ice</span>-Volcano Interaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gudmundsson, M. T.</p> <p>2005-12-01</p> <p>In most cases when eruptions occur within glaciers they lead to rapid <span class="hlt">ice</span> melting, jokulhlaups and/or lahars. Many parameters influence the style of activity and its impact on the environment. These include <span class="hlt">ice</span> thickness (size of glacier), bedrock geometry, magma flow rate and magma composition. The eruptions that have been observed can roughly be divided into: (1) eruptions under several hundred meters thick <span class="hlt">ice</span> on a relatively flat bedrock, (2) eruptions on flat or sloping bed through relatively thin <span class="hlt">ice</span>, and (3) volcanism where effects are limitied to confinement of lava flows or melting of <span class="hlt">ice</span> by pyroclastic flows or surges. This last category (<span class="hlt">ice</span>-contact volcanism) need not cause much <span class="hlt">ice</span> melting. Many of the deposits formed by Pleistocene volcanism in Iceland, British Columbia and Antarctica belong to the first category. An important difference between this type of activity and submarine activity (where pressure is hydrostatic) is that pressure at vents may in many cases be much lower than glaciostatic due to partial support of <span class="hlt">ice</span> cover over vents by the surrounding glacier. Reduced pressure favours explosive activity. Thus the effusive/explosive transition may occur several hundred metres underneath the <span class="hlt">ice</span> surface. Explosive fragmentation of magma leads to much higher rates of heat transfer than does effusive eruption of pillow lavas, and hence much higher melting rates. This effect of reduced pressure at vents will be less pronounced in a large <span class="hlt">ice</span> sheet than in a smaller glacier or <span class="hlt">ice</span> <span class="hlt">cap</span>, since the hydraulic gradient that drives water away from an eruption site will be lower in the large glacier. This may have implications for form and type of eruption deposits and their relationship with <span class="hlt">ice</span> thickness and glacier size.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AdAtS..35...27K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AdAtS..35...27K"><span>Atmospheric precursors of and response to anomalous Arctic sea <span class="hlt">ice</span> in CMIP5 models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelleher, Michael; Screen, James</p> <p>2018-01-01</p> <p>This study examines pre-industrial control simulations from CMIP5 climate models in an effort to better understand the complex relationships between Arctic sea <span class="hlt">ice</span> and the stratosphere, and between Arctic sea <span class="hlt">ice</span> and cold winter temperatures over Eurasia. We present normalized regressions of Arctic sea-<span class="hlt">ice</span> area against several atmospheric variables at extended lead and lag times. Statistically significant regressions are found at leads and lags, suggesting both atmospheric precursors of, and responses to, low sea <span class="hlt">ice</span>; but generally, the regressions are stronger when the atmosphere leads sea <span class="hlt">ice</span>, including a weaker polar stratospheric vortex indicated by positive polar <span class="hlt">cap</span> height anomalies. Significant positive midlatitude eddy heat flux anomalies are also found to precede low sea <span class="hlt">ice</span>. We argue that low sea <span class="hlt">ice</span> and raised polar <span class="hlt">cap</span> height are both a response to this enhanced midlatitude eddy heat flux. The so-called "warm Arctic, cold continents" anomaly pattern is present one to two months before low sea <span class="hlt">ice</span>, but is absent in the months following low sea <span class="hlt">ice</span>, suggesting that the Eurasian cooling and low sea <span class="hlt">ice</span> are driven by similar processes. Lastly, our results suggest a dependence on the geographic region of low sea <span class="hlt">ice</span>, with low Barents-Kara Sea <span class="hlt">ice</span> correlated with a weakened polar stratospheric vortex, whilst low Sea of Okhotsk <span class="hlt">ice</span> is correlated with a strengthened polar vortex. Overall, the results support a notion that the sea <span class="hlt">ice</span>, polar stratospheric vortex and Eurasian surface temperatures collectively respond to large-scale changes in tropospheric circulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150006626&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCAPS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150006626&hterms=CAPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCAPS"><span>Variations in Surface Texture of the North Polar Residual <span class="hlt">Cap</span> of Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Milkovich, S. M.; Byrne, S.; Russell, P. S.</p> <p>2011-01-01</p> <p>The northern polar residual <span class="hlt">cap</span> (NPRC) of Mars is a water <span class="hlt">ice</span> deposit with a rough surface made up of pits, knobs, and linear depressions on scales of tens of meters. This roughness manifests as a series of bright mounds and dark hollows in visible images; these bright and dark patches have a characteristic wavelength and orientation. Spectral data indicate that the surface of the NPRC is composed of large-grained (and therefore old) water <span class="hlt">ice</span>. Due to the presence of this old <span class="hlt">ice</span>, it is thought that the NPRC is in a current state of net loss of material a result potentially at odds with impact crater statistics, which suggest ongoing deposition over the past 10-20 Kyr.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016QSRv..150...55P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016QSRv..150...55P"><span>Long-term record of Barents Sea <span class="hlt">Ice</span> Sheet advance to the shelf edge from a 140,000 year record</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pope, Ed L.; Talling, Peter J.; Hunt, James E.; Dowdeswell, Julian A.; Allin, Joshua R.; Cartigny, Matthieu J. B.; Long, David; Mozzato, Alessandro; Stanford, Jennifer D.; Tappin, David R.; Watts, Millie</p> <p>2016-10-01</p> <p>The full-glacial extent and deglacial behaviour of marine-based <span class="hlt">ice</span> sheets, such as the Barents Sea <span class="hlt">Ice</span> Sheet, is well documented since the Last Glacial Maximum about 20,000 years ago. However, reworking of older sea-floor sediments and landforms during repeated Quaternary advances across the shelf typically obscures their longer-term behaviour, which hampers our understanding. Here, we provide the first detailed long-term record of Barents Sea <span class="hlt">Ice</span> Sheet advances, using the timing of debris-flows on the Bear Island Trough-Mouth Fan. <span class="hlt">Ice</span> advanced to the shelf edge during four distinct periods over the last 140,000 years. By far the largest sediment volumes were delivered during the oldest advance more than 128,000 years ago. Later advances occurred from 68,000 to 60,000, 39,400 to 36,000 and 26,000 to 20,900 years before present. The debris-flows indicate that the dynamics of the Saalian and the Weichselian Barents Sea <span class="hlt">Ice</span> Sheet were very different. The repeated <span class="hlt">ice</span> advance and retreat cycles during the Weichselian were shorter lived than those seen in the Saalian. Sediment composition shows the configuration of the <span class="hlt">ice</span> sheet was also different between the two glacial periods, implying that the <span class="hlt">ice</span> feeding the Bear Island <span class="hlt">Ice</span> stream came predominantly from Scandinavia during the Saalian, whilst it drained more <span class="hlt">ice</span> from east of <span class="hlt">Svalbard</span> during the Weichselian.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C21B0322Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C21B0322Z"><span>Sensing the bed-rock movement due to <span class="hlt">ice</span> unloading from space using InSAR time-series</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, W.; Amelung, F.; Dixon, T. H.; Wdowinski, S.</p> <p>2014-12-01</p> <p><span class="hlt">Ice</span>-sheets in the Arctic region are retreating rapidly since late 1990s. Typical <span class="hlt">ice</span> loss rates are 0.5 - 1 m/yr at the Canadian Arctic Archipelago, ~ 1 m/yr at the Icelandic <span class="hlt">ice</span> sheets, and several meters per year at the edge of Greenland <span class="hlt">ice</span> sheet. Such load decreasing causes measurable (several millimeter per year) deformation of the Earth's crust from Synthetic Aperture Radar Interferometry (InSAR). Using small baseline time-series analysis, this signal is retrieved after noises such as orbit error, atmospheric delay and DEM error being removed. We present results from Vatnajokull <span class="hlt">ice</span> <span class="hlt">cap</span>, Petermann glacier and Barnes <span class="hlt">ice</span> <span class="hlt">cap</span> using ERS, Envisat and TerraSAR-X data. Up to 2 cm/yr relative radar line-of-sight displacement is detected. The pattern of deformation matches the shape of <span class="hlt">ice</span> sheet very well. The result in Iceland was used to develop a new model for the <span class="hlt">ice</span> mass balance estimation from 1995 to 2010. Other applications of this kind of technique include validation of ICESat or GRACE based <span class="hlt">ice</span> sheet model, Earth's rheology (Young's modulus, viscosity and so on). Moreover, we find a narrow (~ 1km) uplift zone close to the periglacial area of Petermann glacier which may due to a special rheology under the <span class="hlt">ice</span> stream.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGC43C0754S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGC43C0754S"><span>Trace Element Determination from the Guliya <span class="hlt">Ice</span> Core to Characterize Aerosol Deposition over the Western Tibetan Plateau during the Last 500 Years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sierra Hernandez, R.; Gabrielli, P.; Beaudon, E.; Wegner, A.; Thompson, L. G.</p> <p>2014-12-01</p> <p>The Tibetan Plateau or Third Pole covers over 5 million km2, and has ~46,000 glaciers that collectively contain one of the Earth's largest stores of fresh water. The Guliya <span class="hlt">ice</span> <span class="hlt">cap</span> located in the western Kunlun Shan on the Qinghai-Tibetan Plateau, China, is the largest (> 200 km2) <span class="hlt">ice</span> <span class="hlt">cap</span> in the subtropical zone. In 1992, a 308.6 m <span class="hlt">ice</span> core to bedrock was recovered from the Guliya <span class="hlt">ice</span> <span class="hlt">cap</span>. The deepest 20 meters yielded the first record extending back through the last glacial cycle found outside of the Polar Regions. Because of its continental location on the northwestern side of the Tibetan Plateau, the atmospheric circulation over the Guliya <span class="hlt">ice</span> <span class="hlt">cap</span> is dominated by westerly air flow from the Eurasian region. Therefore the site is expected to be unaffected by the fallout of anthropogenic trace metals originating from the inner Asian continent and rather may serve to characterize trace metal emissions from the western countries. Here we present preliminary results of the determination of 29 trace elements, Rb, Sr, Nb, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Ta, Tl, Pb, Bi, U, Li, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, and As, from Guliya <span class="hlt">ice</span> core samples spanning the period 1500 - 1992 AD at seasonal (1750-1992 AD) and annual (1500-1750 AD) resolution. This Guliya trace element record will complement the developing records from the Dasuopu glacier, central Himalaya, and from the Puruogangri <span class="hlt">ice</span> <span class="hlt">cap</span> in the western Tanggula Shan in central Tibetan Plateau, which in contrast to Guliya are influenced by the monsoon. We investigate the possible sources both natural and anthropogenic of atmospheric trace elements and their fluxes over the Tibetan Plateau during the last 500 years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24056048','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24056048"><span>Selected anthropogenic and natural radioisotopes in the Barents Sea and off the western coast of <span class="hlt">Svalbard</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Leppänen, Ari-Pekka; Kasatkina, Nadezhda; Vaaramaa, Kaisa; Matishov, Gennady G; Solatie, Dina</p> <p>2013-12-01</p> <p>The Murmansk Marine Biological Institute (MMBI) performed high-latitude expeditions to the Barents Sea during 2007-2009 where a scientist from the Radiation and Nuclear Safety Authority (STUK) participated. The aim of the expeditions was to study and map the current radiological situation throughout the Barents Sea. In the expeditions, samples of seawater, sediment and biota were collected for radioactivity studies. The (90)Sr and (137)Cs isotopes were analysed from the seawater samples and no spatial distribution in the concentrations of (90)Sr and (137)Cs was found. The sediment samples were analysed for γ-emitting isotopes. In the statistical analysis performed only the (90)Sr was found to have no spatial distribution. In the (137)Cs concentrations two areas containing higher concentrations were observed: one in the western part of <span class="hlt">Svalbard</span> and another in Franz Victoria Trough near the Franz Josef Land archipelago. The increase in the western coast of <span class="hlt">Svalbard</span> suggests an Atlantic influence while in the Franz Victoria Trough source regions are possibly more complex. Since (137)Cs in marine sediments mainly originates from terrestrial sources, finding higher concentrations in the northern part of the Barents Sea may also suggest a contribution of (137)Cs carried by the ocean currents and by sea <span class="hlt">ice</span> from the outside Barents Sea. In addition to γ spectrometric measurements, the sediment samples were radiochemically analysed for (210)Pb. It was found that the unsupported fraction of (210)Pb showed significant spatial variation. The fraction of unsupported (210)Pb was reduced to 40-70% near Bear Island, Edge Island and in the Franz Josef Land archipelago. In these regions the sea is typically covered with sea <span class="hlt">ice</span> during winter. The relatively low fraction of unsupported (210)Pb is possibly caused by blocking of wet and dry deposition of (210)Pb onto the sea by winter sea <span class="hlt">ice</span>. In biota samples, only small traces, at the level of 0.2 Bq/kg w.w. of (137)Cs, were found</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040085646&hterms=Saunders&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D10%26Ntt%3DSaunders%252C%2BM','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040085646&hterms=Saunders&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D10%26Ntt%3DSaunders%252C%2BM"><span>CryoScout: A Descent Through the Mars Polar <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hecht, M. H.; Saunders, R. S.</p> <p>2003-01-01</p> <p>CryoScout was proposed as a subsurface investigation of the stratigraphic climate record embedded in Mars North Polar <span class="hlt">cap</span>. After landing on a gentle landscape in the midst of the mild summer season, CryoScout was to use the continuous polar sunlight to power the descent of a cryobot, a thermal probe, into the <span class="hlt">ice</span> at a rate of about 1 m per day. CryoScout would probe deep enough into this time capsule to see the effects of planetary obliquity variations and discrete events such as dust storms or volcanic eruptions. By penetrating tens of meters of <span class="hlt">ice</span>, the mission would explore at least one of the dominant "MOC layers" observed in exposed layered terrain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..MAR.R0002T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..MAR.R0002T"><span>Earth's Climate History from Glaciers and <span class="hlt">Ice</span> Cores</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, Lonnie</p> <p>2013-03-01</p> <p>Glaciers serve both as recorders and early indicators of climate change. Over the past 35 years our research team has recovered climatic and environmental histories from <span class="hlt">ice</span> cores drilled in both Polar Regions and from low to mid-latitude, high-elevation <span class="hlt">ice</span> fields. Those <span class="hlt">ice</span> core -derived proxy records extending back 25,000 years have made it possible to compare glacial stage conditions in the Tropics with those in the Polar Regions. High-resolution records of δ18O (in part a temperature proxy) demonstrate that the current warming at high elevations in the mid- to lower latitudes is unprecedented for the last two millennia, although at many sites the early Holocene was warmer than today. Remarkable similarities between changes in the highland and coastal cultures of Peru and regional climate variability, especially precipitation, imply a strong connection between prehistoric human activities and regional climate. <span class="hlt">Ice</span> cores retrieved from shrinking glaciers around the world confirm their continuous existence for periods ranging from hundreds to thousands of years, suggesting that current climatological conditions in those regions today are different from those under which these <span class="hlt">ice</span> fields originated and have been sustained. The ongoing widespread melting of high-elevation glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span>, particularly in low to middle latitudes, provides strong evidence that a large-scale, pervasive and, in some cases, rapid change in Earth's climate system is underway. Observations of glacier shrinkage during the 20th and 21st century girdle the globe from the South American Andes, the Himalayas, Kilimanjaro (Tanzania, Africa) and glaciers near Puncak Jaya, Indonesia (New Guinea). The history and fate of these <span class="hlt">ice</span> <span class="hlt">caps</span>, told through the adventure, beauty and the scientific evidence from some of world's most remote mountain tops, provide a global perspective for contemporary climate. NSF Paleoclimate Program</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC21F..01T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC21F..01T"><span>High-amplitude, centennial-scale climate oscillations during the last glacial in the western Third Pole as recorded in the Guliya <span class="hlt">ice</span> <span class="hlt">cap</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, L. G.; Yao, T.; Mosley-Thompson, E.; Wu, G.; Davis, M. E.; Tian, L.; Lin, P. N.</p> <p>2015-12-01</p> <p>The Guliya <span class="hlt">ice</span> <span class="hlt">cap</span>, located in the Kunlun Mountains in the western Third Pole (TP) region near the northern limit of the southwest monsoon influence, may be the only non-polar <span class="hlt">ice</span> field that provides detailed histories of climate and environment over the last glacial cycle. A continuous climate record from an <span class="hlt">ice</span> core drilled in 1992 contains Eemian <span class="hlt">ice</span>, and basal temperatures measured that year confirmed that the record was not being removed from the bottom. The δ18O record throughout Marine Isotope Stage 2 (MIS2) displays the occurrence of high-amplitude (~20‰) episodes of ~200-year periodicity, and the aerosol records suggest snow cover, regional vegetation and fire frequency that vary in synchrony. These oscillations might reflect the movement of the northernmost penetration of the monsoon precipitation through the Late Glacial Stage, which is restricted by the topographic barrier posed by the Kunlun range, and might also reflect solar-driven nonlinearities in the climate system such as sudden shifts in the jet stream. Recent model simulations suggest that glacial cooling over China was significantly amplified by stationary waves, and the Guliya MIS2 oscillations could reflect cyclical variability in these waves. These results are supported by clumped isotope thermometry of carbonates from the Chinese Loess Plateau, which indicate a 6 to 7oC decrease in Last Glacial Maximum summer temperatures. These studies will lead to a better understanding of the mechanisms driving such high-frequency, high-amplitude oscillations. A review of the 2015 Sino-American cooperative <span class="hlt">ice</span> core drilling program on Guliya is presented. This program will serve as a flagship for the TP Environment Program, an international, multidisciplinary collaboration among professionals and students in 14 countries designed to investigate environmental changes across the TP. The rapidly warming TP contains ~46,000 glaciers that collectively hold one of Earth's largest stores of fresh water that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.P52A..02R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.P52A..02R"><span>The Arctic Gakkel Vents (AGAVE) Expedition: Technology Development and the Search for Deep-Sea Hydrothermal Vent Fields Under the Arctic <span class="hlt">Ice</span> <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reves-Sohn, R. A.; Singh, H.; Humphris, S.; Shank, T.; Jakuba, M.; Kunz, C.; Murphy, C.; Willis, C.</p> <p>2007-12-01</p> <p>Deep-sea hydrothermal fields on the Gakkel Ridge beneath the Arctic <span class="hlt">ice</span> <span class="hlt">cap</span> provide perhaps the best terrestrial analogue for volcanically-hosted chemosynthetic biological communities that may exist beneath the <span class="hlt">ice</span>-covered ocean of Europa. In both cases the key enabling technologies are robotic (untethered) vehicles that can swim freely under the <span class="hlt">ice</span> and the supporting hardware and software. The development of robotic technology for deep- sea research beneath <span class="hlt">ice</span>-covered oceans thus has relevance to both polar oceanography and future astrobiological missions to Europa. These considerations motivated a technology development effort under the auspices of NASA's ASTEP program and NSF's Office of Polar Programs that culminated in the AGAVE expedition aboard the icebreaker Oden from July 1 - August 10, 2007. The scientific objective was to study hydrothermal processes on the Gakkel Ridge, which is a key target for global studies of deep-sea vent fields. We developed two new autonomous underwater vehicles (AUVs) for the project, and deployed them to search for vent fields beneath the <span class="hlt">ice</span>. We conducted eight AUV missions (four to completion) during the 40-day long expedition, which also included ship-based bathymetric surveys, CTD/rosette water column surveys, and wireline photographic and sampling surveys of remote sections of the Gakkel Ridge. The AUV missions, which lasted 16 hours on average and achieved operational depths of 4200 meters, returned sensor data that showed clear evidence of hydrothermal venting, but for a combination of technical reasons and time constraints, the AUVs did not ultimately return images of deep-sea vent fields. Nevertheless we used our wireline system to obtain images and samples of extensive microbial mats that covered fresh volcanic surfaces on a newly discovered set of volcanoes. The microbes appear to be living in regions where reducing and slightly warm fluids are seeping through cracks in the fresh volcanic terrain. These discoveries</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008Icar..196..488V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008Icar..196..488V"><span>Dust aerosols above the south polar <span class="hlt">cap</span> of Mars as seen by OMEGA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vincendon, M.; Langevin, Y.; Poulet, F.; Bibring, J.-P.; Gondet, B.; Jouglet, D.; Omega Team</p> <p>2008-08-01</p> <p>The time evolution of atmospheric dust at high southern latitudes on Mars has been determined using observations of the south seasonal <span class="hlt">cap</span> acquired in the near infrared (1-2.65 μm) by OMEGA/Mars Express in 2005. Observations at different solar zenith angles and one EPF sequence demonstrate that the reflectance in the 2.64 μm saturated absorption band of the surface CO 2 <span class="hlt">ice</span> is mainly due to the light scattered by aerosols above most places of the seasonal <span class="hlt">cap</span>. We have mapped the total optical depth of dust aerosols in the near-IR above the south seasonal <span class="hlt">cap</span> of Mars from mid-spring to early summer with a time resolution ranging from one day to one week and a spatial resolution of a few kilometers. The optical depth above the south perennial <span class="hlt">cap</span> is determined on a longer time range covering southern spring and summer. A constant set of optical properties of dust aerosols is consistent with OMEGA observations during the analyzed period. Strong variations of the optical depth are observed over small horizontal and temporal scales, corresponding in part to moving dust clouds. The late summer peak in dust opacity observed by Opportunity in 2005 propagated to the south pole contrarily to that observed in mid spring. This may be linked to evidence for dust scavenging by water <span class="hlt">ice</span>-rich clouds circulating at high southern latitudes at this season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014P%26SS...91...60F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014P%26SS...91...60F"><span>Amazonian mid- to high-latitude glaciation on Mars: Supply-limited <span class="hlt">ice</span> sources, <span class="hlt">ice</span> accumulation patterns, and concentric crater fill glacial flow and <span class="hlt">ice</span> sequestration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fastook, James L.; Head, James W.</p> <p>2014-02-01</p> <p>Concentric crater fill (CCF) occurs in the interior of impact craters in mid- to high latitudes on Mars and is interpreted to have formed by glacial <span class="hlt">ice</span> flow and debris covering. We use the characteristics and orientation of deposits comprising CCF, the thickness of pedestal deposits in mid- to high-latitude pedestal craters (Pd), the volumes of the current polar <span class="hlt">caps</span>, and information about regional slopes and <span class="hlt">ice</span> rheology to address questions about (1) the maximum thickness of regional <span class="hlt">ice</span> deposits during the Late Amazonian, (2) the likelihood that these deposits flowed regionally, (3) the geological regions and features most likely to induce <span class="hlt">ice</span>-flow, and (4) the locations and environments in which <span class="hlt">ice</span> is likely to have been sequestered up to the present. We find that regional <span class="hlt">ice</span> flow under Late Amazonian climate conditions requires <span class="hlt">ice</span> thicknesses exceeding many hundreds of meters for slopes typical of the vast majority of the surface of Mars, a thickness for the mid-latitudes that is well in excess of the total volume available from polar <span class="hlt">ice</span> reservoirs. This indicates that although conditions for mid- to high-latitude glaciation may have persisted for tens to hundreds of millions of years, the process is “supply limited”, with a steady state reached when the polar <span class="hlt">ice</span> <span class="hlt">cap</span> water <span class="hlt">ice</span> supply becomes exhausted. Impact craters are by far the most abundant landform with associated slopes (interior wall and exterior rim) sufficiently high to induce glacial <span class="hlt">ice</span> flow under Late Amazonian climate conditions, and topographic slope data show that Amazonian impact craters have been clearly modified, undergoing crater interior slope reduction and floor shallowing. We show that these trends are the predictable response of <span class="hlt">ice</span> deposition and preferential accumulation and retention in mid- to high-latitude crater interiors during episodes of enhanced spin-axis obliquity. We demonstrate that flow from a single episode of an inter-crater terrain layer comparable to Pedestal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860061009&hterms=northern+hemispheres+mars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dnorthern%2Bhemispheres%2Bmars','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860061009&hterms=northern+hemispheres+mars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dnorthern%2Bhemispheres%2Bmars"><span>Measurements of the north polar <span class="hlt">cap</span> of Mars and the earth's Northern Hemisphere <span class="hlt">ice</span> and snow cover</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Foster, J.; Owe, M.; Capen, C.</p> <p>1986-01-01</p> <p>The boundaries of the polar <span class="hlt">caps</span> of Mars have been measured on more than 3000 photographs since 1905 from the plate collection at the Lowell Observatory. For the earth, the polar <span class="hlt">caps</span> have been accurately mapped only since the mid 1960s when satellites were first available to synoptically view the polar regions. The polar <span class="hlt">caps</span> of both planets wax and wane in response to changes in the seasons, and interannual differences in polar <span class="hlt">cap</span> behavior on Mars as well as earth are intimately linked to global energy balance. Data on the year to year variations in the extent of the north polar <span class="hlt">caps</span> of Mars and earth have been assembled and compared, although only 6 years of concurrent data were available for comparison.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120002018','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120002018"><span>Modeling the Quiet Time Outflow Solution in the Polar <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Glocer, Alex</p> <p>2011-01-01</p> <p>We use the Polar Wind Outflow Model (PWOM) to study the geomagnetically quiet conditions in the polar <span class="hlt">cap</span> during solar maximum, The PWOM solves the gyrotropic transport equations for O(+), H(+), and He(+) along several magnetic field lines in the polar region in order to reconstruct the full 3D solution. We directly compare our simulation results to the data based empirical model of Kitamura et al. [2011] of electron density, which is based on 63 months of Akebono satellite observations. The modeled ion and electron temperatures are also compared with a statistical compilation of quiet time data obtained by the EISCAT <span class="hlt">Svalbard</span> Radar (ESR) and Intercosmos Satellites (Kitamura et al. [2011]). The data and model agree reasonably well. This study shows that photoelectrons play an important role in explaining the differences between sunlit and dark results, ion composition, as well as ion and electron temperatures of the quiet time polar wind solution. Moreover, these results provide validation of the PWOM's ability to model the quiet time ((background" solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70184662','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70184662"><span>Geographic variation of PCB congeners in polar bears (Ursus maritimus) from <span class="hlt">Svalbard</span> east to the Chukchi Sea</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Andersen, M.; Lie, E.; Derocher, A.E.; Belikov, S.E.; Bernhoft, A.; Boltunov, Andrei N.; Garner, G.W.; Skaare, J.U.; Wiig, Øystein</p> <p>2001-01-01</p> <p>We present data on geographic variation in polychlorinated biphenyl (PCB) congeners in adult female polar bears (Ursus maritimus) from <span class="hlt">Svalbard</span> eastward to the Chukchi Sea. Blood samples from 90 free-living polar bears were collected in 1987–1995. Six PCB congeners, penta to octa chlorinated (PCB-99, -118, -153, -156, -180, -194), were selected for this study. Differences between areas were found in PCB levels and congener patterns. Bears from Franz Josef Land (11,194 ng/g lipid weight) and the Kara Sea (9,412 ng/g lw) had similar ΣPCB levels and were higher than all other populations (<span class="hlt">Svalbard</span> 5,043 ng/g lw, East Siberian Sea 3,564 ng/g lw, Chukchi Sea 2,465 ng/g lw). <span class="hlt">Svalbard</span> PCB levels were higher than those from the Chukchi Sea. Our results, combined with earlier findings, indicate that polar bears from Franz Josef Land and the Kara Sea have the highest PCB levels in the Arctic. Decreasing trends were seen eastwards and westwards from this region. Of the congeners investigated in the present study, the lower chlorinated PCBs are increasing and the high chlorinated PCBs are decreasing from <span class="hlt">Svalbard</span> eastward to the Chukchi Sea. Different pollution sources, compound transport patterns and regional prey differences could explain the variation in PCB congener levels and patterns between regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1914576F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1914576F"><span>CALICE: Calibrating Plant Biodiversity in Glacier <span class="hlt">Ice</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Festi, Daniela; Cristofori, Antonella; Vernesi, Cristiano; Zerbe, Stefan; Wellstein, Camilla; Maggi, Valter; Oeggl, Klaus</p> <p>2017-04-01</p> <p>The objective of the project is to reconstruct plant biodiversity and its trend archived in Alpine glacier <span class="hlt">ice</span> by pollen and eDNA (environmental DNA) during the last five decades by analyzing a 40 m <span class="hlt">ice</span> core. For our study we chose the Adamello glacier (Trentino - Südtirol, Lombardia) because of i) the good preservation conditions for pollen and eDNA in <span class="hlt">ice</span>, ii) the thickness of the <span class="hlt">ice</span> <span class="hlt">cap</span> (270m) and iii) the expected high time resolution. The biodiversity estimates gained by pollen analysis and eDNA will be validated by historical biodiversity assessments mainly based on vegetation maps, aerial photos and vegetation surveys in the catchment area of the Adamello glacier for the last five decades. This historical reconstruction of biodiversity trends will be performed on a micro-, meso- and macro-scale (5, 20-50 and 50-100 Km radius, respectively). The results will serve as a calibration data set on biodiversity for future studies, such as the second step of the coring by the POLLiCE research consortium (pollice.fmach.it). In fact, arrangements are currently been made to drill the complete <span class="hlt">ice</span> <span class="hlt">cap</span> and retrieve a 270 m thick core which has the potential to cover a time span of minimum 400 years up to several millennia. This second stage will extend the time scale and enable the evaluation of dissimilarity/similarity of modern biodiversity in relation to Late Holocene trends. Finally, we believe this case study has the potential to be applied in other glaciated areas to evaluate biodiversity for large regions (e.g. central Asian mountain ranges, Tibet and Tian Shan or the Andes).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26468217','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26468217"><span>Cecal bacterial communities in wild Japanese rock ptarmigans and captive <span class="hlt">Svalbard</span> rock ptarmigans.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ushida, Kazunari; Segawa, Takahiro; Tsuchida, Sayaka; Murata, Koichi</p> <p>2016-02-01</p> <p>Preservation of indigenous gastrointestinal microbiota is deemed to be critical for successful captive breeding of endangered wild animals, yet its biology is poorly understood. Here, we investigated cecal bacterial communities in wild Japanese rock ptarmigans (Lagopus muta japonica) and compared them with those in <span class="hlt">Svalbard</span> rock ptarmigans (L. m. hyperborea) in captivity. Ultra-deep sequencing of 16S rRNA gene indicated that the community structure of cecal microbiota in wild rock ptarmigans was remarkably different from that in captive <span class="hlt">Svalbard</span> rock ptarmigans. Fundamental differences between bacterial communities in the two groups of birds were detected at the phylum level. Firmicutes, Actinobacteria, Bacteroidetes and Synergistetes were the major phyla detected in wild Japanese rock ptarmigans, whereas Firmicutes alone occupied more than 80% of abundance in captive <span class="hlt">Svalbard</span> rock ptarmigans. Furthermore, unclassified genera of Coriobacteriaceae, Synergistaceae, Bacteroidaceae, Actinomycetaceae, Veillonellaceae and Clostridiales were the major taxa detected in wild individuals, whereas in zoo-reared birds, major genera were Ruminococcus, Blautia, Faecalibacterium and Akkermansia. Zoo-reared birds seemed to lack almost all rock ptarmigan-specific bacteria in their intestine, which may explain the relatively high rate of pathogenic infections affecting them. We show evidence that preservation and reconstitution of indigenous cecal microflora are critical for successful ex situ conservation and future re-introduction plan for the Japanese rock ptarmigan.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH41E..07Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH41E..07Z"><span>Marginal <span class="hlt">Ice</span> Zone Processes Observed from Unmanned Aerial Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zappa, C. J.</p> <p>2015-12-01</p> <p>Recent years have seen extreme changes in the Arctic. Marginal <span class="hlt">ice</span> zones (MIZ), or areas where the "<span class="hlt">ice</span>-albedo feedback" driven by solar warming is highest and <span class="hlt">ice</span> melt is extensive, may provide insights into the extent of these changes. Furthermore, MIZ play a central role in setting the air-sea CO2 balance making them a critical component of the global carbon cycle. Incomplete understanding of how the sea-<span class="hlt">ice</span> modulates gas fluxes renders it difficult to estimate the carbon budget in MIZ. Here, we investigate the turbulent mechanisms driving mixing and gas exchange in leads, polynyas and in the presence of <span class="hlt">ice</span> floes using both field and laboratory measurements. Measurements from unmanned aerial systems (UAS) in the marginal <span class="hlt">ice</span> zone were made during 2 experiments: 1) North of Oliktok Point AK in the Beaufort Sea were made during the Marginal <span class="hlt">Ice</span> Zone Ocean and <span class="hlt">Ice</span> Observations and Processes EXperiment (MIZOPEX) in July-August 2013 and 2) Fram Strait and Greenland Sea northwest of Ny-Ålesund, <span class="hlt">Svalbard</span>, Norway during the Air-Sea-<span class="hlt">Ice</span> Physics and Biogeochemistry Experiment (ASIPBEX) April - May 2015. We developed a number of new payloads that include: i) hyperspectral imaging spectrometers to measure VNIR (400-1000 nm) and NIR (900-1700 nm) spectral radiance; ii) net longwave and net shortwave radiation for <span class="hlt">ice</span>-ocean albedo studies; iii) air-sea-<span class="hlt">ice</span> turbulent fluxes as well as wave height, <span class="hlt">ice</span> freeboard, and surface roughness with a LIDAR; and iv) drone-deployed micro-drifters (DDµD) deployed from the UAS that telemeter temperature, pressure, and RH as it descends through the atmosphere and temperature and salinity of the upper meter of the ocean once it lands on the ocean's surface. Visible and IR imagery of melting <span class="hlt">ice</span> floes clearly defines the scale of the <span class="hlt">ice</span> floes. The IR imagery show distinct cooling of the skin sea surface temperature (SST) as well as an intricate circulation and mixing pattern that depends on the surface current, wind speed, and near</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.3559B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.3559B"><span>Influence of Large Igneous Provinces on <span class="hlt">Svalbard</span> tectonics and sedimentation from the Late Mesozoic through Cenozoic: Insight from (U-Th)/He zircon and apatite thermochronology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barnes, Christopher; Schneider, David; Majka, Jaroslaw</p> <p>2016-04-01</p> <p><span class="hlt">Svalbard</span>, the northwestern sub-aerial exposure of the Barents Shelf, offers significant insight into the geodynamics of the High Arctic. The tectonics and sedimentation on <span class="hlt">Svalbard</span> from the Late Mesozoic through Cenozoic can be attributed to two Large Igneous Provinces: the High Arctic Large Igneous Province (HALIP; 130-90 Ma) and the North Atlantic Large Igneous Province (NAIP; 62-55 Ma). The relationship between the HALIP and the tectonics of the High Arctic remains somewhat unclear, whereas the NAIP is directly linked to opening of the North Atlantic Ocean. This study attempts to establish links between the HALIP and geodynamics of the High Arctic, and reveals the far-field tectonic consequences of the NAIP on <span class="hlt">Svalbard</span> and the High Arctic. We focus on the Southwestern Caledonian Basement Terrane of <span class="hlt">Svalbard</span>, characterized by the West Spitsbergen Fold and Thrust Belt, formed during the Eurekan Orogeny (c. 55-33 Ma). Crystalline basement was sampled from four regions (Prins Karls Forland, Oscar II Land, Wedel Jarlsberg Land, and Sørkapp Land) for the purpose of zircon and apatite (U-Th)/He thermochronometry which allows for resolution of thermal events below 200°C. We forward model our datasets using HeFTy software to produce temperature-time histories for each of these regions, and compare these thermal models with <span class="hlt">Svalbard</span> stratigraphy to resolve the geodynamics of <span class="hlt">Svalbard</span> from the Late Mesozoic through Cenozoic. The Cretaceous stratigraphy of <span class="hlt">Svalbard</span> is characterized by a short-lived Mid-Cretaceous sub-aerial unconformity (c. 129 Ma) and a significant Late Cretaceous unconformity (c. 105-65 Ma). Our thermal models reveal a Mid-Cretaceous heating event, suggesting an increasing geothermal gradient coeval with development of the first unconformity. This may indicate that short-lived domal-uplift, related to the arrival of the HALIP plume, was a primary control on <span class="hlt">Svalbard</span> tectonics and sedimentary deposition throughout the Mid-Cretaceous. Late Cretaceous</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1914046W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1914046W"><span>Bayesian inference of <span class="hlt">ice</span> thickness from remote-sensing data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Werder, Mauro A.; Huss, Matthias</p> <p>2017-04-01</p> <p>Knowledge about <span class="hlt">ice</span> thickness and volume is indispensable for studying <span class="hlt">ice</span> dynamics, future sea-level rise due to glacier melt or their contribution to regional hydrology. Accurate measurements of glacier thickness require on-site work, usually employing radar techniques. However, these field measurements are time consuming, expensive and sometime downright impossible. Conversely, measurements of the <span class="hlt">ice</span> surface, namely elevation and flow velocity, are becoming available world-wide through remote sensing. The model of Farinotti et al. (2009) calculates <span class="hlt">ice</span> thicknesses based on a mass conservation approach paired with shallow <span class="hlt">ice</span> physics using estimates of the surface mass balance. The presented work applies a Bayesian inference approach to estimate the parameters of a modified version of this forward model by fitting it to both measurements of surface flow speed and of <span class="hlt">ice</span> thickness. The inverse model outputs <span class="hlt">ice</span> thickness as well the distribution of the error. We fit the model to ten test glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> and quantify the improvements of thickness estimates through the usage of surface <span class="hlt">ice</span> flow measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17..991E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17..991E"><span>Alteration of glacigenic landforms by gravitational mass movements, Ragnarbreen and Ebbabreen, <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ewertowski, Marek; Pleskot, Krzysztof; Tomczyk, Aleksandra</p> <p>2015-04-01</p> <p>The extensive recession of <span class="hlt">Svalbard</span>'s glaciers exposed areas containing large amount of dead-<span class="hlt">ice</span> covered by relatively thin - usually less than a couple of meters - veneer of debris. This landscape can be very dynamic, mainly due to the mass movement processes and dead-<span class="hlt">ice</span> melting. Continuous redistribution of sediments causes several phases of debris transfer and relief inversion. Hence, the primary glacial deposits released from <span class="hlt">ice</span> are subsequently transferred by mass movement processes, until they finally reach more stable position. Investigations of dynamics of the mass movement and the way in which they alter the property of glacigenic sediments are therefore cruicial for proper understanding of sedimentary records of previous glaciations. The main objectives of this study were to: (1) quantify short-term dynamic of mass wasting processes; (2) investigate the transformation of the sediment's characteristic by mass wasting processes; (3) asses the contribution of different process to the overall dynamic of proglacial landscape. We focused on the mass-wasting processes in the forelands of two glaciers, Ebbabreen and Ragnarbreen, located near the Petuniabukta at the northern end of the Billefjorden, Spitsbergen. Repetitive topographic scanning was combined with sedimentological analysis of: grain size, clast shape in macro and micro scale and thin sections. Debris falls, slides, rolls and flows were the most important processes leading to reworking of glacigenic sediments and altering their properties. Contribution of different processes to the overall dynamic of the landforms was related mainly to the local conditions. Four different morphological types of sites were identified: (1) near vertical <span class="hlt">ice</span>-cliffs covered with debris, transformed mainly due to dead-<span class="hlt">ice</span> backwasting and debris falls and slides, (2) steep debris slopes with exposed <span class="hlt">ice</span>-cores dominated by debris slides, (3) gentle sediment-mantled slopes transformed due to debris flows, and (4) non</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7441E..0PH','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7441E..0PH"><span>Life in <span class="hlt">ice</span>: implications to astrobiology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoover, Richard B.; Pikuta, Elena V.</p> <p>2009-08-01</p> <p>During previous research expeditions to Siberia, Alaska and Antarctica, it was observed that glaciers and <span class="hlt">ice</span> wedges contained bacterial cells that became motile as soon as the <span class="hlt">ice</span> melted. This phenomenon of live bacteria in <span class="hlt">ice</span> was first documented for microbes in ancient <span class="hlt">ice</span> cores from Vostok, Antarctica. The first validly published species of Pleistocene bacteria alive on Earth today was Carnobacterium pleistocenium. This extremophile had remained for 32,000 years, encased in <span class="hlt">ice</span> recently exposed in the Fox Tunnel of Alaska. These frozen bacteria began to swim as soon as the <span class="hlt">ice</span> was thawed. Dark field microscopy studies revealed that large numbers of bacteria exhibited motility as soon as glacial <span class="hlt">ice</span> was melted during our recent Expeditions to Alaska and Antarctica led to the conclusion that microbial life in <span class="hlt">ice</span> was not a rare phenomenon. The ability of bacteria to remain alive while frozen in <span class="hlt">ice</span> for long periods of time is of great significance to Astrobiology. In this paper, we describe the recent observations and advance the hypothesis that life in <span class="hlt">ice</span> provides valuable clues to how we can more easily search for evidence of life on the Polar <span class="hlt">Caps</span> of Mars, comets and other icy bodies of our Solar System. It is suggested that cryopanspermia may have played a far more important role in Origin of Life on Earth and the distribution of Life throughout the Cosmos and than previously thought possible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20446731','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20446731"><span>Photoreductive dissolution of iron oxides trapped in <span class="hlt">ice</span> and its environmental implications.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Kitae; Choi, Wonyong; Hoffmann, Michael R; Yoon, Ho-Il; Park, Byong-Kwon</p> <p>2010-06-01</p> <p>The availability of iron has been thought to be a main limiting factor for the productivity of phytoplankton and related with the uptake of atmospheric CO(2) and algal blooms in fresh and sea waters. In this work, the formation of bioavailable iron (Fe(II)(aq)) from the dissolution of iron oxide particles was investigated in the <span class="hlt">ice</span> phase under both UV and visible light irradiation. The photoreductive dissolution of iron oxides proceeded slowly in aqueous solution (pH 3.5) but was significantly accelerated in polycrystalline <span class="hlt">ice</span>, subsequently releasing more bioavailable ferrous iron upon thawing. The enhanced photogeneration of Fe(II)(aq) in <span class="hlt">ice</span> was confirmed regardless of the type of iron oxides [hematite, maghemite (gamma-Fe(2)O(3)), goethite (alpha-FeOOH)] and the kind of electron donors. The <span class="hlt">ice</span>-enhanced dissolution of iron oxides was also observed under visible light irradiation, although the dissolution rate was much slower compared with the case of UV radiation. The iron oxide particles and organic electron donors (if any) in <span class="hlt">ice</span> are concentrated and aggregated in the liquid-like grain boundary region (freeze concentration effect) where protons are also highly concentrated (lower pH). The enhanced photodissolution of iron oxides should occur in this confined boundary region. We hypothesized that electron hopping through the interconnected grain boundaries of iron oxide particles facilitates the separation of photoinduced charge pairs. The outdoor experiments carried out under ambient solar radiation of Ny-Alesund (<span class="hlt">Svalbard</span>, 78 degrees 55'N) also showed that the generation of dissolved Fe(II)(aq) via photoreductive dissolution is enhanced when iron oxides are trapped in <span class="hlt">ice</span>. Our results imply that the <span class="hlt">ice</span>(snow)-covered surfaces and <span class="hlt">ice</span>-cloud particles containing iron-rich mineral dusts in the polar and cold environments provide a source of bioavailable iron when they thaw.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70027322','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70027322"><span>An onboard data analysis method to track the seasonal polar <span class="hlt">caps</span> on Mars</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wagstaff, K.L.; Castano, R.; Chien, S.; Ivanov, A.B.; Pounders, E.; Titus, T.N.; ,</p> <p>2005-01-01</p> <p>The Martian seasonal CO2 <span class="hlt">ice</span> <span class="hlt">caps</span> advance and retreat each year. They are currently studied using instruments such as the THermal EMission Imaging System (THEMIS), a visible and infra-red camera on the Mars Odyssey spacecraft [1]. However, each image must be downlinked to Earth prior to analysis. In contrast, we have developed the Bimodal Image Temperature (BIT) histogram analysis method for onboard detection of the <span class="hlt">cap</span> edge, before transmission. In downlink-limited scenarios when the entire image cannot be transmitted, the location of the <span class="hlt">cap</span> edge can still be identified and sent to Earth. In this paper, we evaluate our method on uncalibrated THEMIS data and find 1) agreement with manual <span class="hlt">cap</span> edge identifications to within 28.2 km, and 2) high accuracy even with a smaller analysis window, yielding large reductions in memory requirements. This algorithm is currently being considered as a capability enhancement for the Odyssey second extended mission, beginning in fall 2006.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800047931&hterms=sea+ice+albedo&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsea%2Bice%2Balbedo','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800047931&hterms=sea+ice+albedo&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsea%2Bice%2Balbedo"><span>The seasonal cycle of snow cover, sea <span class="hlt">ice</span> and surface albedo</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Robock, A.</p> <p>1980-01-01</p> <p>The paper examines satellite data used to construct mean snow cover <span class="hlt">caps</span> for the Northern Hemisphere. The zonally averaged snow cover from these maps is used to calculate the seasonal cycle of zonally averaged surface albedo. The effects of meltwater on the surface, solar zenith angle, and cloudiness are parameterized and included in the calculations of snow and <span class="hlt">ice</span> albedo. The data allows a calculation of surface albedo for any land or ocean 10 deg latitude band as a function of surface temperature <span class="hlt">ice</span> and snow cover; the correct determination of the <span class="hlt">ice</span> boundary is more important than the snow boundary for accurately simulating the <span class="hlt">ice</span> and snow albedo feedback.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70029193','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70029193"><span>A microphysically-based approach to modeling emissivity and albedo of the martian seasonal <span class="hlt">caps</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Eluszkiewicz, J.; Moncet, J.-L.; Titus, T.N.; Hansen, G.B.</p> <p>2005-01-01</p> <p>A new model of albedo and emissivity of the martian seasonal <span class="hlt">caps</span> represented as porous CO2 slabs containing spherical voids and dust particles is described. In the model, a radiative transfer model is coupled with a microphysical model in order to link changes in albedo and emissivity to changes in porosity caused by <span class="hlt">ice</span> metamorphism. The coupled model is capable of reproducing temporal changes in the spectra of the <span class="hlt">caps</span> taken by the Thermal Emission Spectrometer onboard the Mars Global Surveyor and it can be used as the forward model in the retrievals of the <span class="hlt">caps</span>' physical properties (porosity, dust abundance, void and dust grain size) from the spectra. Preliminary results from such inversion studies are presented. ?? 2004 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC41G..03B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC41G..03B"><span>Central Tibetan Plateau atmospheric trace metals contamination: a 500-year record from the Puruogangri <span class="hlt">ice</span> core</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beaudon, E.; Gabrielli, P.; Sierra Hernandez, R.; Wegner, A.; Thompson, L. G.</p> <p>2017-12-01</p> <p>Since the 1980s, Asia has experienced enormous industrial development from rapid population growth, industrialization and consequent large-scale environmental changes. The inherent generated atmospheric pollution currently contributes to half of all Earth's anthropogenic trace metals emissions. Asian trace metal aerosols, when deposited on glaciers of the surrounding mountains of the Tibetan Plateau (TP), leave a characteristic chemical fingerprint. Interpreting trace element (TE) records from glaciers implies a thorough comprehension of their provenance and temporal variability. It is then essential to discriminate the TEs' natural background components from their anthropogenic components. Here we present 500-year TE records from the Puruogangri <span class="hlt">ice</span> core (Tibet, China) that provide a highly resolved account of the impact of past atmospheric influences, environmental processes and human activities on the central TP. A decreasing aeolian dust input to the <span class="hlt">ice</span> <span class="hlt">cap</span> allowed the detection of an atmospheric pollution signal. The anthropogenic pollution contribution emerges in the record since the early 1900s and increases substantially after 1935. The metallurgy (Zn, Pb and steel smelting) emission products from the former Soviet Union and especially from central Asia likely enhanced the anthropogenic deposition to the Puruogangri <span class="hlt">ice</span> <span class="hlt">cap</span> between 1935 and 1980, suggesting that the westerlies served as a conveyor of atmospheric pollution to central Tibet. The impact of this industrial pollution cumulated with that of the hemispheric coal and gasoline combustion which are respectively traced by Sb and Pb enrichment in the <span class="hlt">ice</span>. The Chinese steel production accompanying the Great Leap Forward (1958-1961) and the Chinese Cultural Revolution (1966-1976) is proposed as a secondary but proximal source of Pb pollution affecting the <span class="hlt">ice</span> <span class="hlt">cap</span> between 1958 and 1976. The most recent decade (1980-1992) of the enrichment time series suggests that Puruogangri <span class="hlt">ice</span> <span class="hlt">cap</span> recorded the early</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20171208_Archive_e001496.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20171208_Archive_e001496.html"><span>Glaciers and Sea Level Rise</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-05-15</p> <p>An airplane drops essential support on the Austfonna <span class="hlt">Ice</span> <span class="hlt">Cap</span> in <span class="hlt">Svalbard</span> (Norwegian Arctic). The triangular structure is a corner reflector used as ground reference for airborne radar surveys. To learn about the contributions of glaciers to sea level rise, visit: www.nasa.gov/topics/earth/features/glacier-sea-rise.html Credit: Andrea Taurisano, Norwegian Polar Institute NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA02373&hterms=fingerprints&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfingerprints','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA02373&hterms=fingerprints&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfingerprints"><span>Mars South Polar <span class="hlt">Cap</span> 'Fingerprint' Terrain</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>This picture is illuminated by sunlight from the upper left.<p/>Some portions of the martian south polar residual <span class="hlt">cap</span> have long, somewhat curved troughs instead of circular pits. These appear to form in a layer of material that may be different than that in which 'swiss cheese' circles and pits form, and none of these features has any analog in the north polar <span class="hlt">cap</span> or elsewhere on Mars. This picture shows the 'fingerprint' terrain as a series of long, narrow depressions considered to have formed by collapse and widening by sublimation of <span class="hlt">ice</span>. Unlike the north polar <span class="hlt">cap</span>, the south polar region stays cold enough in summer to retain frozen carbon dioxide. Viking Orbiter observations during the late 1970s showed that very little water vapor comes off the south polar <span class="hlt">cap</span> during summer, indicating that any frozen water that might be there remains solid throughout the year.<p/>This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image was obtained in early southern spring on August 4, 1999. It shows an area 3 x 5 kilometers (1.9 x 3.1 miles) at a resolution of about 7.3 meters (24 ft) per pixel. Located near 86.0oS, 53.9oW.<p/>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2981580','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2981580"><span>Reduced Metabolic Cost of Locomotion in <span class="hlt">Svalbard</span> Rock Ptarmigan (Lagopus muta hyperborea) during Winter</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lees, John; Nudds, Robert; Stokkan, Karl-Arne; Folkow, Lars; Codd, Jonathan</p> <p>2010-01-01</p> <p>The <span class="hlt">Svalbard</span> rock ptarmigan, Lagopus muta hyperborea experiences extreme photoperiodic and climatic conditions on the Arctic archipelago of <span class="hlt">Svalbard</span>. This species, however, is highly adapted to live in this harsh environment. One of the most striking adaptations found in these birds is the deposition, prior to onset of winter, of fat stores which may comprise up to 32% of body mass and are located primarily around the sternum and abdominal region. This fat, while crucial to the birds' survival, also presents a challenge in that the bird must maintain normal physiological function with this additional mass. In particular these stores are likely to constrain the respiratory system, as the sternum and pelvic region must be moved during ventilation and carrying this extra load may also impact upon the energetic cost of locomotion. Here we demonstrate that winter birds have a reduced cost of locomotion when compared to summer birds. A remarkable finding given that during winter these birds have almost twice the body mass of those in summer. These results suggest that <span class="hlt">Svalbard</span> ptarmigan are able to carry the additional winter fat without incurring any energetic cost. As energy conservation is paramount to these birds, minimising the costs of moving around when resources are limited would appear to be a key adaptation crucial for their survival in the barren Arctic environment. PMID:21125015</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ERL.....8c5044Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ERL.....8c5044Z"><span>Large cryoconite aggregates on a <span class="hlt">Svalbard</span> glacier support a diverse microbial community including ammonia-oxidizing archaea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zarsky, Jakub D.; Stibal, Marek; Hodson, Andy; Sattler, Birgit; Schostag, Morten; Hansen, Lars H.; Jacobsen, Carsten S.; Psenner, Roland</p> <p>2013-09-01</p> <p>The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in <span class="hlt">Svalbard</span> which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, <span class="hlt">ice</span> and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and amoA genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16468388','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16468388"><span>Brominated flame retardants in polar bears (Ursus maritimus) from Alaska, the Canadian Arctic, East Greenland, and <span class="hlt">Svalbard</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Muir, Derek C G; Backus, Sean; Derocher, Andrew E; Dietz, Rune; Evans, Thomas J; Gabrielsen, Geir W; Nagy, John; Norstrom, Ross J; Sonne, Christian; Stirling, Ian; Taylor, Mitch K; Letcher, Robert J</p> <p>2006-01-15</p> <p>Polybrominated diphenyl ethers (PBDEs) were determined in adipose tissue of adult and subadult female polar bears sampled between 1999 and 2002 from sub-populations in Arctic Canada, eastern Greenland, and <span class="hlt">Svalbard</span>, and in males and females collected from 1994 to 2002 in northwestern Alaska. Only 4 congeners (BDE47, 99, 100, and 153) were consistently identified in all samples. BDE47 was the major PBDE congener representing from 65% to 82% of the sum (sigma) PBDEs. Age was not a significant covariate for individual PBDEs or sigmaPBDE. Higher proportions of BDE 99, 100, and 153 were generally found in samples from the Canadian Arctic than from <span class="hlt">Svalbard</span> or the Bering-Chukchi Sea area of Alaska. Geometric mean sigmaPBDE concentrations were highest for female polar bear fat samples collected from <span class="hlt">Svalbard</span> (50 ng/g lipid weight (lw)) and East Greenland (70 ng/g lw). Significantly lower sigmaPBDE concentrations were found in fat of bears from Canada and Alaska (means ranging from 7.6 to 22 ng/g lw).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1814173L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1814173L"><span>Evaporites on <span class="hlt">Ice</span>: Experimental Assessment of Evaporites Formation on Antarctica (and on Martian North Polar Residual <span class="hlt">Cap</span>)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Losiak, Anna; Derkowski, Arkadiusz; Skala, Aleksander; Trzcinski, Jerzy</p> <p>2016-04-01</p> <p>Evaporites are highly water soluble minerals, formed as a result of the evaporation or freezing of bodies of water. They are common weathering minerals found on rocks (including meteorites) on Antarctic <span class="hlt">ice</span> sheet [1,2,3,4]. The water necessary for the reaction is produced by melting of <span class="hlt">ice</span> below the dark-colored meteorites which can heat up to a few degrees above 0 °C due to insolation heating during wind-free summer days [5,6]. The Martian North Polar Residual <span class="hlt">Cap</span> is surrounded by a young [7] dune field that is rich in evaporitic mineral: gypsum [8]. Its existence implies that relatively recently in the Martian history (in late Amazonian, when surface conditions were comparable to the current ones) there was a significant amount of liquid water present on the Mars surface. One of the proposed solutions to this problem is that gypsum is formed by weathering on/in <span class="hlt">ice</span> [9,10,11,12,13], similarly to the process occurring on the Antarctic <span class="hlt">ice</span> sheet. Recently, Losiak et al. 2015 showed that that during the warmest days of the Martian summer, solar irradiation may be sufficient to melt pure water <span class="hlt">ice</span> located below a layer of dark dust particles lying on the steepest sections of the equator-facing slopes of the spiral troughs within Martian NPRC. Under the current irradiation conditions, melting is possible in very restricted areas of the NPRC and it lasts for up to couple of hours, but during the times of high irradiance at the north pole [15] this process could have been much more pronounced. Liquid water can be metastable at the NPRC because the pressure during the summer season is ~760-650 Pa [16] which is above the triple point of water. The rate of free-surface "clean" liquid water evaporation under average Martian conditions determined experimentally by [17] is comparable to the rate of melting determined by [21] (if there is no wind at the surface). In the current study we attempt to determine experimentally how many melting-freezing cycles are required to form</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPSC...11.1008C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPSC...11.1008C"><span>Hyperspectral characterisation of the Martian south polar residual <span class="hlt">cap</span> using CRISM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Campbell, J. D.; Sidiropoulos, P.; Muller, J.-P.</p> <p>2017-09-01</p> <p>We present our research on hyperspectral characterization of the Martian South Polar Residual <span class="hlt">Cap</span> (SPRC), with a focus on the detection of organic signatures within the dust content of the <span class="hlt">ice</span>. The SPRC exhibits unique CO2 <span class="hlt">ice</span> sublimation features known colloquially as 'Swiss Cheese Terrain' (SCT). These flat floored, circular depressions are highly dynamic, and may expose dust particles previously trapped within the <span class="hlt">ice</span> in the depression walls and partially on the floors. Here we identify suitable regions for potential dust exposure on the SPRC, and utilise data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on board NASA's Mars Reconnaissance Orbiter (MRO) satellite to examine infrared spectra of dark regions to establish their mineral composition, to eliminate the effects of <span class="hlt">ices</span> on sub-pixel dusty features, and to assess whether ther might be signatures indicative of Polycyclic Aromatic Hydrocarbons (PAHs). Spectral mapping has identified compositional differences between depression rims and the majority of the SPRC and CRISM spectra have been corrected to minimise the influence of CO2 and H2O <span class="hlt">ice</span>. Whilst no conclusive evidence for PAHs has been found, depression rims are shown to have higher water content than regions of featureless <span class="hlt">ice</span>, and there are indications of magnesium carbonate within the dark, dusty regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.P72C..06R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.P72C..06R"><span>Seasonally-Active Water on Mars: Vapour, <span class="hlt">Ice</span>, Adsorbate, and the Possibility of Liquid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Richardson, M. I.</p> <p>2002-12-01</p> <p>Seasonally-active water can be defined to include any water reservoir that communicates with other reservoirs on time scales of a year or shorter. It is the interaction of these water reservoirs, under the influence of varying solar radiation and in conjunction with surface and atmospheric temperatures, that determines the phase-stability field for water at the surface, and the distribution of water in various forms below, on, and above the surface. The atmosphere is the critical, dynamical link in this cycling system, and also (fortunately) one of the easiest to observe. Viking and Mars Global Surveyor observations paint a strongly asymmetric picture of the global seasonal water cycle, tied proximately to planetary eccentricity, and the existence of residual <span class="hlt">ice</span> <span class="hlt">caps</span> of different composition at the two poles. The northern summer experiences the largest water vapour columns, and is associated with sublimation from the northern residual water <span class="hlt">ice</span> <span class="hlt">cap</span>. The southern summer residual carbon dioxide <span class="hlt">ice</span> <span class="hlt">cap</span> is cold trap for water. Asymmetry in the water cycle is an unsolved problem. Possible solutions may involve the current timing of perihelion (the water <span class="hlt">cap</span> resides at the pole experiencing the longer but cooler summer), the trapping of water <span class="hlt">ice</span> in the northern hemisphere by tropical water <span class="hlt">ice</span> clouds, and the bias in the annual-average, zonal-mean atmospheric circulation resulting from the zonal-mean difference in the elevation of the northern and southern hemispheres. Adsorbed and frozen water have proven harder to constrain. Recent Odyssey Gamma Ray Spectrometer results suggest substantial ground <span class="hlt">ice</span> in the mid- and high-latitudes, but this water is likely below the seasonal skin depth for two reasons: the GRS results are best fit with such a model, and GCM models of the water cycle produce dramatically unrealistic atmospheric vapour distributions when such a very near surface, GRS-like distribution is initialized - ultimately removing the water to the northern and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930010628','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930010628"><span>Antarctic lakes (above and beneath the <span class="hlt">ice</span> sheet): Analogues for Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rice, J. W., Jr.</p> <p>1992-01-01</p> <p>The perennial <span class="hlt">ice</span> covered lakes of the Antarctic are considered to be excellent analogues to lakes that once existed on Mars. Field studies of <span class="hlt">ice</span> covered lakes, paleolakes, and polar beaches were conducted in the Bunger Hills Oasis, Eastern Antarctica. These studies are extended to the Dry Valleys, Western Antarctica, and the Arctic. Important distinctions were made between <span class="hlt">ice</span> covered and non-<span class="hlt">ice</span> covered bodies of water in terms of the geomorphic signatures produced. The most notable landforms produced by <span class="hlt">ice</span> covered lakes are <span class="hlt">ice</span> shoved ridges. These features form discrete segmented ramparts of boulders and sediments pushed up along the shores of lakes and/or seas. Sub-<span class="hlt">ice</span> lakes have been discovered under the Antarctic <span class="hlt">ice</span> sheet using radio echo sounding. These lakes occur in regions of low surface slope, low surface accumulations, and low <span class="hlt">ice</span> velocity, and occupy bedrock hollows. The presence of sub-<span class="hlt">ice</span> lakes below the Martian polar <span class="hlt">caps</span> is possible. The discovery of the Antarctic sub-<span class="hlt">ice</span> lakes raises possibilities concerning Martian lakes and exobiology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12493194','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12493194"><span>Contaminants in <span class="hlt">Svalbard</span> polar bear samples archived since 1967 and possible population level effects.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Derocher, Andrew E; Wolkers, Hans; Colborn, Theo; Schlabach, Martin; Larsen, Thor S; Wiig, Øystein</p> <p>2003-01-01</p> <p>Blood plasma samples were collected in 1967 from 32 polar bears (Ursus maritimus) in eastern <span class="hlt">Svalbard</span>. These samples were stored frozen until 2001 and then analyzed for 33 polychlorinated biphenyls (PCB), two toxaphene congeners, DDTs, chlordanes (CHL), hexachlorobenzene, hexachlorocyclohexanes (HCHs), and polybrominated flame retardants (biphenyls and diphenyl ethers). The 1967 pollutant levels were compared with values from 1993 to 1994 for adult females and adult males to obtain insights into the historical development of pollution in the Norwegian Arctic. Differences in the OC levels measured between 1967 and 1993-1994 ranged from a decrease (PCB 187 and p,p-DDE) to unchanged in both sexes (PCBs 105, 118, 209, and HCH) to an increase in females (PCBs 99, 128, and CHL), to increases in both sexes (PCBs 138, 153, 156, 157, 170, 180, 194, and 206). The maximum change was a nine-fold increase in PCB 157 in adult females. Changes from 1967 to 1993-1994 in contaminant pattern expressed relative to PCB 153 could be explained by a combination of selective metabolism and accumulation of organochlorines in polar bears and temporal changes in the contaminant mixture being transported to the Arctic. Harvest of polar bears in <span class="hlt">Svalbard</span> ended in 1973 and it appears that most pollutant levels were increasing at the same time that the population was expected to recover from over-harvest. The mean age of adult females in the <span class="hlt">Svalbard</span> population was similar to other populations where pollution levels are lower but harvest is intense. Females with cubs-of-the-year > or =16 years old are uncommon in the population for unknown reasons. The impacts of contaminants on the <span class="hlt">Svalbard</span> polar bear population are inconclusive but there are suggestions of contaminant-related population level effects that could have resulted from reproductive impairment of females, lower survival rates of cubs, or increased mortality of reproductive females. Copyright 2002 Elsevier Science B.V.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70022977','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70022977"><span>TES premapping data: Slab <span class="hlt">ice</span> and snow flurries in the Martian north polar night</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Titus, T.N.; Kieffer, H.H.; Mullins, K.F.; Christensen, P.R.</p> <p>2001-01-01</p> <p>In the 1970s, Mariner and Viking spacecraft observations of the north polar region of Mars revealed polar brightness temperatures that were significantly below the expected kinetic temperatures for CO2 sublimation. For the past few decades, the scientific community has speculated as to the nature of these Martian polar cold spots. Thermal Emission Spectrometer (TES) thermal spectral data have shown these cold spots to result largely from fine-grained, CO2 and have constrained most of these cold spots to the surface (or near-surface). Cold spot formation is strongly dependent on topography, forming preferentially near craters and on polar slopes. TES data, combined with Mars Orbiter Laser Altimeter (MOLA) cloud data, suggest atmospheric condensates form a small fraction of the observed cold spots. TES observations of spectra close to a blackbody indicate that another major component of the polar <span class="hlt">cap</span> is slab CO2 <span class="hlt">ice</span>; these spectrally bland regions commonly have a low albedo. The cause is uncertain but may result from most of the light being reflected toward the specular direction, from the slab <span class="hlt">ice</span> being intrinsically dark, or from it being transparent. Regions of the <span class="hlt">cap</span> where the difference between the brightness temperatures at 18 ??m (T18) and 25 ??m (T25) is less than 5?? are taken to indicate deposits of slab <span class="hlt">ice</span>. Slab <span class="hlt">ice</span> is the dominant component of the polar <span class="hlt">cap</span> at latitudes outside of the polar night. Copyright 2001 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP51A1043L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP51A1043L"><span>A transient fully coupled climate-<span class="hlt">ice</span>-sheet simulation of the last glacial inception</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lofverstrom, M.; Otto-Bliesner, B. L.; Lipscomb, W. H.; Fyke, J. G.; Marshall, S.; Sacks, B.; Brady, E. C.</p> <p>2017-12-01</p> <p>The last glacial inception occurred around 115 ka, following a relative minimum in the Northern Hemisphere summer insolation. It is believed that small and spatially separated <span class="hlt">ice</span> <span class="hlt">caps</span> initially formed in the high elevation regions of northern Canada, Scandinavia, and along the Siberian Arctic coast. These <span class="hlt">ice</span> <span class="hlt">caps</span> subsequently migrated down in the valleys where they coalesced and formed the initial seeds of the large coherent <span class="hlt">ice</span> masses that covered the northern parts of the North American and Eurasian continents over most of the last glacial cycle. Sea level records show that the initial growth period lasted for about 10 kyrs, and the resulting <span class="hlt">ice</span> sheets may have lowered the global sea level by as much as 30 to 50 meters. Here we examine the transient climate system evolution over the period between 118 and 110 ka, using the fully coupled Community Earth System Model, version 2 (CESM2). This model features a two-way coupled high-resolution (4x4 km) <span class="hlt">ice</span>-sheet component (Community <span class="hlt">Ice</span> Sheet model, version 2; CISM2) that simulates <span class="hlt">ice</span> sheets as an interactive component of the climate system. We impose a transient forcing protocol where the greenhouse gas concentrations and the orbital parameters follow the nominal year in the simulation; the model topography is also dynamically evolving in order to reflect changes in <span class="hlt">ice</span> elevation throughout the simulation. The analysis focuses on how the climate system evolves over this time interval, with a special focus on glacial inception in the high-latitude continents. Results will highlight how the evolving <span class="hlt">ice</span> sheets compare to data and previous model based reconstructions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20403839','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20403839"><span>Response of faults to climate-driven changes in <span class="hlt">ice</span> and water volumes on Earth's surface.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hampel, Andrea; Hetzel, Ralf; Maniatis, Georgios</p> <p>2010-05-28</p> <p>Numerical models including one or more faults in a rheologically stratified lithosphere show that climate-induced variations in <span class="hlt">ice</span> and water volumes on Earth's surface considerably affect the slip evolution of both thrust and normal faults. In general, the slip rate and hence the seismicity of a fault decreases during loading and increases during unloading. Here, we present several case studies to show that a postglacial slip rate increase occurred on faults worldwide in regions where <span class="hlt">ice</span> <span class="hlt">caps</span> and lakes decayed at the end of the last glaciation. Of note is that the postglacial amplification of seismicity was not restricted to the areas beneath the large Laurentide and Fennoscandian <span class="hlt">ice</span> sheets but also occurred in regions affected by smaller <span class="hlt">ice</span> <span class="hlt">caps</span> or lakes, e.g. the Basin-and-Range Province. Our results do not only have important consequences for the interpretation of palaeoseismological records from faults in these regions but also for the evaluation of the future seismicity in regions currently affected by deglaciation like Greenland and Antarctica: shrinkage of the modern <span class="hlt">ice</span> sheets owing to global warming may ultimately lead to an increase in earthquake frequency in these regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22000675','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22000675"><span>Glaciers and <span class="hlt">ice</span> sheets as a biome.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anesio, Alexandre M; Laybourn-Parry, Johanna</p> <p>2012-04-01</p> <p>The tundra is the coldest biome described in typical geography and biology textbooks. Within the cryosphere, there are large expanses of <span class="hlt">ice</span> in the Antarctic, Arctic and alpine regions that are not regarded as being part of any biome. During the summer, there is significant melt on the surface of glaciers, <span class="hlt">ice</span> <span class="hlt">caps</span> and <span class="hlt">ice</span> shelves, at which point microbial communities become active and play an important role in the cycling of carbon and other elements within the cryosphere. In this review, we suggest that it is time to recognise the cryosphere as one of the biomes of Earth. The cryospheric biome encompasses extreme environments and is typified by truncated food webs dominated by viruses, bacteria, protozoa and algae with distinct biogeographical structures. Copyright © 2011 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040062528&hterms=melting+ice+caps&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmelting%2Bice%2Bcaps','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040062528&hterms=melting+ice+caps&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmelting%2Bice%2Bcaps"><span>The Subsurface <span class="hlt">Ice</span> Probe (SIPR): A Low-Power Thermal Probe for the Martian Polar Layered Deposits</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cardell, G.; Hecht, M. H.; Carsey, F. D.; Engelhardt, H.; Fisher, D.; Terrell, C.; Thompson, J.</p> <p>2004-01-01</p> <p>The distinctive layering visible in images from Mars Global Surveyor of the Martian polar <span class="hlt">caps</span>, and particularly in the north polar <span class="hlt">cap</span>, indicates that the stratigraphy of these polar layered deposits may hold a record of Martian climate history covering millions of years. On Earth, <span class="hlt">ice</span> sheets are cored to retrieve a pristine record of the physical and chemical properties of the <span class="hlt">ice</span> at depth, and then studied in exacting detail in the laboratory. On the Martian north polar <span class="hlt">cap</span>, coring is probably not a practical method for implementation in an autonomous lander. As an alternative, thermal probes that drill by melting into the <span class="hlt">ice</span> are feasible for autonomous operation, and are capable of reasonable approximations to the scientific investigations performed on terrestrial cores, while removing meltwater to the surface for analysis. The Subsurface <span class="hlt">Ice</span> Probe (SIPR) is such a probe under development at JPL. To explore the dominant climate cycles, it is postulated that tens of meters of depth should be profiled, as this corresponds to the vertical separation of the major layers visible in the MOC images [1]. Optical and spectroscopic analysis of the layers, presumably demarcated by embedded dust and possibly by changes in the <span class="hlt">ice</span> properties, would contribute to the construction of a chronology. Meltwater analysis may be used to determine the soluble chemistry of the embedded dust, and to monitor gradients of atmospheric gases, particularly hydrogen and oxygen, and isotopic variations that reflect atmospheric conditions at the time the layer was deposited. Thermal measurements can be used to determine the geothermal gradient and the bulk mechanical properties of the <span class="hlt">ice</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA02369.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA02369.html"><span>"Cottage Cheese" Texture on the Martian North Polar <span class="hlt">Cap</span> in Summer</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2000-04-24</p> <p>This image is illuminated by sunlight from the upper left. Martian Dairy Products? If parts of the south polar <span class="hlt">cap</span> can look like swiss cheese (see "Martian "Swiss Cheese""), then parts of the north polar <span class="hlt">cap</span> might as well look like some kind of cheese, too. This picture shows a cottage cheese-like texture on the surface of a part of the residual--summertime--north polar <span class="hlt">cap</span>. The north polar <span class="hlt">cap</span> surface is mostly covered by pits, cracks, small bumps and knobs. In this image, the <span class="hlt">cap</span> surface appears bright and the floors of pits look dark. Based upon observations made by the Mariner 9 and Viking orbiters in the 1970s, the north polar residual <span class="hlt">cap</span> is thought to contain mostly water <span class="hlt">ice</span> because its summertime temperature is usually near the freezing point of water and water vapor was observed by the Vikings to be coming off the <span class="hlt">cap</span> during summer. The south residual <span class="hlt">cap</span> is different--its temperatures in summer remain cold enough to freeze carbon dioxide, and very little to no water vapor has been observed to come off the south <span class="hlt">cap</span> in summer. The pits that have developed on the north polar <span class="hlt">cap</span> surface are closely-spaced relative to the very different depressions in the south polar <span class="hlt">cap</span>. The pits are estimated from the length of shadows cast in them to be less than about 2 meters (5.5 feet) deep. These pits probably develop slowly over thousands of years of successive spring and summer seasons. This picture was taken by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) during northern summer on April 5, 1999. The picture is located near 82.1°N, 329.6°W and covers an area 1.5 km wide by 3 km long (0.9 x 1.8 miles) at a resolution of 3 meters (10 ft) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA02369</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRC..122.5566F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRC..122.5566F"><span>Effects of sea-<span class="hlt">ice</span> and biogeochemical processes and storms on under-<span class="hlt">ice</span> water fCO2 during the winter-spring transition in the high Arctic Ocean: Implications for sea-air CO2 fluxes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fransson, Agneta; Chierici, Melissa; Skjelvan, Ingunn; Olsen, Are; Assmy, Philipp; Peterson, Algot K.; Spreen, Gunnar; Ward, Brian</p> <p>2017-07-01</p> <p>We performed measurements of carbon dioxide fugacity (fCO2) in the surface water under Arctic sea <span class="hlt">ice</span> from January to June 2015 during the Norwegian young sea <span class="hlt">ICE</span> (N-<span class="hlt">ICE</span>2015) expedition. Over this period, the ship drifted with four different <span class="hlt">ice</span> floes and covered the deep Nansen Basin, the slopes north of <span class="hlt">Svalbard</span>, and the Yermak Plateau. This unique winter-to-spring data set includes the first winter-time under-<span class="hlt">ice</span> water fCO2 observations in this region. The observed under-<span class="hlt">ice</span> fCO2 ranged between 315 µatm in winter and 153 µatm in spring, hence was undersaturated relative to the atmospheric fCO2. Although the sea <span class="hlt">ice</span> partly prevented direct CO2 exchange between ocean and atmosphere, frequently occurring leads and breakup of the <span class="hlt">ice</span> sheet promoted sea-air CO2 fluxes. The CO2 sink varied between 0.3 and 86 mmol C m-2 d-1, depending strongly on the open-water fractions (OW) and storm events. The maximum sea-air CO2 fluxes occurred during storm events in February and June. In winter, the main drivers of the change in under-<span class="hlt">ice</span> water fCO2 were dissolution of CaCO3 (ikaite) and vertical mixing. In June, in addition to these processes, primary production and sea-air CO2 fluxes were important. The cumulative loss due to CaCO3 dissolution of 0.7 mol C m-2 in the upper 10 m played a major role in sustaining the undersaturation of fCO2 during the entire study. The relative effects of the total fCO2 change due to CaCO3 dissolution was 38%, primary production 26%, vertical mixing 16%, sea-air CO2 fluxes 16%, and temperature and salinity insignificant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=22180','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=22180"><span>Diversity of Holocene life forms in fossil glacier <span class="hlt">ice</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Willerslev, Eske; Hansen, Anders J.; Christensen, Bent; Steffensen, Jørgen Peder; Arctander, Peter</p> <p>1999-01-01</p> <p>Studies of biotic remains of polar <span class="hlt">ice</span> <span class="hlt">caps</span> have been limited to morphological identification of plant pollen and spores. By using sensitive molecular techniques, we now demonstrate a much greater range of detectable organisms; from 2000- and 4000-year-old <span class="hlt">ice</span>-core samples, we obtained and characterized 120 clones that represent at least 57 distinct taxa and reveal a diversity of fungi, plants, algae, and protists. The organisms derive from distant sources as well as from the local arctic environment. Our results suggest that additional taxa may soon be readily identified, providing a plank for future studies of deep <span class="hlt">ice</span> cores and yielding valuable information about ancient communities and their change over time. PMID:10393940</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.4366H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.4366H"><span>Deciphering the evolution of the last Eurasian <span class="hlt">ice</span> sheets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hughes, Anna; Gyllencreutz, Richard; Mangerud, Jan; Svendsen, John Inge</p> <p>2016-04-01</p> <p>Glacial geologists need <span class="hlt">ice</span> sheet-scale chronological reconstructions of former <span class="hlt">ice</span> extent to set individual records in a wider context and compare interpretations of <span class="hlt">ice</span> sheet response to records of past environmental changes. <span class="hlt">Ice</span> sheet modellers require empirical reconstructions on size and volume of past <span class="hlt">ice</span> sheets that are fully documented, specified in time and include uncertainty estimates for model validation or constraints. Motivated by these demands, in 2005 we started a project (Database of the Eurasian Deglaciation, DATED) to compile and archive all published dates relevant to constraining the build-up and retreat of the last Eurasian <span class="hlt">ice</span> sheets, including the British-Irish, Scandinavian and <span class="hlt">Svalbard</span>-Barents-Kara Seas <span class="hlt">ice</span> sheets (BIIS, SIS and SBKIS respectively). Over 5000 dates were assessed for reliability and used together with published <span class="hlt">ice</span>-sheet margin positions to reconstruct time-slice maps of the <span class="hlt">ice</span> sheets' extent, with uncertainty bounds, every 1000 years between 25-10 kyr ago and at four additional periods back to 40 kyr ago. Ten years after the idea for a database was conceived, the first version of results (DATED-1) has now been released (Hughes et al. 2016). We observe that: i) both the BIIS and SBKIS achieve maximum extent, and commence retreat earlier than the larger SIS; ii) the eastern terrestrial margin of the SIS reached its maximum extent up to 7000 years later than the westernmost marine margin; iii) the combined maximum <span class="hlt">ice</span> volume (~24 m sea-level equivalent) was reached c. 21 ka; iv) large uncertainties exist; predominantly across marine sectors (e.g. the timing of coalescence and separation of the SIS and BKIS) but also in well-studied areas due to conflicting yet equally robust data. In just three years since the DATED-1 census (1 January 2013), the volume of new information (from both dates and mapped glacial geomorphology) has grown significantly (~1000 new dates). Here, we present the DATED-1 results in the context of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016QSRv..152..118H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016QSRv..152..118H"><span>Episodic expansion of Drangajökull, Vestfirðir, Iceland, over the last 3 ka culminating in its maximum dimension during the Little <span class="hlt">Ice</span> Age</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harning, David J.; Geirsdóttir, Áslaug; Miller, Gifford H.; Anderson, Leif</p> <p>2016-11-01</p> <p>Non-linear climate change is often linked to rapid changes in ocean circulation, especially around the North Atlantic. As the Polar Front fluctuated its latitudinal position during the Holocene, Iceland's climate was influenced by both the warm Atlantic currents and cool, sea <span class="hlt">ice</span>-bearing Arctic currents. Drangajökull is Iceland's fifth largest <span class="hlt">ice</span> <span class="hlt">cap</span>. Climate proxies in lake sediment cores, dead vegetation emerging from beneath the <span class="hlt">ice</span> <span class="hlt">cap</span>, and moraine segments identified in a new DEM constrain the episodic expansion of the <span class="hlt">ice</span> <span class="hlt">cap</span> over the past 3 ka. Collectively, our data show that Drangajökull was advancing at ∼320 BCE, 180 CE, 560 CE, 950 CE and 1400 CE and in a state of recession at ∼450 CE, 1250 CE and after 1850 CE. The Late Holocene maximum extent of Drangajökull occurred during the Little <span class="hlt">Ice</span> Age (LIA), occupying 262 km2, almost twice its area in 2011 CE and ∼20% larger than recent estimates of its LIA dimensions. Biological proxies from the sediment fill in a high- and low-elevation lake suggest limited vegetation and soil cover at high elevations proximal to the <span class="hlt">ice</span> <span class="hlt">cap</span>, whereas thick soil cover persisted until ∼750 CE at lower elevations near the coast. As Drangajökull expanded into the catchment of the high-elevation lake beginning at ∼950 CE, aquatic productivity diminished, following a trend of regional cooling supported by proxy records elsewhere in Iceland. Correlations between episodes of Drangajökull's advance and the documented occurrence of drift <span class="hlt">ice</span> on the North Icelandic Shelf suggest export and local production of sea <span class="hlt">ice</span> influenced the evolution of NW Iceland's Late Holocene climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012QSRv...48...61L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012QSRv...48...61L"><span>Dating High Arctic Holocene relative sea level changes using juvenile articulated marine shells in raised beaches</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Long, Antony J.; Strzelecki, Mateusz C.; Lloyd, Jerry M.; Bryant, Charlotte L.</p> <p>2012-08-01</p> <p>High Arctic raised beaches provide evidence for changes in relative sea-level (RSL), sea-<span class="hlt">ice</span> extent, storminess, and variations in sediment supply. In many High Arctic areas, driftwood and whale bone are usually the preferred targets for radiocarbon dating, with marine shells a third choice because of their often large age and height uncertainties with respect to former sea level. Here we detail a new approach to sampling marine shells that reduces these problems by targeting juvenile, articulated specimens of Astarte borealis that are washed onto the beach under storm conditions and become incorporated into the beach crest. Radiocarbon dates from articulated valves of A. borealis from eight raised beaches from Billefjorden, <span class="hlt">Svalbard</span>, provide a chronology for Holocene beach ridge formation and RSL change that compares favourably to the most precise records developed from elsewhere in <span class="hlt">Svalbard</span> using driftwood or whale bone. We demonstrate the value of this new approach by comparing our record with previously published RSL data from eastern <span class="hlt">Svalbard</span> to test different models of Late Weichselian <span class="hlt">ice</span> load in this region. We find support for a major <span class="hlt">ice</span> dome centred south and east of Kong Karls Land but no evidence for a significant <span class="hlt">ice</span> dome located over easternmost Spitsbergen or southern Hinlopen Strait as proposed from recent marine geophysical survey. The approach is potentially applicable elsewhere in <span class="hlt">Svalbard</span> and the High Arctic to address questions of RSL change and beach ridge chronology, and hence wider questions regarding palaeoclimate and <span class="hlt">ice</span> load history.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930010622&hterms=water+cycle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwater%2Bcycle','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930010622&hterms=water+cycle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwater%2Bcycle"><span>The Mars water cycle at other epochs: Recent history of the polar <span class="hlt">caps</span> and layered terrain</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jakosky, Bruce M.; Henderson, Bradley G.; Mellon, Michael T.</p> <p>1992-01-01</p> <p>The Martian polar <span class="hlt">caps</span> and layered terrain presumably evolves by the deposition and removal of small amounts of water and dust each year, the current <span class="hlt">cap</span> attributes therefore represent the incremental transport during a single year as integrated over long periods of time. The role was studied of condensation and sublimation of water <span class="hlt">ice</span> in this process by examining the seasonal water cycle during the last 10(exp 7) yr. In the model, axial obliquity, eccentricity, and L sub s of perihelion vary according to dynamical models. At each epoch, the seasonal variations in temperature are calculated at the two poles, keeping track of the seasonal CO2 <span class="hlt">cap</span> and the summertime sublimation of water vapor into the atmosphere; net exchange of water between the two <span class="hlt">caps</span> is calculated based on the difference in the summertime sublimation between the two <span class="hlt">caps</span> (or on the sublimation from one <span class="hlt">cap</span> if the other is covered with CO2 frost all year). Results from the model can help to explain (1) the apparent inconsistency between the timescales inferred for layer formation and the much older crater retention age of the <span class="hlt">cap</span> and (2) the difference in sizes of the two residual <span class="hlt">caps</span>, with the south being smaller than the north.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA02374&hterms=apron&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D10%26Ntt%3Dapron','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA02374&hterms=apron&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D10%26Ntt%3Dapron"><span>South Polar <span class="hlt">Cap</span> Erosion and Aprons</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>This scene is illuminated by sunlight from the upper left.<p/>While Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images have shown that the north and south polar <span class="hlt">cap</span> surfaces are very different from each other, one thing that the two have in common is that they both seem to have been eroded. Erosion in the north appears mostly to come in the form of pits from which <span class="hlt">ice</span> probably sublimed to vapor and was transported away from the polar <span class="hlt">cap</span> by wind. Erosion in the south takes on a wider range of possible processes that include collapse, slumping and mass-movement on slopes, and probably sublimation. Among the landforms created by these process on the south polar <span class="hlt">cap</span> are the 'aprons' that surround mesas and buttes of remnant layers such as the two almost triangular features in the lower quarter of this image. The upper slopes of the two triangular features show a stair-stepped pattern that suggest these hills are layered.<p/>This image shows part of the south polar residual <span class="hlt">cap</span> near 86.9oS, 78.5oW, and covers an area approximately 1.2 by 1.0 kilometers (0.7 x 0.6 miles) in size. The image has a resolution of 2.2 meters per pixel. The picture was taken on September 11, 1999.<p/>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35.3450Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35.3450Z"><span>Recession of the Northern polar <span class="hlt">cap</span> from the PFS Mars Express observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zasova, L. V.; Formisano, V.; Moroz, V. I.; Giuranna, M.; Grassi, D.; Hansen, G.; Ignatiev, N. I.; Maturilli, A.; Pfs Team</p> <p></p> <p>Planetary Fourier Spectrometer (PFS) has two spectral channels, devoted to the thermal and solar reflected spectral range investigations. The first observations by PFS of the Northern hemisphere ,which includes the North pole, occurred at Ls= 342 (northern winter). Surface temperature alone the orbit shows that the CO2 <span class="hlt">ice</span> polar <span class="hlt">cap</span>, where the surface temperature is found around 150K and below, is extended down to about 62 N. The spectra at latitudes above 80 N are obtained at polar darkness and at latitudes below 80 at illumination by the low Sun. Retrieved temperature profiles of the atmosphere at darkness show that temperature of the atmosphere is low enough to allow the CO2 condensation up to about 25 km. Between 70 and 80 latitude the upper levels of the atmosphere are heated by the Sun, but condensation of the CO2 may occur in the near surface layer below 5 km. The water <span class="hlt">ice</span> clouds exist at lower latitudes with maximum opacity at the edge of the polar <span class="hlt">cap</span>. More detailed investigation of the data obtained in winter as well as of the measurements in the northern spring will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://kidshealth.org/en/teens/contraception-cap.html','NIH-MEDLINEPLUS'); return false;" href="https://kidshealth.org/en/teens/contraception-cap.html"><span>Cervical <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... Videos for Educators Search English Español The Cervical <span class="hlt">Cap</span> KidsHealth / For Teens / The Cervical <span class="hlt">Cap</span> What's in ... Call the Doctor? Print What Is a Cervical <span class="hlt">Cap</span>? A cervical <span class="hlt">cap</span> is a small cup made ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1810633W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1810633W"><span><span class="hlt">Ice</span> Mass Changes in the Russian High Arctic from Repeat High Resolution Topography.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Willis, Michael; Zheng, Whyjay; Pritchard, Matthew; Melkonian, Andrew; Morin, Paul; Porter, Claire; Howat, Ian; Noh, Myoung-Jong; Jeong, Seongsu</p> <p>2016-04-01</p> <p>We use a combination of ASTER and cartographically derived Digital Elevation Models (DEMs) supplemented with WorldView DEMs, the ArcticDEM and ICESat lidar returns to produce a time-series of <span class="hlt">ice</span> changes occurring in the Russian High Arctic between the mid-20th century and the present. Glaciers on the western, Barents Sea coast of Novaya Zemlya are in a state of general retreat and thinning, while those on the eastern, Kara Sea coast are retreating at a slower rate. Franz Josef Land has a complicated pattern of thinning and thickening, although almost all the thinning is associated with rapid outlet glaciers feeding <span class="hlt">ice</span> shelves. Severnaya Zemlya is also thinning in a complicated manner. A very rapid surging glacier is transferring mass into the ocean from the western periphery of the Vavilov <span class="hlt">Ice</span> <span class="hlt">Cap</span> on October Revolution Island, while glaciers feeding the former Matusevich <span class="hlt">Ice</span> Shelf continue to thin at rates that are faster than those observed during the operational period of ICESat, between 2003 and 2009. Passive microwave studies indicate the total number of melt days is increasing in the Russian Arctic, although much of the melt may refreeze within the firn. It is likely that <span class="hlt">ice</span> dynamic changes will drive mass loss for the immediate future. The sub-marine basins beneath several of the <span class="hlt">ice</span> <span class="hlt">caps</span> in the region suggest the possibility that mass loss rates may accelerate in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMS...154..192W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMS...154..192W"><span>Seasonality of vertical flux and sinking particle characteristics in an <span class="hlt">ice</span>-free high arctic fjord-Different from subarctic fjords?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wiedmann, Ingrid; Reigstad, Marit; Marquardt, Miriam; Vader, Anna; Gabrielsen, Tove M.</p> <p>2016-02-01</p> <p>The arctic Adventfjorden (78°N, 15°E, <span class="hlt">Svalbard</span>) used to be seasonally <span class="hlt">ice</span>-covered but has mostly been <span class="hlt">ice</span>-free since 2007. We used this <span class="hlt">ice</span>-free arctic fjord as a model area to investigate (1) how the vertical flux of biomass (chlorophyll a and particulate organic carbon, POC) follows the seasonality of suspended material, (2) how sinking particle characteristics change seasonally and affect the vertical flux, and (3) if the vertical flux in the <span class="hlt">ice</span>-free arctic fjord with glacial runoff resembles the flux in subarctic <span class="hlt">ice</span>-free fjords. During seven field investigations (December 2011-September 2012), suspended biomass was determined (5, 15, 25, and 60 m), and short-term sediment traps were deployed (20, 30, 40, and 60 m), partly modified with gel-filled jars to study the size and frequency distribution of sinking particles. During winter, resuspension from the seafloor resulted in large, detrital sinking particles. Intense sedimentation of fresh biomass occurred during the spring bloom. The highest POC flux was found during autumn (770-1530 mg POC m- 2 d- 1), associated with sediment-loaded glacial runoff and high pteropod abundances. The vertical biomass flux in the <span class="hlt">ice</span>-free arctic Adventfjorden thus resembled that in subarctic fjords during winter and spring, but a higher POC sedimentation was observed during autumn.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=ice+AND+antarctica&id=EJ069907','ERIC'); return false;" href="https://eric.ed.gov/?q=ice+AND+antarctica&id=EJ069907"><span>Putting Radioactive Wastes on <span class="hlt">Ice</span>: A Proposal for an International Radionuclide Depository in Antarctica</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Zeller, E. J.; And Others</p> <p>1973-01-01</p> <p>Describes need for creating permanent disposal of high-level radioactive wastes accumulating in different countries. Possibilities of establishing facilities for this purpose in Antarctic <span class="hlt">ice</span> <span class="hlt">cap</span> are examined. (PS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996E%26PSL.144..605H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996E%26PSL.144..605H"><span>Deposition of atmospheric heavy metals to the Greenland <span class="hlt">ice</span> sheet from the 1783-1784 volcanic eruption of Laki, Iceland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hong, Sungmin; Candelone, Jean-Pierre; Boutron, Claude F.</p> <p>1996-11-01</p> <p>In order to assess better the influence of major volcanic events on the large scale atmospheric cycles of heavy metals, Greenland <span class="hlt">ice</span> dated from the time of the fallouts from the great 1783-1784 eruption of Laki volcano in Iceland has been analysed for Pb, Cd, Cu, Zn and sulphate. The concentrations of the four heavy metals investigated are found to be greatly enhanced in the <span class="hlt">ice</span> layers which correspond to the fallouts from the eruption, confirming that such events do modify the atmospheric cycles of heavy metals. Cumulative fallout of heavy metals to the whole Greenland <span class="hlt">ice</span> <span class="hlt">cap</span> from the 1783-1784 Laki eruption ranges from 1 t for Pb and Cd to 40 t for Zn. For Cd, Cu and Zn, it represents a few percent of the cumulative anthropogenic fallout to the <span class="hlt">ice</span> <span class="hlt">cap</span> from the Industrial Revolution to the present.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018QSRv..183..164G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018QSRv..183..164G"><span>Holocene multi-proxy environmental reconstruction from lake Hakluytvatnet, Amsterdamøya Island, <span class="hlt">Svalbard</span> (79.5°N)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gjerde, Marthe; Bakke, Jostein; D'Andrea, William J.; Balascio, Nicholas L.; Bradley, Raymond S.; Vasskog, Kristian; Ólafsdóttir, Sædis; Røthe, Torgeir O.; Perren, Bianca B.; Hormes, Anne</p> <p>2018-03-01</p> <p>High resolution proxy records of past climate are sparse in the Arctic due to low organic production that restricts the use of radiocarbon dating and challenging logistics that make data collection difficult. Here, we present a new lake record from lake Hakluytvatnet at Amsterdamøya island (79.5°N), the northwesternmost island on <span class="hlt">Svalbard</span>. Multi-proxy analyses of lake sediments in combination with geomorphological mapping reveal large environmental shifts that have taken place at Amsterdamøya during the Holocene. A robust chronology has been established for the lake sediment core through 28 AMS radiocarbon ages, and this gives an exceptionally well-constrained age control for a lake at this latitude. The Holocene was a period with large changes in the Hakluytvatnet catchment, and the onset of the Neoglacial (ca. 5 ka) marks the start of modern-day conditions in the catchment. The Neoglacial is characterized by fluctuations in the minerogenic input to the lake as well as internal productivity, and we suggest that these fluctuations are driven by atmospherically forced precipitation changes as well as sea <span class="hlt">ice</span> extent modulating the amount of moisture that can reach Hakluytvatnet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.C21A0427M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.C21A0427M"><span>Subglacial carbonate precipitates on central Baffin Island, Arctic Canada may constrain basal conditions for the Foxe sector of the Laurentide <span class="hlt">Ice</span> Sheet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, G. H.; Refsnider, K. A.</p> <p>2009-12-01</p> <p>Extensive, widespread carbonate deposits on gneissic bedrock have recently been discovered around the Barnes <span class="hlt">Ice</span> <span class="hlt">Cap</span>, central Baffin Island. Deposits range from conglomeratic crack-fillings ≤5 cm thick to laminated, striated films plastered on bedrock surfaces, often in the lee of obstacles. A single outcrop of these carbonates was first described by Andrews et al. (1972, Canadian Journal of Earth Sciences, 9, 233-238) and was interpreted as an early Tertiary limestone based on the presence of warm-climate palynomorphs including Liriodendron (tulip tree), Ulmus (elm), and Taxodium (cypress). However, recent fieldwork in the region has demonstrated that these carbonates are far more ubiquitous than previously thought and found on both glacially-polished bedrock surfaces and till boulders that melted out in recent decades from Laurentide <span class="hlt">ice</span> at the base of the Barnes <span class="hlt">Ice</span> <span class="hlt">Cap</span>. In many cases, these carbonates exhibit the characteristic morphologies of subglacial carbonates (flutes, furrows, and striations parallel to the direction of <span class="hlt">ice</span> flow, columnar spicules, and tufa-dam-like forms). A few deposits include angular sands, gravels, and pebbles. The nearest carbonate bedrock is Paleozoic limestone flooring Foxe Basin 130 km west of the Barnes <span class="hlt">Ice</span> <span class="hlt">Cap</span> summit. While subglacial carbonate deposits have been documented adjacent to retreating mountain and outlet glaciers and in areas previously covered by Pleistocene <span class="hlt">ice</span> sheets, few localities are distant from carbonate bedrock. Thus, the carbon required for carbonate deposition in the Barnes region was either (1) derived from Paleozoic limestone and dissolved in subglacial water that was subject to long-distance transport, or (2) there was sufficient trapped atmospheric CO2 in the <span class="hlt">ice</span> to yield alkaline basal meltwater which hydrolyzed calcium-bearing silicates in the local bedrock. Given the volume of carbonate deposited at some sites, we find the latter model unlikely. If the former model is applicable, these carbonates</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1611876G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1611876G"><span>Towards an <span class="hlt">Ice</span>-Free Arctic Ocean in Summertime</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gascard, Jean Claude</p> <p>2014-05-01</p> <p>Dividing the Arctic Ocean in two parts, the so-called Atlantic versus the Pacific sector, two distinct modes of variability appear for characterizing the Arctic sea-<span class="hlt">ice</span> extent from 70°N up to 80°N in both sectors. The Atlantic sector seasonal sea-<span class="hlt">ice</span> extent is characterized by a longer time scale than the Pacific sector with a break up melting season starting in May and reaching a peak in June-July, one month earlier than the Pacific sector of the Arctic Ocean revealing a faster time evolution and a larger spatial amplitude than the Atlantic sector. During recent years like 2007, sea-<span class="hlt">ice</span> extent with sea-<span class="hlt">ice</span> concentration above 15% retreated from 4 millions km2 to about 1 million km2 in the Arctic Pacific sector between 70° and 80°N except for 2012 when most of sea-<span class="hlt">ice</span> melted away in this region. That explained most of the differences between the two extreme years 2007 and 2012. In the Atlantic sector, Arctic sea-<span class="hlt">ice</span> retreated from 2 millions km2 to nearly 0 during recent years including 2007 and 2012. The Atlantic inflow North of <span class="hlt">Svalbard</span> and Franz Josef Land is more likely responsible for a northward retreat of the <span class="hlt">ice</span> edge in that region. The important factor is not only that the Arctic summer sea-<span class="hlt">ice</span> minimum extent decreased by 3 or 4 millions km2 over the past 10 years but also that the melting period was steadily increasing by one to two days every year during that period. An important factor concerns the strength of the freezing that can be quantified in terms of Freezing Degree Days FDD accumulated during the winter-spring season and the strength of the melting (MDD) that can be accumulated during the summer season. FDD and MDD have been calculated for the past 30 years all over the Arctic Ocean using ERA Interim Reanalysis surface temperature at 2m height in the atmosphere. It is clear that FDD decreased significantly by more than 2000 FDD between 1980 and 2012 which is equivalent to the sensible heat flux corresponding to more than a meter of sea-<span class="hlt">ice</span></p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008GMS...180.....D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008GMS...180.....D"><span>Arctic Sea <span class="hlt">Ice</span> Decline: Observations, Projections, Mechanisms, and Implications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>DeWeaver, Eric T.; Bitz, Cecilia M.; Tremblay, L.-Bruno</p> <p></p> <p>This volume addresses the rapid decline of Arctic sea <span class="hlt">ice</span>, placing recent sea <span class="hlt">ice</span> decline in the context of past observations, climate model simulations and projections, and simple models of the climate sensitivity of sea <span class="hlt">ice</span>. Highlights of the work presented here include • An appraisal of the role played by wind forcing in driving the decline; • A reconstruction of Arctic sea <span class="hlt">ice</span> conditions prior to human observations, based on proxy data from sediments; • A modeling approach for assessing the impact of sea <span class="hlt">ice</span> decline on polar bears, used as input to the U.S. Fish and Wildlife Service's decision to list the polar bear as a threatened species under the Endangered Species Act; • Contrasting studies on the existence of a "tipping point," beyond which Arctic sea <span class="hlt">ice</span> decline will become (or has already become) irreversible, including an examination of the role of the small <span class="hlt">ice</span> <span class="hlt">cap</span> instability in global warming simulations; • A significant summertime atmospheric response to sea <span class="hlt">ice</span> reduction in an atmospheric general circulation model, suggesting a positive feedback and the potential for short-term climate prediction. The book will be of interest to researchers attempting to understand the recent behavior of Arctic sea <span class="hlt">ice</span>, model projections of future sea <span class="hlt">ice</span> loss, and the consequences of sea <span class="hlt">ice</span> loss for the natural and human systems of the Arctic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000096520','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000096520"><span>Environmental Effects on Volcanic Eruptions:From Deep Ocean to Deep Space. Chapter 3. Volcanism and <span class="hlt">Ice</span> Interactions on Earth and Mars. Chapter 3</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chapman, Mary G.; Allen, Carlton C.; Gudmundsson, Magnus T.; Gulick, Virginia C.; Jakobsson, Sveinn P.; Lucchitta, Baerbel K.; Skilling, Ian P.; Waitt, Richard B.</p> <p>2000-01-01</p> <p>CONCLUSION Volcano/<span class="hlt">ice</span> interactions produce meltwater. Meltwater can enter the groundwater cycle and under the influence of hydrothermal systems, it can be later discharged to form channels and valleys or cycled upward to melt permafrost. Water or <span class="hlt">ice</span>-saturated ground can erupt into phreatic craters when covered by lava. Violent mixing of meltwater and volcanic material and rapid release can generate lahars or jokulhlaups, that have the ability to freight coarse material, great distances downslope from the vent. Eruption into meltwater generate unique appearing edifices, that are definitive indicators of volcano/<span class="hlt">ice</span> interaction. These features are hyaloclastic ridges or mounds and if <span class="hlt">capped</span> by lava, tuyas. On Earth, volcano/<span class="hlt">ice</span> interactions are limited to alpine regions and <span class="hlt">ice-capped</span> polar and temperate regions. On Mars, where precipitation may be an ancient phenomenon, these interactions may be limited to areas of ground <span class="hlt">ice</span> accumulation or the northern lowlands where water may have ponded fairly late in martian history. The recognition of features caused by volcano/<span class="hlt">ice</span> interactions could provide strong constraints for the history of volatiles on Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29498209','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29498209"><span>An <span class="hlt">ice</span>-binding and tandem beta-sandwich domain-containing protein in Shewanella frigidimarina is a potential new type of <span class="hlt">ice</span> adhesin.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vance, Tyler D R; Graham, Laurie A; Davies, Peter L</p> <p>2018-04-01</p> <p>Out of the dozen different <span class="hlt">ice</span>-binding protein (IBP) structures known, the DUF3494 domain is the most widespread, having been passed many times between prokaryotic and eukaryotic microorganisms by horizontal gene transfer. This ~25-kDa β-solenoid domain with an adjacent parallel α-helix is most commonly associated with an N-terminal secretory signal peptide. However, examples of the DUF3494 domain preceded by tandem Bacterial Immunoglobulin-like (BIg) domains are sometimes found, though uncharacterized. Here, we present one such protein (SfIBP_1) from the Antarctic bacterium Shewanella frigidimarina. We have confirmed and characterized the <span class="hlt">ice</span>-binding activity of its <span class="hlt">ice</span>-binding domain using thermal hysteresis measurements, fluorescent <span class="hlt">ice</span> plane affinity analysis, and <span class="hlt">ice</span> recrystallization inhibition assays. X-ray crystallography was used to solve the structure of the SfIBP_1 <span class="hlt">ice</span>-binding domain, to further characterize its <span class="hlt">ice</span>-binding surface and unique method of stabilizing or '<span class="hlt">capping</span>' the ends of the solenoid structure. The latter is formed from the interaction of two loops mediated by a combination of tandem prolines and electrostatic interactions. Furthermore, given their domain architecture and membrane association, we propose that these BIg-containing DUF3494 IBPs serve as <span class="hlt">ice</span>-binding adhesion proteins that are capable of adsorbing their host bacterium onto <span class="hlt">ice</span>. Submitted new structure to the Protein Data Bank (PDB: 6BG8). © 2018 Federation of European Biochemical Societies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850015318&hterms=clay&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dclay','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850015318&hterms=clay&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dclay"><span>Properties of Filamentary Sublimation Residues from Dispersions of Clay in <span class="hlt">Ice</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stephens, J. B.; Parker, T. J.; Saunders, R. S.; Laue, E. G.; Fanale, F. P.</p> <p>1985-01-01</p> <p>The properties of sublimate residues are of considerable interest in studies of the thermal modeling of Martian and cometary <span class="hlt">ice</span> surfaces. The study of the formation of sand grains from this mantle on Martian polar <span class="hlt">ice</span> is also supported by these experiments. To understand these properties, a series of low temperature vacuum experiments were run during which dirty <span class="hlt">ices</span> that might be expected to be found in Martian polar <span class="hlt">caps</span> and in comet nuclei were made and then freeze dried. In addition to using particulate material of appropriate grain size and minerology, particle nucleated <span class="hlt">ices</span> were simulated by dispersing the particulates in the <span class="hlt">ice</span> so that they did not contact one another. This noncontact dispersion was the most difficult requirement to achieve but the most rewarding in that it produced a new filamentary sublimate residue that was not a relic of the frozen dispersion. If the siliceous particles are allowed to touch one another in the <span class="hlt">ice</span> the structure of the contacting particles in the <span class="hlt">ice</span> will remain as a relic after the <span class="hlt">ice</span> is sublimed away.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRC..123..201C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRC..123..201C"><span>Mesoscale Eddy Activity and Transport in the Atlantic Water Inflow Region North of <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crews, L.; Sundfjord, A.; Albretsen, J.; Hattermann, T.</p> <p>2018-01-01</p> <p>Mesoscale eddies are known to transport heat and biogeochemical properties from Arctic Ocean boundary currents to basin interiors. Previous hydrographic surveys and model results suggest that eddy formation may be common in the Atlantic Water (AW) inflow area north of <span class="hlt">Svalbard</span>, but no quantitative eddy survey has yet been done for the region. Here vorticity and water property signatures are used to identify and track AW eddies in an eddy-resolving sea <span class="hlt">ice</span>-ocean model. The boundary current sheds AW eddies along most of the length of the continental slope considered, from the western Yermak Plateau to 40°E, though eddies forming east of 20°E are likely more important for slope-to-basin transport. Eddy formation seasonality reflects seasonal stability properties of the boundary current in the eastern portion of the study domain, but on and immediately east of the Yermak Plateau enhanced eddy formation during summer merits further investigation. AW eddies tend to be anticyclonic, have radii close to the local deformation radius, and be centered in the halocline. They transport roughly 0.16 Sv of AW and, due to their warm cores, 1.0 TW away from the boundary current. These findings suggest eddies may be important for halocline ventilation in the Eurasian Basin, as has been shown for Pacific Water eddies in the Canadian Basin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1916334M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1916334M"><span>Clay mineral distribution along the southern and western <span class="hlt">Svalbard</span> continental margin in association with contouritic deposition: insights for environmental and oceanographic reconstruction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Musco, Maria Elena; Caricchi, Chiara; Giulia Lucchi, Renata; Princivalle, Francesco; GIorgetti, Giovanna; Caburlotto, Andrea</p> <p>2017-04-01</p> <p>The Kveithola and Storfjorden troughs are two glacial depositional systems, situated South of the <span class="hlt">Svalbard</span> Archipelago (North Western Barents Sea), that during the last glaciation (MIS-2) have hosted <span class="hlt">ice</span> streams, which contributed to the build-up of the relative Trough Mouth Fans (TMFs) on the continental slope. The sedimentary record contained in TMFs provides several proxies that can be useful for reconstructing the <span class="hlt">ice</span>-streams dynamics during glacial periods, the onset of deglaciation and the climatic variability during interglacials. The TMF slopes facing the two troughs have been investigated during several international oceanographic cruises: SVAIS onboard R/V BIO Hespérides; EGLACOM, onboard R/V OGS Explora; PNRA Project CORIBAR, onboard R/V Maria S. Marien; Eurofleets-2 PREPARED, onboard RV-G.O. Sars. For this study we have focused on XRD analyses on clay minerals, collected from seven cores, taken during these cruises, and XRF analyses have also been conducted on the whole length of the cores. Clay mineral assemblages are controlled by source rock composition, physical-chemical weathering, transport and depositional mechanisms. In polar areas clay mineral analysis can be used also for reconstructing sedimentary processes, associated with glacial and interglacial conditions. Moreover in the North western Barents Sea smectite is considered a good proxy for reconstructing the North Atlantic Current strength, giving thus additional indication on the palaeoceanographic conditions associated with climatic changes. Here we present a first correlation among these cores, aiming to describe the clay mineral distribution in response to the climatic variations that followed the Last Glacial Maximum and describe the changes in <span class="hlt">ice</span>-stream dynamics and related oceanographic/environmental changes along the margin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/21054562-multi-mice-nuclear-powered-mobile-probes-explore-deep-interiors-ice-sheets-mars-jovian-moons','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/21054562-multi-mice-nuclear-powered-mobile-probes-explore-deep-interiors-ice-sheets-mars-jovian-moons"><span>Multi-MICE: Nuclear Powered Mobile Probes to Explore Deep Interiors of the <span class="hlt">Ice</span> Sheets on Mars and the Jovian Moons</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Maise, George; Powell, James; Paniagua, John</p> <p>2007-01-30</p> <p>The multi-kilometer thick Polar <span class="hlt">Caps</span> on Mars contain unique and important data about the multi-million year history of its climate, geology, meteorology, volcanology, cosmic ray and solar activity, and meteor impacts. They also may hold evidence of past life on Mars, including microbes, microfossils and biological chemicals. The objective of this paper is to describe a probe that can provide access to the data locked in the Polar <span class="hlt">Caps</span>. The MICE (Mars <span class="hlt">Ice</span> <span class="hlt">Cap</span> Explorer) system would explore the Polar <span class="hlt">Cap</span> interiors using mobile probes powered by compact, lightweight nuclear reactors. The probes would travel 100's of meters per daymore » along melt channels in the <span class="hlt">ice</span> sheets created by hot water jets from the 500 kW(th) nuclear reactors, ascending and descending, either vertically or at an angle to the vertical, reaching bedrock at kilometers beneath the surface. The powerful reactor will be necessary to provide sufficient hot water at high velocity to penetrate the extensive horizontal dust/sand layers that separate layers of <span class="hlt">ice</span> in the Mars <span class="hlt">Ice</span> <span class="hlt">Caps</span>. MICE reactors can operate at 500 kW(th) for more than 4 years, and much longer in practice, since power level will be much lower when the probes are investigating locations in detail at low or zero speed. Multiple probes, e.g. six, would be deployed in an interactive network, continuously communicating by RF and acoustic signals with each other and with the surface lander spacecraft. In turn, the lander would continuously communicate in real time, subject to speed of light delays, with scientists on Earth to transmit data and receive instructions for the MICE probes. Samples collected by the probes could be brought to the lander, for return to the Earth at the end of the mission.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017TCry...11.1327R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017TCry...11.1327R"><span>Brief communication: The global signature of post-1900 land <span class="hlt">ice</span> wastage on vertical land motion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Riva, Riccardo E. M.; Frederikse, Thomas; King, Matt A.; Marzeion, Ben; van den Broeke, Michiel R.</p> <p>2017-06-01</p> <p>Melting glaciers, <span class="hlt">ice</span> <span class="hlt">caps</span> and <span class="hlt">ice</span> sheets have made an important contribution to sea-level rise through the last century. Self-attraction and loading effects driven by shrinking <span class="hlt">ice</span> masses cause a spatially varying redistribution of ocean waters that affects reconstructions of past sea level from sparse observations. We model the solid-earth response to <span class="hlt">ice</span> mass changes and find significant vertical deformation signals over large continental areas. We show how deformation rates have been strongly varying through the last century, which implies that they should be properly modelled before interpreting and extrapolating recent observations of vertical land motion and sea-level change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22861821','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22861821"><span>Cryptococcus species (Tremellales) from glacial biomes in the southern (Patagonia) and northern (<span class="hlt">Svalbard</span>) hemispheres.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>de Garcia, Virginia; Zalar, Polona; Brizzio, Silvia; Gunde-Cimerman, Nina; van Broock, María</p> <p>2012-11-01</p> <p>Cryptococcus species (Basidiomycota) were isolated as the predominant yeast from glacial biomes of both Patagonia (Argentina) and the <span class="hlt">Svalbard</span> archipelago (Norway). For a selected group of Cryptococcus belonging to Tremellales, assimilative profile, production of extracellular hydrolytic enzymes and ribosomal DNA internal transcribed spacer and large subunit (D1/D2) sequences were analysed. Cryptococcus victoriae, which was originally described from Antarctica, was the most frequently found species at both locations. High variability within the species was observed and described at the genotypic and phenotypic levels, two newly described species were found in both Patagonia and <span class="hlt">Svalbard</span>: Cryptococcus fonsecae and Cryptococcus psychrotolerans. Two other new species were found only in Patagonia: Cryptococcus frias and Cryptococcus tronadorensis. Three additional new taxa were found, but they are not named as they were only represented by single isolates. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3365033','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3365033"><span>Pre-Partum Diet of Adult Female Bearded Seals in Years of Contrasting <span class="hlt">Ice</span> Conditions</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hindell, Mark A.; Lydersen, Christian; Hop, Haakon; Kovacs, Kit M.</p> <p>2012-01-01</p> <p>Changing patterns of sea-<span class="hlt">ice</span> distribution and extent have measurable effects on polar marine systems. Beyond the obvious impacts of key-habitat loss, it is unclear how such changes will influence <span class="hlt">ice</span>-associated marine mammals in part because of the logistical difficulties of studying foraging behaviour or other aspects of the ecology of large, mobile animals at sea during the polar winter. This study investigated the diet of pregnant bearded seals (Erignathus barbatus) during three spring breeding periods (2005, 2006 and 2007) with markedly contrasting <span class="hlt">ice</span> conditions in <span class="hlt">Svalbard</span> using stable isotopes (δ13C and δ15N) measured in whiskers collected from their newborn pups. The δ15N values in the whiskers of individual seals ranged from 11.95 to 17.45 ‰, spanning almost 2 full trophic levels. Some seals were clearly dietary specialists, despite the species being characterised overall as a generalist predator. This may buffer bearded seal populations from the changes in prey distributions lower in the marine food web which seems to accompany continued changes in temperature and <span class="hlt">ice</span> cover. Comparisons with isotopic signatures of known prey, suggested that benthic gastropods and decapods were the most common prey. Bayesian isotopic mixing models indicated that diet varied considerably among years. In the year with most fast-<span class="hlt">ice</span> (2005), the seals had the greatest proportion of pelagic fish and lowest benthic invertebrate content, and during the year with the least <span class="hlt">ice</span> (2006), the seals ate more benthic invertebrates and less pelagic fish. This suggests that the seals fed further offshore in years with greater <span class="hlt">ice</span> cover, but moved in to the fjords when <span class="hlt">ice</span>-cover was minimal, giving them access to different types of prey. Long-term trends of sea <span class="hlt">ice</span> decline, earlier <span class="hlt">ice</span> melt, and increased water temperatures in the Arctic are likely to have ecosystem-wide effects, including impacts on the forage bases of pagophilic seals. PMID:22693616</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22693616','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22693616"><span>Pre-partum diet of adult female bearded seals in years of contrasting <span class="hlt">ice</span> conditions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hindell, Mark A; Lydersen, Christian; Hop, Haakon; Kovacs, Kit M</p> <p>2012-01-01</p> <p>Changing patterns of sea-<span class="hlt">ice</span> distribution and extent have measurable effects on polar marine systems. Beyond the obvious impacts of key-habitat loss, it is unclear how such changes will influence <span class="hlt">ice</span>-associated marine mammals in part because of the logistical difficulties of studying foraging behaviour or other aspects of the ecology of large, mobile animals at sea during the polar winter. This study investigated the diet of pregnant bearded seals (Erignathus barbatus) during three spring breeding periods (2005, 2006 and 2007) with markedly contrasting <span class="hlt">ice</span> conditions in <span class="hlt">Svalbard</span> using stable isotopes (δ(13)C and δ(15)N) measured in whiskers collected from their newborn pups. The δ(15)N values in the whiskers of individual seals ranged from 11.95 to 17.45 ‰, spanning almost 2 full trophic levels. Some seals were clearly dietary specialists, despite the species being characterised overall as a generalist predator. This may buffer bearded seal populations from the changes in prey distributions lower in the marine food web which seems to accompany continued changes in temperature and <span class="hlt">ice</span> cover. Comparisons with isotopic signatures of known prey, suggested that benthic gastropods and decapods were the most common prey. Bayesian isotopic mixing models indicated that diet varied considerably among years. In the year with most fast-<span class="hlt">ice</span> (2005), the seals had the greatest proportion of pelagic fish and lowest benthic invertebrate content, and during the year with the least <span class="hlt">ice</span> (2006), the seals ate more benthic invertebrates and less pelagic fish. This suggests that the seals fed further offshore in years with greater <span class="hlt">ice</span> cover, but moved in to the fjords when <span class="hlt">ice</span>-cover was minimal, giving them access to different types of prey. Long-term trends of sea <span class="hlt">ice</span> decline, earlier <span class="hlt">ice</span> melt, and increased water temperatures in the Arctic are likely to have ecosystem-wide effects, including impacts on the forage bases of pagophilic seals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.8876P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.8876P"><span>Sedimentary response to <span class="hlt">ice</span> stream advance and retreat on the Storfjorden Trough Mouth Fan (NW Barents Sea), during Late Weichselian</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pedrosa, Mayte; Camerlengui, Angelo; de Mol, Ben; Lucchi, Renata. G.; Úrgeles, Roger; Rebesco, Michele; Winsborrow, Monica; Laberg, Jan. S.; Andreassen, Karin; Accettella, Daniela</p> <p>2010-05-01</p> <p>This seafloor morphological study of the Storfjorden Trough Mouth Fan (TMF) (offshore <span class="hlt">Svalbard</span>, NW Barents Sea) is based on new multibeam bathymetry and chirp sub-bottom profiler data acquired in 2007 during the BIO Hespérides cruise SVAIS that provides an unprecedented image of the sedimentary processes that accompanied the last advance and retreat of the Storfjorden <span class="hlt">Ice</span> Stream. Compared to other glacial-marine sedimentary systems (such as the adjacent Bjørnøyrenna TMF), the Storfjorden TMF system is small and associated to a relatively small terrestrial <span class="hlt">ice</span> sheet, approximately 40.000 km2, with local provenance from <span class="hlt">Svalbard</span> and the Spitsbergen Bank. Due to this short distance from the <span class="hlt">ice</span> source to the calving areas and the resulting short residence time of <span class="hlt">ice</span> in the <span class="hlt">ice</span> sheet, therefore the glacio -marine system of the Storfjorden reacts rapidly to climatic changes. The Storfjorden continental slope is characterized by three depositional lobes, produced by focused sedimentation at the terminus of <span class="hlt">ice</span> streams that have changed their location with time. The superficial morphology features associated to the two northernmost lobes are straight gullies in the upper slope, and debris lobes starting from the midslope onwards. The seafloor expression of the southernmost lobe, adjacent to the much smaller Kveithola TMF, demonstrate almost no gully incisions and is dominated by the widespread occurrence of small-scale submarine landslides. The subbottom profiles illustrate that sediment failures occurred throughout the Late Neogene evolution of the southern Storfjorden and Kveithola margin, including large-scale mass transport deposits of up to 200 m thick. Seismic facies of the Neogene sequence shows an alternation of glacigenic debris flows and laminated sediment drape inferred to be plumites. Gullies incising glacigenic debris flows at the surface and subsurface and are filled by an interglacial drape sequence. The gullies are formed during each deglaciation phase</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Icar..251..211B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Icar..251..211B"><span>Transient bright "halos" on the South Polar Residual <span class="hlt">Cap</span> of Mars: Implications for mass-balance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Becerra, Patricio; Byrne, Shane; Brown, Adrian J.</p> <p>2015-05-01</p> <p>Spacecraft imaging of Mars' south polar region during mid-southern summer of Mars year 28 (2007) observed bright halo-like features surrounding many of the pits, scarps and slopes of the heavily eroded carbon dioxide <span class="hlt">ice</span> of the South Polar Residual <span class="hlt">Cap</span> (SPRC). These features had not been observed before, and have not been observed since. We report on the results of an observational study of these halos, and spectral modeling of the SPRC surface at the time of their appearance. Image analysis was performed using data from MRO's Context Camera (CTX), and High Resolution Imaging Science Experiment (HiRISE), as well as images from Mars Global Surveyor's (MGS) Mars Orbiter Camera (MOC). Data from MRO's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) were used for the spectral analysis of the SPRC <span class="hlt">ice</span> at the time of the halos. These data were compared with a Hapke reflectance model of the surface to constrain their formation mechanism. We find that the unique appearance of the halos is intimately linked to a near-perihelion global dust storm that occurred shortly before they were observed. The combination of vigorous summertime sublimation of carbon dioxide <span class="hlt">ice</span> from sloped surfaces on the SPRC and simultaneous settling of dust from the global storm, resulted in a sublimation wind that deflected settling dust particles away from the edges of these slopes, keeping these areas relatively free of dust compared to the rest of the <span class="hlt">cap</span>. The fact that the halos were not exhumed in subsequent years indicates a positive mass-balance for flat portions of the SPRC in those years. A net accumulation mass-balance on flat surfaces of the SPRC is required to preserve the <span class="hlt">cap</span>, as it is constantly being eroded by the expansion of the pits and scarps that populate its surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRC..123.1827B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRC..123.1827B"><span>Land <span class="hlt">Ice</span> Freshwater Budget of the Arctic and North Atlantic Oceans: 1. Data, Methods, and Results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bamber, J. L.; Tedstone, A. J.; King, M. D.; Howat, I. M.; Enderlin, E. M.; van den Broeke, M. R.; Noel, B.</p> <p>2018-03-01</p> <p>The freshwater budget of the Arctic and sub-polar North Atlantic Oceans has been changing due, primarily, to increased river runoff, declining sea <span class="hlt">ice</span> and enhanced melting of Arctic land <span class="hlt">ice</span>. Since the mid-1990s this latter component has experienced a pronounced increase. We use a combination of satellite observations of glacier flow speed and regional climate modeling to reconstruct the land <span class="hlt">ice</span> freshwater flux from the Greenland <span class="hlt">ice</span> sheet and Arctic glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> for the period 1958-2016. The cumulative freshwater flux anomaly exceeded 6,300 ± 316 km3 by 2016. This is roughly twice the estimate of a previous analysis that did not include glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span> outside of Greenland and which extended only to 2010. From 2010 onward, the total freshwater flux is about 1,300 km3/yr, equivalent to 0.04 Sv, which is roughly 40% of the estimated total runoff to the Arctic for the same time period. Not all of this flux will reach areas of deep convection or Arctic and Sub-Arctic seas. We note, however, that the largest freshwater flux anomalies, grouped by ocean basin, are located in Baffin Bay and Davis Strait. The land <span class="hlt">ice</span> freshwater flux displays a strong seasonal cycle with summer time values typically around five times larger than the annual mean. This will be important for understanding the impact of these fluxes on fjord circulation, stratification, and the biogeochemistry of, and nutrient delivery to, coastal waters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA19712.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA19712.html"><span>Pluto: The <span class="hlt">Ice</span> Plot Thickens</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2015-07-15</p> <p>The latest spectra from New Horizons Ralph instrument reveal an abundance of methane <span class="hlt">ice</span>, but with striking differences from place to place across the frozen surface of Pluto. In the north polar <span class="hlt">cap</span>, methane <span class="hlt">ice</span> is diluted in a thick, transparent slab of nitrogen <span class="hlt">ice</span> resulting in strong absorption of infrared light. In one of the visually dark equatorial patches, the methane <span class="hlt">ice</span> has shallower infrared absorptions indicative of a very different texture. An Earthly example of different textures of a frozen substance: a fluffy bank of clean snow is bright white, but compacted polar <span class="hlt">ice</span> looks blue. New Horizons' surface composition team has begun the intricate process of analyzing Ralph data to determine the detailed compositions of the distinct regions on Pluto. This is the first detailed image of Pluto from the Linear Etalon Imaging Spectral Array, part of the Ralph instrument on New Horizons. The observations were made at three wavelengths of infrared light, which are invisible to the human eye. In this picture, blue corresponds to light of wavelengths 1.62 to 1.70 micrometers, a channel covering a medium-strong absorption band of methane <span class="hlt">ice</span>, green (1.97 to 2.05 micrometers) represents a channel where methane <span class="hlt">ice</span> does not absorb light, and red (2.30 to 2.33 micrometers) is a channel where the light is very heavily absorbed by methane <span class="hlt">ice</span>. The two areas outlined on Pluto show where Ralph observations obtained the spectral traces at the right. Note that the methane absorptions (notable dips) in the spectrum from the northern region are much deeper than the dips in the spectrum from the dark patch. The Ralph data were obtained by New Horizons on July 12, 2015. http://photojournal.jpl.nasa.gov/catalog/PIA19712</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28587979','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28587979"><span>Diet and metabolic state are the main factors determining concentrations of perfluoroalkyl substances in female polar bears from <span class="hlt">Svalbard</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tartu, Sabrina; Bourgeon, Sophie; Aars, Jon; Andersen, Magnus; Lone, Karen; Jenssen, Bjørn Munro; Polder, Anuschka; Thiemann, Gregory W; Torget, Vidar; Welker, Jeffrey M; Routti, Heli</p> <p>2017-10-01</p> <p>Perfluoroalkyl substances (PFASs) have been detected in organisms worldwide, including Polar Regions. The polar bear (Ursus maritimus), the top predator of Arctic marine ecosystems, accumulates high concentrations of PFASs, which may be harmful to their health. The aim of this study was to investigate which factors (habitat quality, season, year, diet, metabolic state [i.e. feeding/fasting], breeding status and age) predict PFAS concentrations in female polar bears captured on <span class="hlt">Svalbard</span> (Norway). We analysed two perfluoroalkyl sulfonates (PFSAs: PFHxS and PFOS) and C 8 -C 13 perfluoroalkyl carboxylates (PFCAs) in 112 plasma samples obtained in April and September 2012-2013. Nitrogen and carbon stable isotope ratios (δ 15 N, δ 13 C) in red blood cells and plasma, and fatty acid profiles in adipose tissue were used as proxies for diet. We determined habitat quality based on movement patterns, capture position and resource selection functions, which are models that predict the probability of use of a resource unit. Plasma urea to creatinine ratios were used as proxies for metabolic state (i.e. feeding or fasting state). Results were obtained from a conditional model averaging of 42 general linear mixed models. Diet was the most important predictor of PFAS concentrations. PFAS concentrations were positively related to trophic level and marine diet input. High PFAS concentrations in females feeding on the eastern part of <span class="hlt">Svalbard</span>, where the habitat quality was higher than on the western coast, were likely related to diet and possibly to abiotic factors. Concentrations of PFSAs and C 8 -C 10 PFCAs were higher in fasting than in feeding polar bears and PFOS was higher in females with cubs of the year than in solitary females. Our findings suggest that female polar bears that are exposed to the highest levels of PFAS are those 1) feeding on high trophic level sea <span class="hlt">ice</span>-associated prey, 2) fasting and 3) with small cubs. Copyright © 2017 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C33B1192G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C33B1192G"><span>Direct observations of atmosphere - sea <span class="hlt">ice</span> - ocean interactions during Arctic winter and spring storms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Graham, R. M.; Itkin, P.; Granskog, M. A.; Assmy, P.; Cohen, L.; Duarte, P.; Doble, M. J.; Fransson, A.; Fer, I.; Fernandez Mendez, M.; Frey, M. M.; Gerland, S.; Haapala, J. J.; Hudson, S. R.; Liston, G. E.; Merkouriadi, I.; Meyer, A.; Muilwijk, M.; Peterson, A.; Provost, C.; Randelhoff, A.; Rösel, A.; Spreen, G.; Steen, H.; Smedsrud, L. H.; Sundfjord, A.</p> <p>2017-12-01</p> <p>To study the thinner and younger sea <span class="hlt">ice</span> that now dominates the Arctic the Norwegian Young Sea <span class="hlt">ICE</span> expedition (N-<span class="hlt">ICE</span>2015) was launched in the <span class="hlt">ice</span>-covered region north of <span class="hlt">Svalbard</span>, from January to June 2015. During this time, eight local and remote storms affected the region and rare direct observations of the atmosphere, snow, <span class="hlt">ice</span> and ocean were conducted. Six of these winter storms passed directly over the expedition and resulted in air temperatures rising from below -30oC to near 0oC, followed by abrupt cooling. Substantial snowfall prior to the campaign had already formed a snow pack of approximately 50 cm, to which the February storms contributed an additional 6 cm. The deep snow layer effectively isolated the <span class="hlt">ice</span> cover and prevented bottom <span class="hlt">ice</span> growth resulting in low brine fluxes. Peak wind speeds during winter storms exceeded 20 m/s, causing strong snow re-distribution, release of sea salt aerosol and sea <span class="hlt">ice</span> deformation. The heavy snow load caused widespread negative freeboard; during sea <span class="hlt">ice</span> deformation events, level <span class="hlt">ice</span> floes were flooded by sea water, and at least 6-10 cm snow-<span class="hlt">ice</span> layer was formed. Elevated deformation rates during the most powerful winter storms damaged the <span class="hlt">ice</span> cover permanently such that the response to wind forcing increased by 60 %. As a result of a remote storm in April deformation processes opened about 4 % of the total area into leads with open water, while a similar amount of <span class="hlt">ice</span> was deformed into pressure ridges. The strong winds also enhanced ocean mixing and increased ocean heat fluxes three-fold in the pycnocline from 4 to 12 W/m2. Ocean heat fluxes were extremely large (over 300 W/m2) during storms in regions where the warm Atlantic inflow is located close to surface over shallow topography. This resulted in very large (5-25 cm/day) bottom <span class="hlt">ice</span> melt and in cases flooding due to heavy snow load. Storm events increased the carbon dioxide exchange between the atmosphere and ocean but also affected the pCO2 in surface waters</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20171208_Archive_e000190.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20171208_Archive_e000190.html"><span>Arctic Sea <span class="hlt">Ice</span> Is Losing Its Bulwark Against Warming Summers</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-12-08</p> <p>Arctic sea <span class="hlt">ice</span>, the vast sheath of frozen seawater floating on the Arctic Ocean and its neighboring seas, has been hit with a double whammy over the past decades: as its extent shrunk, the oldest and thickest <span class="hlt">ice</span> has either thinned or melted away, leaving the sea <span class="hlt">ice</span> <span class="hlt">cap</span> more vulnerable to the warming ocean and atmosphere. “What we’ve seen over the years is that the older <span class="hlt">ice</span> is disappearing,” said Walt Meier, a sea <span class="hlt">ice</span> researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This older, thicker <span class="hlt">ice</span> is like the bulwark of sea <span class="hlt">ice</span>: a warm summer will melt all the young, thin <span class="hlt">ice</span> away but it can’t completely get rid of the older <span class="hlt">ice</span>. But this older <span class="hlt">ice</span> is becoming weaker because there’s less of it and the remaining old <span class="hlt">ice</span> is more broken up and thinner, so that bulwark is not as good as it used to be.” Read more: go.nasa.gov/2dPJ9zT NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C13B0433B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C13B0433B"><span>Glaciological reconstruction of Holocene <span class="hlt">ice</span> margins in northwestern Greenland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Birkel, S. D.; Osterberg, E. C.; Kelly, M. A.; Axford, Y.</p> <p>2014-12-01</p> <p>The past few decades of climate warming have brought overall margin retreat to the Greenland <span class="hlt">Ice</span> Sheet. In order to place recent and projected changes in context, we are undertaking a collaborative field-modeling study that aims to reconstruct the Holocene history of <span class="hlt">ice</span>-margin fluctuation near Thule (~76.5°N, 68.7°W), and also along the North <span class="hlt">Ice</span> <span class="hlt">Cap</span> (NIC) in the Nunatarssuaq region (~76.7°N, 67.4°W). Fieldwork reported by Kelly et al. (2013) reveals that <span class="hlt">ice</span> in the study areas was less extensive than at present ca. 4700 (GIS) and ca. 880 (NIC) cal. years BP, presumably in response to a warmer climate. We are now exploring Holocene <span class="hlt">ice</span>-climate coupling using the University of Maine <span class="hlt">Ice</span> Sheet Model (UMISM). Our approach is to first test what imposed climate anomalies can afford steady state <span class="hlt">ice</span> margins in accord with field data. A second test encompasses transient simulation of the Holocene, with climate boundary conditions supplied by existing paleo runs of the Community Climate System Model version 4 (CCSM4), and a climate forcing signal derived from Greenland <span class="hlt">ice</span> cores. In both cases, the full <span class="hlt">ice</span> sheet is simulated at 10 km resolution with nested domains at 0.5 km for the study areas. UMISM experiments are underway, and results will be reported at the meeting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRE..123..864C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRE..123..864C"><span>The Penetration of Solar Radiation Into Carbon Dioxide <span class="hlt">Ice</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chinnery, H. E.; Hagermann, A.; Kaufmann, E.; Lewis, S. R.</p> <p>2018-04-01</p> <p>Icy surfaces behave differently to rocky or regolith-covered surfaces in response to irradiation. A key factor is the ability of visible light to penetrate partially into the subsurface. This results in the solid-state greenhouse effect, as <span class="hlt">ices</span> can be transparent or translucent to visible and shorter wavelengths, while opaque in the infrared. This can lead to significant differences in shallow subsurface temperature profiles when compared to rocky surfaces. Of particular significance for modeling the solid-state greenhouse effect is the e-folding scale, otherwise known as the absorption scale length, or penetration depth, of the <span class="hlt">ice</span>. While there have been measurements for water <span class="hlt">ice</span> and snow, pure and with mixtures, to date, there have been no such measurements published for carbon dioxide <span class="hlt">ice</span>. After an extensive series of measurements we are able to constrain the e-folding scale of CO2 <span class="hlt">ice</span> for the cumulative wavelength range 300 to 1,100 nm, which is a vital parameter in heat transfer models for the Martian surface, enabling us to better understand surface-atmosphere interactions at Mars' polar <span class="hlt">caps</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C33B0796S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C33B0796S"><span>Quantifying Suspended Sediment Concentration from Subglacial Sediment Plumes Discharging from Two <span class="hlt">Svalbard</span> Tidewater Glaciers using Landsat 8 and In Situ Measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schild, K. M.; Hawley, R. L.; Chipman, J. W.; Benn, D.</p> <p>2016-12-01</p> <p>Marine-terminating outlet glaciers discharge most of an <span class="hlt">ice</span> sheet's mass loss through iceberg calving, submarine melting, and meltwater runoff. While calving can be quantified by in situ and remote sensing observations, meltwater runoff, submarine melting, and the subglacial transport of meltwater are not well constrained due to inherent difficulties measuring the subglacial and proglacial environments. Previous studies have used sediment plumes and suspended sediment concentration (SSC) as a proxy for glacier meltwater runoff at land-terminating glaciers. However, the relationship between satellite reflectacne and SSC, established predominantly from land-terminating glacier data, does not relate well for tidewater glaciers. Additionally, the difficulties in sampling the near terminus region of large tidewater glaciers makes it challenging to accurately constrain or identify the relationship between sediment plumes and satellite reflectance. In this study we use simultaneous Landsat 8 imagery and in situ fjord measurements at two <span class="hlt">Svalbard</span> tidewater glaciers to establish a relationship between SSC and Landsat 8 surface reflectacne in a tidewater glacier Setting. Results from fieldwork conducted during low and peak meltwater runoff periods at Kronebreen and Tunabreen glaciers will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890016428','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890016428"><span>Possible significance of cubic water-<span class="hlt">ice</span>, H2O-Ic, in the atmospheric water cycle of Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gooding, James L.</p> <p>1988-01-01</p> <p>The possible formation and potential significance of the cubic <span class="hlt">ice</span> polymorph on Mars is discussed. When water-<span class="hlt">ice</span> crystallizes on Earth, the ambient conditions of temperature and pressure result in the formation of the hexagonal <span class="hlt">ice</span> polymorph; however, on Mars, the much lower termperature and pressures may permit the crystallization of the cubic polymorph. Cubic <span class="hlt">ice</span> has two properties of possible importance on Mars: it is an excellant nucleator of other volatiles (such as CO2), and it undergoes an exothermic transition to hexagonal <span class="hlt">ice</span> at temperatures above 170 K. These properties may have significant implications for both martian cloud formation and the development of the seasonal polar <span class="hlt">caps</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1614223Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1614223Z"><span>Microbial cell retention in a melting High Arctic snowpack, <span class="hlt">Svalbard</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zarsky, Jakub; Björkman, Mats; Kühnel, Rafael; Hell, Katherina; Hodson, Andy; Sattler, Birgit; Psenner, Roland</p> <p>2014-05-01</p> <p>Introduction The melting snow pack represents a highly dynamic system not only for chemical compounds but also for bacterial cells. Microbial activity was found at subzero temperatures in <span class="hlt">ice</span> veins when liquid water persists due to high concentration of ions on the surface of snow crystals and brine channels between large <span class="hlt">ice</span> crystals in <span class="hlt">ice</span>. Several observations also suggest microbial activity under subzero temperatures in seasonal snow. Even with regard to the spatial and temporal relevance of snow ecosystems, microbial activity in such an extreme habitat represents a relatively small proportion in the carbon flux of the global ecosystem and even of the glacial ecosystems specifically. On the other hand, it represents a remarkable piece of mosaic of the microbial activity in glacial ecosystems because the snow pack represents the first contact between the atmosphere and cryosphere. This topic also embodies vital crossovers to biogeochemistry and ecotoxicology, offering a quantitative view of utilization of various substrates relevant for downstream ecosystems. Here we present our study of the dynamics of both solvents and cells suspended in meltwater of the melting snowpack on a high arctic glacier to demonstrate the spatio-temporal constraint of interaction between solvent and bacterial cells in this environment. Method We used 6 lysimeters inserted into the bottom of the snowpack to collect replicated samples of melt water before it comes into contact with basal <span class="hlt">ice</span> or slush layer at the base of the snow pack. The sampling site was chosen at Midre Lovénbreen (<span class="hlt">Svalbard</span>, Kongsfjorden, MLB stake 6) where the snow pack showed melting on the surface but the basal <span class="hlt">ice</span> was still dry. Sampling was conducted in June 2010 for a period of 10 days once per day and the snow profile was sampled according to distinguished layers in the profile at the beginning of the field mission and as bulk at its end. The height of snow above the lysimeters dropped from the initial 74 cm</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.mayoclinic.org/diseases-conditions/cradle-cap/symptoms-causes/syc-20350396?p=1','NIH-MEDLINEPLUS'); return false;" href="https://www.mayoclinic.org/diseases-conditions/cradle-cap/symptoms-causes/syc-20350396?p=1"><span>Cradle <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>Cradle <span class="hlt">cap</span> Overview Cradle <span class="hlt">cap</span> causes crusty or oily scaly patches on a baby's scalp. The condition isn't painful or itchy. But it can ... scales that aren't easy to remove. Cradle <span class="hlt">cap</span> usually clears up on its own in a ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009QSRv...28.3101G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009QSRv...28.3101G"><span>Reconstructing the last Irish <span class="hlt">Ice</span> Sheet 2: a geomorphologically-driven model of <span class="hlt">ice</span> sheet growth, retreat and dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Greenwood, Sarah L.; Clark, Chris D.</p> <p>2009-12-01</p> <p>The <span class="hlt">ice</span> sheet that once covered Ireland has a long history of investigation. Much prior work focussed on localised evidence-based reconstructions and <span class="hlt">ice</span>-marginal dynamics and chronologies, with less attention paid to an <span class="hlt">ice</span> sheet wide view of the first order properties of the <span class="hlt">ice</span> sheet: centres of mass, <span class="hlt">ice</span> divide structure, <span class="hlt">ice</span> flow geometry and behaviour and changes thereof. In this paper we focus on the latter aspect and use our new, countrywide glacial geomorphological mapping of the Irish landscape (>39 000 landforms), and our analysis of the palaeo-glaciological significance of observed landform assemblages (article Part 1), to build an <span class="hlt">ice</span> sheet reconstruction yielding these fundamental <span class="hlt">ice</span> sheet properties. We present a seven stage model of <span class="hlt">ice</span> sheet evolution, from initiation to demise, in the form of palaeo-geographic maps. An early incursion of <span class="hlt">ice</span> from Scotland likely coalesced with local <span class="hlt">ice</span> <span class="hlt">caps</span> and spread in a south-westerly direction 200 km across Ireland. A semi-independent Irish <span class="hlt">Ice</span> Sheet was then established during <span class="hlt">ice</span> sheet growth, with a branching <span class="hlt">ice</span> divide structure whose main axis migrated up to 140 km from the west coast towards the east. <span class="hlt">Ice</span> stream systems converging on Donegal Bay in the west and funnelling through the North Channel and Irish Sea Basin in the east emerge as major flow components of the maximum stages of glaciation. <span class="hlt">Ice</span> cover is reconstructed as extending to the continental shelf break. The Irish <span class="hlt">Ice</span> Sheet became autonomous (i.e. separate from the British <span class="hlt">Ice</span> Sheet) during deglaciation and fragmented into multiple <span class="hlt">ice</span> masses, each decaying towards the west. Final sites of demise were likely over the mountains of Donegal, Leitrim and Connemara. Patterns of growth and decay of the <span class="hlt">ice</span> sheet are shown to be radically different: asynchronous and asymmetric in both spatial and temporal domains. We implicate collapse of the <span class="hlt">ice</span> stream system in the North Channel - Irish Sea Basin in driving such asymmetry, since rapid</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Icar..292..144C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Icar..292..144C"><span>Interannual and seasonal changes in the south seasonal polar <span class="hlt">cap</span> of Mars: Observations from MY 28-31 using MARCI</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Calvin, W. M.; Cantor, B. A.; James, P. B.</p> <p>2017-08-01</p> <p>The Mars Color Imager (MARCI) camera on the Mars Reconnaissance Orbiter provides daily synoptic coverage that allows monitoring of seasonal <span class="hlt">cap</span> retreat and interannual changes that occur between Mars Years (MY) and over the southern summer. We present the first analysis of this data for the southern seasonal <span class="hlt">cap</span> evolution observed in MY 28, 29, 30 and 31 (2/2007 to 07/2013). Observation over multiple Mars years allows us to compare changes between years as well as longer-term evolution of the high albedo deposits at the poles. Seasonal <span class="hlt">cap</span> retreat is similar in all years and to retreats observed in other years by both optical and thermal instruments. The cryptic terrain has a fairly consistent boundary in each year, but numerous small-scale variations occur in each MY observed. Additionally, numerous small dark deposits are identified outside the classically identified cyptic region, including Inca City and other locations not previously noted. The large water <span class="hlt">ice</span> outlier is observed to retain seasonal frost the longest (outside the polar dome) and is also highly variable in each MY. The development of the cryptic/anti-cryptic hemispheres is inferred to occur due to albedo variations that develop after dust venting starts and may be caused by recondensation of CO2 <span class="hlt">ice</span> on the brightest and coldest regions controlled by topographic winds. Ground <span class="hlt">ice</span> may play a role in which regions develop cryptic terrain, as there is no elevation control on either cryptic terrain or the late season brightest deposits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/3050407','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/3050407"><span>The cervical <span class="hlt">cap</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p></p> <p>1988-10-07</p> <p>The US Food and Drug Administration has approved marketing of the Prentif cavity-rim cervical <span class="hlt">cap</span>. This contraceptive device is being distributed in the US and Canada by Cervical <span class="hlt">Cap</span> Ltd, Los Gatos, California. The Prentif <span class="hlt">cap</span> is available in 4 sizes: 22, 25, 28, and 31 mm inside diameter, with a length of 1 1/4-1 1/2 inches. In a multicenter trial involving 522 diaphragm users and 581 <span class="hlt">cap</span> users followed for 2 years, the <span class="hlt">cap</span> was 82.6% effective and the diaphragm was 83.3% effective in preventing pregnancy. When pregnancies attributable to user failure were excluded, these rates were increased to 93.6% for the <span class="hlt">cap</span> and 95.4% for the diaphragm. 4% of <span class="hlt">cap</span> users compared with only 1.7% of diaphragm users in this study developed abnormal Pap smears after 3 months of use; in addition, a higher proportion of <span class="hlt">cap</span> users became infected with Gardnerella vaginalis and Monilia. Theoretical hazards include toxic shock syndrome and endometriosis due to backflow of menstrual fluids. <span class="hlt">Cap</span> users are advised to undergo a Pap test after 3 months of use and discontinue <span class="hlt">cap</span> use if the results are abnormal. The <span class="hlt">cap</span> should not be used during menstruation. Although the <span class="hlt">cap</span> can be left in place for up to 48 hours, its position should be checked before and after each episode of intercourse. The cervical <span class="hlt">cap</span> requires less spermicide than the diaphragm and is not as messy. In addition, it can be left in the vagina twice as long as the diaphragm, without additional spermicide. Since the <span class="hlt">cap</span> is smaller than the diaphragm and does not cover the vaginal wall, some women find intercourse more pleasurable with this device.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010002509&hterms=geological&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dgeological','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010002509&hterms=geological&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dgeological"><span>The Residual Polar <span class="hlt">Caps</span> of Mars: Geological Differences and Possible Consequences</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thomas, P. C.; Sullivan, R.; Ingersoll, A. P.; Murray, B. C.; Danielson, G. E.; Herkenhoff, K. E.; Soderblom, L.; Malin, M. C.; Edgett, K. S.; James, P. B.</p> <p>2000-01-01</p> <p>The Martian polar regions have been known to have thick layered sequences (presumed to consist of silicates and <span class="hlt">ice</span>), CO2 seasonal frost, and residual frosts that remain through the summer: H2O in the north, largely CO2 in the south. The relationship of the residual frosts to the underlying layered deposits could not be determined from Viking images. The Mars Orbiter Camera on Mars Global Surveyor has provided a 50-fold increase in resolution that shows more differences between the two poles. The north residual <span class="hlt">cap</span> surface has rough topography of pits, cracks, and knobs, suggestive of ablational forms. This topography is less than a few meters in height, and grades in to surfaces exposing the layers underneath. In contrast, the south residual <span class="hlt">cap</span> has distinctive collapse and possibly ablational topography emplaced in four or more layers, each approx. two meters thick. The top surface has polygonal depressions suggestive of thermal contraction cracks. The collapse and erosional forms include circular and cycloidal depressions, long sinuous troughs, and nearly parallel sets of troughs. The distinctive topography occurs throughout the residual <span class="hlt">cap</span> area, but not outside it. Unconformities exposed in polar layers, or other layered materials, do not approximate the topography seen on the south residual <span class="hlt">cap</span>. The coincidence of a distinct geologic feature, several layers modified by collapse, ablation, and mass movement with the residual <span class="hlt">cap</span> indicates a distinct composition and/or climate compared to both the remainder of the south polar layered units and those in the north.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA41B2620J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA41B2620J"><span>Characteristics of ionospheric electron density profiles in the auroral and polar <span class="hlt">cap</span> regions from long-term incoherent scatter radar observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jee, G.; Kim, E.; Kwak, Y. S.; Kim, Y.; Kil, H.</p> <p>2017-12-01</p> <p>We investigate the climatological characteristics of the ionospheric electron density profiles in the auroral and polar <span class="hlt">cap</span> regions in comparison with the mid-latitude ionosphere using incoherent scatter radars (ISR) observations from <span class="hlt">Svalbard</span> (78.15N, 16.05E), Tromso (69.59N, 19.23E), and Millstone Hill (42.6N, 288.5E) during a period of 1995 - 2015. Diurnal variations of electron density profiles from 100 to 500 km are compared among the three radar observations during equinox, summer and winter solstice for different solar and geomagnetic activities. Also investigated are the physical characteristics of E-region and F-region peak parameters of electron density profiles in the auroral and polar <span class="hlt">cap</span> regions, which are significantly different from the mid-latitude ionosphere. In the polar ionosphere, the diurnal variations of density profiles are extremely small in summer hemisphere. Semiannual anomaly hardly appears for all latitudes, but winter anomaly occurs at mid-latitude and auroral ionospheres for high solar activity. Nighttime density becomes larger than daytime density in the winter polar <span class="hlt">cap</span> ionosphere for high solar activity. The E-region peak is very distinctive in the nighttime auroral region and the peak height is nearly constant at about 110 km for all conditions. Compared with the F-region peak density, the E-region peak density does not change much with solar activity. Furthermore, the E-region peak density can be even larger than F-region density for low solar activity in the auroral region, particularly during disturbed condition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017QSRv..169..148P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017QSRv..169..148P"><span>Deglaciation of the Eurasian <span class="hlt">ice</span> sheet complex</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patton, Henry; Hubbard, Alun; Andreassen, Karin; Auriac, Amandine; Whitehouse, Pippa L.; Stroeven, Arjen P.; Shackleton, Calvin; Winsborrow, Monica; Heyman, Jakob; Hall, Adrian M.</p> <p>2017-08-01</p> <p>2.5 × 106 km2 and drained the present day Vistula, Elbe, Rhine and Thames rivers through the Seine Estuary. During the Bølling/Allerød oscillation after c. 14.6 ka BP, two major proglacial lakes formed in the Baltic and White seas, buffering meltwater pulses from eastern Fennoscandia through to the Younger Dryas when these massive proglacial freshwater lakes flooded into the North Atlantic Ocean. Deglaciation temporarily abated during the Younger Dryas stadial at 12.9 ka BP, when remnant <span class="hlt">ice</span> across <span class="hlt">Svalbard</span>, Franz Josef Land, Novaya Zemlya, Fennoscandia and Scotland experienced a short-lived but dynamic re-advance. The final stage of deglaciation converged on present day <span class="hlt">ice</span> cover around the Scandes mountains and the Barents Sea by 8.7 ka BP, although the phase-lagged isostatic recovery still continues today.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11538596','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11538596"><span>Temperature of nitrogen <span class="hlt">ice</span> on Pluto and its implications for flux measurements.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tryka, K A; Brown, R H; Cruikshank, D P; Owen, T C; Geballe, T R; DeBergh, C</p> <p>1994-01-01</p> <p>Previous work by K.A. Tryka et al. (Science 261, 751-754, 1993) has shown that the profile of the 2.148-micrometers band of solid nitrogen can be used as a "thermometer" and determined the temperature of nitrogen <span class="hlt">ice</span> on Triton to be 38(+2)-1 K. Here we reevaluate that data and refine the temperature value to 38 +/- 1 K. Applying the same technique to Pluto we determine that the temperature of the N2 <span class="hlt">ice</span> on that body is 40 +/- 2 K. Using this result we have created a nonisothermal flux model of the Pluto-Charon system. The model treats Pluto as a body with symmetric N2 polar <span class="hlt">caps</span> and an equatorial region devoid of N2. Comparison with the infrared and millimeter flux measurements shows that the published fluxes are consistent with models incorporating extensive N2 polar <span class="hlt">caps</span> (down to +/- 15 degrees or +/- 20 degrees latitude) and an equatorial region with a bolometric albedo < or = 0.2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950053532&hterms=pluto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dpluto','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950053532&hterms=pluto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dpluto"><span>Temperature of nitrogen <span class="hlt">ice</span> on Pluto and its implications for flux measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tryka, Kimberly A.; Brown, Robert H.; Chruikshank, Dale P.; Owen, Tobias C.; Geballe, Thomas R.; Debergh, Catherine</p> <p>1994-01-01</p> <p>Previous work by K. A. Tryka et al. (1993) has shown that the profile of the 2.148-micron band of solid nitrogen can be used as a 'thermometer' and determined the tempertature of nitrogen <span class="hlt">ice</span> on Triton to be 38(sup +2)(sub -1) K. Here we reevalute that data and refine the temperature value to 38 +/- 1 K. Applying the same technique to Pluto we determine that the temperature of the N2 <span class="hlt">ice</span> on that body is 40 +/- 2 K. Using this result we have created a nonisothermal flux model of the Pluto-Charon system. The model treats Pluto as a body with symmetric N2 polar <span class="hlt">caps</span> and an equatorial region devoid of N2. Comparison with the infrared and millimeter flux measurements shows that the published fluxes are consistent with models incorporating extensive N2 polar <span class="hlt">caps</span> (down to +/- 15 deg ot +/- 20 deg latitude) and an equatorial region with a bolometric albedo less than or equal to 0.2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Icar..308...61C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Icar..308...61C"><span>A search for polycyclic aromatic hydrocarbons over the Martian South Polar Residual <span class="hlt">Cap</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Campbell, J. D.; Sidiropoulos, P.; Muller, J.-P.</p> <p>2018-07-01</p> <p>We present our research on compositional mapping of the Martian South Polar Residual <span class="hlt">Cap</span> (SPRC), especially the detection of organic signatures within the dust content of the <span class="hlt">ice</span>, based on hyperspectral data analysis. The SPRC is the main region of interest for this investigation, because of the unique CO2 <span class="hlt">ice</span> sublimation features that cover the surface. These flat floored, circular depressions are highly dynamic, and we infer frequently expose dust particles previously trapped within the <span class="hlt">ice</span> during the wintertime. Here we identify suitable regions for potential dust exposure on the SPRC, and utilise data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on board NASA's Mars Reconnaissance Orbiter (MRO) satellite to examine infrared spectra of dark regions assumed to be composed mainly of dust particles to establish their mineral composition, to eliminate the effects of <span class="hlt">ices</span> on sub-pixel dusty features, and to look for signatures indicative of Polycyclic Aromatic Hydrocarbons (PAHs). Spectral mapping has identified compositional differences between depression rims and the majority of the SPRC and CRISM spectra have been corrected to minimise the influence of CO2 <span class="hlt">ice</span>. Whilst no conclusive evidence for PAHs has been found within the detectability limits of the CRISM instrument, depression rims are shown to have higher water content than regions of featureless <span class="hlt">ice</span>, and there are possible indications of magnesium carbonate within the dark, dusty regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940007582&hterms=CO2+H2O&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DCO2%2BH2O','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940007582&hterms=CO2+H2O&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DCO2%2BH2O"><span>An observational search for CO2 <span class="hlt">ice</span> clouds on Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bell, James F., III; Calvin, Wendy M.; Pollack, James B.; Crisp, David</p> <p>1993-01-01</p> <p>CO2 <span class="hlt">ice</span> clouds were first directly identified on Mars by the Mariner 6 and 7 infrared spectrometer limb scans. These observations provided support for early theoretical modeling efforts of CO2 condensation. Mariner 9 IRIS temperature profiles of north polar hood clouds were interpreted as indicating that these clouds were composed of H2O <span class="hlt">ice</span> at lower latitudes and CO2 <span class="hlt">ice</span> at higher latitudes. The role of CO2 condensation on Mars has recently received increased attention because (1) Kasting's model results indicated that CO2 cloud condensation limits the magnitude of the proposed early Mars CO2/H2O greenhouse, and (2) Pollack el al.'s GCM results indicated that the formation of CO2 <span class="hlt">ice</span> clouds is favorable at all polar latitudes during the fall and winter seasons. These latter authors have shown that CO2 clouds play an important role in the polar energy balance, as the amount of CO2 contained in the polar <span class="hlt">caps</span> is constrained by a balance between latent heat release, heat advected from lower latitudes, and thermal emission to space. The polar hood clouds reduce the amount of CO2 condensation on the polar <span class="hlt">caps</span> because they reduce the net emission to space. There have been many extensive laboratory spectroscopic studies of H2O and CO2 <span class="hlt">ices</span> and frosts. In this study, we use results from these and other sources to search for the occurrence of diagnostic CO2 (and H2O) <span class="hlt">ice</span> and/or frost absorption features in ground based near-infrared imaging spectroscopic data of Mars. Our primary goals are (1) to try to confirm the previous direct observations of CO2 clouds on Mars; (2) to determine the spatial extent, temporal variability, and composition (H2O/CO2 ratio) of any clouds detected; and (3) through radiative transfer modeling, to try to determine the mean particle size and optical depth of polar hood clouds, thus, assessing their role in the polar heat budget.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeCoA.222..406K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeCoA.222..406K"><span>Complementary biomarker-based methods for characterising Arctic sea <span class="hlt">ice</span> conditions: A case study comparison between multivariate analysis and the PIP25 index</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Köseoğlu, Denizcan; Belt, Simon T.; Smik, Lukas; Yao, Haoyi; Panieri, Giuliana; Knies, Jochen</p> <p>2018-02-01</p> <p>The discovery of IP25 as a qualitative biomarker proxy for Arctic sea <span class="hlt">ice</span> and subsequent introduction of the so-called PIP25 index for semi-quantitative descriptions of sea <span class="hlt">ice</span> conditions has significantly advanced our understanding of long-term paleo Arctic sea <span class="hlt">ice</span> conditions over the past decade. We investigated the potential for classification tree (CT) models to provide a further approach to paleo Arctic sea <span class="hlt">ice</span> reconstruction through analysis of a suite of highly branched isoprenoid (HBI) biomarkers in ca. 200 surface sediments from the Barents Sea. Four CT models constructed using different HBI assemblages revealed IP25 and an HBI triene as the most appropriate classifiers of sea <span class="hlt">ice</span> conditions, achieving a >90% cross-validated classification rate. Additionally, lower model performance for locations in the Marginal <span class="hlt">Ice</span> Zone (MIZ) highlighted difficulties in characterisation of this climatically-sensitive region. CT model classification and semi-quantitative PIP25-derived estimates of spring sea <span class="hlt">ice</span> concentration (SpSIC) for four downcore records from the region were consistent, although agreement between proxy and satellite/observational records was weaker for a core from the west <span class="hlt">Svalbard</span> margin, likely due to the highly variable sea <span class="hlt">ice</span> conditions. The automatic selection of appropriate biomarkers for description of sea <span class="hlt">ice</span> conditions, quantitative model assessment, and insensitivity to the c-factor used in the calculation of the PIP25 index are key attributes of the CT approach, and we provide an initial comparative assessment between these potentially complementary methods. The CT model should be capable of generating longer-term temporal shifts in sea <span class="hlt">ice</span> conditions for the climatically sensitive Barents Sea.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA43B2650J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA43B2650J"><span>Occurrence of ion upflow associated with ion/electron heating in the polar <span class="hlt">cap</span> and cusp regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ji, E. Y.; Jee, G.; Kwak, Y. S.</p> <p>2017-12-01</p> <p>We investigate the occurrence frequency of ion upflow in association with ion/electron heating in the polar <span class="hlt">cap</span> and cusp regions, using the data obtained from the European Incoherent Scatter <span class="hlt">Svalbard</span> radar (ESR) during the period of 2000 to 2010. We classify the upflow events by four cases: driven by ion heating (case 1), electron heating (case 2), both ion and electron heatings (case 3), and without any heating (case 4). The statistical analysis of the data shows that the upflow normaly starts at around 350 km altitude and the occurrence seems to peak at 11 MLT. Among the four cases, the occurrence frequency of the upflow is maximized for the case 3 and then followed by case 2, case 1 and case 3, which indicates that both ion and electron heatings are associated with ion upflow. At around 500 km altitude, however, the occurrence frequency is maximized when there is no heating (case 4). We also investigate the dependence of the occurrence frequency of the upflow on Kp and F10.7 indices. The maximum occurrence frequency seems to occur at moderate geomagnetic condition (2 ≤ Kp < 5). As for the solar activity, the occurrence frequency is higher for low solar activity than for high solar activity. The results of this study suggest that the ion upflow occurring in the polar <span class="hlt">cap</span>/cusp region is mostly driven by both ion and electron heatings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C21C0359C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C21C0359C"><span>Buried CO2 <span class="hlt">Ice</span> traces in South Polar Layered Deposits of Mars detected by radar sounder</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Castaldo, L.; Mège, D.; Orosei, R.; Séjourné, A.</p> <p>2014-12-01</p> <p>SHARAD (SHAllow RADar) is the subsurface sounding radar provided by the Italian Space Agency (ASI) as a facility instrument to NASA's 2005 Mars Reconnaissance Orbiter (MRO). The Reduced Data Record of SHARAD data covering the area of the South Polar Layered Deposits (SPLD), has been used. The elaboration and interpretation of the data, aimed to estimate electromagnetic properties of surface layers, has been performed in terms of permittivity. The theory of electromagnetic scattering from fractal surfaces, and the estimation of geometric parameters from topographic data by Mars Orbiter Laser Altimeter (MOLA) which was one of five instruments on board the Mars Global Surveyor (MGS) spacecraft, has been used. A deep analysis of inversion has been made on all Mars and extended to the South Polar <span class="hlt">Caps</span> in order to extract the area with a permittivity constant of CO2 <span class="hlt">ice</span>. Several corrections have been applied to the data, moreover the calibration of the signal requires the determination of a constant that takes into account the power gain due to the radar system and the surface in order to compensate the power losses due to the orbitographic phenomena. The determination of regions with high probability of buried CO2 <span class="hlt">ice</span> in the first layer of the Martian surface, is obtained extracting the real part of the permittivity constant of the CO2 <span class="hlt">ice</span> (~2), estimated by other means. The permittivity of CO2<span class="hlt">ice</span> is extracted from the Global Permittivity Map of Mars using the global standard deviation of itself as following: ɛCO2<span class="hlt">ice</span>=ɛCO2<span class="hlt">ice</span>+ Σ (1)where Σ=±std(ɛMapMars)/2Figure 1(a) shows the south polar areas where the values of the permittivity point to the possibility of a CO2 <span class="hlt">ice</span> layer. Figure 1(b) is the corresponding geologic map. The comparison between the two maps indicates that the area with probable buried CO2 overlaps Hesperian and Amazonian polar units (Hp, Hesperian plains-forming deposits marked by narrow sinuous, anabranching ridges and irregular depressions, and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.C41D..06W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.C41D..06W"><span>Large-area surveys for black carbon and other light-absorbing impurities in snow: Arctic, Antarctic, North America, China (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Warren, S. G.; Doherty, S. J.; Hegg, D.; Dang, C.; Zhang, R.; Grenfell, T. C.; Brandt, R. E.; Clarke, A. D.; Zatko, M.</p> <p>2013-12-01</p> <p>Absorption of radiation by <span class="hlt">ice</span> is extremely weak at visible and near-UV wavelengths, so small amounts of light-absorbing impurities (LAI) in snow can dominate the absorption of sunlight at these wavelengths, reducing the albedo relative to that of pure snow and leading to earlier snowmelt. Snow samples were collected in Alaska, Canada, Greenland, <span class="hlt">Svalbard</span>, Norway, Russia, and the Arctic Ocean, on tundra, glaciers, <span class="hlt">ice</span> <span class="hlt">caps</span>, sea <span class="hlt">ice</span>, and frozen lakes, and in boreal forests. Snow was collected mostly in spring, when the entire winter snowpack was accessible for sampling. Snow was also collected at 67 sites in western North America. Expeditions from Lanzhou University obtained black carbon (BC) amounts at 84 sites in northeast and northwest China. BC was measured at 3 locations on the Antarctic Plateau, and at 5 sites on East Antarctic sea <span class="hlt">ice</span>. The snow is melted and filtered; the filters are analyzed in a spectrophotometer. Median BC mixing ratios in snow range over 4 orders of magnitude from 0.2 ng/g in Antarctica to 1000 ng/g in northeast China. Chemical analyses, input to a receptor model, indicate that the major source of BC in most of the Arctic is biomass burning, but industrial sources dominate in <span class="hlt">Svalbard</span> and the central Arctic Ocean. Non-BC impurities, principally brown (organic) carbon, are typically responsible for ~40% of the visible and ultraviolet absorption. In northeast China BC is the dominant LAI, but in Inner Mongolia soil dominates. When the snow surface layer melts, much of the BC is left at the top of the snowpack rather than carried away in meltwater, thus causing a positive feedback on snowmelt. This process was quantified through field studies in Greenland, Alaska, and Norway, where we found that only 10-30% of the BC is removed with meltwater. The BC content of the Arctic atmosphere has declined markedly since 1989, according to the continuous measurements of near-surface air in Canada, Alaska, and <span class="hlt">Svalbard</span>. Correspondingly, our recent BC</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A42C..05D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A42C..05D"><span>Arctic spring ozone reduction associated with projected sea <span class="hlt">ice</span> loss</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deser, C.; Sun, L.; Tomas, R. A.; Polvani, L. M.</p> <p>2013-12-01</p> <p>The impact of Arctic sea <span class="hlt">ice</span> loss on the stratosphere is investigated using the Whole-Atmosphere Community Climate Model (WACCM), by prescribing the sea <span class="hlt">ice</span> in the late 20th century and late 21st century, respectively. The localized Sea Surface Temperature (SST) change associated with sea <span class="hlt">ice</span> melt is also included in the future run. Overall, the model simulates a negative annular-mode response in the winter and spring. In the stratosphere, polar vortex strengthens from February to April, peaking in March. Consistent with it, there is an anomalous cooling in the high-latitude stratosphere, and polar <span class="hlt">cap</span> ozone reduction is up to 20 DU. Since the difference between these two runs lies only in the sea <span class="hlt">ice</span> and localized SST in the Arctic, the stratospheric circulation and ozone changes can be attributed to the surface forcing. Eliassen-Palm analysis reveals that the upward propagation of planetary waves is suppressed in the spring as a consequence of sea <span class="hlt">ice</span> loss. The reduction in propagation causes less wave dissipation and thus less zonal wind deceleration in the extratropical stratosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1913594F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1913594F"><span>Surface elevation change over the Patagonia <span class="hlt">Ice</span> Fields using CryoSat-2 swath altimetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Foresta, Luca; Gourmelen, Noel; José Escorihuela, MarÍa; Garcia Mondejar, Albert; Wuite, Jan; Shepherd, Andrew; Roca, Mònica; Nagler, Thomas; Brockley, David; Baker, Steven; Nienow, Pete</p> <p>2017-04-01</p> <p>Satellite altimetry has been traditionally used in the past few decades to infer elevation of land <span class="hlt">ice</span>, quantify changes in <span class="hlt">ice</span> topography and infer mass balance estimates over large and remote areas such as the Greenland and Antarctic <span class="hlt">ice</span> sheets. Radar Altimetry (RA) is particularly well suited to this task due to its all-weather year-round capability of observing the <span class="hlt">ice</span> surface. However, monitoring of <span class="hlt">ice</span> <span class="hlt">caps</span> (area < 104 km^2) as well as mountain glaciers has proven more challenging. The large footprint of a conventional radar altimeter and relatively coarse ground track coverage are less suited to monitoring comparatively small regions with complex topography, so that mass balance estimates from RA rely on extrapolation methods to regionalize elevation change. Since 2010, the European Space Agency's CryoSat-2 (CS-2) satellite has collected <span class="hlt">ice</span> elevation measurements over <span class="hlt">ice</span> <span class="hlt">caps</span> with its novel radar altimeter. CS-2 provides higher density of observations w.r.t. previous satellite altimeters, reduces the along-track footprint using Synthetic Aperture Radar (SAR) processing and locates the across-track origin of a surface reflector in the presence of a slope with SAR Interferometry (SARIn). Here, we exploit CS-2 as a swath altimeter [Hawley et al., 2009; Gray et al., 2013; Christie et al., 2016; Ignéczi et al., 2016, Foresta et al., 2016] over the Southern and Northern Patagonian <span class="hlt">Ice</span> Fields (SPI and NPI, respectively). The SPI and NPI are the two largest <span class="hlt">ice</span> masses in the southern hemisphere outside of Antarctica and are thinning very rapidly in recent decades [e.g Rignot et al., 2003; Willis et al, 2012]. However, studies of surface, volume and mass change in the literature, covering the entire SPI and NPI, are limited in number due to their remoteness, extremely complex topography and wide range of slopes. In this work, we present rates of surface elevation change for five glaciological years between 2011-2016 using swath-processed CS-2 SARIn heights and</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900065506&hterms=nitrogen+balance&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dnitrogen%2Bbalance','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900065506&hterms=nitrogen+balance&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dnitrogen%2Bbalance"><span>Zonally averaged thermal balance and stability models for nitrogen polar <span class="hlt">caps</span> on Triton</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stansberry, John A.; Lunine, J. I.; Porco, C. C.; Mcewen, A. S.</p> <p>1990-01-01</p> <p>Voyager four-color imaging data of Triton are analyzed to calculate the bolometric hemispheric albedo as a function of latitude and longitude. Zonal averages of these data have been incorporated into a thermal balance model involving insolation, reradiation, and latent heat of sublimation of N2 <span class="hlt">ice</span> for the surface. The current average bolometric albedo of Triton's polar <span class="hlt">caps</span> is 0.8, implying an effective temperature of 34.2 K and a surface pressure of N2 of 1.6 microbar for unit emissivity. This pressure is an order of magnitude lower than the surface pressure of 18 microbar inferred from Voyager data (Broadfoot et al., 1989; Conrath et al., 1989), a discrepancy that can be reconciled if the emissivity of the N2 on Triton's surface is 0.66. The model predicts that Triton's surface north of 15 deg N latitude is experiencing deposition of N2 frosts, as are the bright portions of the south polar <span class="hlt">cap</span> near the equator. This result explains why the south <span class="hlt">cap</span> covers nearly the entire southern hemisphere of Triton.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://kidshealth.org/en/parents/cradle-cap.html','NIH-MEDLINEPLUS'); return false;" href="https://kidshealth.org/en/parents/cradle-cap.html"><span>Cradle <span class="hlt">Cap</span> (For Parents)</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... Safe Videos for Educators Search English Español Cradle <span class="hlt">Cap</span> (Infantile Seborrheic Dermatitis) KidsHealth / For Parents / Cradle <span class="hlt">Cap</span> ( ... many babies develop called cradle <span class="hlt">cap</span>. About Cradle <span class="hlt">Cap</span> Cradle <span class="hlt">cap</span> is the common term for seborrheic ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=228012','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=228012"><span>PREVALENCE OF ANTIBODIES AGAINST TOXOPLASMA GONDII IN POLAR BEARS (URSUS MARITIMUS) FROM <span class="hlt">SVALBARD</span> AND EAST GREENLAND</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Serum samples from 419 polar bears (Ursus maritimus) from <span class="hlt">Svalbard</span> and the Barents Sea (collected 1990 - 2000) and 108 polar bears from East Greenland (collected 1999 - 2004) were assayed for antibodies against Toxoplasma gondii using the modified agglutination test (MAT). Antibody prevalences were ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015TCry....9..255D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015TCry....9..255D"><span>Regional melt-pond fraction and albedo of thin Arctic first-year drift <span class="hlt">ice</span> in late summer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Divine, D. V.; Granskog, M. A.; Hudson, S. R.; Pedersen, C. A.; Karlsen, T. I.; Divina, S. A.; Renner, A. H. H.; Gerland, S.</p> <p>2015-02-01</p> <p>The paper presents a case study of the regional (≈150 km) morphological and optical properties of a relatively thin, 70-90 cm modal thickness, first-year Arctic sea <span class="hlt">ice</span> pack in an advanced stage of melt. The study combines in situ broadband albedo measurements representative of the four main surface types (bare <span class="hlt">ice</span>, dark melt ponds, bright melt ponds and open water) and images acquired by a helicopter-borne camera system during <span class="hlt">ice</span>-survey flights. The data were collected during the 8-day <span class="hlt">ICE</span>12 drift experiment carried out by the Norwegian Polar Institute in the Arctic, north of <span class="hlt">Svalbard</span> at 82.3° N, from 26 July to 3 August 2012. A set of > 10 000 classified images covering about 28 km2 revealed a homogeneous melt across the study area with melt-pond coverage of ≈ 0.29 and open-water fraction of ≈ 0.11. A decrease in pond fractions observed in the 30 km marginal <span class="hlt">ice</span> zone (MIZ) occurred in parallel with an increase in open-water coverage. The moving block bootstrap technique applied to sequences of classified sea-<span class="hlt">ice</span> images and albedo of the four surface types yielded a regional albedo estimate of 0.37 (0.35; 0.40) and regional sea-<span class="hlt">ice</span> albedo of 0.44 (0.42; 0.46). Random sampling from the set of classified images allowed assessment of the aggregate scale of at least 0.7 km2 for the study area. For the current setup configuration it implies a minimum set of 300 images to process in order to gain adequate statistics on the state of the <span class="hlt">ice</span> cover. Variance analysis also emphasized the importance of longer series of in situ albedo measurements conducted for each surface type when performing regional upscaling. The uncertainty in the mean estimates of surface type albedo from in situ measurements contributed up to 95% of the variance of the estimated regional albedo, with the remaining variance resulting from the spatial inhomogeneity of sea-<span class="hlt">ice</span> cover.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23770554','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23770554"><span>Chronology of Pu isotopes and 236U in an Arctic <span class="hlt">ice</span> core.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wendel, C C; Oughton, D H; Lind, O C; Skipperud, L; Fifield, L K; Isaksson, E; Tims, S G; Salbu, B</p> <p>2013-09-01</p> <p>In the present work, state of the art isotopic fingerprinting techniques are applied to an Arctic <span class="hlt">ice</span> core in order to quantify deposition of U and Pu, and to identify possible tropospheric transport of debris from former Soviet Union test sites Semipalatinsk (Central Asia) and Novaya Zemlya (Arctic Ocean). An <span class="hlt">ice</span> core chronology of (236)U, (239)Pu, and (240)Pu concentrations, and atom ratios, measured by accelerator mass spectrometry in a 28.6m deep <span class="hlt">ice</span> core from the Austfonna glacier at Nordaustlandet, <span class="hlt">Svalbard</span> is presented. The <span class="hlt">ice</span> core chronology corresponds to the period 1949 to 1999. The main sources of Pu and (236)U contamination in the Arctic were the atmospheric nuclear detonations in the period 1945 to 1980, as global fallout, and tropospheric fallout from the former Soviet Union test sites Novaya Zemlya and Semipalatinsk. Activity concentrations of (239+240)Pu ranged from 0.008 to 0.254 mBq cm(-2) and (236)U from 0.0039 to 0.053 μBq cm(-2). Concentrations varied in concordance with (137)Cs concentrations in the same <span class="hlt">ice</span> core. In contrast to previous published results, the concentrations of Pu and (236)U were found to be higher at depths corresponding to the pre-moratorium period (1949 to 1959) than to the post-moratorium period (1961 and 1962). The (240)Pu/(239)Pu ratio ranged from 0.15 to 0.19, and (236)U/(239)Pu ranged from 0.18 to 1.4. The Pu atom ratios ranged within the limits of global fallout in the most intensive period of nuclear atmospheric testing (1952 to 1962). To the best knowledge of the authors the present work is the first publication on biogeochemical cycles with respect to (236)U concentrations and (236)U/(239)Pu atom ratios in the Arctic and in <span class="hlt">ice</span> cores. Copyright © 2013 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912103C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912103C"><span>Growth chronology of Greenland Cockles (Serripes groenlandicus) from Bear Island, <span class="hlt">Svalbard</span>, Norway</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carroll, Michael; Ambrose, William; Locke, William; Wanamaker, Alan</p> <p>2017-04-01</p> <p>Climate change is occurring rapidly in the Arctic, and observing the links between environmental drivers and biological effects can provide key information on the ecosystem consequences of climate change. Analysis of shell-based records of mollusks (sclerochronology) provides an effective and expanding approach to reconstructing environmental-ecological linkages. In particular, annually resolved archives can be key indicators of how climate change manifests in the marine ecosystem. We developed a master growth chronology of the Greenland Cockle (Serripes groenlandicus) from Bear Island (Bjørnøya), <span class="hlt">Svalbard</span>, Norway (74°41'N, 18°56'E) from analysis of annual shell increments. The chronology was developed from 20 individuals ranging in age from 24 to 45 years old (the oldest known individuals of this species to date). The chronology, expressed as a standardized growth index (SGI), extended from 1968 to 2012 and exhibited a cyclical pattern, with decadal periods of high growth, alternating with slower growth intervals. We also identified significant relationships between large-scale climate regimes (e.g. NAO, AMO), local environmental conditions (e.g. sea temperature, sea <span class="hlt">ice</span>), and shell growth. Additionally, growth chronologies, and environmental linkages were compared from this, near the southern extent of the Barents Sea polar front, with other Arctic locations influenced by different water masses to examine the nature of the environmental regulation on shell growth of this species in the Barents Sea and Arctic Ocean. We conclude that the Greenland Cockle is quite sensitive to environmental changes over annual to decadal scales and therefore can serve as a proxy of climate change effects on ecosystem processes in the Arctic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950053175&hterms=viscoelastic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dviscoelastic','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950053175&hterms=viscoelastic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dviscoelastic"><span>Predictions of vertical uplift caused by changing polar <span class="hlt">ice</span> volumes on a viscoelastic earth</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wahr, John; Dazhong, Han; Trupin, Andrew</p> <p>1995-01-01</p> <p>Measurements of crustal uplift from bedrock around the edges of Antarctica or Greenland could help constrain the mass balance of those <span class="hlt">ice</span> <span class="hlt">caps</span>. Present-day changes in <span class="hlt">ice</span> could cause vertical displacement rates of several mm/yr around Antarctica and up to 10-15 mm/yr around Greenland. Horizontal displacement rates are likely to be about 1/3 the vertical rates. The viscoelastic response of the earth to past changes in <span class="hlt">ice</span> could cause uplift rates that are several times larger. By measuring both gravity and vertical displacements, it is possible to remove the viscoelastic effects, so that the observations can be used to constrain present-day thickness changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004DPS....36.4104M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004DPS....36.4104M"><span>Transport of Water <span class="hlt">Ice</span> to the Martian South Pole 25,000 years ago</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Montmessin, F.; Haberle, R. M.; Forget, F.</p> <p>2004-11-01</p> <p>Whereas most of studies on recent climate change address the fate of water with changing obliquities, we would like to show how the precession cycle might affect the stability of the north polar <span class="hlt">cap</span> on much faster timescales. This study is motivated by the desire to highlight the potential dichotomy, in terms of water stability, between the poles. Not only does this study address perihelion timing, it focuses on the most recent and most significant change of Mars climate. To do so, we use the General Circulation Model (GCM) developed at LMD (Paris/France) to explore the change in water cycle patterns induced by shifting the perihelion date. It is found that, potentially, water <span class="hlt">ice</span> could have been continuously transferred from north to south pole during episods of "reversed" perihelions. These results have important implications with regards to the recent discovery of thick water <span class="hlt">ice</span> sheets partially uncovered at the edge of the CO2 residual <span class="hlt">cap</span>. This work has been funded by the National Research council.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ISPAr41B7...71C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ISPAr41B7...71C"><span>Ir Spectral Mapping of the Martian South Polar Residual <span class="hlt">CAP</span> Using Crism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Campbell, Jacqueline; Sidiropoulos, Panagiotis; Muller, Jan-Peter</p> <p>2016-06-01</p> <p>Polycyclic aromatic hydrocarbons (PAHs) are considered to be important in theories of abiogenesis (Allamandola, 2011) . There is evidence that PAHs have been detected on two icy Saturnian satellites using the Visual and Infrared Mapping Spectrometer (VIMS) on the Cassini spacecraft (Cruikshank et al., 2007). The hypothesised presence of PAHs in Mars south polar <span class="hlt">cap</span> has not been systematically examined even though the Mars south polar <span class="hlt">cap</span> may allow the preservation of organic molecules that are typically destroyed at the Martian surface by UV radiation (Dartnell et al. 2012). This hypothesis is supported by recent analyses of South Polar Residual <span class="hlt">Cap</span> (SPRC) structural evolution (Thomas et al., 2009) that suggest the possibility that seasonal and long term sublimation may excavate dust particles from within the polar <span class="hlt">ice</span>. Periodic sublimation is believed to be responsible for the formation of so-called "Swiss Cheese Terrain", a unique surface feature found only in the Martian south polar residual <span class="hlt">cap</span> consisting of flat floored, circular depressions (Byrne, 2009). We show the first examples of work towards the detection of PAHs in Swiss Cheese Terrain, using data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), on board NASA's Mars Reconnaissance Orbiter (MRO). CRISM is designed to search for mineralogical indications of past and present water, thus providing extensive coverage of the south polar <span class="hlt">cap</span>. In this work, we discuss whether CRISM infrared spectra can be used to detect PAHs in Swiss Cheese Terrain and demonstrate a number of maps showing shifts in spectral profiles over the SPRC.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.G31C0929H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.G31C0929H"><span>Long term <span class="hlt">ice</span> sheet mass change rates and inter-annual variability from GRACE gravimetry.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harig, C.</p> <p>2017-12-01</p> <p>The GRACE time series of gravimetry now stretches 15 years since its launch in 2002. Here we use Slepian functions to estimate the long term <span class="hlt">ice</span> mass trends of Greenland, Antarctica, and several glaciated regions. The spatial representation shows multi-year to decadal regional shifts in accelerations, in agreement with increases in radar derived <span class="hlt">ice</span> velocity. Interannual variations in <span class="hlt">ice</span> mass are of particular interest since they can directly link changes in <span class="hlt">ice</span> sheets to the drivers of change in the polar ocean and atmosphere. The spatial information retained in Slepian functions provides a tool to determine how this link varies in different regions within an <span class="hlt">ice</span> sheet. We present GRACE observations of the 2013-2014 slowdown in mass loss of the Greenland <span class="hlt">ice</span> sheet, which was concentrated in specific parts of the <span class="hlt">ice</span> sheet and in certain months of the year. We also discuss estimating the relative importance of climate factors that control <span class="hlt">ice</span> mass balance, as a function of location of the glacier/<span class="hlt">ice</span> <span class="hlt">cap</span> as well as the spatial variation within an <span class="hlt">ice</span> sheet by comparing gravimetry with observations of surface air temperature, ocean temperature, etc. as well as model data from climate reanalysis products.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008epsc.conf..659R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008epsc.conf..659R"><span>Debris flows of the mountain massif of Hjorthfjellet and Adventtoppen, <span class="hlt">Svalbard</span>: Implications for gullies on mountains in the Argyre basin, Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reiss, D.; Hiesinger, H.; Zanetti, M.; Hauber, E.; Johnsson, A.; Carlsson, E.; Raack, J.; Olvmo, M.; Johansson, H. A. B.; Johansson, L.; Fredriksson, S.; Schmidt, H. T.; McDaniel, S.; Heldmann, J. L.; McKay, C. P.</p> <p>2008-09-01</p> <p>Martian gullies resemble terrestrial features formed by mass-wasting processes of a flowing mixture of clastic debris and water (debris flows). Their existence on Mars is interpreted to indicate liquid water in the recent past because of their pristine appearance, their stratigraphic relationships to young surface features, their lack of superimposed impact craters, and their distinct albedo relative to the surroundings, indicating limited dust cover [1]. The global distribution of gullies is limited to midand high-latitudes poleward of 30° in both hemispheres, with the highest frequency in the 30°- 50° latitude bands [1, 2]. Gullies occur preferentially on poleward-facing slopes [1, 2, 3, 4]. The most likely and physically most plausible medium to explain the gully morphology is liquid water [e.g., 1, 5]. Two main theories exist for the water source. One holds that water was released from the subsurface [1]. The other proposes that water is deposited as nearsurface <span class="hlt">ice</span> or snow from the atmosphere and is subsequently melted by insolation [6, 7]. Debris flows found in Arctic climates on Earth could be an equitable analog for the Martian gullies. A comparative analysis might help to understand their formation mechanisms and the latitude-dependent, but clustered distribution as well as their specific orientations. The comparative analysis in the Arctic environment of <span class="hlt">Svalbard</span> will be carried out in July/August of 2008. First results of the analog study of gullies will be presented at the conference. Debris flows on <span class="hlt">Svalbard</span> <span class="hlt">Svalbard</span> is located at 76°-81°N and 10°-35°E (Fig. 1), in the discontinuous zone of permafrost. Because the landscape of <span class="hlt">Svalbard</span> is under the influence of the polar desert climate, it is a good analog for comparative Martian studies. These were performed in the last two years in the valley of Longyearbyen and on costal slopes of Isfjorden [8]. This study is complementary to the one described by Carlsson et al., 2008, this issue). Here we</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=317577','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=317577"><span>First plant-parasitic mites (acari: eriophyoidea) recorded from <span class="hlt">Svalbard</span>, including the description of a new species</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Eriophyoidea are minute phytophagous mites with great economic importance and great invasive potential. In spite of their impact on ecosystem functions, the knowledge of eriophyoid mites fauna in Arctic is lacking. Until now, only eight eriophyoid mite species were known from this region. <span class="hlt">Svalbard</span> a...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Geomo.261....1C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Geomo.261....1C"><span>Response of <span class="hlt">ice</span> caves to weather extremes in the southeastern Alps, Europe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Colucci, R. R.; Fontana, D.; Forte, E.; Potleca, M.; Guglielmin, M.</p> <p>2016-05-01</p> <p>High altitude karstic environments often preserve permanent <span class="hlt">ice</span> deposits within caves, representing the lesser-known portion of the cryosphere. Despite being not so widespread and easily reachable as mountain glaciers and <span class="hlt">ice</span> <span class="hlt">caps</span>, <span class="hlt">ice</span> caves preserve much information about past environmental changes and climatic evolution. We selected 1111 <span class="hlt">ice</span> caves from the existing cave inventory, predominantly but not exclusively located in the periglacial domain where permafrost is not dominant (i.e., with mean annual air temperature < 3 °C but not in a permafrost environment). The influence of climate and topography on <span class="hlt">ice</span> cave distribution is also investigated. In order to assess the thickness and the inner structure of the deposits, we selected two exemplary <span class="hlt">ice</span> caves in the Canin massif (Julian Alps) performing several multifrequency GPR surveys. A strong influence of global and local climate change in the evolution of the <span class="hlt">ice</span> deposits has been particularly highlighted in the dynamic <span class="hlt">ice</span> cave type, especially in regard to the role of weather extremes. The natural response of <span class="hlt">ice</span> caves to a warming climate could lead to a fast reduction of such <span class="hlt">ice</span> masses. The increased occurrence of weather extremes, especially warmer and more intense precipitation caused by higher mean 0 °C-isotherms, could in fact be crucial in the future mass balance evolution of such permanent <span class="hlt">ice</span> deposits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017QSRv..167...30S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017QSRv..167...30S"><span>Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based <span class="hlt">ice</span> stream in western Scotland, 21-16 ka</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Small, David; Benetti, Sara; Dove, Dayton; Ballantyne, Colin K.; Fabel, Derek; Clark, Chris D.; Gheorghiu, Delia M.; Newall, Jennifer; Xu, Sheng</p> <p>2017-07-01</p> <p>Understanding how marine-based <span class="hlt">ice</span> streams operated during episodes of deglaciation requires geochronological data that constrain both timing of deglaciation and changes in their flow behaviour, such as that from unconstrained <span class="hlt">ice</span> streaming to topographically restricted flow. We present seventeen new 10Be exposure ages from glacial boulders and bedrock at sites in western Scotland within the area drained by the Hebrides <span class="hlt">Ice</span> Stream, a marine-based <span class="hlt">ice</span> stream that drained a large proportion of the former British-Irish <span class="hlt">Ice</span> Sheet. Exposure ages from Tiree constrain deglaciation of a topographic high within the central zone of the <span class="hlt">ice</span> stream, from which convergent flowsets were produced during <span class="hlt">ice</span> streaming. These ages thus constrain thinning of the Hebrides <span class="hlt">Ice</span> Stream, which, on the basis of supporting information, we infer to represent cessation of <span class="hlt">ice</span> streaming at 20.6 ± 1.2 ka, 3-4 ka earlier than previously inferred. A period of more topographically restricted flow produced flow indicators superimposed on those relating to full <span class="hlt">ice</span> stream conditions, and exposure ages from up-stream of these constrain deglaciation to 17.5 ± 1.0 ka. Complete deglaciation of the marine sector of the Hebrides <span class="hlt">Ice</span> Stream occurred by 17-16 ka at which time the <span class="hlt">ice</span> margin was located near the present coastline. Exposure ages from the southernmost Outer Hebrides (Mingulay and Barra) indicate deglaciation at 18.9 ± 1.0 and 17.1 ± 1.0 ka respectively, demonstrating that an independent <span class="hlt">ice</span> <span class="hlt">cap</span> persisted on the southern Outer Hebrides for 3-4 ka after initial <span class="hlt">ice</span> stream deglaciation. This suggests that deglaciation of the Hebrides <span class="hlt">Ice</span> Stream was focused along major submarine troughs. Collectively, our data constrain initial deglaciation and changes in flow regime of the Hebrides <span class="hlt">Ice</span> Stream, final deglaciation of its marine sector, and deglaciation of the southern portion of the independent Outer Hebrides <span class="hlt">Ice</span> <span class="hlt">Cap</span>, providing chronological constraints on future numerical reconstructions of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.C54A..01W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.C54A..01W"><span>30 years of Arctic sea <span class="hlt">ice</span> thickness measurements by Royal Navy submarines</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wadhams, P.; Hughes, N.; Rodrigues, J. M.; Toberg, N.</p> <p>2009-12-01</p> <p> resolution three-dimensional images of the sea <span class="hlt">ice</span> underside allowing for rapid demarcation of first and multi-year <span class="hlt">ice</span> regimes along with pressure ridge classification and orientation. In order to estimate the rate of thinning of the Arctic sea <span class="hlt">ice</span> we compare the <span class="hlt">ice</span> thickness distributions of 2004 and 2007 with those derived from similar types of sonars that have been fitted to UK submarines on cruises since 1976. Of these, <span class="hlt">ice</span> draft data obtained during a cruise in April 1991, and re-processing to the same standard as 2004 and 2007, has special significance because of the vast amount of data collected in Fram Strait, on the way to the Pole along the prime meridian and a survey of a region of the Arctic Ocean north of <span class="hlt">Svalbard</span> and Franz Joseph Land.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMOS11B1654B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMOS11B1654B"><span>Skin Temperature Processes in the Presence of Sea <span class="hlt">Ice</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brumer, S. E.; Zappa, C. J.; Brown, S.; McGillis, W. R.; Loose, B.</p> <p>2013-12-01</p> <p>Monitoring the sea-<span class="hlt">ice</span> margins of polar oceans and understanding the physical processes at play at the <span class="hlt">ice</span>-ocean-air interface is essential in the perspective of a changing climate in which we face an accelerated decline of <span class="hlt">ice</span> <span class="hlt">caps</span> and sea <span class="hlt">ice</span>. Remote sensing and in particular InfraRed (IR) imaging offer a unique opportunity not only to observe physical processes at sea-<span class="hlt">ice</span> margins, but also to measure air-sea exchanges near <span class="hlt">ice</span>. It permits monitoring <span class="hlt">ice</span> and ocean temperature variability, and can be used for derivation of surface flow field allowing investigating turbulence and shearing at the <span class="hlt">ice</span>-ocean interface as well as ocean-atmosphere gas transfer. Here we present experiments conducted with the aim of gaining an insight on how the presence of sea <span class="hlt">ice</span> affects the momentum exchange between the atmosphere and ocean and investigate turbulence production in the interplay of <span class="hlt">ice</span>-water shear, convection, waves and wind. A set of over 200 high resolution IR imagery records was taken at the US Army Cold Regions Research and Engineering Laboratory (CRREL, Hanover NH) under varying <span class="hlt">ice</span> coverage, fan and pump settings. In situ instruments provided air and water temperature, salinity, subsurface currents and wave height. Air side profiling provided environmental parameters such as wind speed, humidity and heat fluxes. The study aims to investigate what can be gained from small-scale high-resolution IR imaging of the <span class="hlt">ice</span>-ocean-air interface; in particular how sea <span class="hlt">ice</span> modulates local physics and gas transfer. The relationship between water and <span class="hlt">ice</span> temperatures with current and wind will be addressed looking at the ocean and <span class="hlt">ice</span> temperature variance. Various skin temperature and gas transfer parameterizations will be evaluated at <span class="hlt">ice</span> margins under varying environmental conditions. Furthermore the accuracy of various techniques used to determine surface flow will be assessed from which turbulence statistics will be determined. This will give an insight on how <span class="hlt">ice</span> presence</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014TCD.....8.3699D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014TCD.....8.3699D"><span>Regional albedo of Arctic first-year drift <span class="hlt">ice</span> in advanced stages of melt from the combination of in situ measurements and aerial imagery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Divine, D. V.; Granskog, M. A.; Hudson, S. R.; Pedersen, C. A.; Karlsen, T. I.; Divina, S. A.; Gerland, S.</p> <p>2014-07-01</p> <p>The paper presents a case study of the regional (≈ 150 km) broadband albedo of first year Arctic sea <span class="hlt">ice</span> in advanced stages of melt, estimated from a combination of in situ albedo measurements and aerial imagery. The data were collected during the eight day <span class="hlt">ICE</span>12 drift experiment carried out by the Norwegian Polar Institute in the Arctic north of <span class="hlt">Svalbard</span> at 82.3° N from 26 July to 3 August 2012. The study uses in situ albedo measurements representative of the four main surface types: bare <span class="hlt">ice</span>, dark melt ponds, bright melt ponds and open water. Images acquired by a helicopter borne camera system during <span class="hlt">ice</span> survey flights covered about 28 km2. A subset of > 8000 images from the area of homogeneous melt with open water fraction of ≈ 0.11 and melt pond coverage of ≈ 0.25 used in the upscaling yielded a regional albedo estimate of 0.40 (0.38; 0.42). The 95% confidence interval on the estimate was derived using the moving block bootstrap approach applied to sequences of classified sea <span class="hlt">ice</span> images and albedo of the four surface types treated as random variables. Uncertainty in the mean estimates of surface type albedo from in situ measurements contributed some 95% of the variance of the estimated regional albedo, with the remaining variance resulting from the spatial inhomogeneity of sea <span class="hlt">ice</span> cover. The results of the study are of relevance for the modeling of sea <span class="hlt">ice</span> processes in climate simulations. It particularly concerns the period of summer melt, when the optical properties of sea <span class="hlt">ice</span> undergo substantial changes, which existing sea <span class="hlt">ice</span> models have significant diffuculty accurately reproducing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11689941','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11689941"><span>Thinning of the <span class="hlt">ice</span> sheet in northwest Greenland over the past forty years.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Paterson, W S; Reeh, N</p> <p>2001-11-01</p> <p>Thermal expansion of the oceans, as well as melting of glaciers, <span class="hlt">ice</span> sheets and <span class="hlt">ice</span> <span class="hlt">caps</span> have been the main contributors to global sea level rise over the past century. The greatest uncertainty in predicting future sea level changes lies with our estimates of the mass balance of the <span class="hlt">ice</span> sheets in Greenland and Antarctica. Satellite measurements have been used to determine changes in these <span class="hlt">ice</span> sheets on short timescales, demonstrating that surface-elevation changes on timescales of decades or less result mainly from variations in snow accumulation. Here we present direct measurements of the changes in surface elevation between 1954 and 1995 on a traverse across the north Greenland <span class="hlt">ice</span> sheet. Measurements over a time interval of this length should reflect changes in <span class="hlt">ice</span> flow-the important quantity for predicting changes in sea level-relatively unperturbed by short-term fluctuations in snow accumulation. We find only small changes in the eastern part of the transect, except for some thickening of the north <span class="hlt">ice</span> stream. On the west side, however, the thinning rates of the <span class="hlt">ice</span> sheet are significantly higher and thinning extends to higher elevations than had been anticipated from previous studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21345322','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21345322"><span>Rabies in an Arctic fox on the <span class="hlt">Svalbard</span> archipelago, Norway, January 2011.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Orpetveit, I; Ytrehus, B; Vikoren, T; Handeland, K; Mjos, A; Nissen, S; Blystad, H; Lund, A</p> <p>2011-02-17</p> <p>We report a case of rabies in an Arctic fox. In January 2011 a fox attacked dogs belonging to a meteorological station in the <span class="hlt">Svalbard</span> archipelago, Norway. Rabies virus was detected in the fox's brain post-mortem. The dogs had been vaccinated against rabies and their antibody levels were protective. Post-exposure prophylaxis was administered to staff at the station. Rabies vaccination is recommended for inhabitants and visitors to the Arctic who may be in contact with wild animals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1611108L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1611108L"><span>Glaciers and small <span class="hlt">ice</span> <span class="hlt">caps</span> in the macro-scale hydrological cycle - an assessment of present conditions and future changes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lammers, Richard; Hock, Regine; Prusevich, Alexander; Bliss, Andrew; Radic, Valentina; Glidden, Stanley; Grogan, Danielle; Frolking, Steve</p> <p>2014-05-01</p> <p>Glacier and small <span class="hlt">ice</span> <span class="hlt">cap</span> melt water contributions to the global hydrologic cycle are an important component of human water supply and for sea level rise. This melt water is used in many arid and semi-arid parts of the world for direct human consumption as well as indirect consumption by irrigation for crops, serving as frozen reservoirs of water that supplement runoff during warm and dry periods of summer when it is needed the most. Additionally, this melt water reaching the oceans represents a direct input to sea level rise and therefore accurate estimates of this contribution have profound economic and geopolitical implications. It has been demonstrated that, on the scale of glacierized river catchments, land surface hydrological models can successfully simulate glacier contribution to streamflow. However, at global scales, the implementation of glacier melt in hydrological models has been rudimentary or non-existent. In this study, a global glacier mass balance model is coupled with the University of New Hampshire Water Balance/Transport Model (WBM) to assess recent and projected future glacier contributions to the hydrological cycle over the global land surface (excluding the <span class="hlt">ice</span> sheets of Greenland and Antarctica). For instance, results of WBM simulations indicate that seasonal glacier melt water in many arid climate watersheds comprises 40 % or more of their discharge. Implicitly coupled glacier and WBM models compute monthly glacier mass changes and resulting runoff at the glacier terminus for each individual glacier from the globally complete Randolph Glacier Inventory including over 200 000 glaciers. The time series of glacier runoff is aggregated over each hydrological modeling unit and delivered to the hydrological model for routing downstream and mixing with non-glacial contribution of runoff to each drainage basin outlet. WBM tracks and uses glacial and non-glacial components of the in-stream water for filling reservoirs, transfers of water between</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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