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Sample records for arctic kara sea

  1. Organic carbon flow in the Ob, Yenisey Rivers and Kara Sea of the Arctic region.

    PubMed

    Krishnamurthy, R V; Machavaram, M; Baskaran, M; Brooks, J M; Champs, M A

    2001-09-01

    Stable carbon isotope and elemental C/N ratios of the organic fraction of a set of samples along a transect in the Ob and Yenisey Rivers into the Kara Sea in the Arctic were measured. Previously, the concentrations of 239,240Pu and 137Cs in these same samples had been determined. The coupled measurements were carried out to assess possible connectivity between organic carbon flow into the Kara Sea and transport of radioactive nuclides in this marine environment. Organic carbon flow into the Kara Sea is influenced significantly by terrigenous sources carried by the Ob and Yenisey Rivers. The carbon isotope-organic carbon relationship provides evidence that a rich source of terrigenous carbon exists in the riverine system. A weak, but significant relationship between stable carbon isotope ratio and 137Cs suggests that most of the 137Cs is derived from riverine particles, as compared to Pu which is also derived from in situ scavenging within the water column.

  2. How does the SST variability over the western North Atlantic Ocean control Arctic warming over the Barents–Kara Seas?

    NASA Astrophysics Data System (ADS)

    Jung, Ok; Sung, Mi-Kyung; Sato, Kazutoshi; Lim, Young-Kwon; Kim, Seong-Joong; Baek, Eun-Hyuk; Jeong, Jee-Hoon; Kim, Baek-Min

    2017-03-01

    Arctic warming over the Barents–Kara Seas and its impacts on the mid-latitude circulations have been widely discussed. However, the specific mechanism that brings the warming still remains unclear. In this study, a possible cause of the regional Arctic warming over the Barents–Kara Seas during early winter (October–December) is suggested. We found that warmer sea surface temperature anomalies over the western North Atlantic Ocean (WNAO) modulate the transient eddies overlying the oceanic frontal region. The altered transient eddy vorticity flux acts as a source for the Rossby wave straddling the western North Atlantic and the Barents–Kara Seas (Scandinavian pattern), and induces a significant warm advection, increasing surface and lower-level temperature over the Eurasian sector of the Arctic Ocean. The importance of the sea surface temperature anomalies over the WNAO and subsequent transient eddy forcing over the WNAO was also supported by both specially designed simple model experiments and general circulation model experiments.

  3. Macrozooplankton of the Arctic - The Kara Sea in relation to environmental conditions

    NASA Astrophysics Data System (ADS)

    Dvoretsky, Vladimir G.; Dvoretsky, Alexander G.

    2017-03-01

    The distribution, abundance, biomass and diversity of macrozooplankton were studied in relation to hydrological conditions in the Kara Sea during July-September 2012. Multivariate analysis of macrozooplankton density data identified a clear division between the community structure of the deepwater, shelf and estuarine zones. The first assemblage along the Novaya Zemlya Archipelago in the western part of the Kara Sea was characterized by high total abundance/biomass (80,450 ind. m-2/16.9 g dry mass m-2) and was dominated by Calanus glacialis, C. hyperboreus, C. finmarchicus and Metridia longa. The second assemblage in the central part of the Kara Sea was similar in species composition but differed in term of abundance and biomass (15,300 ind. m-2/2.7 g DM m-2). The lowest abundance/biomass (2130 ind. m-2/0.3 g DM m-2) was measured in the third assemblage, the Ob Shallow region, which was characterized by the presence of estuarine taxa and was heavily influenced by freshwater discharge. Parasagitta elegans, Mertensia ovum, Aglantha digitale, Aeginopsis laurentii, Dimophyes arctica and Clione limacina were present mainly as young stages suggesting reproduction of these species in July-August. Canonical correspondence analysis revealed that hydrological factors (salinity and temperature) and geographical variables (latitude, longitude and depth) were the main predictors of macrozooplankton community structures in the Kara Sea. Comparison of our data with other regions in the Arctic demonstrated similarity in the taxonomic composition and density of major large-bodied groups (i.e. amphipods, krill, medusae, pteropods, chaetognaths).

  4. Furfural-based polymers for the sealing of reactor vessels dumped in the Arctic Kara Sea

    SciTech Connect

    HEISER,J.H.; COWGILL,M.G.; SIVINTSEV,Y.V.; ALEXANDROV,V.P.; DYER,R.S.

    1996-10-07

    Between 1965 and 1988, 16 naval reactor vessels were dumped in the Arctic Kara Sea. Six of the vessels contained spent nuclear fuel that had been damaged during accidents. In addition, a container holding {approximately} 60% of the damaged fuel from the No. 2 reactor of the atomic icebreaker Lenin was dumped in 1967. Before dumping, the vessels were filled with a solidification agent, Conservant F, in order to prevent direct contact between the seawater and the fuel and other activated components, thereby reducing the potential for release of radionuclides into the environment. The key ingredient in Conservant F is furfural (furfuraldehyde). Other constituents vary, depending on specific property requirements, but include epoxy resin, mineral fillers, and hardening agents. In the liquid state (prior to polymerization) Conservant F is a low viscosity, homogeneous resin blend that provides long work times (6--9 hours). In the cured state, Conservant F provides resistance to water and radiation, has high adhesion properties, and results in minimal gas evolution. This paper discusses the properties of Conservant F in both its cured and uncured states and the potential performance of the waste packages containing spent nuclear fuel in the Arctic Kara Sea.

  5. 2009/2010 Eurasian Cold Winter and Loss of Arctic Sea-ice over Barents/Kara Sea

    NASA Astrophysics Data System (ADS)

    Shim, T.; Kim, B.; Kim, S.

    2012-12-01

    In 2009/2010 winter, a few extreme cold events and heavy snowfall occurred over central North America, north western Europe, and East Asia exerting a severe social and economic impacts. In this study, we performed modeling experiments to examine the role of substantially reduced Arctic sea-ice over Barents/Kara Sea on the 2009/2010 cold winters. Although several previous studies investigated cause of the extreme events and emphasized the large snow-covered area over Siberia in autumn 2009, we note that the area extent of Arctic sea-ice over Barents/Kara sea in autumn 2009 was anomalously low and the possible impact from Arctic for the extreme cold events has not been presented. To investigate the influence from the Arctic, we designed three model runs using Community Atmosphere Model Version 3 (CAM3). Each simulation differs by the prescribed surface boundary conditions: (a) CTRL - climatological seasonal cycle of sea surface temperature (SST) and sea-ice concentration (SIC) are prescribed everywhere, (b) EXP_65N - SST and SIC inside the Arctic circle (north of 65°N) are replaced by 2009/2010 values. Elsewhere, the climatology is used, (c) EXP_BK - Same with (b) except that SIC and SST are fixed only over Barents/Kara Sea where the sea-ice area dropped significantly in 2009/2010 winter. Model results from EXP_65N and EXP_BK commonly showed a large increase of air temperature in the lower troposphere where Arctic sea-ice showed a large reduction. Also, compared with the observation, model successfully captured thickened geopotential height in the Arctic and showed downstream wave propagation toward midlatitude. From the analysis, we reveal that this large dipolar Arctic-midlatitude teleconnection pattern in the upper troposphere easily propagate upward and played a role in the weakening of polar vortex. This is also confirmed in the observation. However, the timing of excitation of upward propagating wave in EXP_65N and EXP_BK were different and thus the timing of

  6. Kara Sea radioactivity assessment.

    PubMed

    Osvath, I; Povinec, P P; Baxter, M S

    1999-09-30

    Investigations following five international expeditions to the Kara Sea have shown that no radiologically significant contamination has occurred outside of the dumping sites in Novaya Zemlya bays. Increased levels of radionuclides in sediment have only been observed in Abrosimov and Stepovoy Bays very close to dumped containers. Evaluations of radionuclide inventories in water and sediment of the open Kara Sea and Novaya Zemlya bays as well as soil from the shore of Abrosimov bay have shown that radionuclide contamination of the open Kara Sea is mainly due to global fallout, with smaller contributions from the Sellafield reprocessing plant, the Chernobyl accident run-off from the Ob and Yenisey rivers and local fallout. Computer modelling results have shown that maximum annual doses of approximately 1 mSv are expected for a hypothetical critical group subsisting on fish caught in the Novaya Zemlya bays whereas populations living on the mainland can be expected to receive doses at least three orders of magnitude lower.

  7. 1993-94-95 Kara sea field experiments and analysis. 1995 progress report to onr Arctic Nuclear Waste Assessment Program

    SciTech Connect

    Phillips, G.W.; August, R.A.; King, S.E.; Young, D.K.; Bennett, R.H.

    1996-01-14

    This progress report covers field work and laboratory analysis efforts for quantifying the environmental threat of radioactive waste released in the Arctic seas adjacent to the former Soviet Union and for studying the various transport mechanisms by which this radioactivity could effect populations of the U.S. and other countries bordering the Arctic. We obtained water, sediment, biological samples and oceanographic data from several cruises to the Kara Sea and adjacent waters and conducted detailed laboratory analyses of the samples for radionuclides and physical biological properties. In addition, we obtained water and sediment samples and conducted on site low level radionuclide analysis on the Angara, Yenisey River system which drains a major part of the Siberian industrial heartland and empties into the Kara Sea. We report on radionuclide concentrations, on radionuclide transport and scrubbing by sediments, on adsorption by suspended particles, on transport by surface and benthic boundary layer currents, on the effects of benthic and demersal organisms, on studies of long term monitoring in the Arctic, and on an interlaboratory calibration for radionuclide analysis.

  8. Cryolithic zone and Arctic shelf under conditions of climate changes as exemplified by the Kara Sea basin

    NASA Astrophysics Data System (ADS)

    Khodzher, T.

    2012-04-01

    In 2009-2011, a number of interdisciplinary surveys were carried out in the Lower Yenisei River, the Kara Sea shelf. Comprehensive analysis of the environmental state revealed no significant anthropogenic effect on atmosphere and water bodies in the Kara sector of the Arctic. Morphotype diversity of cysts of chrysophycean algae were for the first time studied in water and bottom sediments in the mixing zone of marine and river waters. A collection was composed from 100 strains of organotrophic psychrotolerant microorganisms with different level of activity. There was recorded a great variety of spore forming microorganisms of the genus Bacillus tolerant to extreme natural conditions. Distribution patterns of organic material were determined in the coastal-shelf zone of the Kara Sea. Shores composed of glacial complex contributed a large amount of organic carbon (2-3%) to the seas. Concentrations of organic carbon and nitrogen in sediments depended on type of sediments and sedimentation conditions. Concentration ratio Corg/Norg and isotopic ratio 13C/12C demonstrated that contribution of terrigenous component to organic matter of sediments decreased towards the open sea. Comprehensive survey of 7 thermokarst lakes (from 66.6° to 72.7° N) showed that these lakes are low-mineralised (30-80 mg/l) with high oxygen content (9-11 mgO/l). Degradation of permafrost for the past 170 years was reconstructed using results of analyses of chemical and biological composition of bottom sediments in thermokarst lakes. Degradation process of permafrost causing the formation of these lakes started in the 1930-60s. Beginning from the 1950s, this process accelerated followed by temperature maxima with the time lag of 5-7 years. These reconstructions of paleogeographic conditions of the past based on studies of thermokarst Arctic lakes appeared to be prospective and require further investigations. This work was supported by RAS Presidium, Programme No. 21, Project No. 21.7.

  9. Hydrographic responses to regional covariates across the Kara Sea

    NASA Astrophysics Data System (ADS)

    Mäkinen, Jussi; Vanhatalo, Jarno

    2016-12-01

    The Kara Sea is a shelf sea in the Arctic Ocean which has a strong spatiotemporal hydrographic variation driven by river discharge, air pressure, and sea ice. There is a lack of information about the effects of environmental variables on surface hydrography in different regions of the Kara Sea. We use a hierarchical spatially varying coefficient model to study the variation of sea surface temperature (SST) and salinity (SSS) in the Kara Sea between years 1980 and 2000. The model allows us to study the effects of climatic (Arctic oscillation index (AO)) and seasonal (river discharge and ice concentration) environmental covariates on hydrography. The hydrographic responses to covariates vary considerably between different regions of the Kara Sea. River discharge decreases SSS in the shallow shelf area and has a neutral effect in the northern Kara Sea. The responses of SST and SSS to AO show the effects of different wind and air pressure conditions on water circulation and hence on hydrography. Ice concentration has a constant effect across the Kara Sea. We estimated the average SST and SSS in the Kara Sea in 1980-2000. The average August SST over the Kara Sea in 1995-2000 was higher than the respective average in 1980-1984 with 99.9% probability and August SSS decreased with 77% probability between these time periods. We found a support that the winter season AO has an impact on the summer season hydrography, and temporal trends may be related to the varying level of winter season AO index.

  10. Evidence for Holocene centennial variability in sea ice cover based on IP25 biomarker reconstruction in the southern Kara Sea (Arctic Ocean)

    NASA Astrophysics Data System (ADS)

    Hörner, Tanja; Stein, Rüdiger; Fahl, Kirsten

    2017-10-01

    The Holocene is characterized by the late Holocene cooling trend as well as by internal short-term centennial fluctuations. Because Arctic sea ice acts as a significant component (amplifier) within the climate system, investigating its past long- and short-term variability and controlling processes is beneficial for future climate predictions. This study presents the first biomarker-based (IP25 and PIP25) sea ice reconstruction from the Kara Sea (core BP00-07/7), covering the last 8 ka. These biomarker proxies reflect conspicuous short-term sea ice variability during the last 6.5 ka that is identified unprecedentedly in the source region of Arctic sea ice by means of a direct sea ice indicator. Prominent peaks of extensive sea ice cover occurred at 3, 2, 1.3 and 0.3 ka. Spectral analysis of the IP25 record revealed 400- and 950-year cycles. These periodicities may be related to the Arctic/North Atlantic Oscillation, but probably also to internal climate system fluctuations. This demonstrates that sea ice belongs to a complex system that more likely depends on multiple internal forcing.

  11. Evidence for Holocene centennial variability in sea ice cover based on IP25 biomarker reconstruction in the southern Kara Sea (Arctic Ocean)

    NASA Astrophysics Data System (ADS)

    Hörner, Tanja; Stein, Rüdiger; Fahl, Kirsten

    2017-02-01

    The Holocene is characterized by the late Holocene cooling trend as well as by internal short-term centennial fluctuations. Because Arctic sea ice acts as a significant component (amplifier) within the climate system, investigating its past long- and short-term variability and controlling processes is beneficial for future climate predictions. This study presents the first biomarker-based (IP25 and PIP25) sea ice reconstruction from the Kara Sea (core BP00-07/7), covering the last 8 ka. These biomarker proxies reflect conspicuous short-term sea ice variability during the last 6.5 ka that is identified unprecedentedly in the source region of Arctic sea ice by means of a direct sea ice indicator. Prominent peaks of extensive sea ice cover occurred at 3, 2, 1.3 and 0.3 ka. Spectral analysis of the IP25 record revealed 400- and 950-year cycles. These periodicities may be related to the Arctic/North Atlantic Oscillation, but probably also to internal climate system fluctuations. This demonstrates that sea ice belongs to a complex system that more likely depends on multiple internal forcing.

  12. Effect of river run-off on the distribution of marine invertebrate larvae in the southern Kara Sea (Russian Arctic)

    NASA Astrophysics Data System (ADS)

    Fetzer, Ingo; Deubel, Hendrik

    2006-04-01

    Within the generally oligotroph Arctic marine environment river outlets are favoured by many planktonic and benthic organisms due to their high input of organic carbon. The retention of pelagic larvae within nursery grounds and/or the ability to return to their parental grounds prior to settlement is one important factor for the persistence of benthic communities in such river influenced areas. The southern Kara Sea is strongly controlled by high freshwater inputs from the Ob and Yenisei Rivers, which create a pronounced bi-layered pycnocline with a warm fresh/brackish water layer on top and a cold high saline marine layer below. The dispersal of five meroplanktonic species and settled juveniles (the brittle star Ophiocten sericeum, and the polychaetes Micronephtys minuta, Nereimyra aphroditoides, Phyllodoce groenlandica and Prionospio cirrifera) in relation to the adult distribution patterns was investigated. For all apart from P. cirrifera the highest densities of larvae were found in the upper brackish water layer. To assess size-at-settlement, the body sizes of larvae and newly settled juveniles were estimated and compared. Dispersal patterns ranged from virtually no adaption to river run-off as in the common, stenohaline O. sericeum and M. minuta (7 ind. m - 3 , 459 μm) to local retention as in N. aphroditoides (7 ind. m - 3 , 541 μm) and P. groenlandica (0.5 ind. m - 3 , 1121 μm) retained by horizontal eddies created by the outflow. Adults of P. cirrifera, which were exclusively restricted to the estuary of the Yenisei River, showed a well adapted reproductive behaviour to ensure a high retention potential of their progenies. The larvae (1.5 ind. m - 3 , 1513 μm) were only present in the lower water layers, most probably taking advantage of the prevailing near bottom counter current retaining them within their hatching areas.

  13. Glaciotectonised Quaternary sediments at Cape Shpindler, Yugorski Peninsula, Arctic Russia: implications for glacial history, ice movements and Kara Sea Ice Sheet configuration

    NASA Astrophysics Data System (ADS)

    Lokrantz, Hanna; Ingólfsson, Ólafur; Forman, Steven L.

    2003-09-01

    The coastal cliffs of Cape Shpindler, Yugorski Peninsula, Arctic Russia, occupy a key position for recording overriding ice sheets during past glaciations in the Kara Sea area, either from the Kara Sea shelf or the uplands of Yugorski Peninsula/Polar Urals. This study on Late Quaternary glacial stratigraphy and glaciotectonic structures of the Cape Shpindler coastal cliffs records two glacier advances and two ice-free periods older than the Holocene. During interglacial conditions, a sequence of marine to fluvial sediments was deposited. This was followed by a glacial event when ice moved southwards from an ice-divide over Novaya Zemlya and overrode and disturbed the interglacial sediments. After a second period of fluvial deposition, under interstadial or interglacial conditions, the area was again subject to glacial overriding, with the ice moving northwards from an inland ice divide. The age-control suggests that the older glacial event could possibly belong to marine oxygen isotope stage (MOIS) 8, Drenthe (300-250 ka), and that the underlying interglacial sediments might be Holsteinian (>300 ka). One implication of this is that relict glacier ice, buried in sediments and incorporated into the permafrost, may survive several interglacial and interstadial events. The younger glacial event recognised in the Cape Shpindler sequence is interpreted to be of Early-to-Middle Weichselian age. It is suggested to correlate to a regional glaciation around 90 or 60 ka. The Cape Shpindler record suggests more complex glacial dynamics during that glaciation than can be explained by a concentric ice sheet located in the Kara Sea, as suggested by recent geological and model studies. Copyright

  14. Leaching of radionuclides from furfural-based polymers used to solidify reactor compartments and components disposed of in the Arctic Kara Sea

    SciTech Connect

    HEISER,J.H.; SIVINTSEV,Y.; ALEXANDROV,V.P.; DYER,R.S.

    1999-09-01

    Within the course of operating its nuclear navy, the former Soviet Union (FSU) disposed of reactor vessels and spent nuclear fuel (SNF) in three fjords on the east coast of Novaya Zemlya and in the open Kara Sea within the Novaya Zemlya Trough during the period 1965 to 1988. The dumping consisted of 16 reactors, six of which contained SNF and one special container that held ca. 60% of the damaged SNF and the screening assembly from the No. 2 reactor of the atomic icebreaker Lenin. At the time, the FSU considered dumping of decommissioned nuclear submarines with damaged cores in the bays of and near by the Novaya Zemlya archipelago in the Arctic Kara Sea to be acceptable. To provide an additional level of safety, a group of Russian scientists embarked upon a course of research to develop a solidification agent that would provide an ecologically safe barrier. The barrier material would prevent direct contact of seawater with the SNF and the resultant leaching and release of radionuclides. The solidification agent was to be introduced by flooding the reactors vessels and inner cavities. Once introduced the agent would harden and form an impermeable barrier. This report describes the sample preparation of several ``Furfurol'' compositions and their leach testing using cesium 137 as tracer.

  15. Possible criticality of marine reactors dumped in the Kara Sea

    SciTech Connect

    Warden, J.M.; Mount, M.; Lynn, N.M.

    1997-05-01

    The largest inventory of radioactive materials dumped in the Kara Sea by the former Soviet Union comes from the spent nuclear fuel (SNF) of seven marine reactors. Using corrosion models derived for the International Arctic Seas Assessment Project (IASAP), the possibility of some of the SNF achieving criticality through structural and material changes has been investigated. Although remote, the possibility cannot at this stage be ruled out.

  16. Nutrients in the Kara Sea: Distribution, Variability, and Budgets.

    NASA Astrophysics Data System (ADS)

    Novikhin, A.

    2003-04-01

    The Kara Sea is located far to the north from the Polar circle on the shallow Siberian shelf. The climate conditions of the sea are severe and the sea is covered by ice during most part of the year. Changeable hydrometeorological, ice, and biological conditions, complicated bottom relief, indented shoreline and numerous islands form a multilayered and mosaic water column structure in the Kara Sea. One of the remarkable features of the Kara Sea is a large continental runoff, which consists of about 40 % of total river runoff into the Arctic seas. The great Siberian rivers Ob and Yenisei transport more than 150 million tones of suspended and dissolved organic and inorganic matter to the sea every year. This additional nutrient influx plays an important ecological role, because it stimulates primary production. The river runoff is one of the main sources of the terrestrial organic matter for the Kara Sea. To study nutrient variability and distributions the data set from the US-Russian Electronic Hydrochemical Atlas of the Arctic Ocean which containing more than 15000 stations from 1906 till 2000 and the new data, obtained in the Russian-German expeditions were used. The main results of the studies of nutrient spatial and temporal variability in the river plume area and also in the deep troughs St. Anna, Voronin, and Novozemelsky are reported. Nutrient budgeting studies in the Ob and Yenisei estuaries reveal that the Ob Gulf is net production of inorganic nitrogen and phosphorus. The Yenisei Gulf is net removal of inorganic nitrogen and phosphorus during the year.

  17. Concentrations of trace elements and iron in the Arctic soils of Belyi Island (the Kara Sea, Russia): patterns of variation across landscapes.

    PubMed

    Moskovchenko, D V; Kurchatova, A N; Fefilov, N N; Yurtaev, A A

    2017-05-01

    The concentrations of several trace elements and iron were determined in 26 soil samples from Belyi Island in the Kara Sea (West Siberian sector of Russian Arctic). The major types of soils predominating in the soil cover were sampled. The concentrations of trace elements (mg kg(-1)) varied within the following ranges: 119-561 for Mn, 9.5-126 for Zn, 0.082-2.5 for Cd, <0.5-19.2 for Cu, <0.5-132 for Pb, 0.011-0.081 for Hg, <0.5-10.3 for Co, and 7.6-108 for Cr; the concentration of Fe varied from 3943 to 37,899 mg kg(-1). The impact of particular soil properties (pH, carbon and nitrogen contents, particle-size distribution) on metal concentrations was analyzed by the methods of correlation, cluster, and factor analyses. The correlation analysis showed that metal concentrations are negatively correlated with the sand content and positively correlated with the contents of silt and clay fractions. The cluster analysis allowed separation of the soils into three clusters. Cluster I included the soils with the high organic matter content formed under conditions of poor drainage; cluster II, the low-humus sandy soils of the divides and slopes; and cluster III, saline soils of coastal marshes. It was concluded that the geomorphic position largely controls the soil properties. The obtained data were compared with data on metal concentrations in other regions of the Russian Arctic. In general, the concentrations of trace elements in the studied soils were within the ranges typical of the background Arctic territories. However, some soils of Belyi Island contained elevated concentrations of Pb and Cd.

  18. Carbon dioxide fluxes across the atmosphere-water-coastal eroded ice complex in the Arctic Ocean: Laptev and Kara seas

    NASA Astrophysics Data System (ADS)

    Semiletov, I. P.; Pipko, I. I.; Kosmach, D.; Salyuk, A.; Dudarev, O. V.; Repina, I.; Shakhova, N. E.

    2007-12-01

    Despite the significant progress that has been made in Arctic biogeochemical studies, large discrepancies still exist between recent estimations of the carbon balance and cycling in the Arctic seas [Romankevich and Vetrov, 2001; Stein and Macdonald, 2003; Macdonald et al., 2006] because reliable data are lacking. The Arctic Ocean has been suggested to be a net sink for atmospheric CO2, favoured by cold, relatively low salinity surface layers). Unfortunately, estimates of annual CO2 uptake from the atmosphere vary widely from 1700 × billions moles (Anderson, et al., 1998) up to 11000 billions moles (Lyakhin and Rusanov, 1983), due to high spatial variability and a difficulty of establishing representative values. To fill this gap with a substantial quantity of good-quality data is one of the primary purposes of this study. During the September 2006 expedition in the Laptev Sea and along the Northern Sea Route five research platforms were used to accomplish field work: the ice-strengthened commercial vessel Kapitan Danilkin, two small vessels, the TB 0012 and the Neptun, an Mi-8 helicopter, and diesel icebreaker Kapitan Dranitsyn. CO2 and CH4 fluxes were measured using micrometeorological methods, enclosure methods, or both. In our CO2 and CH4 exchange study setup, momentum and the fluxes of sensible and latent heat were measured using the eddy-correlation technique, which is the most direct micrometeorological method. Dynamics of the carbonate system was studied using pH- TALK technique. Preliminary results: 1. The coastal area of the Laptev Sea, strongly influenced by coastal erosion and river input of terrestrial carbon (suspended and dissolved), acts as a strong source of CO2 into the atmosphere. CO2 flux from the sea surface/nearshore zone ranged between 0.31 - 0.4 μM/?/sec (for comparison, ? release from the tundra soil ranged between 0.03 - 0.18 μM/?/sec). The highest rates of ? emission were measured in the freshly-exposed eroded depressions. 2. CO2 fluxes

  19. Zaliv Kara-Bogaz-Gol, Caspian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The large eastern embayment of the Caspian Sea, the Zaliv Kara-Bogaz-Gol, provides astronauts the chance to observe several oceanographic phenomena. This view taken by the STS-111 crew from the Space Shuttle in June 2002 shows the sun reflecting off the surface waters that surround the spit that defines the Zaliv Kara-Bogaz-Gol from the open Caspian Sea. The sunglint reveals the flow of fresher water through the spit channel and into the bay. Old shorelines and accretionary features can be seen on the spit, as well as the dam that was constructed in 1980 to stop the flow into the lower Kara-Bogaz-Gol basin. The Caspian Sea has experienced dramatic changes in water levels throughout the past 100 years. From the 1930s until 1978, the water levels in the Caspian had dropped nearly 3 m. In 1980, in response to the rapidly dropping sea level, a dam was constructed to prevent water from flowing into the shallow and restricted Kara-Bogaz-Gol basin, resulting in the drying up of the bay. The dam was partially opened a few years later, and completely opened in 1992 when Caspian water levels started to rise quickly. Today, sea levels are more than 2.6 m higher than the 1978 levels, and, as shown here, water flows freely into the salty waters of the Zaliv Kara-Bogaz-Gol. Astronauts have also been documenting the coastlines around the Caspian Sea that have been impacted by the large sea level fluctuations. Astronaut photograph STS111-E-5485 was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  20. Potential for rapid transport of contaminants from the Kara Sea.

    PubMed

    Pfirman, S L; Kögeler, J W; Rigor, I

    1997-08-25

    Export of sea ice from the Kara Sea may redistribute contaminants entrained from atmospheric, marine and riverine sources. Ice exiting the Kara Sea ice to the north, will influence the Fram Strait, Svalbard and Barents Sea regions. Kara Sea ice may also be exported to the Barents Sea through straits north and south of Novaya Zemlya. Some ice from the Kara Sea makes its way into the Laptev Sea to the north and south of Severnaya Zemlya. Data on ice exchange and contaminant levels are not adequate to assess contaminant flux.

  1. A lithosphere-scale structural model of the Barents Sea and Kara Sea region

    NASA Astrophysics Data System (ADS)

    Klitzke, P.; Faleide, J. I.; Scheck-Wenderoth, M.; Sippel, J.

    2014-07-01

    The Barents Sea and Kara Sea region as part of the European Arctic shelf, is geologically situated between the Proterozoic East-European Craton in the south and early Cenozoic passive margins in the north and the west. Proven and inferred hydrocarbon resources encouraged numerous industrial and academic studies in the last decades which brought along a wide spectrum of geological and geophysical data. By evaluating all available interpreted seismic refraction and reflection data, geological maps and previously published 3-D-models, we were able to develop a new lithosphere-scale 3-D-structural model for the greater Barents Sea and Kara Sea region. The sedimentary part of the model resolves four major megasequence boundaries (earliest Eocene, mid-Cretaceous, mid-Jurassic and mid-Permian). Downwards, the 3-D-structural model is complemented by the top crystalline crust, the Moho and a newly calculated lithosphere-asthenosphere boundary (LAB). The thickness distribution of the main megasequences delineates five major subdomains differentiating the region (the northern Kara Sea, the southern Kara Sea, the eastern Barents Sea, the western Barents Sea and the oceanic domain comprising the Norwegian-Greenland Sea and the Eurasia Basin). The vertical resolution of five sedimentary megasequences allows comparing for the first time the subsidence history of these domains directly. Relating the sedimentary structures with the deeper crustal/lithospheric configuration sheds some light on possible causative basin forming mechanisms that we discuss. The newly calculated LAB deepens from the typically shallow oceanic domain in three major steps beneath the Barents and Kara shelves towards the West-Siberian Basin in the east. Thereby, we relate the shallow continental LAB and slow/hot mantle beneath the southwestern Barents Sea with the formation of deep Paleozoic/Mesozoic rift basins. Thinnest continental lithosphere is observed beneath Svalbard and the NW Barents Sea where no

  2. Environment and biology of the Kara Sea: a general view for contamination studies.

    PubMed

    Miquel, J C

    2001-01-01

    The recent revelation that over the past 30 years there has been a history of dumping waste including high-level radioactive wastes in the shallow Kara Sea has caused wide-spread concern. The potential impact of these contaminants and other non-nuclear pollutants in the Arctic ecosystem and on human health need to be assessed and, thus, a better insight gained on radioecological processes in cold waters. The present paper proposes a general view on the biology and the environment of the Kara Sea, as a basic tool for the experimental and modelling assessments of the impact of these contaminants.

  3. A comprehensive view of Kara Sea polynya dynamics, sea-ice compactness and export from model and remote sensing data

    NASA Astrophysics Data System (ADS)

    Kern, S.; Harms, I.; Bakan, S.; Chen, Y.

    2005-08-01

    The Shelf Seas of the Arctic are known for their large sea-ice production. This paper presents a comprehensive view of the Kara Sea sea-ice cover from high-resolution numerical modeling and space-borne microwave radiometry. As given by the latter the average polynya area in the Kara Sea takes a value of 21.2 × 103 km2 +/- 9.1 × 103 km2 for winters (Jan.-Apr.) 1996/97 to 2000/01, being as high as 32.0 × 103 km2 in 1999/2000 and below 12 × 103 km2 in 1998/99. Day-to-day variations of the Kara Sea polynya area can be as high as 50 × 103 km2. For the seasons 1996/97 to 2000/01 the modeled cumulative winter ice-volume flux out of the Kara Sea varied between 100 km3a-1 and 350 km3a-1. Modeled high (low) ice export coincides with a high (low) average and cumulative polynya area, and with a low (high) sea-ice compactness in the Kara Sea from remote sensing data, and with a high (low) sea-ice drift speed across its northern boundary derived from independent model data for the winters 1996/97 to 2000/01.

  4. Phosphatized calcareous conglomerate from the Kara Sea floor

    NASA Astrophysics Data System (ADS)

    Baturin, G. N.; Dubinchuk, V. T.; Pokrovsky, B. G.; Novigatsky, A. N.; Dmitrenko, O. B.; Oskina, N. S.

    2016-09-01

    Trawling of the bottom in the northeastern Kara Sea during cruise 125 of the R/V Professor Shtokman in 2013 recovered a block of cavernous, partly phosphatized carbonate rock consisting of biogenic carbonate material and partly crystallized diagenetic calcite. The fauna remains are mainly Oligocene-Pliocene planktonic and benthic foraminifers, with less common Oligocene-Miocene coccoliths and single wormlike organisms. Part of the phosphatized material in caverns is impregnated by manganese and iron oxides and enriched in heavy and trace metals. According to the oxygen isotopic composition, this rock formed under moderate temperature conditions. In terms of morphology, mineralogy, and the abundance of organic remains, the block is comparable to methanogenic carbonates found in other parts of the ocean, but shows no isotopically light carbon signatures typical of methane activity. This indicates the diversity of the carbon isotope composition of the Arctic carbonates.

  5. Quantitative distribution of the meiobenthos in Baidaratskaya Bay (Kara Sea)

    NASA Astrophysics Data System (ADS)

    Udalov, A. A.; Kondar, D. V.; Miljutina, M. A.; Miljutin, D. M.; Sapojnikov, F. V.; Mokievsky, V. O.

    2017-01-01

    The quantitative characteristics and spatial distribution of the meiobenthos in Baidaratskaya Bay (Kara sea) were analyzed based on data collected in 1994-2007. The extremely high density of the meiobenthos (up to 8121 ind/10 cm2, average 2318 ind/10 cm2) makes it possible to consider Baidaratskaya Bay among the most productive Arctic regions. The spatial distribution of the meiobenthos was mostly determined by the depth and sediment properties in the subtidal zone of the bay. The density of meiobenthic organisms decreased with depth, and with the increase of the small sediment fraction. The difference in the meiobenthic densities between the two coastal areas of the bay (Yamal and Jugora CAs) is also revealed. Such difference caused by the combined effects of small-scale and mesoscale factors, mainly by the grain size. Opposite changes in the meio- and macrobenthic biomass with depth is shown.

  6. Modelling the dispersion of 137Cs and 239Pu released from dumped waste in the Kara Sea

    NASA Astrophysics Data System (ADS)

    Harms, Ingo H.

    1997-10-01

    Three-dimensional, baroclinic, circulation models are applied to study the dispersal of radioactivity in the Barents Sea and Kara Sea. The release is supposed to occur at underwater dump sites for radioactive waste in the Kara Sea, used by the former Soviet Union. Two different spatial scales of dispersion are considered: the regional scale (the far field), which covers the shelves of the Barents and Kara Seas and the local scale (the near field) which is focused mainly on Abrasimov Bay where the dumping partly took place. The regional-scale model results suggest that, even for a worst case scenario, the radioactive contamination of Siberian coastal waters would be relatively small compared to observations in other marine systems (e.g the Baltic Sea and the Irish Sea). Realistic gradual release scenarios show very low concentrations in the central and eastern Kara Sea. A significant contamination of surrounding seas like the Laptev Sea, the Arctic Ocean or the Barents Sea by radioactive waste dispersion from the Kara Sea seems to be unlikely.

  7. Phytoplankton in the northwestern Kara Sea

    NASA Astrophysics Data System (ADS)

    Sukhanova, I. N.; Flint, M. V.; Druzhkova, E. I.; Sazhin, A. F.; Sergeeva, V. M.

    2015-07-01

    Studies were conducted in the northwestern Kara Sea in late September of 2007 and 2011. The assessment of species, size, structure, abundance, and biomass of phytoplankton and the role of autotrophic and heterotrophic components in phytocenoses was conducted. The abundance of autotrophic micro-, nanoand picoplankton increased by more than an order of magnitude in each of the following smaller-sized groups of algae. Microphytoplankton dominated in the total biomass of autotrophic phytoplankton. The wet biomass of microphytoplankton was 2.5 times higher than the wet biomass of nanophytoplankton and 5 times higher than that of picoplankton. Nanophytoplankton dominated in abundance and biomass in the heterotrophic component of phytoplankton. The ratio of the total abundance of autotrophic and heterotrophic phytotoplankton was 7: 1, the ratio of the wet biomass of the both groups was 2.5: 1, and the proportion of the carbon biomass was 2: 1. Three biotopes were distinguished in the area of the outer shelf, the continental slope, and the deepwater area adjacent to the St. Anna Trough, which differed in composition and quantitative characteristics of phytocenoses. Frontal zones dividing the biotopes are characterized by high phytoplankton biomass and the dominance of diatoms in the community (more than 40% of the total biomass), which indicates the local availability of "new" nutrients for planktonic algae.

  8. Mechanism of seasonal Arctic sea ice evolution and Arctic amplification

    NASA Astrophysics Data System (ADS)

    Kim, Kwang-Yul; Hamlington, Benjamin D.; Na, Hanna; Kim, Jinju

    2016-09-01

    Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains thin in winter only in the Barents-Kara seas. Excessive turbulent heat flux through the sea surface exposed to air due to sea ice reduction warms the atmospheric column. Warmer air increases the downward longwave radiation and subsequently surface air temperature, which facilitates sea surface remains to be free of ice. This positive feedback mechanism is not clearly observed in the Laptev, East Siberian, Chukchi, and Beaufort seas, since sea ice refreezes in late fall (November) before excessive turbulent heat flux is available for warming the atmospheric column in winter. A detailed seasonal heat budget is presented in order to understand specific differences between the Barents-Kara seas and Laptev, East Siberian, Chukchi, and Beaufort seas.

  9. Modeling the potential radionuclide transport by the Ob and Yenisey Rivers to the Kara Sea.

    PubMed

    Paluszkiewicz, T; Hibler, L F; Richmond, M C; Bradley, D J; Thomas, S A

    2001-01-01

    A major portion of the former Soviet Union (FSU) nuclear program is located in the West Siberian Basin. Among the many nuclear facilities are three production reactors and the spent nuclear fuel reprocessing sites, Mayak, Tomsk-7, and Krasnoyarsk-26, which together are probably responsible for the majority of the radioactive contamination found in the Ob and Yenisey River systems that feed into the Arctic Ocean through the Kara Sea. This manuscript describes ongoing research to estimate radionuclide fluxes to the Kara Sea from these river systems. Our approach is to apply a hierarchy of simple models that use existing and forthcoming data to quantify the transport and fate of radionuclide contaminants via various environmental pathways. We present an initial quantification of the contaminant inventory, hydrology, meteorology, and sedimentology of the Ob River system and preliminary conclusions from portions of the Ob River model.

  10. Modulation of Stratospheric Sudden Warming properties associated with sea-ice reduction in the Barents-Kara Sea

    NASA Astrophysics Data System (ADS)

    Hoshi, Kazuhira; Ukita, Jinro; Honda, Meiji; Nakamura, Tetsu; Yamazaki, Koji

    2017-04-01

    There has been much discussion on climatological impacts of the Arctic sea ice reduction through stratosphere-troposphere coupling, in particular those from Barents-Kara sea ice anomalies. Both observational and modeling studies indicate that this stratospheric pathway becomes more apparent after 2000. This was concurrent with a period of frequent stratospheric sudden warming (SSW) occurrence. Here we postulate that the Arctic sea-ice reduction would modulate SSWs and examined temporal and spatial characteristics of the tropospheric conditions during SSWs. In particular we compared respective tropospheric conditions between the light and heavy Barents-Kara sea ice years based on the Japanese 55-year reanalysis data for the period of 1979-2015. First, we identify SSW events based on the daily Northern Annular Mode index, the leading principal component time series of geopotential height at 10 hPa northward 20°N, for the winter (December-February) period. Using an early-winter (December) Barents-Kara sea-ice criterion, those SSW events are classified into 14 low sea ice and 23 high sea ice SSW events. For the low sea ice case, the tropospheric precursor (10 days prior to the starting date) is characterized by the wave pattern over the Eurasia (anticyclonic anomalies over the central Eurasia and cyclonic anomalies over the eastern Eurasia), which resembles a spatial pattern of the stationary Rossby wave response to the sea ice reduction in the Barents-Kara Sea. This anomalous wave pattern is in phase with the climatological wavenumber-2 structure. At the lower stratospheric level, the wavenumber-2 component contributes more to the vertical wave activity flux than the wavenumber-1 component does. After the SSW, the negative phase of the Arctic Oscillation and Eurasian cooling appear at the surface level due to significant downward propagation of the signals in the stratosphere. In contrast, SSWs in the high sea ice years are marked with more dominant contribution from

  11. Features of the continental runoff distribution over the Kara Sea

    NASA Astrophysics Data System (ADS)

    Polukhin, A. A.; Makkaveev, P. N.

    2017-01-01

    This paper considers different types of the continental runoff distribution over the Kara Sea depending on hydrological and meteorological processes based on 1993-2014 expedition data of the Shirshov Institute of Oceanology. The results of calculating the relative contribution of fresh water from several sources (the Ob and Yenisei rivers and melted ice) using hydrochemical parameters are also given.

  12. Phase distribution of elements in ferromanganese nodules of the Kara Sea

    NASA Astrophysics Data System (ADS)

    Baturin, G. N.; Dubinchuk, V. T.; Novigatsky, A. N.

    2016-11-01

    The relation of nonferrous metals and other elements to the main mineral phases in iron-manganese ore is a matter of interest in theoretical and practical terms and has long been discussed by experts. However, opinions on this issue diverge due to the vast variety of conditions of ore formation. This is particularly applicable to ferromanganese nodules of the Kara Sea. The results published here demonstrate that the ferromanganese nodules of the Arctic seas accumulate the same range of elements as pelagic ocean nodules, but in different concentrations and proportions: the contents of most ore elements is decreased by a significant influx of clastic material.

  13. Lithosphere-scale 3D gravity modelling of the Barents Sea and Kara Sea

    NASA Astrophysics Data System (ADS)

    Klitzke, P.; Faleide, J.; Sippel, J.; Scheck-Wenderoth, M.

    2013-12-01

    The Barents - Kara Sea region covers the major part of the European Arctic shelf. Its northern and western boundaries are young passive margins which originate from early Paleocene-Eocene opening of the Eurasia Basin and the Norwegian-Greenland Sea. In contrast, the basement of the Barents and Kara shelves has been consolidated much earlier, during three major late Precambrian to Permian orogenies. Additionally, the shelf experienced multiple episodes of localised subsidence which resulted in the formation of ultra-deep sedimentary basins varying strongly in their geometry between different subregions. Consequently, the preserved sedimentary record is interrupted by major megasequence boundaries that are well-described in the western Barents Sea. Using this subdivision for the sedimentary record, we traced four major megasequence boundaries across the Barents and Kara shelves by analysing interpreted seismic refraction and reflection data, geological maps and previously published 3D-models. We integrate this shallow information into a 3D geological model and complement the latter downward with the top crystalline crust, the Moho and a new lithosphere-asthenosphere boundary. The sedimentary units have been assigned physical properties considering the respective lithology to calculate a depth-dependent density distribution. Thereby, the obtained bulk densities also account for late Cenozoic uplift/erosion and the maximum Pleistocene ice sheet thickness. For the lithospheric mantle, the density distribution is constrained by an earlier published velocity model (Levshin et al., 2007). On the base of isostatic calculations and 3D gravity modelling the density configuration of the crystalline crust and the geometry of potential high-density bodies is investigated. Finally, we correlate preserved sediment maxima and reconstructed erosion maps with subsedimentary velocity and density variations to gain new insights into the development of Barents and Kara Sea basins

  14. [Comparative analysis of sea-ice diatom species composition in the seas of Russian Arctic].

    PubMed

    Il'iash, L V; Zhitina, L S

    2009-01-01

    Comparative analysis of species composition of ice diatom algae (IDA) of the White, Barents, Kara, Laptev, East Siberian, Chukchi Seas and the Basin of the Arctic Ocean was conducted on the basis of both original and published data. Species composition of IDA counts 567 taxa including 122 centric and 446 pennate diatoms. The freshwater algae composed about 18% of the total species number. In the White Sea, IDA were the most numerous (272 taxa), in the Kara Sea they are the least numerous (57 taxa). The species compositions in different seas differ significantly from each other. Similarity of IDA was consistent with the Arctic Ocean circulation and ice drift. IDA of Chukchi, East Siberian and Laptev Seas are the most similar, as are IDA of White and Kara Seas. Similarity of IDA of Chukchi Sea to those of other seas decrease in the west direction. IDA species differences between regions within one sea could be greater than those between different seas.

  15. The fate of gas hydrates in the Barents Sea and Kara Sea region

    NASA Astrophysics Data System (ADS)

    Klitzke, Peter; Scheck-Wenderoth, Magdalena; Schicks, Judith; Luzi-Helbing, Manja; Cacace, Mauro; Jacquey, Antoine; Sippel, Judith; Faleide, Jan Inge

    2016-04-01

    The Barents Sea and Kara Sea are located in the European Arctic. Recent seismic lines indicate the presence of gas hydrates in the Barents Sea and Kara Sea region. Natural gas hydrates contain huge amounts of methane. Their stability is mainly sensitive to pressure and temperature conditions which make them susceptible for climate change. When not stable, large volumes of methane will be released in the water column and - depending on the water depth - may also be released into the atmosphere. Therefore, studying the evolution in time and space of the gas hydrates stability zone in the Barents Sea region is of interest for both environmental impact and energy production. In this study, we assess the gas hydrate inventory of the Barents Sea and Kara Sea under the light of increasing ocean bottom temperatures in the next 200 years. Thereby, we make use of an existing 3D structural and thermal model which resolves five sedimentary units, the crystalline crust and the lithospheric mantle. The sedimentary units are characterised by the prevailing lithology and porosity including effects of post-depositional erosion which strongly affect the local geothermal gradient. Governing equations for the conductive 3D thermal field and momentum balance have been integrated in a massively parallel finite-element-method based framework (MOOSE). The MOOSE framework provides a powerful and flexible platform to solve multiphysics problems implicitly on unstructured meshes. First we calculate the present-day steady-state 3D thermal field. Subsequently, we use the latter as initial condition to calculate the transient 3D thermal field for the next 200 years considering an ocean temperature model as upper boundary. Temperature and load distributions are then used to calculate the thickness of the gas hydrate stability zone for each time step. The results show that the gas hydrate stability zone strongly varies in the region due to the local geothermal gradient changes. The latter

  16. Impact of continental runoff and melted sea ice on spatial distribution of carbonate parameters and nutrients in the Kara and Laptev Seas

    NASA Astrophysics Data System (ADS)

    Polukhin, Alexander; Kostyleva, Anna; Protsenko, Elizaveta; Stepanova, Svetlana; Yakubov, Shamil; Makkaveev, Petr

    2016-04-01

    It is well-known that the Kara and Laptev seas are strongly affected by large amount of fresh water coming from the great Siberian rivers (the Ob' River, the Yenisei River and the Lena River). Expeditions of the Shirshov Institute of Oceanology were directed on investigation of freshening of these two Arctic seas. We have large collection of data (CTD, nutrients, carbonate system parameters) from the Kara Sea expeditions (1993, 2007, 2011, 2013, 2014 years) and the newest data from the last expedition to the Kara and Laptev Seas in 2015. Employment of these materials along with archival data on mentioned seas gives us an opportunity to trace variability of hydrochemical parameters in conditions of changing climate. From year to year in our expeditions we see reduction of sea-ice cover on the water area of the Kara Sea, changes in freshwater discharge and different seasonal variability of hydrochemical structure under influence of continental runoff. Moreover we notice some falling of carbonate system parameters such as pH and alkalinity. Hereby we can estimate processes of acidification in the Russian Arctic and reveal main stressors. This work is supported by Russian Science Foundation (project №14-50-00095).

  17. Summer population structure of the copepods Paraeuchaeta spp. in the Kara Sea

    NASA Astrophysics Data System (ADS)

    Dvoretsky, Vladimir G.; Dvoretsky, Alexander G.

    2015-02-01

    High Arctic seas are poorly studied due to difficulties to access and sample seas with extensive sea ice cover. The current study investigated the distribution of the large deepwater copepods Paraeuchaeta spp. (Paraeuchaeta glacialis) in the summer season in the Kara Sea. The total abundance of P. glacialis varied from 10 to 1210 × 10- 2 ind m- 3 sampled with a Juday net and from 2 to 490 × 10- 2 ind m- 3 sampled with a IKS-80 net. The highest abundances were recorded at the deepwater stations. Nauplii dominated the population of Paraeuchaeta spp. comprising 23% of the total abundance. Unimodal size spectra were found for most of the age stages that suggests the presence of one generation during the year. Clutch size and egg size tended to increase with P. glacialis female prosome length and individual biomass.

  18. Small scale spatial variability of temperature and salinity in the Kara Sea basing on observations in September, 2011

    NASA Astrophysics Data System (ADS)

    Izhitskiy, Alexander; Zavialov, Peter

    2013-04-01

    The Kara Sea, the marginal sea in the Arctic Ocean, receives a large volume of freshwater (1290 km3/year on long term average) from the Ob, Yenisey and other rivers. In consequence, a large part of sea's area is influenced by fresh water discharge. Spreading in the surface layer of the sea, continental runoff largely modulates spatial variability of temperature and salinity. Depending on geographic location, atmospheric forcing conditions, water circulation etc., this variability is characterized by different scales. The objective of the study is the estimation of thermohaline variability scales in the surface layer and its connection with governing factors. The study is based on the results of the latest (September, 2011) survey of the Shirshov Institute to the Kara Sea (59th cruise of the RV Akademik Mstislav Keldysh). Data used in this study includes high-resolution (frequency 4 Hz) measurements of temperature and salinity at the surface of the Kara Sea conducted using a pump-through CTD system. These measurements were conducted along the vessel track, covering the whole area of the sea, during 24 days period and allowed for horizontal resolution as high as ~100 m. Additionally, the principal meteorological parameters such as temperature, pressure and wind velocity and direction were recorded by a shipboard automatic meteorological station. Basing on the obtained measurements, we determine the representative water types at the surface of the Kara Sea for the fall season. Processing of such a detailed data allows us to indentify regions of the sea, where the thermohaline characteristics have the most intense variability. We also investigate the dependence between wind conditions and magnitude and scales of the thermohaline variability. Finally, we find the typical spatial scales of the variability for different parts of the sea.

  19. A seasonal comparison of zooplankton communities in the Kara Sea - With special emphasis on overwintering traits

    NASA Astrophysics Data System (ADS)

    Kosobokova, Ksenia Nikolaevna; Hirche, Hans-Juergen

    2016-06-01

    Siberian marginal seas cover large parts of the marine Arctic and host unique zooplankton communities. Detailed knowledge of their community structure and life history traits is a prerequisite to predict their response to ongoing and future climate and anthropogenic changes although winter data is extremely rare. Here data are presented from winter samples (February and April) in four biogeographic regions of the Kara Sea. Comparison of community composition and zooplankton abundance/biomass with data collected during summer showed lower diversity in winter, mainly due to the absence of freshwater species. In contrast to many other northern regions, seasonal biomass differences were relatively small. Year-round high biomass is maintained through a large share of small copepod species and constantly high share of the chaetognath Parasagitta elegans. An advanced state of gonad maturation and reproduction was observed in winter in herbivorous, omnivorous, and carnivorous species, e.g. the copepods Calanus glacialis, Drepanopus bungei, Limnocalanus macrurus, Oithona similis, Pseudocalanus major, Pseudocalanus minutus/acuspes, Paraeuchaeta glacialis, Microcalanus pygmaeus, and euphausiids, hydromedusae, and pteropods. Meroplanktonic larvae of nudibranchia, polychaeta and bivalvia were also registered. Close to the Yenisei mouth, abundance of eggs and larvae of various taxa exceeded older stages. Our data show that the brackish-water zone of the Kara Sea hosts specific communities with omnivorous species efficiently exploiting local resources during the winter and utilizing them for winter reproduction.

  20. Benthic fauna of Tsivolki Bay (Novaya Zemlya Archipelago, Kara Sea)

    NASA Astrophysics Data System (ADS)

    Chava, A. I.; Udalov, A. A.; Vedenin, A. A.; Simakov, M. I.; Shchuka, S. A.; Mokievsky, V. O.

    2017-01-01

    Benthic fauna in Tsivolki Bay (Novaya Zemlya Archipelago, Kara Sea) has been studied during the voyage of the R/V Professor Shtokman in 2013 and 2014. A peculiar feature of the bay is the presence of the Serp i Molot glacier in its inner part, which determines the extremely high content of suspended particles in the water column. The bay is divided into three parts: the inner part (close to the glacier), the middle basin, and the outer slope. These parts are separated from each other by several rises. Benthic communities changed gradually from the inner part of the bay towards the outer slope. Three communities were described from the data of nine grab stations (26 samples). The apex of the bay is occupied by the depleted community dominated by the isopod Saduria sabini and the bivalve Yoldiella lenticula, which can successfully survive the increased mineral sedimentation. In the middle basin, it is replaced by the transitional community with Ennucula tenuis and Portlandia arctica being the main dominants. Finally, the outer slope is inhabited by the community typical for the open parts of the Kara Sea. It is dominated by Astarte crenata, Ophiacantha bidentata, and Ophiopleura borealis. The main reason for macrobenthic distribution in the studied region is the content of mineral particles in the water column and bottom layers.

  1. Sorption of radioactive contaminants by sediment from the Kara Sea.

    PubMed

    Fuhrmann, M; Zhou, H; Neiheisel, J; Dyer, R

    2001-01-01

    The purpose of this study is to quantify some of the parameters needed to perform near-field modelling of sites in the Kara Sea that were impacted by the disposal of radioactive waste. The parameters of interest are: the distribution coefficients (Kd) for several important radionuclides, the mineralogy of the sediment, and the relationship of Kd to liquid-to-solid ratio. Sediment from the Kara Sea (location: 73 degrees 00'N, 58 degrees 00'E) was sampled from a depth of 287 m on August 23/24, 1992. Analysis of the material included mineralogy, grain size and total organic carbon (TOC). Uptake kinetics were determined for 85Sr, 137Cs, 241Am, 99Tc, 1251, 232U and 210Pb and distribution coefficients (Kd) were determined for these radionuclides using batch type experiments. Sorption isotherms, developed for 137Cs, 85Sr and 99Tc, were linear in each case. Increasing the liquid-to-solid ratio strongly increased uptake of 137Cs and moderately increased uptake of 99Tc. Analysis for anthropogenic radionuclides indicated the presence only of 239/240Pu in the sediment with the highest activity (at the top section of the core) being 0.420 Bq kg(-1). Other anthropogenic radionuclides were below detection limits.

  2. On the link between Barents-Kara sea ice variability and European blocking

    NASA Astrophysics Data System (ADS)

    Ruggieri, P.; Buizza, R.; Visconti, G.

    2016-05-01

    This study examines the connection between the variability of sea ice concentration in the Barents and Kara (B-K) seas and winter European weather on an intraseasonal time scale. Low sea ice regimes in autumn and early winter over the B-K seas are shown to affect the strength and position of the polar vortex, and increase the frequency of blocking regimes over the Euro-Atlantic sector in late winter. A hypothesis is presented on the mechanism that links sea ice over the B-K seas and circulation regimes in the North Atlantic, and is investigated considering 34 years of European Centre for Medium-Range Weather Forecasts reanalysis data. Four key steps have been identified, starting from a local response of the near-surface fluxes and modification of the upper tropospheric wave pattern, to the stratospheric adjustment and the tropospheric response in the North Atlantic. The proposed mechanism explains the delayed, late winter response of the North Atlantic Oscillation to the late autumn sea ice reduction, which has been found both in observations and model experiments. It also provides valuable insights on how the reduction of Arctic sea ice can influence the position of the tropospheric jet in the Euro-Atlantic sector.

  3. Human impact on dynamics of Barents and Kara Seas Coasts

    NASA Astrophysics Data System (ADS)

    Ogorodov, Stanislav

    2013-04-01

    The coasts of Barents and Kara Seas which are composed of unconsolidated deposits have poor erosion resistance qualities. In natural conditions such coasts may retreat with a rate of 1 to 2 m a year. Under the influence of human activities this rate can double and even triple. Over the last twenty years the human impact on the natural coastal geosystems has noticeably increased due to the latest oil and gas developments on the sea shelf and coasts of the Russian North. A range of facilities - oil custody terminals for drilling and production platforms, submerged pipelines, ports and other industrial features and residential infrastructure - are currently being operated in the coastal and shelf zones. In most of the cases no morphodynamic or lithodynamic features of the coastal zone had been taken into account during the construction or operation of these facilities. This results in a disturbance of the sediment transport in the coastal zone, which triggers active erosion of both the shore itself and the coastal slope beneath. The operated facilities themselves are then threatened as their destruction is possible and often no new facilities can be constructed in the disturbed area. The operating companies have to bear forced nonmanufacturing expenses to protect or move their facilities of oil and gas industry to new areas. We may cite here three instances for Barents and Kara Seas where human impact has already brought in negative effects. One of the examples is Varandey Coast of the Barents Sea. From 1979 to 2012 a deliberate destruction of the dune chain of the barrier beach by vehicle traffic and a removal of the beach material for construction needs led to a quick intensification of the coastal retreat here. And now, storm surges without hindrance penetrate inland for several kilometers. Let's move further east to the Kara Sea: on to Kharasavey Coast to the Yamal Peninsula. A large-scale extraction of sediments from the coastal slope has resulted in a depletion

  4. New atmospheric methane observations in the Kara, Laptev, and East Siberian Seas during SWERUS-C3

    NASA Astrophysics Data System (ADS)

    Thornton, B. F.; Crill, P. M.; Semiletov, I. P.

    2014-12-01

    We present a first look at a new, extensive dataset of atmospheric methane observations during the SWERUS-C3 cruise in July and August 2014. The path of the icebreaker Oden during the expedition traversed the Arctic Ocean across the Kara, Laptev and East Siberian Seas from Tromsø, Norway to Barrow, Alaska. Atmospheric methane and carbon dioxide concentrations were measured at 1 Hz resolution throughout the journey. Air was sampled at four different heights, ranging from 9 to 35 m above the sea surface. At limited stations when the ship was anchored in shallow waters of the Laptev Sea, additional in situ measurements were made at 4 m above the sea surface. Further, in-situ isotopic observations of (delta)13C-methane and (delta)D-methane were made throughout the journey. This unprecedented dataset of atmospheric methane across the outer Russian Arctic continental shelf seas may help us to make top-down estimations of methane release from the ice-covered Kara, Laptev, and East Siberian Seas to the atmosphere.

  5. Lithological and geochemical typification of surface bottom sediments in the Kara Sea

    NASA Astrophysics Data System (ADS)

    Rusakov, V. Yu.; Kuzhmina, T. G.; Levitan, M. A.; Toropchenova, E. S.; Zhylkina, A. V.

    2017-01-01

    The Kara Sea is part of the Western Arctic shelf of Eurasia. The deposition of sediments in this shallow sea is largely determined by solid runoff from two great Siberian rivers (the Yenisei and Ob) and the glacial periods when the sea area repeatedly (during the Quaternary) dried up and was covered by continental glaciers. The rise of the World Ocean due to Holocene warming resulted in a significant expansion of the sea area to the south and complete degradation of the ice sheet. In this article, new data on the geochemical composition of the surface (0- to 2-cm) layer of sea-bottom sediments are considered, which reflects the spatial distribution of marine sediments during the maximum sea level. Cluster analysis of the variance for 24 chemical elements reveals sediment chemotypes, and critical analysis of their relationship with lithotypes is performed. The presented data have been collected on cruises of the R/V Akademik Boris Petrov in 2000, 2001, and 2003 and the R/V Akademik Mstislav Keldysh in 2015.

  6. Phytoplankton succession in the Ob-Yenisei Shallow zone of the Kara Sea based on Russian databases

    NASA Astrophysics Data System (ADS)

    Makarevich, P. R.; Larionov, V. V.; Moiseev, D. V.

    2015-07-01

    Here, data about the taxonomic composition and spatial distribution of planktonic microalgae in the Ob Bay and the southern Kara Sea in north Russia were analyzed during all hydrological seasons over 11 years (1996-2006). Data were obtained through detailed in situ observations. These data are part of our arctic phytoplankton database. Phytoplankton inhabiting the near shore continental area of the Kara Sea exhibited four phases in the annual succession cycle: a prevernal phase (cryoflora bloom), a vernal phase (ice-edge bloom), a summer-fall phase (mixed synthesis phase), and a winter phase (dormant phase). These phases were clearly differentiated based on the composition of dominant phytoplankton species complexes and quantitative characteristics (i.e., microalgal number and biomass). In the study region, which is completely covered by ice for most of the year (from October to June), the process of primary production begins at the same time as in ice-free coastal areas. Sub-ice blooming and growth of cryoflora initiate beneath the ice cover, long before it breaks down. In addition, from July to October, high phytoplankton biomass was recorded in Ob Bay and in areas adjacent to the Ob-Yenisei shallows. This information provides quantitative evidence for the higher productivity of waters off the Obestuary, compared to other coastal areas in the Kara Sea. The main factor responsible for this phenomenon is the permanent (during the warm season) transport of living and dead organic matter by river runoff to shelf waters.

  7. Lithospheric strength and elastic thickness of the Barents Sea and Kara Sea region

    NASA Astrophysics Data System (ADS)

    Gac, Sébastien; Klitzke, Peter; Minakov, Alexander; Faleide, Jan Inge; Scheck-Wenderoth, Magdalena

    2016-11-01

    Interpretation of tomography data indicates that the Barents Sea region has an asymmetric lithospheric structure characterized by a thin and hot lithosphere in the west and a thick and cold lithosphere in the east. This suggests that the lithosphere is stronger in the east than in the west. This asymmetric lithosphere strength structure may have a strong control on the lithosphere response to tectonic and surface processes. In this paper, we present computed strength and effective elastic thickness maps of the lithosphere of the Barents Sea and Kara Sea region. Those are estimated using physical parameters from a 3D lithospheric model of the Barents Sea and Kara Sea region. The lithospheric strength is computed assuming a temperature-dependent ductile and brittle rheology for sediments, crust and mantle lithosphere. Results show that lithospheric strength and elastic thickness are mostly controlled by the lithosphere thickness. The model generally predicts much larger lithospheric strength and elastic thickness for the Proterozoic parts of the East Barents Sea and Kara Sea. Locally, the thickness and lithology of the continental crust disturb this general trend. At last, the gravitational potential energy (GPE) is computed. Our results show that the difference in GPE between the Barents Sea and the Mid-Atlantic Ridge provides a net horizontal force large enough to cause contraction in the western and central Barents Sea.

  8. Trends in trace organic and metal concentrations in the Pechora and Kara Seas and adjacent rivers

    SciTech Connect

    Brooks, J.M.; Champ, M.A.; Wade, T.L.; Kennicutt, M.C. II; Chambers, L.; Davis, T.

    1995-12-31

    Trace organic (pesticides, PCBs, PAHs and dioxin/furan) and trace metal concentrations have been measured in surficial sediment and tissue (i.e., clam, fish liver and flesh) samples from the Pechora and Kara Seas and their adjacent rivers -- Pechora, Ob and Yenisey Rivers. Total PAH, PCB and total DDT and chlordane concentrations ranged in surficial sediments from n.d. to 810 ppb, n.d.--8.7 ppb, n.d.--1.2 ppb, and n.d.--1.2 ppb, respectively, in a suite of 40 samples from the Kara Sea and its adjacent rivers. The highest concentrations of many of the trace organic and metal contaminants were found in the lower part of the Yenisey River below the salt wedge. Some trace metals (As for example) were elevated in the Pechora River dispositional plume region. Dioxin ranged from 1.36 to 413 ppt in a subset of 20 sediment samples. Higher trace organic contaminant concentrations compared to sediments were found in tissue samples from the region, especially fish liver samples. Concentrations as high as 1,114 ppb total PAHs, 89 ppb chlordane, 1,011 ppb for total DDT and 663 ppb PCBs were found in some fish liver samples. Dioxin concentrations in tissue samples ranged from 11.7 to 61 ppt. Concentrations of many trace organic and metal contaminants in these Russian marginal seas are influenced by inputs from these large Arctic rivers. Many organic contaminant concentrations in sediments are low, however detecting these compounds in tissue show they are bioavailable.

  9. Recent Ostracoda of the Laptev and Kara seas as indicators of bottom water environments

    NASA Astrophysics Data System (ADS)

    Stepanova, A.; Taldenkova, E.; Bauch, H. A.; Simstich, J.

    2003-04-01

    Ostracods from coretop sediments collected at 56 localities from different parts of the Laptev and Kara seas were investigated for assemblage studies. A total of 48 species belonging to 25 genera have been identified. Three assemblages have been established in the Laptev Sea that are linked to certain ranges in water depth and bottom salinities as well as water circulation and sea-ice transportation. The species-rich and abundant assemblages of the western and central Laptev Sea could be related to Atlantic waters occupying the upper continental slope. These include relatively deep-water species that show clear affinities to the North Atlantic and Arctic Ocean (Cytheropteron biconvexa, C. testudo, C. simplex, C. nodosoalatum, C. inflatum, C. porterae, Krithe glacialis, K. minima, Pseudocythere caudata, Polycope punctata, P. orbicularis). In the eastern middle shelf region, the assemblage is comprised of Acanthocythereis dunelmensis together with other normal marine species (Semicytherura complanata, Elofsonella concinna, Cluthia cluthae). This latter assemblage is distributed within the region of the winter flaw polynya which is believed to be the main area of sediment entrainment into sea ice. The inner shelf assemblage of the southern Laptev Sea is dominated by shallow-water euryhaline species (Paracyprideis pseudopunctillata and Heterocyprideis sorbyana) with admixture of brackish-water species Cytheromorpha macchesneyi. The fact that many shallow-water ostracod species were found on the upper continental slope seems to be a result of ice-rafting which these ostracods are probably able to survive. Preliminary studies of ostracods from the eastern Kara Sea coretop samples allowed distinguishing three different assemblages. One of them reported from the Ob’ estuary is completely different from the Laptev Sea assemblages being comprised of freshwater species only. Two other assemblages can be referred to as a brackish-water and marine ones. Taxonimically poor

  10. Skill improvement of dynamical seasonal Arctic sea ice forecasts

    NASA Astrophysics Data System (ADS)

    Krikken, Folmer; Schmeits, Maurice; Vlot, Willem; Guemas, Virginie; Hazeleger, Wilco

    2016-05-01

    We explore the error and improve the skill of the outcome from dynamical seasonal Arctic sea ice reforecasts using different bias correction and ensemble calibration methods. These reforecasts consist of a five-member ensemble from 1979 to 2012 using the general circulation model EC-Earth. The raw model reforecasts show large biases in Arctic sea ice area, mainly due to a differently simulated seasonal cycle and long term trend compared to observations. This translates very quickly (1-3 months) into large biases. We find that (heteroscedastic) extended logistic regressions are viable ensemble calibration methods, as the forecast skill is improved compared to standard bias correction methods. Analysis of regional skill of Arctic sea ice shows that the Northeast Passage and the Kara and Barents Sea are most predictable. These results show the importance of reducing model error and the potential for ensemble calibration in improving skill of seasonal forecasts of Arctic sea ice.

  11. Springtime microwave emissivity changes in the southern Kara Sea

    NASA Technical Reports Server (NTRS)

    Crane, Robert G.; Anderson, Mark R.

    1994-01-01

    Springtime microwave brightness temperatures over first-year ice are examined for the southern Kara Sea. Snow emissivity changes are revealed by episodic drops in the 37- to 18-GHz brightness temperature gradient ratio measured by the Nimbus 7 scanning multichannel microwave radiometer. We suggest that the negative gradient ratios in spring 1982 result from increased scatter at 37 GHz due to the formation of a near-surface hoar layer. This interpretation is supported by the results of a surface radiation balance model that shows the melt signature occurring at below freezing temperatures but under clear-sky conditions with increased solar input to the surface. Published observations from the Greenland ice cap show a surface hoar layer forming under similar atmospheric conditions owing to the increased penetration and absorption of solar radiation just below the surface layer. In spring/early summer 1984 similar gradient ratio signatures occur. They appear to be due to several days of freeze-thaw cycling following the movement of a low-pressure system through the region. These changes in surface emissivity represent the transition from winter to summer conditions (as defined by the microwave response) and are shown to be regional in extent and to vary with the synoptic circulations.

  12. Benthic fauna of Blagopoluchiya Bay (Novaya Zemlya Archipelago, Kara Sea)

    NASA Astrophysics Data System (ADS)

    Udalov, A. A.; Vedenin, A. A.; Simakov, M. I.

    2016-09-01

    The benthic fauna was studied in the Blagopoluchiya Bay (Kara Sea, Novaya Zemlya Archipelago) during an expedition of the R/V Professor Shtokman in autumn 2013. The inner basin of the bay, with depths of around 150 m, is separated from the outer slope of Novaya Zemlya by a shoal 30 m in depth. Six macrobenthic communities were described at nine stations (25 bottom grab samples) taken along a transect from the inner part of the bay to the outer part of the slope. The depths, position on the transect axis and sediment types were the major factors influencing the distribution of the communities. The benthic abundance and biomass in the inner and outer parts of the bay did not differ significantly. The diversity of macrobenthic organisms (α-diversity as the number of species in the sample and β-diversity as the rate of increase in species number in the area) was lower in the inner part of the bay. The intertidal zone (littoral) has been described. The littoral fauna was very poor; it comprised only the amphipods Gammarus setosus inhabiting the near-surface area.

  13. Integrated multidisciplinary processing and interpretation of geophysical data acquired on transects in Barents and Kara seas

    NASA Astrophysics Data System (ADS)

    Roslov, Yu. V.; Sakoulina, T. S.

    2003-04-01

    INTEGRATED MULTIDISCIPLINARY PROCESSING AND INTERPRETATION OF GEOPHYSICAL DATA ACQUIRED ON TRANSECTS IN BARENTS AND KARA SEAS Yu.V. Roslov (1), T.S. Sakoulina (1) (1 - SEVMORGEO State Geophysical Co., 36 Rosenstein St, 198095, St Petersburg, Russia, roslov @sevmorgeo.com) According to Russian arctic offshore transect program State Company Sevmorgeo in cooperation with other Russian state companies carry out multidisciplinary investigations on transects 1-AR and 2-AR in Barents and Kara Seas. Investigations include the following geophysical methods: 4C wide angle refraction/reflection profiling (WARRP), CDP seismic, airborn and/or marine gravity and magnetic. Three levels of the integration has been used on processing and interpretation stage. First, different approaches of kinematic inverse problem and tomographic reconstruction have been applied for kinematic parameters of 4C WARRP data processing. That has allowed extracting of maximum information from the data acquired. As a result stable P and S velocity models have been obtained. Second, dynamic WARRP image focused mainly on Moho boundary has been integrated with CDP image in order to improve the sedimentary layer structure. Third, seismic images have been proven with gravity and magnetic data reaching the model, which fits to observed potential fields. Also gravity and magnetic data successfully fill out information gap in the places where there is a lack of seismic data. Some original technologies of data processing have been developed in the framework of the project. Finally, within the range defined by the data processed the integrated geological-geophysical images the Kara-Barents Shelf Plate structure whole Earth crust thickness along transects 1-AR and 2-AR have been obtained. New geophysical data acquired have forced reviewing of our nderstanding of Barents region geological structure. First of all it concern to south and north Barents depressions. South Barents depression is well known as a geological

  14. Characteristics of radionuclide accumulation in benthic organisms and fish of the Barents and Kara Seas

    SciTech Connect

    Matishov, G.G.; Matishov, D.G.; Rissanen, C.

    1995-05-01

    Artificial radionuclides play a specific role in the hydrochemical, geochemical, and hydrobiological processes that are currently occurring in the western Arctic. The existing data on radioactive contamination of different plant and animal species inhabiting the sea shelf are fragmentary. Hence, it was difficult to follow the transformation of radionuclides during their transmission along food chains, from phyto- and zoo-plankton to benthos, fish, birds, and marine mammals. In 1990-1994, the Murmansk Institute of Marine Biology organized expeditions to collect samples of residues on the sea floor and also of benthos, benthic fish, macrophytes, and other organisms inhabiting the shelf of the Barents and Kara Seas. These samples were tested for cesium-137, cesium-134, strontium-90, plutonium-239, plutonium-240, americium-241, and cobalt-60 in Rovaniemi (Finland) by the regional radiation administration of the Finnish Centre for Radiation and Nuclear Safety. Over 1000 tests were made. Their results provided new data on the content and distribution of these radionuclides among different components of marine ecosystems. 7 refs.

  15. Distribution of trace gases and aerosols in the troposphere over West Siberia and Kara Sea

    NASA Astrophysics Data System (ADS)

    Belan, Boris D.; Arshinov, Mikhail Yu.; Paris, Jean-Daniel; Nédélec, Philippe; Ancellet, Gérard; Pelon, Jacques; Berchet, Antoine; Arzoumanian, Emmanuel; Belan, Sergey B.; Penner, Johannes E.; Balin, Yurii S.; Kokhanenko, Grigorii; Davydov, Denis K.; Ivlev, Georgii A.; Kozlov, Artem V.; Kozlov, Alexander S.; Chernov, Dmitrii G.; Fofonov, Alexader V.; Simonenkov, Denis V.; Tolmachev, Gennadii

    2015-04-01

    The Arctic is affected by climate change much stronger than other regions of the globe. Permafrost thawing can lead to additional methane release, which enhances the greenhouse effect and warming, as well as changes of Arctic tundra ecosystems. A great part of Siberian Arctic is still unexplored. Ground-based investigations are difficult to be carried out in this area due to it is an out-of-the-way place. So, in spite of the high cost, aircraft-based in-situ measurements can provide a good opportunity to fill up the gap in data on the atmospheric composition over this region. The ninth YAK-AEROSIB campaign was focused on the airborne survey of Arctic regions of West Siberia. It was performed in October 2014. During the campaign, the high-precision in-situ measurements of CO2, CH4, CO, O3, black carbon and aerososls, including aerosol lidar profiles, have been carried out in the Siberian troposphere from Novosibirsk to Kara Sea. Vertical distributions of the above atmospheric constituents will be presented. This work was supported by LIA YAK-AEROSIB, CNRS (France), the French Ministry of Foreign Affairs, CEA (France), the Branch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5); State contracts of the Ministry of Education and Science of Russia No. 14.604.21.0100, (RFMTFIBBB210290) and No. 14.613.21.0013 (RFMEFI61314X0013); Interdisciplinary integration projects of the Siberian Branch of the Russian Academy of Science No. 35, No. 70 and No. 131; and Russian Foundation for Basic Research (grants No. 14-05-00526 and 14-05-00590).

  16. A 3D gravity and thermal model for the Barents Sea and Kara Sea

    NASA Astrophysics Data System (ADS)

    Klitzke, Peter; Sippel, Judith; Faleide, Jan Inge; Scheck-Wenderoth, Magdalena

    2016-08-01

    In the frame of this study, we investigate the lithosphere-scale 3D physical state of the Barents Sea and Kara Sea region. Therefore, we test an existing 3D structural model against the gravitational field by considering the heterogeneous upper mantle to further assess the structural and density configuration of the continental crystalline crust. The resulting 3D density configuration of the crust is discussed in terms of its relationships with the spatial distribution of tectonically different domains. In addition, it provides the base for a lithology-controlled parameterisation of the crust with thermal properties to calculate the 3D conductive thermal field. The deeper thermal field is controlled by the depth configuration of the lithosphere-asthenosphere boundary. Accordingly, deeper isotherms such as the 450 °C isotherm deepen from below the rifted SW Barents Sea towards the intracratonic basins of the eastern Barents Sea and Kara Sea, indicating an increase of the lithospheric strength in the same direction. Temperature measurements of the upper 800 m below the SW Barents Sea reveal an increased thermal gradient which cannot be reproduced by a steady-state 3D conductive model alone. Beside fault-induced fluid flow to be active there, an alternative scenario could involve a phase of subsidence long enough to increase the temperature of the upper 800 m, followed by an uplift and erosion phase that prevented the positive thermal anomaly to propagate towards larger depths. The final lithosphere-scale 3D model is the first to integrate the geological, density and thermal configuration of the entire Barents Sea and Kara Sea region and hence provides an ideal base for future thermomechanical studies addressing, for instance, questions on the present-day, past and future relationships between lithospheric strength and deformation.

  17. Arctic Sea Ice Maximum 2011

    NASA Image and Video Library

    AMSR-E Arctic Sea Ice: September 2010 to March 2011: Scientists tracking the annual maximum extent of Arctic sea ice said that 2011 was among the lowest ice extents measured since satellites began ...

  18. International Arctic Seas Assessment Project.

    PubMed

    Sjöblom, K L; Salo, A; Bewers, J M; Cooper, J; Dyer, R S; Lynn, N M; Mount, M E; Povinec, P P; Sazykina, T G; Schwarz, J; Scott, E M; Sivintsev, Y V; Tanner, J E; Warden, J M; Woodhead, D

    1999-09-30

    The International Atomic Energy Agency responded to the news that the former Soviet Union had dumped radioactive wastes in the shallow waters of the Arctic Seas, by launching the International Arctic Seas Assessment Project in 1993. The project had two objectives: to assess the risks to human health and to the environment associated with the radioactive wastes dumped in the Kara and Barents Seas; and to examine possible remedial actions related to the dumped wastes and to advise on whether they are necessary and justified. The current radiological situation in the Arctic waters was examined to assess whether there is any evidence for releases from the dumped waste. Potential future releases from the dumped wastes were predicted, concentrating on the high-level waste objects containing the major part of the radionuclide inventory of the wastes. Environmental transport of released radionuclides was modelled and the associated radiological impact on humans and the biota was assessed. The feasibility, costs and benefits of possible remedial measures applied to a selected high-level waste object were examined. Releases from identified dumped objects were found to be small and localised to the immediate vicinity of the dumping sites. Projected future annual doses to members of the public in typical local population groups were very small, less than 1 microSv--corresponding to a trivial risk. Projected future doses to a hypothetical group of military personnel patrolling the foreshore of the fjords in which wastes have been dumped were higher, up to 4 mSv/year, which still is of the same order as the average annual natural background dose. Moreover, since any of the proposed remedial actions were estimated to cost several million US$ to implement, remediation was not considered justified on the basis of potentially removing a collective dose of 10 man Sv. Doses calculated to marine fauna were insignificant, orders of magnitude below those at which detrimental effects on

  19. The distribution of the suspended matter concentration in the Kara Sea in September 2007 based on ship and satellite data

    NASA Astrophysics Data System (ADS)

    Burenkov, V. I.; Goldin, Yu. A.; Kravchishina, M. D.

    2010-10-01

    The distribution of the suspended particulate matter concentration in the Kara Sea is analyzed based on ship and satellite data. The statistical relationships between the suspended matter concentration and the optical characteristics were revealed. Charts of the distribution of the suspended matter concentration in the Kara Sea were plotted, which confirmed that the application of optical methods for analyzing the spatial distribution of the suspended matter is effective. The most turbid waters were observed in the Ob Gulf, Yenisei Bay, the Baidaratskaya Gulf, and the adjacent regions. The smallest concentrations of suspended matter were observed in the central and western parts of the Kara Sea.

  20. Bacteriohopanepolyol distribution in Yenisei River and Kara Sea suspended particulate matter and sediments traces terrigenous organic matter input

    NASA Astrophysics Data System (ADS)

    De Jonge, Cindy; Talbot, Helen M.; Bischoff, Juliane; Stadnitskaia, Alina; Cherkashov, Georgy; Sinninghe Damsté, Jaap S.

    2016-02-01

    Bacteriohopanepolyols (BHPs) are ubiquitous bacterial membrane lipids, encountered in soils, river and marine suspended particulate matter (SPM) and sediments. Their abundance and distribution provides a direct means to identify bacterial inputs and can be used to trace soil-derived bacterial organic matter (OM) and in some cases the presence of bacterial groups and their activities in aquatic systems. We have studied the BHP distribution in the SPM of a major Siberian River (Yenisei River) that crosses a large latitudinal gradient, draining a large part of Mongolia and Siberian Russia. The Yenisei River is the main river to flow into the Kara Sea, a shelf sea of the Arctic Ocean. We show that the BHP distribution and concentration of SPM and surface sediments of the Yenisei Outflow in the Kara Sea allow to trace soil-marker BHPs and evaluate the performance of the R‧soil index, a proxy developed to trace bacterial soil-derived OM. Soil-marker BHPs are present in the Yenisei River, and their concentration decreases from the Yenisei River Outflow into the offshore marine sediments. The R‧soil correlates well with an independent proxy for bacterial OM, the BIT-index (r2 = 0.82) and has a moderate correlation with the δ13Corg values, a bulk OM proxy for terrigenous input (r2 = 0.44). Consequently, the R‧soil index performs well in the Kara Sea, strengthening its application for tracing bacterial OM in the Arctic Ocean, both in modern and downcore sediments. Furthermore, a suite of BHPs that are characteristic for methanotrophic bacteria, i.e. 35-aminobacteriohopane-30,31,32,33,34-pentol (aminopentol) and 35-aminobacteriohopane-31,32,33,34-tetrol (aminotetrol), is encountered in the Yenisei Outflow sediments. These components are partly sourced from terrigenous sources, but are likely also produced in-situ in the marine sediments. The distribution of the pentafunctionalized cyclitol ether BHP in the marine systems is noteworthy, and indicates that it can

  1. Offshore permafrost decay and massive seabed methane escape in water depths >20 m at the South Kara Sea shelf

    NASA Astrophysics Data System (ADS)

    Portnov, A.; Mienert, J.; Cherkashov, G. A.

    2013-12-01

    migrate. Discontinuous and local permafrost areas may exist further offshore in up to 115 m water depth. This study provides one of the key examples of an Arctic marine shelf where seafloor gas release is widespread and where permafrost degradation is an ongoing process. These initial results provided targets for drilling and data acquisition in the summer of 2013 and for future research cruises in the Kara Sea. A better understanding of hydrocarbon seepage at the seafloor is important for assessing both the natural release of gas to the atmosphere and the hydrocarbon potential for new exploration regions like the Kara Sea.

  2. Arctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Stroeve, J. C.; Fetterer, F.; Knowles, K.; Meier, W.; Serreze, M.; Arbetter, T.

    2004-12-01

    Of all the recent observed changes in the Arctic environment, the reduction of sea ice cover stands out most prominantly. Several independent analysis have established a trend in Arctic ice extent of -3% per decade from the late 1970s to the late 1990s, with a more pronounced trend in summer. The overall downward trend in ice cover is characterized by strong interannual variability, with a low September ice extent in one year typically followed by recovery the next September. Having two extreme minimum years, such as what was observed in 2002 and 2003 is unusual. 2004 marks the third year in a row of substantially below normal sea ice cover in the Arctic. Early summer 2004 appeared unusual in terms of ice extent, with May a record low for the satellite period (1979-present) and June also exhibiting below normal ice extent. August 2004 extent is below that of 2003 and large reductions in ice cover are observed once again off the coasts of Siberia and Alaska and the Greenland Sea. Neither the 2002 or 2003 anomaly appeared to be strongly linked to the positive phase of the Arctic Oscillation (AO) during the preceding winter. Similarly, the AO was negative during winter 2003/2004. In the previous AO framework of Rigor et al (2002), a positive winter AO implied preconditioning of the ice cover to extensive summer decay. In this hypothesis, the AO does not explain all aspects of the recent decline in Arctic ice cover, such as the extreme minima of 2002, 2003 and 2004. New analysis by Rigor and Wallace (2004) suggest that the very positive AO state from 1989-1995 can explain the recent sea ice minima in terms of changes in the Arctic surface wind field associated with the previous high AO state. However, it is also reasonable to expect that a general decrease in ice thickness accompanying warming would manifest itself as greater sensitivity of the ice pack to wind forcings and albedo feedbacks. The decrease in multiyear ice and attendant changes in ice thickness

  3. Twenty-five winters of unexpected Eurasian cooling unlikely due to Arctic sea-ice loss

    NASA Astrophysics Data System (ADS)

    McCusker, Kelly E.; Fyfe, John C.; Sigmond, Michael

    2016-11-01

    Surface air temperature over central Eurasia decreased over the past twenty-five winters at a time of strongly increasing anthropogenic forcing and Arctic amplification. It has been suggested that this cooling was related to an increase in cold winters due to sea-ice loss in the Barents-Kara Sea. Here we use over 600 years of atmosphere-only global climate model simulations to isolate the effect of Arctic sea-ice loss, complemented with a 50-member ensemble of atmosphere-ocean global climate model simulations allowing for external forcing changes (anthropogenic and natural) and internal variability. In our atmosphere-only simulations, we find no evidence of Arctic sea-ice loss having impacted Eurasian surface temperature. In our atmosphere-ocean simulations, we find just one simulation with Eurasian cooling of the observed magnitude but Arctic sea-ice loss was not involved, either directly or indirectly. Rather, in this simulation the cooling is due to a persistent circulation pattern combining high pressure over the Barents-Kara Sea and a downstream trough. We conclude that the observed cooling over central Eurasia was probably due to a sea-ice-independent internally generated circulation pattern ensconced over, and nearby, the Barents-Kara Sea since the 1980s. These results improve our knowledge of high-latitude climate variability and change, with implications for our understanding of impacts in high-northern-latitude systems.

  4. Relating Regional Arctic Sea Ice and climate extremes over Europe

    NASA Astrophysics Data System (ADS)

    Ionita-Scholz, Monica; Grosfeld, Klaus; Lohmann, Gerrit; Scholz, Patrick

    2016-04-01

    The potential increase of temperature extremes under climate change is a major threat to society, as temperature extremes have a deep impact on environment, hydrology, agriculture, society and economy. Hence, the analysis of the mechanisms underlying their occurrence, including their relationships with the large-scale atmospheric circulation and sea ice concentration, is of major importance. At the same time, the decline in Arctic sea ice cover during the last 30 years has been widely documented and it is clear that this change is having profound impacts at regional as well as planetary scale. As such, this study aims to investigate the relation between the autumn regional sea ice concentration variability and cold winters in Europe, as identified by the numbers of cold nights (TN10p), cold days (TX10p), ice days (ID) and consecutive frost days (CFD). We analyze the relationship between Arctic sea ice variation in autumn (September-October-November) averaged over eight different Arctic regions (Barents/Kara Seas, Beaufort Sea, Chukchi/Bering Seas, Central Arctic, Greenland Sea, Labrador Sea/Baffin Bay, Laptev/East Siberian Seas and Northern Hemisphere) and variations in atmospheric circulation and climate extreme indices in the following winter season over Europe using composite map analysis. Based on the composite map analysis it is shown that the response of the winter extreme temperatures over Europe is highly correlated/connected to changes in Arctic sea ice variability. However, this signal is not symmetrical for the case of high and low sea ice years. Moreover, the response of temperatures extreme over Europe to sea ice variability over the different Arctic regions differs substantially. The regions which have the strongest impact on the extreme winter temperature over Europe are: Barents/Kara Seas, Beaufort Sea, Central Arctic and the Northern Hemisphere. For the years of high sea ice concentration in the Barents/Kara Seas there is a reduction in the number

  5. Isotope parameters (δD, δ18O) and sources of freshwater input to Kara Sea

    NASA Astrophysics Data System (ADS)

    Dubinina, E. O.; Kossova, S. A.; Miroshnikov, A. Yu.; Fyaizullina, R. V.

    2017-01-01

    The isotope characteristics (δD, δ18O) of Kara Sea water were studied for quantitative estimation of freshwater runoff at stations located along transect from Yamal Peninsula to Blagopoluchiya Bay (Novaya Zemlya). Freshwater samples were studied for glaciers (Rose, Serp i Molot) and for Yenisei and Ob estuaries. As a whole, δD and δ18O are higher in glaciers than in river waters. isotope composition of estuarial water from Ob River is δD =-131.4 and δ18O =-17.6‰. Estuarial waters of Yenisei River are characterized by compositions close to those of Ob River (-134.4 and-17.7‰), as well as by isotopically "heavier" compositions (-120.7 and-15.8‰). Waters from studied section of Kara Sea can be product of mixing of freshwater (δD =-119.4, δ18O =-15.5) and seawater (S = 34.9, δD = +1.56, δ18O = +0.25) with a composition close to that of Barents Sea water. isotope parameters of water vary significantly with salinity in surface layer, and Kara Sea waters are desalinated along entire studied transect due to river runoff. concentration of freshwater is 5-10% in main part of water column, and <5% at a depth of >100 m. maximum contribution of freshwater (>65%) was recorded in surface layer of central part of sea.

  6. Microphysical and chemical characteristics of near-water aerosol over White and Kara Seas

    NASA Astrophysics Data System (ADS)

    Terpugova, S. A.; Polkin, V. V.; Panchenko, M. V.; Golobokova, L. P.; Kozlov, V. S.; Shmargunov, V. P.; Shevchenko, V. P.; Lisitzin, A. P.

    2009-04-01

    The results are presented of five-year-long (2003-2007) study of the spatial - temporal variability of the near-water aerosol in the water area of White and Kara Seas (55, 64, 71 and 80-th cruises of RV "Professor Shtockman"; 53 and 54-th cruises of RV "Akademik Mstislav Keldysh"). Measurements of aerosol microphysical characteristics were carried out by means of the automated mobile aerosol complex consisting of nephelometer, photoelectric counter and aethalometer. The aerosol disperse composition was studied with photoelectric counter in 256 size intervals from 0.4 to 10 m. About 1500 series of measurements were carried out in White Sea, and about 1400 series in Kara Sea. Chemical characteristics of aerosol were determined from samples collected on aerosol filters (92 samples were collected in White Sea and 48 in Kara Sea). The ion composition was determined under laboratory conditions. The H+, Na+, K+, Ca2+, Mg2+, NH4+, Cl-, NO3-, HCO3-, SO42- ions were under examination. Comparing aerosol characteristics of two seas, one can note that the mean values of the aerosol content parameters in Kara Sea are less than in White Sea. The ratio of the aerosol mass concentration are from 2 (Yamal Peninsula, northern part of Novaya Zemlya) to 9 times (Blagopoluchia Bay, Ob' Gulf). The differences in the concentration of black carbon vary from 3 (Yamal Peninsula) to 17 times (Blagopoluchia Bay). The differences in the aerosol number concentration NA are not so big. The values NA near Kara Gate, Yamal Peninsula and northern part of Novaya Zemlya are practically the same as in White Sea. The concentration NA at Ob' gulf is one order of magnitude less than in White sea. The obtained aerosol volume size distributions were approximated by the sums of two fractions, submicron and coarse, with lognormal size distributions. The mean volume size distribution of submicron fraction in White Sea is approximated by the distribution with the variance of the radius logarithm s=0.6 and modal

  7. The influence of climate change on the intensity of ice gouging at the Kara Sea bottom by hummocky formations

    NASA Astrophysics Data System (ADS)

    Ogorodov, Stanislav; Arkhipov, Vasily; Kokin, Osip; Natalia, Shabanova

    2016-04-01

    Sea ice as a zonal factor is an important passive and active relief-forming agent in the coastal-shelf zone of the Arctic and other freezing seas. The most dangerous process in relation to the hydrotechnical facilities is ice gouging - destructive mechanical impact of the ice of the ground, connected with the dynamics of the ice cover, formation of hummocks and stamukhas under the influence of hydrometeorologic factors and of the relief of the coastal-shelf zone. Underestimation of the ice gouging intensity can lead to damage of the engineering facilities, while excessive deepening increases the expenses of the construction. Finding the optimal variant and, by this, decreasing the risks of extreme situations is a relevant task of the science and practice. This task is complicated by the fact that the oil and gas infrastructure within the coastal and shelf areas of the freezing seas is currently being developed in the conditions of global climate change. In the present work, several results of the repeated sounding of bottom ice gouging microrelief within the area of the underwater pipeline crossing of the Baydaratskaya Bay, Kara Sea, are presented. Based on the results of the monitoring, as well as the analysis of literature sources and modeling it has been established that under the conditions of climate warming and sea ice reduction, the zone of the most intensive ice gouging is shifted landwards, on shallower water areas.

  8. Application of inverse technique to study radioactive pollution and mixing processes in the Arctic Seas

    NASA Astrophysics Data System (ADS)

    Ivanov, L. M.; Margolina, T. M.; Danilov, A. I.

    2004-07-01

    Rare noisy observations of the dissolved and suspended Cs 137, and the dissolved Sr 90 collected for years 1985 and 1994, respectively, are utilized through an inverse method to estimate the radionuclide pollution and the mixing time scale, namely the age, of the White and Kara Seas. We demonstrate how uncertainties, such as measurement noise, inhomogeneous station disposition and others depress the identification utility of the radioactive observations in the Arctic Seas to validate regional radioecological models. The special approach estimates the current and mean radionuclide pollution from the rare observations. We found the mean integral amount of cesium (strontium) pollution of the White Sea (in 1985) and Kara Sea (in 1992) did not exceed ˜70 (41) TBq and ˜16 (9) TBq, respectively, and radioactive background of these seas is low in comparing to the Black and Barents Seas. Estimations of the age confirm the fact of the rapid ventilation of the Kara Sea, but not the White Sea. The age ranges from 1-2 years for the Kara Sea till 5-6 years for the White Sea. That factually says about the possibility of the long-term accumulation of radionuclides in the White Sea.

  9. Contribution from the Yenisei River to the total radioactive contamination of the Kara Sea

    SciTech Connect

    Kuznetsov, Yu.V.; Revenko, Yu.A.; Legin, V.K.

    1995-07-01

    An attempt is made to estimate the contribution from the Yenisei River and, therefore, the Krasnoyarsk Mining and Chemical Plant (MCP), which discharged wastewaters to the Yenisei, to the total contamination of the Kara Sea using results from a study of the radioactive contamination of the Yenisei River, Yenisei Bay, Yenisei Gulf, and the Kara Sea itself. Radionuclides generated from using river water in cooling circuits of production reactors make the largest contribution to the total activity. The radioactive contamination of the river decreased by more than 20 times after two of the three operating reactors were shut down. Only several wetlands are actually affected by MCP hundreds of kilometers from the discharge point.

  10. Meiobenthos and nematode community in Yenisei Bay and adjacent parts of the Kara Sea shelf

    NASA Astrophysics Data System (ADS)

    Portnova, D. A.; Garlitska, L. A.; Udalov, A. A.; Kondar, D. V.

    2017-01-01

    Material is collected on a meridional profile from Yenisei Bay to adjacent parts of the Kara Sea shelf. The length of the profile is 550 km; 13 to 62 m depths. A multiple corer and Niemistö corer are used as sampling tools. The meiobenthos is represented by 13 taxa. Nematodes are the most abundant taxon, and harpacticoid copepods (Harpacticoida) are subdominant. The abundance and taxonomic diversity of meiobenthos and nematodes increases from the freshwater part of Yenisei Bay towards the Kara Sea shelf. Three types of taxocene are distinguished: freshwater, brackish-water, and marine. The taxocene of the estuary is not distinguished by any specific set of species and consists of species characteristic of the nematode community both in the freshwater and marine zones. The trophic structure of the taxocene of nematodes in Yenisei Bay is dominated by nematodes with well-defined stoma and are differently armed. The estuary and shelf are dominated by selective and nonselective deposit feeders.

  11. Anthropogenic radioactivity in the nordic seas and the arctic ocean — results of a joint project

    NASA Astrophysics Data System (ADS)

    Nies, H.; Harms, I. H.; Karcher, M. J.; Dethleff, D.; Bahe, C.; Kuhlmann, G.; Oberhuber, J. M.; Backhaus, J. O.; Kleine, E.; Loewe, P.; Matishov, D.; Stepanov, A.; Vasiliev, O. F.

    1998-12-01

    The paper presents the results of a joint project combining numerical model studies and field work in order to investigate the dispersion of anthropogenic radioactivity in the Arctic Ocean. The results obtained underline the essential difference between the dispersion of dissolved contaminants in water and the transport of particulate material in sea ice. Coupled ice-ocean models on different spatial scales are applied to study the transit times and major pathways for radioactive contaminant transport in the water column. One of the main sources for radioactive pollution in the Arctic, the discharge of the Sellafield reprocessing plant, was simulated from 1965 until now. The results are compared with measurements and hypothetical release scenarios computed for the the dump sites of radioactive waste in the Kara Sea. Our comparison reveals that the Sellafield signal is by one or two orders of magnitude higher than any potential contamination from Kara Sea dump sites, even if a ’worst case’ scenario is assumed. In order to assess the role of sea ice in contaminant transport, sedimentological data from the Kara Sea and the Arctic Ocean were analysed. The results show that fine-grained Kara Sea sediments from dump site areas are predestined for entrainment into newly forming ice. Observed buoy drifts and simulated trajectories confirm that the Arctic Transpolar Ice Drift is a rather short pathway for pollutant dispersion from the Arctic Ocean to the adjacent Nordic Seas. However, compared to the large volume and contaminant flux in the ocean, the contaminant dispersion by sea ice plays a minor role.

  12. The main moisture sources over Barents/Kara Sea and sea ice loss due to the moisture transport in winter

    NASA Astrophysics Data System (ADS)

    Hua, Lijuan; Zhong, Linhao; Luo, Dehai

    2017-04-01

    This work examines the main sources of moisture and the poleward transport water vapor over Barents/Kara Sea (BKS) during boreal winter of 1979 2015 in the ERA-Interim reanalysis product through a revised dynamic recycling model during boreal winter. The methodology computes the water vapor contributions from sources along 15-day time-reverse trajectories. The large-scale circulation patterns associated with the moisture transport process. The results suggested that water vapor from Northern Atlantic play crucial role in regulating the sea ice loss in Barents Sea and Kara Sea. It seems that positive NAO events tend to transport the Atlantic moisture to the Eastern Europe, and then Ural blocking flow further transports the moisture northward to BKS. The Atlantic moisture approximately takes 3-6 days to BKS through the moisture pathway regulated by NAO and Ural blocking.

  13. Dynamics of the Barents-Kara ice sheet as revealed by quartz sand grain microtextures of the late Pleistocene Arctic Ocean sediments

    NASA Astrophysics Data System (ADS)

    Strand, Kari; Immonen, Ninna

    2010-12-01

    During the entire Quaternary, ice sheets advanced and retreated across the circum-Arctic margins in a series of climate related glacial-interglacial cycles. It is critical to obtain evaluation of the nature of initiated glaciers at the Arctic margins after the pronounced interglacial periods. In this study this will be done by inferring from glacially generated quartz sand grain surface microtextures and related sedimentology extracted from the central Arctic Ocean sediments. These microtextures can be correlated with the generation and fluctuations in the extent of the late Pleistocene Eurasian Ice Sheet i.e. Barents-Kara Ice Sheet. The central Arctic Ocean sediments in the Lomonosov Ridge, having been deposited after the late Pleistocene interglaciations and having had no internal hiatuses, provide an excellent time window for usage of quartz sand grain surface textures for evaluating possible evolving glaciers and continental ice sheets. This is based on the fact that iceberg and sea-ice transported quartz sand grains and their mechanically formed surface textures, created under high cryostatic stress, are diagnostic for glacier thickness and dynamics having been existed in sediment source areas. Sand-sized quartz grains in deep marine sediments favour iceberg or sea-ice transportation with characteristic content of microtextures formed prior this transportation. The sand grain surface microtextures and their frequencies of the selected submarine Lomonosov Ridge sediments during Marine Isotope Stage (MIS) 5 to MIS 3 are analysed using a scanning electron microscope (SEM). Coring during the Arctic Ocean 96 expedition (core 96/12-1pc) provided alternating clay to silty clay sediments which are characterised by prominent silt to sand-size containing intervals. The specific glacial crushing and high cryostatic stress generated features, such as high angularity, conchoidal fractures, steps and sub-parallel linear fractures, were observed from quartz sand grain

  14. Interannual variability of cloudiness in the Norwegian, Barents and Kara Seas from the late 19th century

    NASA Astrophysics Data System (ADS)

    Chernokulsky, Alexander V.; Esau, Igor; Bulygina, Olga N.; Davy, Richard; Mokhov, Igor I.; Outten, Stephen; Semenov, Vladimir A.

    2017-04-01

    The Arctic is a highly sensitive region where numerous processes combine to generate the so-called Arctic amplification. One of the important climate feedbacks is related to the role of clouds. The limited observational record is one of the major challenges in the assessment of Arctic clouds. Here, a long-term climatology of cloudiness over the Norwegian, Barents and Kara Seas (NBK) based on visual surface observations is presented. Annual mean total cloud cover (TCC) over the NBK is almost equal over solid-ice (SI) and open-water (OW) parts of NBK (73±3% and 76±2% respectively). In general, TCC has higher intra- and inter-annual variability over SI than over OW. A decrease of TCC in the middle of the 20th century and an increase in the last few decades was found at individual stations and for the NBK as a whole. In most cases these changes are statistically significant with magnitudes exceeding the data uncertainty that is associated with the surface observations. The most pronounced trends are observed in autumn when the largest changes to the sea-ice concentration (SIC) occur. TCC over SI correlates significantly with SIC in the Barents Sea, with a statistically significant correlation coefficient between annual TCC and SIC of -0.38 for the period 1936-2013. Cloudiness over OW shows non-significant correlation with SIC. An overall increase in the frequency of broken and scattered cloud conditions, and a decrease in the frequency of overcast and cloudless conditions were found over OW. These changes are statistically significant and likely to be connected with the long-term changes of morphological types (an increase of convective and a decrease of stratiform cloud amounts).

  15. Arctic sea ice extents, areas, and trends, 1978-1996

    NASA Astrophysics Data System (ADS)

    Parkinson, Claire L.; Cavalieri, Donald J.; Gloersen, Per; Zwally, H. Jay; Comiso, Josefino C.

    1999-09-01

    Satellite passive-microwave data for November 1978 through December 1996 reveal marked seasonal, regional, and interannual variabilities, with an overall decreasing trend of -34,300±3700 km2/yr (-2.8%/decade) in Arctic sea ice extents over the 18.2-year period. Decreases occur in all seasons and on a yearly average basis, although they are largest in spring and smallest in autumn. Regionally, the Kara and Barents Seas have the largest decreases, at -15,200±1900 km2/yr (-10.5%/decade), followed by the Seas of Okhotsk and Japan, the Arctic Ocean, Greenland Sea, Hudson Bay, and Canadian Archipelago. The yearly average trends for the total, the Kara and Barents Seas, and the Seas of Okhotsk and Japan all have high statistical significance, with the null hypothesis of a 0 slope being rejected at a 99% confidence level. Regions showing increasing yearly average ice extents are Baffin Bay/Labrador Sea, the Gulf of St. Lawrence, and the Bering Sea, with only the increases in the Gulf of St. Lawrence being statistically significant at the 99% level. Hemispheric results for sea ice areas exhibit the same -2.8%/decade decrease as for ice extents and hence a lower absolute decrease (-29,500±3800 km2/yr), with the ice-free area within the ice pack correspondingly decreasing at -4800±1600 km2/yr. Confidence levels for the trends in ice areas and ice-free water areas exceed 99% and 95%, respectively. Nonetheless, interannual variability is high, and, for instance, the Arctic Ocean ice extents have a positive trend 1990-1996, in spite of their negative trend for the time period as a whole.

  16. The bottom topography and dynamics of the Obskaya and Baydaratskaya Bays, Kara Sea

    NASA Astrophysics Data System (ADS)

    Ermolov, A.; Noskov, A.; Ogorodov, S.

    2009-04-01

    The development of the arctic gas fields requires a gas transport system to be laid across the Obskaya Bay and the Baydaratskaya Bay, Kara Sea. Designing, construction and safe operation of the offshore parts of the crossing demands special knowledge about a structure of the bottom topography and coastal zone dynamics. Results of investigation indicate a difference between those regions and common features of structure and evolution. Owing to a quite large scale of research it was possible to detail the bottom topography, to reveal separate elements and forms. The analyses of topography were executed to define the mechanisms and basic phases of relief formation. Accordingly, the geomorphological map describing the bottom topography by the set of parameters (major of them are morphology, morphometry, age, genesis and dynamics) has also become more detailed. Geomorphological structure of a seabed is the important source of the information on location of permafrost relicts, sites of concentration of rip currents, intensive ice bottom gouging, deformations of an underwater coastal slope and other adverse phenomena and dangerous exogenous processes. The analysis of all these data allowed making prediction of bottom topography development, to plan and carry out an engineering construction. Digital model of bottom topography is a basis for engineering constructions designing. Creation of digital models of bottom topography was carried out by the original method consisted of several stages and based on manual author's processing and interpretation of maps. Also a large amount of archival and literary materials on geophysics, geology, geomorphology and paleogeography has been involved for digital model creation with the purpose to determine the features of morphostructure and genesis of the basic elements. It is established, that the geomorphological structure of the bottom of the Baydaratskaya and Obskaya Bays reflects consecutive change of the conditions and relief

  17. Hydrographic structure and variability of the Kara Sea: Implications for pollutant distribution

    NASA Astrophysics Data System (ADS)

    Pavlov, V. K.; Pfirman, S. L.

    Nuclear activity on land and dumping of waste in the Siberian shelf seas mean that the Kara Sea is most likely to experience inputs of radioactivity. Industrial and other anthropogenic activities in the expansive Ob' and Yenisey watersheds also contribute organochlorines, heavy metals and oil to this region. Contaminant fate is influenced by the distribution of the river discharge and processes associated with ice formation and ocean currents. Although average conditions are important in the transport of pollutants, events such as storms and iceberg gouging may be critical in deciding the ultimate fate of dumped and released contaminants.

  18. Human impact on dynamics of western coast of Yamal, Kara sea

    NASA Astrophysics Data System (ADS)

    Kuznetsov, Dmitry; Noskov, Alexey; Belova, Nataliya; Kamalov, Anatoly; Arkhipov, Vasily; Ogorodov, Stanislav

    2010-05-01

    The western coast of Yamal around the site of Bovanenkovo-Ukhta gas pipeline landfall (Baydarata bay, Kara sea) consists of two types of shore, with specific kind of human impact for each of them. These are low and gentle accumulative shores, which in this case are most influenced since the landfall site is situated within this type, and high bluffy abrasion shores. The heaviness of impact depends on degree of anthropogenic activity influencing the topography (this degree relates to proximity to main construction sites and intensity of human activity), and natural relief features, mainly its resistance to anthropogenic destruction and ability to restore itself. Accumulative shores are more resistant to destruction; main morphogenetic processes are marine accumulation (mainly within tideland) and aeolian transport, especially in areas without vegetation (tideland, beach and often the onshore sand bar). In the meantime, most part of construction (dams, roads, buildings, infrastructural sites) is located within accumulative coast, since it's generally more stable and good for construction. Abrasion coast is more prone to destruction because of human activity, but is much less subject to human impact since no direct construction activity is held here, and main types of this impact are usually traffic of heavy motor transport and allocation of construction waste (often brought by the sea). There are the following types of direct human impact on topography at pipeline landfall construction sites: 1) construction of large artificial accumulative bodies (dams, banks, sand deposits), which leads to additional sediment inflow at the site; 2) creation of negative forms like pits and trenches while taking sand material for construction (leads to erosion and decrease in tideland and beach width, rebuilding of submerged bar system); 3) change of surface properties during construction and traffic, destruction or suppression of vegetation (leads to activation of erosion). The

  19. Geology of the Severnaya Zemlya Archipelago and the North Kara Terrane in the Russian high Arctic

    NASA Astrophysics Data System (ADS)

    Lorenz, Henning; Männik, Peep; Gee, David; Proskurnin, Vasilij

    2008-05-01

    The Severnaya Zemlya Archipelago is located at 80°N near the continental shelf break, between the Kara and Laptev seas. Sedimentary successions of Neoproterozoic and Palaeozoic age dominate the bedrock geology. Together with Northern Tajmyr, Severnaya Zemlya constitutes the main land areas of the North Kara Terrane (NKT), which is inferred here to have been a part of the Timanide margin of Baltica, i.e. an integral part of Baltica at least since the Vendian. Vendian turbidites derived from the Timanide Orogen are inferred to have been deposited on Neoproterozoic greenschist facies, granite-intruded basement. Shallow-water siliclastic deposition in the Early to Mid-Cambrian was followed by highly organic-rich shales in the Late Cambrian and influx of more turbidites. An episode of folding, the Kan’on River deformation, separates these formations from the overlying Tremadocian conglomerates and sandstones. In the Early Ordovician, rift-related magmatic rocks accompanied the deposition of variegated marls, sandstones, carbonates and evaporites. Dark shales and gypsiferous limestones characterise the Mid-Ordovician. Late Ordovician quartz-sandstones mark a hiatus, followed by carbonate rocks that extend up into and through most of the Silurian. The latter give way upwards into Old Red Sandstones, which are inferred to have been deposited in a Caledonian foreland basin. Deformation, reaching the area in the latest Devonian or earliest Carboniferous and referred to as the Severnaya Zemlya episode, is thought to be Caledonian-related. The dominating E-vergent structure was controlled by décollement zones in Ordovician evaporite-bearing strata; detachment folds and thrusts developed in the west and were apparently impeded by a barrier of Ordovician igneous rocks in the east. Below the décollement zones, the Neoproterozoic to Early Ordovician succession was deformed into open to close folds. The exposed strata in the lower structural level have been juxtaposed with

  20. Arctic Sea ice model sensitivities.

    SciTech Connect

    Peterson, Kara J.; Bochev, Pavel Blagoveston; Paskaleva, Biliana Stefanova

    2010-12-01

    Arctic sea ice is an important component of the global climate system and, due to feedback effects, the Arctic ice cover is changing rapidly. Predictive mathematical models are of paramount importance for accurate estimates of the future ice trajectory. However, the sea ice components of Global Climate Models (GCMs) vary significantly in their prediction of the future state of Arctic sea ice and have generally underestimated the rate of decline in minimum sea ice extent seen over the past thirty years. One of the contributing factors to this variability is the sensitivity of the sea ice state to internal model parameters. A new sea ice model that holds some promise for improving sea ice predictions incorporates an anisotropic elastic-decohesive rheology and dynamics solved using the material-point method (MPM), which combines Lagrangian particles for advection with a background grid for gradient computations. We evaluate the variability of this MPM sea ice code and compare it with the Los Alamos National Laboratory CICE code for a single year simulation of the Arctic basin using consistent ocean and atmospheric forcing. Sensitivities of ice volume, ice area, ice extent, root mean square (RMS) ice speed, central Arctic ice thickness,and central Arctic ice speed with respect to ten different dynamic and thermodynamic parameters are evaluated both individually and in combination using the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA). We find similar responses for the two codes and some interesting seasonal variability in the strength of the parameters on the solution.

  1. Seasonal variation of the satellite-derived phytoplankton primary production in the Kara Sea

    NASA Astrophysics Data System (ADS)

    Demidov, A. B.; Sheberstov, S. V.; Gagarin, V. I.; Khlebopashev, P. V.

    2017-01-01

    Seasonal variation of the integrated primary production (IPP) and surface chlorophyll (Chl0) in different regions of the Kara Sea was studied from satellite data obtained by the MODIS-Aqua colour scanner and averaged for 2003-2015. The minimum variation of Chl0 concentration during the growing season (from April to October) was 1.5 times in southwestern region and 2 times in the northern region of the sea. It was found that the Chl0 concentration increased slightly in all regions by the end of the growing season. The maximum IPP value recorded in June coincided with the peak level of photosynthetically active radiation (PAR) and maximum river discharge. The IPP value varied in a wider range compared with the Chl0 concentration. The ratio of the maximum and minimum monthly average IPP values varied from 8.9 times in Southwestern region to 11.7 times in the Northern region of the sea. The average increase in the Chl0 concentration was 1.7 times (from 0.78 mg/m3 in April to 1.29 mg/m3 in October). The IPP value varied by a factor of 10.7 (from 26 mg C/m2 per day in October to 279 mg C/m2 per day in June). The article also discusses the influence of water column stratification, the concentration of nutrients, the PAR level, and river discharge on the seasonal IPP dynamics in the Kara Sea.

  2. Methane Release and Pingo-Like Feature Across the South kara Sea Shels, an Area of Thawing Offshore Permafrost

    NASA Astrophysics Data System (ADS)

    Serov, P.; Portnov, A.; Mienert, J.

    2015-12-01

    Thawing subsea permafrost controls methane release from the Russian Arctic shelf having a considerable impact on the climate-sensitive Arctic environment. Our recent studies revealed extensive gas release over an area of at least 7500 km2and presence of pingo-like features (PLFs), showing severe methane leakage, in the South Kara Sea in water depths >20m (Serov et al., 2015). Specifically, we detected shallow methane ebullition sites expressed in water column acoustic anomalies (gas flares and gas fronts) and areas of increased dissolved methane concentrations in bottom water, which might be sufficient sources of carbon for seawater-atmosphere exchange. A study of nature and source of leaking gas was focused on two PLFs, which are acoustically transparent circular mounds towering 5-9 m above the surrounding seafloor. One PLF (PLF 2) connects to biogenic gas from deeper sources, which is reflected in δ13CCH4 values ranging from -55,1‰ to -88,0‰ and δDCH4values varied from -175‰ to -246‰. Low organic matter content (0.52-1.69%) of seafloor sediments restricts extensive in situ methane production. The formation of PLF 2 is directly linked to the thawing of subsea permafrost and, possibly, decomposition of permafrost related gas hydrates. High accumulations of biogenic methane create the necessary forces to push the remaining frozen layers upwards and, therefore, form a topographic feature. We speculate that PLF 1, which shows ubiquitously low methane concentrations, is either a relict submerged terrestrial pingo, or a PLF lacking the necessary underlying methane accumulations. Our model of glacial-interglacial permafrost evolution supports a scenario in which subsea permafrost tapers seaward and pinches out at 20m isobaths, controlling observed methane emissions and development of PLFs. Serov. P., A. Portnov, J. Mienert, P. Semenov, and P. Ilatovskaya (2015), Methane release from pingo-like features across the South Kara Sea shelf, an area of thawnig

  3. Arctic Sea Ice

    NASA Image and Video Library

    2017-09-27

    On July 12, 2011, crew from the U.S. Coast Guard Cutter Healy retrieved a canister dropped by parachute from a C-130, which brought supplies for some mid-mission fixes. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is NASA's two-year shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research takes place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen For updates on the five-week ICESCAPE voyage, visit the mission blog at: go.usa.gov/WwU 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

  4. Distribution of the primary production and chlorophyll a in the Kara Sea in September of 2007

    NASA Astrophysics Data System (ADS)

    Mosharov, S. A.

    2010-12-01

    The studies were performed from September 10 to 29 of 2007 in the Kara Sea in transects westward of the Yamal Peninsula, near the St. Anna Trough, in the Ob River's estuary, and on the adjacent shelf. The concentration of chlorophyll a in the euphotic layer changed from 0.02 to 4.37 mg/m3, amounting on the average to 0.76 mg/m3. The primary production in the water column varied from 10.9 to 148.0 mg C/m2 per day (the mean was 56.9 mg C/m2 per day). It was shown that frontal zones divided the Kara Sea into distinct areas with different productivities. The maximum levels of the primary production were measured in the deep part of the Yamal transect (132.4 mg C/m2 per day) and the shallow Kara Sea shelf near the Ob River's estuary (74.9 mg C/m2 per day). The characteristics of these regions were the low salinity of the surface water layer (19-25 psu) and the elevated silicon content (12.8-28.1 μg-atom Si/l), which is explainable by the river water inflow. The frontal zones of the Yamal Current in the Yamal and Ob transects displayed high values of the assimilation numbers, amounting to 2.32 and 1.49 mg C/mg of chlorophyll per h, respectively (the maximal for the studied regions).

  5. 2013 Arctic Sea Ice Minimum

    NASA Image and Video Library

    After an unusually cold summer in the northernmost latitudes, Arctic sea ice appears to have reached its annual minimum summer extent for 2013 on Sept. 13, the NASA-supported National Snow and Ice ...

  6. Arctic Sea Ice Minimum, 2015

    NASA Image and Video Library

    This animation shows the evolution of the Arctic sea ice cover from its wintertime maximum extent, which was reached on Feb. 25, 2015, and was the lowest on record, to its apparent yearly minimum, ...

  7. Modelled atmospheric response to regional and pan-Arctic sea-ice loss

    NASA Astrophysics Data System (ADS)

    Screen, James

    2017-04-01

    The loss of Arctic sea-ice is already having profound environmental, societal and ecological impacts locally. A highly uncertain area of scientific research, however, is whether such Arctic change has a tangible effect on weather and climate at lower latitudes. There is emerging evidence that the geographical location of sea-ice loss is critically important in determining the large-scale atmospheric circulation response and associated mid-latitude impacts. However, such regional dependencies have not been explored in a thorough and systematic manner. To make progress on this issue, this study analyses ensemble simulations with an atmospheric general circulation model prescribed with sea-ice loss separately in nine regions of the Arctic, to elucidate the distinct responses to regional sea-ice loss. The results suggest that in some regions sea-ice loss triggers large-scale dynamical responses whereas in other regions sea-ice loss induces only local thermodynamical changes. Sea-ice loss in the Barents-Kara Sea is unique in driving a weakening of the stratospheric polar vortex, followed in time by a tropospheric circulation response that resembles the North Atlantic Oscillation. For October-to-March, the largest spatial-scale responses are driven by sea-ice loss in the Barents-Kara Sea and Sea of Okhotsk; however, different regions assume greater importance in other seasons. The atmosphere responds very differently to regional sea-ice losses than to pan-Arctic sea-ice loss, and the latter cannot be obtained by linear addition of the responses to regional sea-ice losses. The results imply that diversity in past studies of the simulated response to Arctic sea-ice loss can be partly explained by the different spatial patterns of sea-ice loss imposed.

  8. Arctic landfast sea ice

    NASA Astrophysics Data System (ADS)

    Konig, Christof S.

    Landfast ice is sea ice which forms and remains fixed along a coast, where it is attached either to the shore, or held between shoals or grounded icebergs. Landfast ice fundamentally modifies the momentum exchange between atmosphere and ocean, as compared to pack ice. It thus affects the heat and freshwater exchange between air and ocean and impacts on the location of ocean upwelling and downwelling zones. Further, the landfast ice edge is essential for numerous Arctic mammals and Inupiat who depend on them for their subsistence. The current generation of sea ice models is not capable of reproducing certain aspects of landfast ice formation, maintenance, and disintegration even when the spatial resolution would be sufficient to resolve such features. In my work I develop a new ice model that permits the existence of landfast sea ice even in the presence of offshore winds, as is observed in mature. Based on viscous-plastic as well as elastic-viscous-plastic ice dynamics I add tensile strength to the ice rheology and re-derive the equations as well as numerical methods to solve them. Through numerical experiments on simplified domains, the effects of those changes are demonstrated. It is found that the modifications enable landfast ice modeling, as desired. The elastic-viscous-plastic rheology leads to initial velocity fluctuations within the landfast ice that weaken the ice sheet and break it up much faster than theoretically predicted. Solving the viscous-plastic rheology using an implicit numerical method avoids those waves and comes much closer to theoretical predictions. Improvements in landfast ice modeling can only verified in comparison to observed data. I have extracted landfast sea ice data of several decades from several sources to create a landfast sea ice climatology that can be used for that purpose. Statistical analysis of the data shows several factors that significantly influence landfast ice distribution: distance from the coastline, ocean depth, as

  9. Vertical distribution of primary production and chlorophyll a in the Kara Sea

    NASA Astrophysics Data System (ADS)

    Demidov, A. B.; Mosharov, S. A.

    2015-07-01

    On the basis of data obtained during three ecosystem expeditions in the Kara Sea, the vertical variability of the primary production (PP) and chlorophyll a (Chl) in autumn was studied. The Chl maximum was detected mainly on the surface (Chl0). A homogenous Chl distribution in the euphotic layer (1% photo-synthetically available radiation) and a nearly linear decrease in the Chl concentration below this layer were observed in waters with Chl0 values of 0.1-0.5 mg/m3. In waters with Chl0 > 0.5 mg/m3, the Chl concentration in the studied layer decreased linearly or exponentially. The subsurface Chl maximum (SCM) was registered weekly and was detected mostly in waters with a Chl0 content of 0.1-0.5 mg/m3. The SCM formation in the Kara Sea was consistent with the general patterns for the World Ocean. Water-column stability, the content of biogenic elements, and the level of subsurface irradiance had an approximately equal effect on SCM formation. The contribution of the SCM to the depth-integrated PP varied from 1 to 27%. The parameterization of vertical profiles of Chl was performed in order to be used in depth-integrated PP models. The Chl maximum on the surface and the negligible SCM facilitate the estimation of depth-integrated PP on the basis of satellite data and the use of vertical-resolution models.

  10. Virioplankton in the Kara Sea: The impact of viruses on mortality of heterotrophic bacteria

    NASA Astrophysics Data System (ADS)

    Kopylov, A. I.; Sazhin, A. F.; Zabotkina, E. A.; Romanova, N. D.

    2015-07-01

    Studies were conducted in shallow and deepwater areas of the Kara Sea. The abundance of bacteria ( N B ) and the abundance of viruses ( N V ) ranged within (19.4-2215.1) × 103 cells/ml and (97.6-5796.8) × 103 particles/ml, respectively. The virus to bacteria ratio varied from 1.4 to 29.1. A positive correlation was found between N B and N V ( R = 0.87, n = 45, p = 0.05. Using electron transmission microscopy it was detected that the frequency of visibly infected cells of bacteria (FVIC) varied from 0.2 to 1.9% of N B . The maximum values of FVIC were recorded in the estuary of the Yenisei River. The infected cells of bacteria contained from 4 to 127 (an average of 12) phages/cell of mature viruses. Virus-mediated mortality of bacteria was 0.5% and varied from 1.4 to 16.1% of the total mortality of bacterioplankton. This indicates a minor role of viruses in the control of overabundance and production of bacterioplankton in the Kara Sea during the surveyed period.

  11. Hydrochemical characteristics of the waters in the western part of the Kara Sea

    NASA Astrophysics Data System (ADS)

    Makkaveev, P. N.; Melnikova, Z. G.; Polukhin, A. A.; Stepanova, S. V.; Khlebopashev, P. V.; Chultsova, A. L.

    2015-07-01

    Hydrochemical study in the Kara Sea was part of the program of the integrated expedition of the 59th cruise of the RV Akademik Mstislav Keldysh. Primary hydrochemical surveys were performed on the sections in the Yenisei Gulf, along the eastern and western branches of the St. Anna Trough, and across the Novozemel'skii Trough. Moreover, a flow-through system throughout, in which pH values of the surface waters were measured and samples for hydrochemical analyses were collected, was operated during vessel movement. A wide set of hydrochemical analyses was carried out, including tests for key nutrients (silicon and different forms of nitrogen and phosphorus), dissolved oxygen, and values of pH and total alkalinity. The report describes the hydrochemical conditions in the southwestern part of the Kara Sea. The basic results are presented and compared to those of the preceding integrated expeditions (49th cruise of the RV Dmitrii Mendeleev in 1993 and 54th cruise of the RV Akademik Mstislav Keldysh in 2007).

  12. Modelling Kara Sea phytoplankton primary production: Development and skill assessment of regional algorithms

    NASA Astrophysics Data System (ADS)

    Demidov, Andrey B.; Kopelevich, Oleg V.; Mosharov, Sergey A.; Sheberstov, Sergey V.; Vazyulya, Svetlana V.

    2017-07-01

    Empirical region-specific (RSM), depth-integrated (DIM) and depth-resolved (DRM) primary production models are developed based on data from the Kara Sea during the autumn (September-October 1993, 2007, 2011). The model is validated by using field and satellite (MODIS-Aqua) observations. Our findings suggest that RSM algorithms perform better than non-region-specific algorithms (NRSM) in terms of regression analysis, root-mean-square difference (RMSD) and model efficiency. In general, the RSM and NRSM underestimate or overestimate the in situ water column integrated primary production (IPP) by a factor of 2 and 2.8, respectively. Additionally, our results suggest that the model skill of the RSM increases when the chlorophyll specific carbon fixation rate, efficiency of photosynthesis and photosynthetically available radiation (PAR) are used as input variables. The parameterization of chlorophyll (chl a) vertical profiles is performed in Kara Sea waters with different trophic statuses. Model validation with field data suggests that the DIM and DRM algorithms perform equally (RMSD of 0.29 and 0.31, respectively). No changes in the performance of the DIM and DRM algorithms are observed (RMSD of 0.30 and 0.31, respectively) when satellite-derived chl a, PAR and the diffuse attenuation coefficient (Kd) are applied as input variables.

  13. Methane release from pingo-like features across the South Kara Sea shelf, an area of thawing offshore permafrost

    NASA Astrophysics Data System (ADS)

    Serov, Pavel; Portnov, Alexey; Mienert, Jurgen; Semenov, Peter; Ilatovskaya, Polina

    2015-08-01

    The Holocene marine transgression starting at ~19 ka flooded the Arctic shelves driving extensive thawing of terrestrial permafrost. It thereby promoted methanogenesis within sediments, the dissociation of gas hydrates, and the release of formerly trapped gas, with the accumulation in pressure of released methane eventually triggering blowouts through weakened zones in the overlying and thinned permafrost. Here we present a range of geophysical and chemical scenarios for the formation of pingo-like formations (PLFs) leading to potential blowouts. Specifically, we report on methane anomalies from the South Kara Sea shelf focusing on two PLFs imaged from high-resolution seismic records. A variety of geochemical methods are applied to study concentrations and types of gas, its character, and genesis. PLF 1 demonstrates ubiquitously low-methane concentrations (14.2-55.3 ppm) that are likely due to partly unfrozen sediments with an ice-saturated internal core reaching close to the seafloor. In contrast, PLF 2 reveals anomalously high-methane concentrations of >120,000 ppm where frozen sediments are completely absent. The methane in all recovered samples is of microbial and not of thermogenic origin from deep hydrocarbon sources. However, the relatively low organic matter content (0.52-1.69%) of seafloor sediments restricts extensive in situ methane production. As a consequence, we hypothesize that the high-methane concentrations at PLF 2 are due to microbial methane production and migration from a deeper source.

  14. Interannual Arctic sea ice variability and associated winter weather patterns: A regional perspective for 1979-2014

    NASA Astrophysics Data System (ADS)

    Chen, Hans W.; Alley, Richard B.; Zhang, Fuqing

    2016-12-01

    Using Arctic sea ice concentration derived from passive microwave satellite observations in autumn and early winter over the 1979-2014 period, the Arctic region was objectively classified into several smaller regions based on the interannual sea ice variability through self-organizing map analyses. The trend in regional sea ice extent (RSIE) in each region was removed using an adaptive, nonlinear, and nonstationary method called Ensemble Empirical Mode Decomposition, which captures well the accelerating decline of Arctic RSIEs in recent decades. Although the linear trend in RSIE is negative in all regions in both seasons, there are marked differences in RSIE trends and variability between regions, with the largest negative trends found during autumn in the Beaufort Sea, the Barents-Kara Seas, and the Laptev-East Siberian Seas. Winter weather patterns associated with the nonlinearly detrended RSIEs show distinct features for different regions and tend to be better correlated with the autumn than early winter RSIE anomalies. Sea ice losses in the Beaufort Sea and the Barents-Kara Seas are both associated with a cooling of Eurasia, but in the former case the circulation anomaly is reminiscent of a Rossby wave train, whereas in the latter case the pattern projects onto the negative phase of the Arctic Oscillation. These results highlight the nonuniform changes in Arctic sea ice and suggest that regional sea ice variations may play a crucial role for the winter weather patterns.

  15. Poleward eddy heat flux anomalies associated with recent Arctic sea ice loss

    NASA Astrophysics Data System (ADS)

    Hoshi, Kazuhira; Ukita, Jinro; Honda, Meiji; Iwamoto, Katsushi; Nakamura, Tetsu; Yamazaki, Koji; Dethloff, Klaus; Jaiser, Ralf; Handorf, Dörthe

    2017-01-01

    Details of the characteristics of upward planetary wave propagation associated with Arctic sea ice loss under present climate conditions are examined using reanalysis data and simulation results. Recent Arctic sea ice loss results in increased stratospheric poleward eddy heat fluxes in the eastern and central Eurasia regions and enhanced upward propagation of planetary-scale waves in the stratosphere. A linear decomposition scheme reveals that this modulation of the planetary waves arises from coupling of the climatological planetary wavefield with temperature anomalies for the eastern Eurasia region and with meridional wind anomalies for the central Eurasia region. Propagation of stationary Rossby wave packets results in a dynamic link between these temperature and meridional wind anomalies with sea ice loss over the Barents-Kara Sea. The results provide strong evidence that recent Arctic sea ice loss significantly modulates atmospheric circulation in winter to modify poleward eddy heat fluxes so as to drive stratosphere-troposphere coupling processes.

  16. Weakening of the Stratospheric Polar Vortex by Arctic Sea-Ice Loss

    SciTech Connect

    Kim, Baek-Min; Son, Seok-Woo; Min, Seung-Ki; Jeong, Jee-Hoon; Kim, Seong-Joong; Zhang, Xiangdong; Shim, Taehyoun; Yoon, Jin-Ho

    2014-09-02

    Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea ice, the mechanism that links sea ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea ice cover during early winter months (November-December), especially over the Barents-Kara seas, enhance the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January- February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes.

  17. Impacts of climate warming and permafrost thaw on the riverine transport of nitrogen and phosphorus to the Kara Sea

    NASA Astrophysics Data System (ADS)

    Frey, Karen E.; McClelland, James W.; Holmes, Robert M.; Smith, Laurence C.

    2007-12-01

    Measurements of nitrogen and phosphorus (N and P) concentrations from previously unstudied streams and rivers throughout west Siberia suggest that climate warming and/or associated permafrost thaw will likely amplify the transport of N and P to the Kara Sea and adjacent Arctic Ocean. We present concentrations of dissolved organic nitrogen (DON), ammonium (NH4-N), nitrate (NO3-N), total dissolved nitrogen (TDN), and total dissolved phosphorus (TDP) from 96 streams and rivers within the Ob'-Irtysh, Nadym, and Pur river drainage basins. The sampled sites span ˜106 km2, a large climatic gradient (˜55°N-68°N), and include 41 cold, permafrost-influenced and 55 warm, permafrost-free watersheds. Concentrations for all measured watersheds average 765 μg L-1 (DON), 19.3 μg L-1 (NH4-N), 36.7 μg L-1 (NO3-N), 821 μg L-1 (TDN), and 104 μg L-1 (TDP). Our results show no statistically significant difference in dissolved inorganic N (NH4-N and NO3-N) between permafrost-influenced and permafrost-free watersheds. However, we do find significantly higher concentrations of DON, TDN, and TDP in permafrost-free watersheds (increasing as a function of watershed peatland coverage) than in permafrost-influenced watersheds. When combined with climate model simulations, these relationships enable a simple "space-for-time" substitution to estimate possible increases in N and P release from west Siberia by the year 2100. Results suggest that predicted climate warming in west Siberia will be associated with ˜32-53% increases in DON concentrations, ˜30-50% increases in TDN concentrations, and 29-47% increases in TDP concentrations as averaged across the region. While such increases in N and P are unlikely to significantly influence primary production in the Kara Sea as a whole, they will likely have large local impacts in the Ob' and Yenisey bays and nearshore environments.

  18. Effect of stratification on wind drift of river runoff in the Kara Sea

    NASA Astrophysics Data System (ADS)

    Zhurbas, N. V.; Zavialov, P. O.

    2015-11-01

    The formation mechanism of the Yenisei and Ob Rivers floodwater lens (detected in the Kara Sea near the eastern coast of Novaya Zemlya in September to October 2007) by wind drift is examined. Numerical calculations of the trajectories of Lagrangian floats launched at the north part of the Yenisei and Ob seaside and transported by drift currents have been performed using actual wind-forcing data. Four different algorithms have been used for calculating the surface drift velocity and the relative wind direction; two account for the effect of density stratification due to the presence of a layer of fresh water on the sea surface. It has been shown that only wind-drift models that take into account the presence of stratification are able to explain the transport of the Yenisei and Ob floodwater to the point of lens detection.

  19. Arctic Sea Ice Model Sensitivities

    NASA Astrophysics Data System (ADS)

    Peterson, K. J.; Bochev, P.; Paskaleva, B.

    2010-12-01

    Arctic sea ice is an important component of the global climate system and, due to feedback effects, the Arctic ice cover is changing rapidly. Predictive mathematical models are of paramount importance for accurate estimates of the future ice trajectory. However, the sea ice components of Global Climate Models (GCMs) vary significantly in their prediction of the future state of Arctic sea ice and have generally underestimated the rate of decline in minimum sea ice extent seen over the past thirty years. One of the contributing factors to this variability is the sensitivity of the sea ice state to internal model parameters. A new sea ice model that holds some promise for improving sea ice predictions incorporates an anisotropic elastic-decohesive rheology and dynamics solved using the material-point method (MPM), which combines Lagrangian particles for advection with a background grid for gradient computations. We evaluate the variability of this MPM sea ice code and compare it with the Los Alamos National Laboratory CICE code for a single year simulation of the Arctic basin using consistent ocean and atmospheric forcing. Sensitivities of ice volume, ice area, ice extent, root mean square (RMS) ice speed, central Arctic ice thickness,and central Arctic ice speed with respect to ten different dynamic and thermodynamic parameters are evaluated both individually and in combination using the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA). We find similar responses for the two codes and some interesting seasonal variability in the strength of the parameters on the solution. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U. S. Department of Energy’s National Nuclear Security Administration under Contract DE-AC04-94-AL85000.

  20. AMSR2 Daily Arctic Sea Ice - 2014

    NASA Image and Video Library

    In this animation, the daily Arctic sea ice and seasonal land cover change progress through time, from March 21, 2014 through the 3rd of August, 2014. Over the water, Arctic sea ice changes from da...

  1. Bacterial and primary production in the pelagic zone of the Kara Sea

    NASA Astrophysics Data System (ADS)

    Sazhin, A. F.; Romanova, N. D.; Mosharov, S. A.

    2010-10-01

    Data on the bacterial and primary production, which were obtained simultaneously for the same water samples, are presented for three regions of the Kara Sea. The samples were collected for the transect westwards of the Yamal Peninsula, along the St. Anna Trough, and the transect in Ob Bay. Direct counts of the DAPI-stained bacterial cells were performed. The bacterial production and grazing rates were determined using a direct method when metabolic inhibitors vancomycin and penicillin were added. The primary production rates were estimated using the 14C method. The average primary production was 112.6, 58.5, and 28.7 mg C m-2 day-1, and the bacterial production was 12.8, 48.9, and 81.6 mg C m-2 day-1 along the Yamal Peninsula, the St. Anna Trough, and Ob Bay, respectively. The average bacterial carbon demand was 34.6, 134.5, and 220.4 mg C m-2 day-1 for these regions, respectively. The data obtained lead us to conclude that the phytoplankton-synthesized organic matter is generally insufficient to satisfy the bacterial carbon demand and may be completely assimilated via the heterotrophic processes in the marine ecosystems. Therefore, the bacterial activity and, consequently, the amount of the synthesized biomass (i.e., the production) both depend directly on the phytoplankton’s condition and activity. We consider these relationships to be characteristics of the Kara Sea’s biota.

  2. Radionuclide bioconcentration factors and sediment partition coefficients in Arctic Seas subject to contamination from dumped nuclear wastes

    SciTech Connect

    Fisher, N.S. . Marine Sciences Research Center); Fowler, S.W.; Boisson, F.; Carroll, J. . Marine Environment Lab.); Rissanen, K. ); Salbu, B. . Lab. for Analytical Chemistry); Sazykina, T.G. ); Sjoeblom, K.L. )

    1999-06-15

    The disposal of large quantities of radioactive wastes in Arctic Seas by the former Soviet Union has prompted interest in the behavior of long-lived radionuclides in polar waters. Previous studies on the interactions of radionuclides prominent in radioactive wastes have focused on temperate waters; the extent to which the bioconcentration factors and sediment partitioning from these earlier studies could be applied to risk assessment analyses involving high latitude systems is unknown. Here the authors present concentrations in seawater and calculated in situ bioconcentration factors for [sup 90]Sr, [sup 137]Cs, and [sup 239+240]Pu (the three most important radionuclides in Arctic risk assessment models) in macroalgae, crustaceans, bivalve molluscs, sea birds, and marine mammals as well as sediment K[sub d] values for 13 radionuclides and other elements in samples taken from the Kara and Barents Seas. The data analysis shows that, typically, values for polar and temperate waters are comparable, but exceptions include 10-fold higher concentration factors for [sup 239+240]Pu in Arctic brown macroalgae, 10-fold lower K[sub d] values for [sup 90]Sr in Kara Sea sediment than in typical temperate coastal sediment, and 100-fold greater Ru K[sub d] values in Kara Sea sediment. For most elements application of temperate water bioconcentration factors and K[sub d] values to Arctic marine systems appears to be valid.

  3. Trace metals in the Ob and Yenisei Rivers' Estuaries (the Kara Sea).

    NASA Astrophysics Data System (ADS)

    Demina, L. L.

    2014-12-01

    Behavior of some trace metals (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni and Pb) in water column (soluble <0.45 µm and particulate fractions) and bottom sediments (surface and cores) along the two transects from the Ob River and Yenisei River Estuaries to the Kara Sea was studied. The length of both transects was about 700 km. Water depth was 12-63 m, O2 dissolved :5.36-9.55 ml l-1. Along the transects salinity increased from 0.07 to 34.2 psu, while the SPM' concentration decreased from 10.31 to 0.31 mg/l. Total suspended particulate matter load is more than one order of magnitude higher in the Ob River Estuary comparing to that of the Yenisei River. It has led to a significant difference between the suspended trace metals' concentrations (µg/l) in water of the two estuaries. With salinity increase along transects Fe susp., Mn susp. and Zn susp. decreased by a factor of 100-500, that has led to a growth of a relative portion of dissolved trace metals followed by their bioaccumulation (Demina et al., 2010). A strong direct correlation between suspended Cu, Fe and SPM mass concentration was found. For the first time along the Yenisei River' Estuary -the Kara Sea transect a direct positive correlation between Cu suspended and volume concentration of SPM (mg/ml3) was found, that was attributed to contribution of phytoplankton aggregates in the SPM composition. A trend of relationship between content of suspended As and pelitic fraction (2-10 µm) of SPM was firstly found in theses basins also. Study of trace metal speciation in the bottom sediments (adsorbed, associated with Fe-Mn (oxyhydr)oxides, organic matter and fixed in the mineral lattice or refractory) has revealed the refractory fraction to be prevailing (70-95% total content) for Fe, Zn, Cu, Co, Ni, Cr, Cd and Pb. That means that toxic heavy metals were not available for bottom fauna. Mn was predominantly found in the adsorbed and (oxyhydr)oxides geochemically labile forms, reflecting the redox condition change

  4. Atmospheric circulation patterns which promote winter Arctic sea ice decline

    NASA Astrophysics Data System (ADS)

    Luo, Binhe; Luo, Dehai; Wu, Lixin; Zhong, Linhao; Simmonds, Ian

    2017-05-01

    The impact of winter atmospheric blocking over the Ural Mountains region (UB) coincident with different phases of the North Atlantic Oscillation (NAO) on the sea ice variability over the Barents and Kara Seas (BKS) in winter is investigated. It is found that the UB in conjunction with the positive phase of the NAO (NAO+) leads to the strongest sea ice decline. During this phase composites and trajectory analyses reveal an efficient moisture pathway to the BKS from the mid-latitude North Atlantic near the Gulf Stream Extension region where water vapor is abundant due to high sea surface temperatures. The NAO+-UB combination is an optimal circulation pattern that significantly increases the BKS water vapor that plays a major role in the BKS warming and sea ice reduction, while the increased sensible and latent heat fluxes play secondary roles. By contrast, much fewer dramatic impacts on the BKS are observed when the UB coincides with the neutral or negative phases of the NAO. Our results present new insights into the complex processes involved with Arctic sea ice reduction and warming. The mechanisms highlighted here potentially offer a perspective into the mechanisms behind Arctic multi-decadal climate variability.

  5. Polar Climate: Arctic sea ice

    USGS Publications Warehouse

    Stone, R.S.; Douglas, David C.; Belchansky, G.I.; Drobot, S.D.

    2005-01-01

    Recent decreases in snow and sea ice cover in the high northern latitudes are among the most notable indicators of climate change. Northern Hemisphere sea ice extent for the year as a whole was the third lowest on record dating back to 1973, behind 1995 (lowest) and 1990 (second lowest; Hadley Center–NCEP). September sea ice extent, which is at the end of the summer melt season and is typically the month with the lowest sea ice extent of the year, has decreased by about 19% since the late 1970s (Fig. 5.2), with a record minimum observed in 2002 (Serreze et al. 2003). A record low extent also occurred in spring (Chapman 2005, personal communication), and 2004 marked the third consecutive year of anomalously extreme sea ice retreat in the Arctic (Stroeve et al. 2005). Some model simulations indicate that ice-free summers will occur in the Arctic by the year 2070 (ACIA 2004).

  6. Radioactive contamination from dumped nuclear waste in the Kara Sea--results from the joint Russian-Norwegian expeditions in 1992-1994.

    PubMed

    Salbu, B; Nikitin, A I; Strand, P; Christensen, G C; Chumichev, V B; Lind, B; Fjelldal, H; Bergan, T D; Rudjord, A L; Sickel, M; Valetova, N K; Føyn, L

    1997-08-25

    Russian-Norwegian expeditions to the Kara Sea and to dumping sites in the fjords of Novaya Zemlya have taken place annually since 1992. In the fjords, dumped objects were localised with sonar and ROV equipped with underwater camera. Enhanced levels of 137Cs, 60Co, 90Sr and 239,240Pu in sediments close to dumped containers in the Abrosimov and Stepovogo fjords demonstrated that leaching from dumped material has taken place. The contamination was inhomogeneously distributed and radioactive particles were identified in the upper 10 cm of the sediments. 137Cs was strongly associated with sediments, while 90Sr was more mobile. The contamination was less pronounced in the areas where objects presumed to be reactor compartments were located. The enhanced level of radionuclides observed in sediments close to the submarine in Stepovogo fjord in 1993 could, however, not be confirmed in 1994. Otherwise, traces of 60Co in sediments were observed in the close vicinity of all localised objects. Thus, the general level of radionuclides in waters, sediments and biota in the fjords is, somewhat higher or similar to that of the open Kara Sea, i.e. significantly lower than in other adjacent marine systems (e.g. Irish Sea, Baltic Sea, North Sea). The main sources contributing to radioactive contamination were global fallout from atmospheric nuclear weapon tests, river transport from Ob and Yenisey, marine transport of discharges from Sellafield, UK and fallout from Chernobyl. Thus, the radiological impact to man and the arctic environment of the observed leakages from dumped radioactive waste today, is considered to be low. Assuming all radionuclides are released from the waste, preliminary assessments indicate a collective dose to the world population of less than 50 man Sv.

  7. Prolonged Effect of the Stratospheric Pathway in Linking Barents-Kara Sea Sea Ice Variability to the Midlatitude Circulation in a Simplified Model

    NASA Astrophysics Data System (ADS)

    Zhang, Pengfei; Wu, Yutian

    2017-04-01

    Observations show a delayed midlatitude circulation response during late winter following early winter Barents-Kara Sea (BKS) sea ice variability. To better understand the dynamical mechanism that accounts for the observed lead-lag correlation, a series of numerical experiments are conducted using a simplified atmospheric general circulation model (AGCM) with a prescribed idealized near-surface heating over the BKS region. A prolonged effect is found in the idealized experiments following the near-surface heating and can be explicitly attributed to the stratospheric pathway and the long time scale in the stratosphere. The analysis of the Eliassen-Palm (EP) flux shows that, as a result of the imposed heating and linear constructive interference, anomalous upward propagating planetary-scale waves are excited and weaken the stratospheric polar vortex. This stratospheric response persists for approximately 1-2 months accompanied by downward migration to the troposphere and the surface. This downward migration largely amplifies and extends the low-level jet deceleration in the midlatitudes and cold air advection over central Asia. The idealized model experiments also suggest that the BKS region is the most effective in affecting the midlatitude circulation than other regions over the Arctic.

  8. Characteristics of Arctic Ocean ice determined from SMMR data for 1979 - Case studies in the seasonal sea ice zone

    NASA Technical Reports Server (NTRS)

    Anderson, M. R.; Crane, R. G.; Barry, R. G.

    1985-01-01

    Sea ice data derived from the Scanning Multichannel Microwave Radiometer are examined for sections of the Arctic Ocean during early summer 1979. The temporary appearance of spuriously high multiyear ice fractions in the seasonal ice zones of the Kara and Barents Seas is a result of surface melt phenomena and the relative responses of the different channels to these effects. These spurious signatures can provide early identification of melt onset and additional information on surface characteristics.

  9. Emschermannia ramificata-a new genus and species of solitary entoproct from the Kara Sea, Russia.

    PubMed

    Borisanova, Anastasia O

    2016-02-24

    A new genus and species of solitary entoproct, Emschermannia ramificata, is described from the Kara Sea. It is an epibiont of the nephtyid polychaete Aglaophamus malmgreni, collected from 25-472 m depth. The species is about 250-300 μm long, with 8-10 tentacles, and buds are formed from a frontal area of the calyx. The calyx and stalk are not separated from each other by a cuticular septum, and a star-cell complex is absent. Emschermannia ramificata attaches to a substratum via a basal plate from which pseudostolons grow. Zooidal morphology conforms to that of the Loxosomatidae, but the attachment structure is unique among solitary entoprocts; it resembles basal plates and stolons of colonial entoprocts, but pseudostolons of Emschermannia serve only for attachment, not for budding. Overall, the morphology of Emschermannia may be considered intermediate between that of solitary and colonial forms, with relevance to evolutionary development within Entoprocta.

  10. Hydrochemical features of the Kara Sea aquatic area in summer 2015

    NASA Astrophysics Data System (ADS)

    Makkaveev, P. N.; Polukhin, A. A.; Kostyleva, A. V.; Protsenko, E. A.; Stepanova, S. V.; Yakubov, Sh. Kh.

    2017-01-01

    During cruise 65 of the R/V Akademik Mstislav Keldysh in the Kara Sea, three transects were executed: one eastwards from the Novaya Zemlya Archipelago and two in the St. Anna and Voronin troughs. It was noted that the continental runoff affected the entire surveyed aquatic area, even at the northern extremity of the Novaya Zemlya Archipelago. The transect along the St. Anna Trough showed the presence of a slope frontal zone overlaid at the surface by a desalinated layer. The Voronin Trough was characterized by sliding of slope waters. The hydrochemical parameters show that the surveys were carried out during a recession of biological activity of the waters and that the peak bloom was over by that time. The hydrochemical structure of waters conformed to early autumn conditions, but before the beginning of intense cooling of surface waters.

  11. The regional influence of the Arctic Oscillation and Arctic Dipole on the wintertime Arctic surface radiation budget and sea ice growth

    NASA Astrophysics Data System (ADS)

    Hegyi, Bradley M.; Taylor, Patrick C.

    2017-05-01

    An analysis of 2000-2015 monthly Clouds and the Earth's Radiant Energy System-Energy Balanced and Filled (CERES-EBAF) and Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA2) data reveals statistically significant fall and wintertime relationships between Arctic surface longwave (LW) radiative flux anomalies and the Arctic Oscillation (AO) and Arctic Dipole (AD). Signifying a substantial regional imprint, a negative AD index corresponds with positive downwelling clear-sky LW flux anomalies (>10 W m-2) north of western Eurasia (0°E-120°E) and reduced sea ice growth in the Barents and Kara Seas in November-February. Conversely, a positive AO index coincides with negative clear-sky LW flux anomalies and minimal sea ice growth change in October-November across the Arctic. Increased (decreased) atmospheric temperature and water vapor coincide with the largest positive (negative) clear-sky flux anomalies. Positive surface LW cloud radiative effect anomalies also accompany the negative AD index in December-February. The results highlight a potential pathway by which Arctic atmospheric variability influences the regional surface radiation budget over areas of Arctic sea ice growth.

  12. The Regional Influence of the Arctic Oscillation and Arctic Dipole on the Wintertime Arctic Surface Radiation Budget and Sea Ice Growth

    NASA Technical Reports Server (NTRS)

    Hegyi, Bradley M.; Taylor, Patrick C.

    2017-01-01

    An analysis of 2000-2015 monthly Clouds and the Earth's Radiant Energy System-Energy Balanced and Filled (CERES-EBAF) and Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA2) data reveals statistically significant fall and wintertime relationships between Arctic surface longwave (LW) radiative flux anomalies and the Arctic Oscillation (AO) and Arctic Dipole (AD). Signifying a substantial regional imprint, a negative AD index corresponds with positive downwelling clear-sky LW flux anomalies (greater than10W m(exp -2)) north of western Eurasia (0 deg E-120 deg E) and reduced sea ice growth in the Barents and Kara Seas in November-February. Conversely, a positive AO index coincides with negative clear-sky LW flux anomalies and minimal sea ice growth change in October-November across the Arctic. Increased (decreased) atmospheric temperature and water vapor coincide with the largest positive (negative) clear-sky flux anomalies. Positive surface LW cloud radiative effect anomalies also accompany the negative AD index in December-February. The results highlight a potential pathway by which Arctic atmospheric variability influences the regional surface radiation budget over areas of Arctic sea ice growth.

  13. Arctic Sea Ice, Summer 2014

    NASA Image and Video Library

    An animation of daily Arctic sea ice extent in summer 2014, from March 21, 2014 to Sept. 17, 2014 – when the ice appeared to reach it’s minimum extent for the year. It’s the sixth lowest minimum se...

  14. Climate-sensitive subsea permafrost and related gas expulsions on the South Kara Sea shelf. Field studies and modeling results.

    NASA Astrophysics Data System (ADS)

    Portnov, Alexey; Mienert, Jurgen; Serov, Pavel

    2015-04-01

    Thawing subsea permafrost controls methane release bearing a considerable impact on the climate-sensitive Arctic environment. Significant expulsion of methane into shallow Russian shelf areas may continue to rise into the atmosphere on the Arctic shelves in response to intense degradation of relict subsea permafrost. The release of formerly trapped gas, essentially methane, is linked to the permafrost evolution. Modeling of the permafrost at the West Yamal shelf allowed describing its evolution from the Late Pleistocene to Holocene. During the previous work we detected extensive emissions of free gas into the water column at the boundary between today's shallow water permafrost and deeper water non-permafrost areas. These gas expulsions formed seismic and hydro-acoustic anomalies on the high-resolution seismic records. We supposed that in the water depths <20m continuous ice-bearing permafrost plays a role of a seal through which gas can not migrate. We integrate 1D modeling results of relict permafrost distributions with these field data from the South Kara Sea. Modeling results suggest a highly-dynamic permafrost system that directly responds to even minor variations of lower and upper boundary conditions, e.g. heat flux from below and/or bottom water temperature changes from above. We present several scenarios of permafrost evolution and show that potentially minimal modern extent of the permafrost at the West Yamal shelf is limited by ~17 m isobaths, whereas maximal probable extent coincides with ~100 m isobaths. The model also predicts seaward tapering of relict permafrost with its maximal thickness 275-390 m near the shore line. We also present sensitivity analysis which define the wider range of modeling results depending on the changing input parameters (e.g. geothermal heat flux, bottom water temperature, porosity of the sediments). The model adapts well to corresponding field data, providing crucial information about the modern permafrost conditions

  15. Transport of contaminants by Arctic sea ice and surface ocean currents

    SciTech Connect

    Pfirman, S.

    1995-12-31

    Sea ice and ocean currents transport contaminants in the Arctic from source areas on the shelves, to biologically active regions often more than a thousand kilometers away. Coastal regions along the Siberian margin are polluted by discharges of agricultural, industrial and military wastes in river runoff, from atmospheric deposition and ocean dumping. The Kara Sea is of particular concern because of deliberate dumping of radioactive waste, as well as the large input of polluted river water. Contaminants are incorporated in ice during suspension freezing on the shelves, and by atmospheric deposition during drift. Ice releases its contaminant load through brine drainage, surface runoff of snow and meltwater, and when the floe disintegrates. The marginal ice zone, a region of intense biological activity, may also be the site of major contaminant release. Potentially contaminated ice from the Kara Sea is likely to influence the marginal ice zones of the Barents and Greenland seas. From studies conducted to date it appears that sea ice from the Kara Sea does not typically enter the Beaufort Gyre, and thus is unlikely to affect the northern Canadian and Alaskan margins.

  16. On Level Ice Thickness Retrieval in the Kara Sea Using MODIS and Envisat ASAR Data

    NASA Astrophysics Data System (ADS)

    Makynen, Marko; Simila, Markku; Cheng, Bin

    2010-12-01

    We propose here an approach to use jointly ENVISAT SAR and MODIS data and high-resolution thermodynamic snow/ice model (HIGHTSI) to estimate the thickness of first-year sea ice in cold winter conditions. For thin ice areas the sea ice thickness is retrieved from the MODIS based ice surface temperature (Ts) and HIRLAM forcing data. When estimating the ice thickness in the older and thicker drift ice areas, ice thickness field produced by HIGHTSI is used as a background field which constraints backscattering coefficient based ice thickness range. Our test data set consists of four MODIS-SAR image pairs taken over the Kara Sea in Dec 2008 - Mar 2009. The MODIS based ice thickness retrievals were consistent with each other. We estimated their uncertainty to be less than 25% for young ice. However, the HIRLAM modelled air temperature seems to be somewhat lower than could be inferred from Ts. This bias affected the MODIS ice thickness retrieval process by decreasing the retrieved ice thickness significantly for thicker ice fields. On a scale 10-100 km the spatial distribution of the ice thickness provided by our algorithm follows roughly the AARI ice charts which were used as a ground truth.

  17. Arctic Sea Ice Changes 2011-2012

    NASA Image and Video Library

    Animation showing changes in monthly Arctic sea ice volume using data from ESA's CryoSat-2 (red dots) and estimates from the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) (solid li...

  18. The International Arctic Seas Assessment Project

    SciTech Connect

    Linsley, G.S.; Sjoeblom, K.L.

    1994-07-01

    The International Arctic Seas Assessment Project (IASAP) was initiated in 1993 to address widespread concern over the possible health and environmental impacts associated with the radioactive waste dumped into the shallow waters of the Arctic Seas. This article discusses the project with these general topics: A brief history of dumping activities; the international control system; perspectives on arctic Seas dumping; the IASAP aims and implementation; the IASAP work plan and progress. 2 figs.

  19. Ice retreat in the Russian Arctic seas and assessment of the availability of the Northern Sea Route from satellite passive microwave observations

    NASA Astrophysics Data System (ADS)

    Shalina, E. V.

    2015-12-01

    This paper presents data on the sea ice area decline in the Northern Hemisphere and in the Russian Arctic seas, on the Northern Sea Route in particular, calculated from passive microwave satellite data. Observations show that the Arctic sea ice has reduced by an average of 5% per decade from November 1978 to the present day. It is noted that, since 2007, the highest sea ice area variability has been observed, which increases the uncertainty of the forecast of the ice coverage in the Arctic seas and thus increases risk for ships in ice-covered waters of northern seas. It is demonstrated that the decrease in summer sea ice area, observed at the end of the melt season, is much more intense than the total decrease in the Arctic sea ice area. On average it is 13% for September for the Arctic as a whole and from 24 to 40% per decade for the seas of the Russian Arctic. The study of changes in the ice conditions in the Northern Sea Route has been carried out for one of the optimal sailing routes. The results indicate a decrease in the ice concentration on the route in the summer months and almost complete route opening in September for the period from 2008 and 2012. It is shown that data from microwave radiometers can be used in the study of ice conditions in the Kara Gates and Vilkitsky Strait. The ice concentration reduction in both water channels is indicated. In the Kara Gates it is 15% and in the Vilkitsky Strait it is 9.5% per decade.

  20. Variability of concentration and composition of hydrocarbons in frontal zones of the Kara Sea

    NASA Astrophysics Data System (ADS)

    Nemirovskaya, I. A.

    2015-07-01

    The distribution and composition of aliphatic and polycyclic aromatic hydrocarbons (HC) in dissolved and particulate forms, as well as in bottom sediments, was studied along the route of a vessel and at stations. It was found that the widest variability of HC concentrations in surface waters was characteristic for the frontal zones of the Yenisei River mouth (4.8-69 µg/L) and for the western branch of the St. Anna Trough (5.5-80.4 µg/L). The increased concentrations of aliphatic HC coincide with those of chlorophyll and particulate matter, as well as with the growth of the intensity of fluorescence, and are caused by natural processes. This is confirmed by HC composition. Bottom sediments are characterized by low HC concentrations, both in terms of dry mass (14 µg/g on average, with the maximum of 36.8 µg/g at station 5018 in the layer of 3-17 cm) and within Corg compositions (0.88%). Natural terrigenous homologues are prevailing in alkane composition of the sediments. The marginal filters of the Ob and Yenisei rivers were compared. It is shown that oil HC transferred by the rivers are deposited in the zone of marginal filters without reaching the open waters of the Kara Sea.

  1. Geochemical and radiation conditions in coastal landscapes of the Kara Sea Gulf (Novaya Zemlya Archipelago)

    NASA Astrophysics Data System (ADS)

    Laverov, N. P.; Velichkin, V. I.; Miroshnikov, A. Yu.; Krupskaya, V. V.; Asadulin, En. E.; Semenkov, I. N.; Usacheva, A. A.; Zakusin, S. V.; Terskaya, E. V.

    2016-03-01

    This work considers terrestrial coastal landscapes of Abrosimov and Stepovoi gulfs and Yuzhnii (Southern) Island in the Novaya Zemlya Archipelago in the Kara Sea. These areas are dominated by horizons of slightly acidic leptosols and lithic leptosols of 10 cm thick (Stepovoi Gulf) and those of weak skeleton acidic lithic leptosols of 10-15 cm thick (Abrosimov Gulf) covered by moss-shrub assemblages. Kaolinite is formed in a rhizosphere fine earth layer; illite is formed along the leptosol sequence. The studied coastal landscapes are characterized by low accumulation potential of chemical elements, including radionuclides, at higher contents of them. Elements such as Fe and Ti are dispersed in sols, whereas P, S, Cl, Cu, Pb, and Zn are accumulated in soils in minor amounts. Plants accumulate S, P, Cl, Sr, Zn, and 137Cs in minor amounts as well. Elements such as Ti, Mn, Fe, Cr, V, Co, Ni, Cu, Rb, Zr, Ba, Th, Y, Nb, Pb, and As are attributed to the group of weak biological adsorption. The specific 137Cs activity (Bq kg-1) amounts to 10-150 in plants, 10-300 in moor leptosol horizons, and 1-40 in mull horizons.

  2. Dipole Anomaly in the Winter Arctic Atmosphere and Its Association with Sea Ice Motion.

    NASA Astrophysics Data System (ADS)

    Wu, Bingyi; Wang, Jia; Walsh, John E.

    2006-01-01

    This paper identified an atmospheric circulation anomaly dipole structure anomaly in the Arctic atmosphere and its relationship with winter sea ice motion, based on the International Arctic Buoy Program (IABP) dataset (1979 98) and datasets from the National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) for the period 1960 2002. The dipole anomaly corresponds to the second-leading mode of EOF of monthly mean sea level pressure (SLP) north of 70°N during the winter season (October March) and accounts for 13% of the variance. One of its two anomalous centers is stably occupied between the Kara Sea and Laptev Sea; the other is situated from the Canadian Archipelago through Greenland extending southeastward to the Nordic seas. The dipole anomaly differs from one described in other papers that can be attributed to an eastward shift of the center of action of the North Atlantic Oscillation. The finding shows that the dipole anomaly also differs from the “Barents Oscillation” revealed in a study by Skeie. Since the dipole anomaly shows a strong meridionality, it becomes an important mechanism to drive both anomalous sea ice exports out of the Arctic Basin and cold air outbreaks into the Barents Sea, the Nordic seas, and northern Europe.When the dipole anomaly remains in its positive phase, that is, negative SLP anomalies appear between the Kara Sea and the Laptev Sea with concurrent positive SLP over from the Canadian Archipelago extending southeastward to Greenland, there are large-scale changes in the intensity and character of sea ice transport in the Arctic basin. The significant changes include a weakening of the Beaufort gyre, an increase in sea ice export out of the Arctic basin through Fram Strait and the northern Barents Sea, and enhanced sea ice import from the Laptev Sea and the East Siberian Sea into the Arctic basin. Consequently, more sea ice appears in the Greenland and the Barents Seas during the

  3. Arctic Sea Ice Variability and Trends, 1979-2006

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.; Cavalieri, Donald J.

    2008-01-01

    Analysis of Arctic sea ice extents derived from satellite passive-microwave data for the 28 years, 1979-2006 yields an overall negative trend of -45,100 +/- 4,600 km2/yr (-3.7 +/- 0.4%/decade) in the yearly averages, with negative ice-extent trends also occurring for each of the four seasons and each of the 12 months. For the yearly averages the largest decreases occur in the Kara and Barents Seas and the Arctic Ocean, with linear least squares slopes of -10,600 +/- 2,800 km2/yr (-7.4 +/- 2.0%/decade) and -10,100 +/- 2,200 km2/yr (-1.5 +/- 0.3%/decade), respectively, followed by Baffin Bay/Labrador Sea, with a slope of -8,000 +/- 2,000 km2/yr) -9.0 +/- 2.3%/decade), the Greenland Sea, with a slope of -7,000 +/- 1,400 km2/yr (-9.3 +/- 1.9%/decade), and Hudson Bay, with a slope of -4,500 +/- 900 km2/yr (-5.3 +/- 1.1%/decade). These are all statistically significant decreases at a 99% confidence level. The Seas of Okhotsk and Japan also have a statistically significant ice decrease, although at a 95% confidence level, and the three remaining regions, the Bering Sea, Canadian Archipelago, and Gulf of St. Lawrence, have negative slopes that are not statistically significant. The 28-year trends in ice areas for the Northern Hemisphere total are also statistically significant and negative in each season, each month, and for the yearly averages.

  4. Arctic Sea Ice Reemergence: The Role of Large-Scale Oceanic and Atmospheric Variability

    NASA Astrophysics Data System (ADS)

    Bushuk, M.; Giannakis, D.; Majda, A.

    2014-12-01

    Arctic sea ice reemergence is a phenomenon in which spring sea ice anomalies are positively correlated with fall anomalies, despite a loss of correlation over the intervening summer months. Pan-Arctic sea ice reemergence is present in both observations and global climate models (GCMs), yet the amplitude and regional details of the reemergence signals vary substantially. In this work, a novel data analysis technique, coupled Nonlinear Laplacian Spectral Analysis (NLSA), is employed to study the spatiotemporal co-variability of sea ice concentration, sea surface temperature (SST), and sea level pressure (SLP) in the Arctic. NLSA modes are obtained for observational data and GCM output, and are used to examine the statistical characteristics and physical mechanisms of sea ice reemergence. It is found that lagged correlation features of the raw sea ice data can be efficiently reproduced using low-dimensional families of modes. These families provide an SST-sea ice reemergence mechanism, in which melt season (spring) sea ice anomalies are imprinted as SST anomalies and stored over the summer months, allowing for sea ice anomalies of the same sign to reappear in the growth season (fall). Moreover, the ice anomalies of each family exhibit clear phase relationships between the Barents-Kara, Bering, and Labrador seas. These regional phase relationships have a natural explanation via the SLP patterns and associated geostrophic winds of each family, which closely resemble the Arctic Oscillation and Arctic Dipole Anomaly. Additionally, the winter-to-winter persistence of these SLP patterns suggests another plausible mechanism for sea ice reemergence.

  5. Trend analysis of Arctic sea ice extent

    NASA Astrophysics Data System (ADS)

    Silva, M. E.; Barbosa, S. M.; Antunes, Luís; Rocha, Conceição

    2009-04-01

    The extent of Arctic sea ice is a fundamental parameter of Arctic climate variability. In the context of climate change, the area covered by ice in the Arctic is a particularly useful indicator of recent changes in the Arctic environment. Climate models are in near universal agreement that Arctic sea ice extent will decline through the 21st century as a consequence of global warming and many studies predict a ice free Arctic as soon as 2012. Time series of satellite passive microwave observations allow to assess the temporal changes in the extent of Arctic sea ice. Much of the analysis of the ice extent time series, as in most climate studies from observational data, have been focussed on the computation of deterministic linear trends by ordinary least squares. However, many different processes, including deterministic, unit root and long-range dependent processes can engender trend like features in a time series. Several parametric tests have been developed, mainly in econometrics, to discriminate between stationarity (no trend), deterministic trend and stochastic trends. Here, these tests are applied in the trend analysis of the sea ice extent time series available at National Snow and Ice Data Center. The parametric stationary tests, Augmented Dickey-Fuller (ADF), Phillips-Perron (PP) and the KPSS, do not support an overall deterministic trend in the time series of Arctic sea ice extent. Therefore, alternative parametrizations such as long-range dependence should be considered for characterising long-term Arctic sea ice variability.

  6. Sea ice thickness and recent Arctic warming

    NASA Astrophysics Data System (ADS)

    Lang, Andreas; Yang, Shuting; Kaas, Eigil

    2017-01-01

    The climatic impact of increased Arctic sea ice loss has received growing attention in the last years. However, little focus has been set on the role of sea ice thickness, although it strongly determines surface heat fluxes. Here ensembles of simulations using the EC-Earth atmospheric model (Integrated Forecast System) are performed and analyzed to quantify the atmospheric impacts of Arctic sea ice thickness change since 1982 as revealed by the sea ice model assimilation Global Ice-Ocean Modeling and Assimilation System. Results show that the recent sea ice thinning has significantly affected the Arctic climate, while remote atmospheric responses are less pronounced owing to a high internal atmospheric variability. Locally, the sea ice thinning results in enhancement of near-surface warming of about 1°C per decade in winter, which is most pronounced over marginal sea ice areas with thin ice. This leads to an increase of the Arctic amplification factor by 37%.

  7. Structure of phytoplankton communities in the Yenisei estuary and over the adjacent Kara Sea shelf

    NASA Astrophysics Data System (ADS)

    Sukhanova, I. N.; Flint, M. V.; Sergeeva, V. M.; Druzhkova, E. I.; Nedospasov, A. A.

    2015-11-01

    Material was collected in the Yenisei estuary and over the adjacent Kara Sea shelf at a quasimeridional transect from 71°49'70″ to 75°59'93″ N in September 2011. The structural characteristics of the phytoplankton community were determined by latitudinal zonality of environmental conditions. Two well-distinguished phytocenoses—freshwater and marine—were found in this region. Phytoplankton in the freshwater part of the estuary was composed solely of the freshwater algae species and was distinguished by the highest numbers (up to 2 × 106 cell/L) and biomass (up to 1.4 mg/L). The marine phytocenoses over the Yenisei shoal was composed of marine neritic species; the abundance and biomass of phytoplankton in this area were significantly lower (0.2 × 106 cell/L and 0.4 mg/L, respectively). The area of intensive interaction of riverine and marine waters—the estuarine frontal zone, with ~130 km latitudinal extension (from 72° to 74° N)—was characterized by a sharp halocline, which separated the desalinated upper layer from the underlying marine water. Freshwater algal species predominated above the halocline, whereas marine species predominated below. The lower border of the euphotic layer was located 8 to 15 m below the halocline. The niche between the halocline and the lower border of the euphotic layer was characterized by high nutrient concentrations, which together with sufficient illumination determined the intensive development of phytoplankton and high values of primary production.

  8. Estimated inventory of radionuclides in former Soviet Union naval reactors dumped in the Kara Sea

    SciTech Connect

    Mount, M.E.; Sheaffer, M.K.; Abbott, D.T.

    1993-07-01

    Radionuclide inventories have been estimated for the reactor cores, reactor components, and primary system corrosion products in the former Soviet Union naval reactors dumped at the Abrosimov Inlet, Tsivolka Inlet, Stepovoy Inlet, Techeniye Inlet, and Novaya Zemlya Depression sites in the Kara Sea between 1965 and 1988. For the time of disposal, the inventories are estimated at 69 to 111 kCi of actinides plus daughters and 3,053 to 7,472 kCi of fission products in the reactor cores, 917 to 1,127 kCi of activation products in the reactor components, and 1.4 to 1.6 kCi of activation products in the primary system corrosion products. At the present time, the inventories are estimated to have decreased to 23 to 38 kCi of actinides plus daughters and 674 to 708 kCi of fission products in the reactor cores, 124 to 126 kCi of activation products in the reactor components, and 0.16 to 0.17 kCi of activation products in the primary system corrosion products. Twenty years from now, the inventories are projected to be 11 to 18 kCi of actinides plus daughters and 415 to 437 kCi of fission products in the reactor cores, 63.5 to 64 kCi of activation products in the reactor components, and 0.014 to 0.015 kCi of activation products in the primary system corrosion products. All actinide activities are estimated to be within a factor of two.

  9. Arctic Ocean sea ice drift origin derived from artificial radionuclides.

    PubMed

    Cámara-Mor, P; Masqué, P; Garcia-Orellana, J; Cochran, J K; Mas, J L; Chamizo, E; Hanfland, C

    2010-07-15

    Since the 1950s, nuclear weapon testing and releases from the nuclear industry have introduced anthropogenic radionuclides into the sea, and in many instances their ultimate fate are the bottom sediments. The Arctic Ocean is one of the most polluted in this respect, because, in addition to global fallout, it is impacted by regional fallout from nuclear weapon testing, and indirectly by releases from nuclear reprocessing facilities and nuclear accidents. Sea-ice formed in the shallow continental shelves incorporate sediments with variable concentrations of anthropogenic radionuclides that are transported through the Arctic Ocean and are finally released in the melting areas. In this work, we present the results of anthropogenic radionuclide analyses of sea-ice sediments (SIS) collected on five cruises from different Arctic regions and combine them with a database including prior measurements of these radionuclides in SIS. The distribution of (137)Cs and (239,240)Pu activities and the (240)Pu/(239)Pu atom ratio in SIS showed geographical differences, in agreement with the two main sea ice drift patterns derived from the mean field of sea-ice motion, the Transpolar Drift and Beaufort Gyre, with the Fram Strait as the main ablation area. A direct comparison of data measured in SIS samples against those reported for the potential source regions permits identification of the regions from which sea ice incorporates sediments. The (240)Pu/(239)Pu atom ratio in SIS may be used to discern the origin of sea ice from the Kara-Laptev Sea and the Alaskan shelf. However, if the (240)Pu/(239)Pu atom ratio is similar to global fallout, it does not provide a unique diagnostic indicator of the source area, and in such cases, the source of SIS can be constrained with a combination of the (137)Cs and (239,240)Pu activities. Therefore, these anthropogenic radionuclides can be used in many instances to determine the geographical source area of sea-ice. Copyright 2010 Elsevier B.V. All

  10. Regional seasonal forecasts of the Arctic sea ice in two coupled climate models

    NASA Astrophysics Data System (ADS)

    Chevallier, Matthieu; Guémas, Virginie; Salas y Mélia, David; Doblas-Reyes, Francisco

    2015-04-01

    The predictive capabilities of two state-of-the-art coupled atmosphere-ocean global climate models (CNRM-CM5.1 and EC-Earth v2.3) in seasonal forecasting of the Arctic sea ice will be presented with a focus on regional skill. 5-month hindcasts of September sea ice area in the Arctic peripherial seas (Barents-Kara seas, Laptev-East Siberian seas, Chukchi sea and Beaufort sea) and March sea ice area in the marginal ice zones (Barents, Greenland, Labrador, Bering and Okhotsk sea) have been produced over the period 1990-2009. Systems mainly differ with respect to the initialization strategy, the ensemble generation techniques and the sea ice components. Predictive skill, assessed in terms of actual and potential predictability, is comparable in the two systems for both summer and winter hindcasts. Most interestingly, the multi-model prediction is often better than individual predictions in several sub-basins, including the Barents sea in the winter and most shelf seas in the summer. Systematic biases are also reduced using the multi-model predictions. Results from this study show that a regional zoom of global seasonal forecasts could be useful for operational needs. This study also show that the multi-model approach may be the step forward in producing accurate and reliable seasonal forecasts based on coupled global climate models.

  11. Creating Arctic Sea Ice Protected Areas?

    NASA Astrophysics Data System (ADS)

    Pfirman, S.; Hoff, K.; Temblay, B.; Fowler, C.

    2008-12-01

    As Arctic sea ice retreats and the Northwest Passage and Northern Sea Route open, the Arctic will experience more extensive human activity than it has ever encountered before. New development will put pressure on a system already struggling to adapt to a changing environment. In this analysis, locations are identified within the Arctic that could be protected from resource extraction, transportation and other development in order to create refuges and protect remnants of sea ice habitat, as the Arctic transitions to ice-free summer conditions. Arctic sea ice forms largely along the Siberian and Alaskan coasts and is advected across the North Pole towards Fram Strait, the Canadian Archipelago and the Barents Sea. In addition to the future loss of ice itself, contaminants entrained in sea ice in one part of the ocean can affect other regions as the ice drifts. Using observations and models of sea ice origins, trajectories and ages, we track sea ice from its origins towards marginal ice zones, mapping pathways and termination locations. Critical sea ice source areas and collection regions are identified with the goal of aiding in the protection of the remaining Arctic sea ice habitat for as long as possible.

  12. Thermohaline circulation in the Arctic Mediterranean Seas

    NASA Astrophysics Data System (ADS)

    Aagaard, K.; Swift, J. H.; Carmack, E. C.

    1985-05-01

    The renewal of the deep North Atlantic by the various overflows of the Greenland-Scotland ridges is only one manifestation of the convective and mixing processes which occur in the various basins and shelf areas to the north: the Arctic Ocean and the Greenland, Iceland, and Norwegian seas, collectively called the Arctic Mediterranean. The traditional site of deep ventilation for these basins is the Greenland Sea, but a growing body of evidence also points to the Arctic Ocean as a major source of deep water. This deep water is relatively warm and saline, and it appears to be a mixture of dense, brine-enriched shelf water with intermediate strata in the Arctic Ocean. The deep water exits the Arctic Ocean along the Greenland slope to mix with the Greenland Sea deep water. Conversely, very cold low-salinity deep water from the Greenland Sea enters the Arctic Ocean west of Spitsbergen. Within the Arctic Ocean, the Lomonosov Ridge excludes the Greenland Sea deep water from the Canadian Basin, leaving the latter warm, saline, and rich in silica. In general, the entire deep-water sphere of the Arctic Mediterranean is constrained by the Greenland-Scotland ridges to circulate internally. Therefore it is certain of the intermediate waters formed in the Greenland and Iceland seas which ventilate the North Atlantic. These waters have a very short residence time in their formation areas and are therefore able to rapidly transmit surface-induced signals into the deep North Atlantic.

  13. Microbial uncultured community of bottom sediments from the bays of Gydan and Yenisei of the Kara Sea

    NASA Astrophysics Data System (ADS)

    Mamaeva, E. V.; Suslova, M. Yu.; Pogodaeva, T. V.; Parfenova, V. V.; Zemskaya, T. I.

    2014-05-01

    Using methods of molecular biology (PCR and cloning), we studied the diversity of microorganisms in the surface layers of bottom sediments from the bays of Gydan and Yenisei of the Kara Sea, which have different component composition of the pore water and mineralization level. Representatives of the domains Bacteria and Archaea were identified based on the analysis of the 16S rRNA gene fragment nucleotide sequences. The composition of the community of microorganisms in the bottom sediments changed with the changing salinity gradient of the pore waters. The phylogenetic analysis of the nucleotide sequences showed that the composition of the microbial communities in the southern parts of these bays was affected by fresh-water flows from rivers and streams from the lakes within the catchment area, whereas that in the northern parts was influenced by sea waters. The results indicate the presence of bacteria in the bottom sediments that are capable of using a wide range of substrates as a carbon source including hydrocarbons and organochlorine and aromatic compounds. These data can also indicate the presence of different pollutants in the sediments of these areas and the potential ability of bacteria to degrade chemical compounds that enter the waters and bottom sediments of the Kara Sea.

  14. Elemental composition of zooplankton in the Kara Sea and the bays on the eastern side of Novaya Zemlya

    NASA Astrophysics Data System (ADS)

    Lobus, N. V.

    2016-11-01

    The chemical composition of zooplankton in the Kara Sea Basin has been studied. Independent samplings of the open sea and the Blagopoluchie and Tsivol'ki bays of Novaya Zemlya testify to the similarity of the distribution pattern of all the studied elements. The chemical composition of samples is predominated by organic carbon (49.5 ± 4.8% of dry weight). The other most important constituent elements are Na, P, S, K, Mg, and Ca. Their average total concentrations are 4.82 ± 0.1%. From an analysis of the composition of major and trace elements of zooplankton in the Kara Sea and the bays of Novaya Zemlya, three groups of elements have been specified: with similar (Corg, K, S, P, Al, Ti, Sc, Cd, Se, Cs, and Rb), lower (Na, Ca, Mg, Fe, Mn, Zn, Sr, Ba, B, Cu, Pb, Cr, Ni, V, Co, Sb, Mo, Ag, Be, Ga, and Hg), and higher (Li, As, and U) contents compared to their mean concentrations in ocean zooplankton.

  15. Movement of a female polar bear (Ursus maritimus) in the Kara Sea during the summer sea-ice break-up.

    PubMed

    Rozhnov, V V; Platonov, N G; Naidenko, S V; Mordvintsev, I N; Ivanov, E A

    2017-01-01

    The polar bear movement trajectory in relation to onset date of the sea-ice break-up was studied in the coastal zone of the Taimyr Peninsula, eastern part of the Kara Sea, using as an example a female polar bear tagged by a radio collar with an Argos satellite transmitter. Analysis of the long-term pattern of ice melting and tracking, by means of satellite telemetry, of the female polar bear who followed the ice-edge outgoing in the north-eastern direction (in summer 2012) suggests that direction of the polar bear movement depends precisely on the direction of the sea-ice cover break-up.

  16. Loss of sea ice in the Arctic.

    PubMed

    Perovich, Donald K; Richter-Menge, Jacqueline A

    2009-01-01

    The Arctic sea ice cover is in decline. The areal extent of the ice cover has been decreasing for the past few decades at an accelerating rate. Evidence also points to a decrease in sea ice thickness and a reduction in the amount of thicker perennial sea ice. A general global warming trend has made the ice cover more vulnerable to natural fluctuations in atmospheric and oceanic forcing. The observed reduction in Arctic sea ice is a consequence of both thermodynamic and dynamic processes, including such factors as preconditioning of the ice cover, overall warming trends, changes in cloud coverage, shifts in atmospheric circulation patterns, increased export of older ice out of the Arctic, advection of ocean heat from the Pacific and North Atlantic, enhanced solar heating of the ocean, and the ice-albedo feedback. The diminishing Arctic sea ice is creating social, political, economic, and ecological challenges.

  17. Influence of global climatic processes on environment The Arctic seas

    NASA Astrophysics Data System (ADS)

    Kholmyansky, Mikhael; Anokhin, Vladimir; Kartashov, Alexandr

    2016-04-01

    One of the most actual problems of the present is changes of environment of Arctic regions under the influence of global climatic processes. Authors as a result of the works executed by them in different areas of the Russian Arctic regions, have received the materials characterising intensity of these processes. Complex researches are carried out on water area and in a coastal zone the White, the Barents, the Kara and the East-Siberian seas, on lake water areas of subarctic region since 1972 on the present. Into structure of researches enter: hydrophysical, cryological observations, direct measurements of temperatures, the analysis of the drill data, electrometric definitions of the parametres of a frozen zone, lithodynamic and geochemical definitions, geophysical investigations of boreholes, studying of glaciers on the basis of visual observations and the analysis of photographs. The obtained data allows to estimate change of temperature of a water layer, deposits and benthonic horizon of atmosphere for last 25 years. On the average they make 0,38⁰C for sea waters, 0,23⁰C for friable deposits and 0,72⁰C for atmosphere. Under the influence of temperature changes in hydrosphere and lithosphere of a shelf cryolithic zone changes the characteristics. It is possible to note depth increase of roof position of the cryolithic zone on the most part of the studied water area. Modern fast rise in temperature high-ice rocks composing coast, has led to avalanche process thermo - denudation and to receipt in the sea of quantity of a material of 1978 three times exceeding level Rise in temperature involves appreciable deviation borders of the Arctic glacial covers. On our monitoring measurements change of the maintenance of oxygen in benthonic area towards increase that is connected with reduction of the general salinity of waters at the expense of fresh water arriving at ice thawing is noticed. It, in turn, leads to change of a biogene part of ecosystem. The executed

  18. Geochemical interpretation of distribution of aromatic hydrocarbons in components of geologic environment of Pechora, Barents and Kara seas.

    NASA Astrophysics Data System (ADS)

    Kursheva, Anna; Petrova, Vera; Litvinenko, Ivan; Morgunova, Inna

    2017-04-01

    Information about the hydrocarbons content (including aromatic ones) in components of geologic environment allows to define common factors in distribution and correlation both nature and technogenic component, and also to reveal the sources of contamination. At that, it should be noted, that hydrocarbons are widely spread in lithosphere and create steady geochemical background, variations are caused here by specifics of initial organic matter, conditions of its accumulation and transformation. The basis of the study are the samples of sea water and deep sea sediments (more than 600 stations), collected in western sector of Arctic region (Pechora, Barents and Kara seas) during the scientific-research expeditions of FSBI "VNIIOkeangeologia" for the period 2000-2010. Total content of aromatic hydrocarbons was defined by spectrofluorometric method using analyzer «FLUORAT-Panorama-02». Certification of data was performed on representative samples based on contents and molecule structure of polycyclic aromatic hydrocarbons using GC-MS (Agilent 5973/6850 GC-MS System). Results of spectrofluorometric analysis of lipid fraction of organic matter of bottom sediments allowed to define specific parameters, which characterize various lithofacies groups of sediments. Thus, sandy residues are characterized by low level of aromatic hydrocarbons (ca. 4.3 μg/g) with prevalence of bi- and tri-aromatic compounds (λmax 270-310 nm). This correlates with low sorption capacity of coarse-grained sediments and absence of organic-mineral component, containing the breakdown products of initial organic matter. Tetra- and penta- aromatic structures prevail in clay sediments (ca. 13.0 μg/g), which are typical components of lipid fraction of organic matter of post sedimentation and early diagenetic stages of transformation. At that, changes of spectral characteristic of sediments in stratigraphic sequence completely reflect processes of diagenetic transformation of organic matter, including

  19. Arctic Sea Ice from March to August 2016

    NASA Image and Video Library

    In this animation, the daily Arctic sea ice and seasonal land cover change progress through time, from the prior sea ice maximum March 24, 2016, through Aug. 13, 2016. The Arctic sea ice cover like...

  20. Skill improvement of seasonal Arctic sea ice forecasts using bias-correction and ensemble calibration

    NASA Astrophysics Data System (ADS)

    Krikken, Folmer; Hazeleger, Wilco; Vlot, Willem; Schmeits, Maurice; Guemas, Virginie

    2016-04-01

    We explore the standard error and skill of dynamical seasonal sea ice forecasts of the Arctic using different bias-correction and ensemble calibration methods. The latter is often used in weather forecasting, but so far has not been applied to Arctic sea ice forecasts. We use seasonal predictions of Arctic sea ice of a 5-member ensemble forecast using the fully coupled GCM EC-Earth, with model initial states obtained by nudging towards ORAS4 and ERA-Interim. The raw model forecasts contain large biases in total sea ice area, especially during the summer months. This is mainly caused by a difference in average seasonal cycle between EC-Earth and observations, which translates directly into the forecasts yielding large biases. Further errors are introduced by the differences in long term trend between the observed sea ice, and the uninitialised EC-earth simulation. We find that extended logistic regression (ELR) and heteroscedastic extended logistic regression (HELR) both prove viable ensemble calibration methods, and improve the forecasts substantially compared to standard bias correction techniques. No clear distinction between ELR and HELR is found. Forecasts starting in May have higher skill (CRPSS > 0 up to 5 months lead time) than forecasts starting in August (2-3 months) and November (2-3 months), with trend-corrected climatology as reference. Analysis of regional skill in the Arctic shows distinct differences, where mainly the Arctic ocean and the Kara and Barents sea prove to be one of the more predictable regions with skilful forecasts starting in May up to 5-6 months lead time. Again, forecasts starting in August and November show much lower regional skill. Overall, it is still difficult to beat relative simple statistical forecasts, but by using ELR and HELR we are getting reasonably close to skilful seasonal forecasts up to 12 months lead time. These results show there is large potential, and need, for using ensemble calibration in seasonal forecasts of

  1. Influence of sea ice on Arctic precipitation

    PubMed Central

    Kopec, Ben G.; Feng, Xiahong; Michel, Fred A.; Posmentier, Eric S.

    2016-01-01

    Global climate is influenced by the Arctic hydrologic cycle, which is, in part, regulated by sea ice through its control on evaporation and precipitation. However, the quantitative link between precipitation and sea ice extent is poorly constrained. Here we present observational evidence for the response of precipitation to sea ice reduction and assess the sensitivity of the response. Changes in the proportion of moisture sourced from the Arctic with sea ice change in the Canadian Arctic and Greenland Sea regions over the past two decades are inferred from annually averaged deuterium excess (d-excess) measurements from six sites. Other influences on the Arctic hydrologic cycle, such as the strength of meridional transport, are assessed using the North Atlantic Oscillation index. We find that the independent, direct effect of sea ice on the increase of the percentage of Arctic sourced moisture (or Arctic moisture proportion, AMP) is 18.2 ± 4.6% and 10.8 ± 3.6%/100,000 km2 sea ice lost for each region, respectively, corresponding to increases of 10.9 ± 2.8% and 2.7 ± 1.1%/1 °C of warming in the vapor source regions. The moisture source changes likely result in increases of precipitation and changes in energy balance, creating significant uncertainty for climate predictions. PMID:26699509

  2. Influence of sea ice on Arctic precipitation.

    PubMed

    Kopec, Ben G; Feng, Xiahong; Michel, Fred A; Posmentier, Eric S

    2016-01-05

    Global climate is influenced by the Arctic hydrologic cycle, which is, in part, regulated by sea ice through its control on evaporation and precipitation. However, the quantitative link between precipitation and sea ice extent is poorly constrained. Here we present observational evidence for the response of precipitation to sea ice reduction and assess the sensitivity of the response. Changes in the proportion of moisture sourced from the Arctic with sea ice change in the Canadian Arctic and Greenland Sea regions over the past two decades are inferred from annually averaged deuterium excess (d-excess) measurements from six sites. Other influences on the Arctic hydrologic cycle, such as the strength of meridional transport, are assessed using the North Atlantic Oscillation index. We find that the independent, direct effect of sea ice on the increase of the percentage of Arctic sourced moisture (or Arctic moisture proportion, AMP) is 18.2 ± 4.6% and 10.8 ± 3.6%/100,000 km(2) sea ice lost for each region, respectively, corresponding to increases of 10.9 ± 2.8% and 2.7 ± 1.1%/1 °C of warming in the vapor source regions. The moisture source changes likely result in increases of precipitation and changes in energy balance, creating significant uncertainty for climate predictions.

  3. Approaching the 2015 Arctic Sea Ice Minimum

    NASA Image and Video Library

    As the sun sets over the Arctic, the end of this year’s melt season is quickly approaching and the sea ice cover has already shrunk to the fourth lowest in the satellite record. With possibly some ...

  4. Remote Sensing of the Arctic Seas.

    ERIC Educational Resources Information Center

    Weeks, W. F.; And Others

    1986-01-01

    Examines remote sensing of the arctic seas by discussing: (1) passive microwave sensors; (2) active microwave sensors; (3) other types of sensors; (4) the future deployment of sensors; (5) data buoys; and (6) future endeavors. (JN)

  5. Multi-year Arctic Sea Ice

    NASA Image and Video Library

    The most visible change in the Arctic region in recent years has been the rapid decline of the perennial ice cover. The perennial ice is the portion of the sea ice floating on the surface of the oc...

  6. Remote Sensing of the Arctic Seas.

    ERIC Educational Resources Information Center

    Weeks, W. F.; And Others

    1986-01-01

    Examines remote sensing of the arctic seas by discussing: (1) passive microwave sensors; (2) active microwave sensors; (3) other types of sensors; (4) the future deployment of sensors; (5) data buoys; and (6) future endeavors. (JN)

  7. Arctic Cyclone Breaks Up Sea Ice

    NASA Image and Video Library

    A powerful storm wreaked havoc on the Arctic sea ice cover in August 2012. This visualization shows the strength and direction of the winds and their impact on the ice: the red vectors represent th...

  8. SONARC: A Sea Ice Monitoring and Forecasting System to Support Safe Operations and Navigation in Arctic Seas

    NASA Astrophysics Data System (ADS)

    Stephenson, S. R.; Babiker, M.; Sandven, S.; Muckenhuber, S.; Korosov, A.; Bobylev, L.; Vesman, A.; Mushta, A.; Demchev, D.; Volkov, V.; Smirnov, K.; Hamre, T.

    2015-12-01

    Sea ice monitoring and forecasting systems are important tools for minimizing accident risk and environmental impacts of Arctic maritime operations. Satellite data such as synthetic aperture radar (SAR), combined with atmosphere-ice-ocean forecasting models, navigation models and automatic identification system (AIS) transponder data from ships are essential components of such systems. Here we present first results from the SONARC project (project term: 2015-2017), an international multidisciplinary effort to develop novel and complementary ice monitoring and forecasting systems for vessels and offshore platforms in the Arctic. Automated classification methods (Zakhvatkina et al., 2012) are applied to Sentinel-1 dual-polarization SAR images from the Barents and Kara Sea region to identify ice types (e.g. multi-year ice, level first-year ice, deformed first-year ice, new/young ice, open water) and ridges. Short-term (1-3 days) ice drift forecasts are computed from SAR images using feature tracking and pattern tracking methods (Berg & Eriksson, 2014). Ice classification and drift forecast products are combined with ship positions based on AIS data from a selected period of 3-4 weeks to determine optimal vessel speed and routing in ice. Results illustrate the potential of high-resolution SAR data for near-real-time monitoring and forecasting of Arctic ice conditions. Over the next 3 years, SONARC findings will contribute new knowledge about sea ice in the Arctic while promoting safe and cost-effective shipping, domain awareness, resource management, and environmental protection.

  9. Structure and evolution of the northern Barents-Kara Sea continental margin from integrated analysis of potential fields, bathymetry and sparse seismic data

    NASA Astrophysics Data System (ADS)

    Minakov, A.; Faleide, J. I.; Glebovsky, V. Yu.; Mjelde, R.

    2012-01-01

    The northern Barents-Kara Sea continental margin is a poorly investigated area because of a permanent ice cover hampering seismic exploration. The available geological and geophysical data show that the magma-poor margin developed in response to early Cenozoic break-up and subsequent opening of the Arctic Eurasia Basin. In this study, a series of crustal-scale geotransects illustrating the architecture of the continental margin are constructed using sparse seismic reflection profiles and a gravity inversion method incorporating a thermal model of rifting. The continental side of the northern Barents Sea margin is underlain by Palaeozoic-Early Mesozoic deep sedimentary basins separated from the oceanic side by the marginal uplift. A bathymetry analysis complements low-resolution seismic data to predict the sedimentary depocenters beyond the shelf break. These depocenters are associated with troughs, perpendicular to the shelf edge. The depocenter in front of the St. Anna Trough may contain a sedimentary section more than 4 km thick. The gravity correction for the effect of sedimentary cover was added to the inversion. This correction used an exponential density-depth function. The inversion supports a narrow and steep continent-ocean transition (COT; ca. 100 km). The conjugate Lomonosov Ridge margin is modelled using the same technique. Palaeoreconstructions were made to predict the break-up setting. The northern Barents Sea-Lomonosov Ridge rift system can be described as an initially narrow symmetric rift. A transitional zone of extreme thinning is assumed between the oldest spreading magnetic anomaly and the stretched continental crust. The free-air gravity anomaly in the western part of the margin can be predicted by the upwelling divergent flow model implying the exhumation of the lower crust and the continental upper mantle within the COT. It is suggested that an episode of shear or oblique extension before breakup is required to explain the observed narrow

  10. Predictability of the Arctic sea ice edge

    NASA Astrophysics Data System (ADS)

    Goessling, H. F.; Tietsche, S.; Day, J. J.; Hawkins, E.; Jung, T.

    2016-02-01

    Skillful sea ice forecasts from days to years ahead are becoming increasingly important for the operation and planning of human activities in the Arctic. Here we analyze the potential predictability of the Arctic sea ice edge in six climate models. We introduce the integrated ice-edge error (IIEE), a user-relevant verification metric defined as the area where the forecast and the "truth" disagree on the ice concentration being above or below 15%. The IIEE lends itself to decomposition into an absolute extent error, corresponding to the common sea ice extent error, and a misplacement error. We find that the often-neglected misplacement error makes up more than half of the climatological IIEE. In idealized forecast ensembles initialized on 1 July, the IIEE grows faster than the absolute extent error. This means that the Arctic sea ice edge is less predictable than sea ice extent, particularly in September, with implications for the potential skill of end-user relevant forecasts.

  11. Arctic sea ice melt, the Polar vortex, and mid-latitude weather: Are they connected?

    NASA Astrophysics Data System (ADS)

    Vihma, Timo; Overland, James; Francis, Jennifer; Hall, Richard; Hanna, Edward; Kim, Seong-Joong

    2015-04-01

    The potential of recent Arctic changes to influence broader hemispheric weather is a difficult and controversial topic with considerable skepticism, as time series of potential linkages are short (<10 years) and the signal-to-noise ratio relative to chaotic weather events is small. A way forward is through further understanding of potential atmospheric dynamic mechanisms. Although not definitive of change in a statistical or in a causality sense, the exceptionally warm Arctic winters since 2007 do contain increased variability according to some climate indices, with six negative (and two positive) Arctic Oscillation atmospheric circulation index events that created meridional flow reaching unusually far north and south. High pressure anomalies developed east of the Ural Mountains in Russia in response to sea-ice loss in the Barents/Kara Seas, which initiated eastward-propagating wave trains of high and low pressure that advected cold air over central and eastern Asia. Increased Greenland blocking and greater geopotential thickness related to low-level temperatures increases led to northerly meridional flow into eastern North America, inducing persistent cold periods. Arctic connections in Europe and western North America are less clear. The quantitative impact of potential Arctic change on mid-latitude weather will not be resolved within the foreseeable future, yet new approaches to high-latitude atmospheric dynamics can contribute to improved extended range forecasts as outlined by the WMO/Polar Prediction Program and other international activities.

  12. Is recent Eurasian winter cooling caused by Arctic sea ice loss?

    NASA Astrophysics Data System (ADS)

    Kim, Hye-Jin; Son, Seok-Woo; Kim, Kwang-Yul; Kug, Jong-Seong; Kim, Baek-Min; Jeong, Jee-Hoon

    2016-04-01

    The observed surface air temperature in the northern mid-latitudes shows a significant cooling trend in recent winters despite greenhouse gas concentrations continuing to rise. Such an unexpected cooling trend since late 1990's is especially strong over the Eurasia. Here, by performing statistical analyses and climate model experiment, we show that the recent Eurasian cooling trend is at least in part caused by Arctic sea ice loss over the Barents and Kara (BK) seas. A significant time-lagged co-variability is observed between autumn sea ice concentrations over BK seas and winter surface air temperature over the Eurasia. More importantly, the timing of a rapid sea ice loss is consistent with the timing of Eurasian cooling. These results indicate that both interannual variability and long-term trend of Eurasian winter surface air temperature are likely influenced by regional sea ice changes over BK seas. This conjecture is confirmed by climate model experiment. A coupled model, GFDL CM2.1, is integrated with a pre-industrial condition except for the Arctic regions where observed sea surface temperature is relaxed. Ensemble simulations successfully reproduce the recent cooling trend over the Eurasia although the timing is bit delayed (i.e., early 2000's instead of late 1990's). However, it is found that this cooling trend is unlikely explained by linear dynamics, and is not associated with changes in atmospheric blocks.

  13. Weakening of the stratospheric polar vortex by Arctic sea-ice loss.

    PubMed

    Kim, Baek-Min; Son, Seok-Woo; Min, Seung-Ki; Jeong, Jee-Hoon; Kim, Seong-Joong; Zhang, Xiangdong; Shim, Taehyoun; Yoon, Jin-Ho

    2014-09-02

    Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea-ice, the mechanism that links sea-ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea-ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea-ice cover during early winter months (November-December), especially over the Barents-Kara seas, enhances the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January-February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes.

  14. Relationship between early autumn Arctic sea ice and East Asian wintertime transient eddy activity

    NASA Astrophysics Data System (ADS)

    Gu, Sen; Zhang, Yang; Wu, Qigang

    2015-04-01

    The Arctic sea ice is suggested with wide impacts on the winter climate over East Asia. In this study, the relationship between the early autumn Arctic sea ice and the wintertime transient eddy activity over East Asia is investigated. Our singular value decomposition (SVD) analysis between the Arctic sea ice concentration (SIC) and transient eddy kinetic energy (EKE) shows that with the decrease in SIC over the Siberia coast, Kara sea and Barents sea, the EKE around the Tibetan Plateau and the downstream regions increase significantly. This leading mode indicates that more than 60% variance of the wintertime East Asian transient eddy activity can be predicted from the SIC three month earlier. Possible dynamical processes responsible for the linkage between SIC and EKE are investigated. In the upstream of Tibetan Plateau, a branch of anomalous wave train is detected propagating southward from Ural Mountains to the North China and Tibet. In the downstream region of Tibetan Plateau, with the decrease in SIC, anomalous increase in synoptic eddy generation is found with the enhanced baroclinicity over the north slope of the Tibetan Plateau, which can result in the increase in EKE as well. Those two dynamical processes both act to enhance the transient eddy activity over East Asia.

  15. Climate change impacts on sea-air fluxes of CO2 in three Arctic seas: a sensitivity study using Earth observation

    NASA Astrophysics Data System (ADS)

    Land, P. E.; Shutler, J. D.; Cowling, R. D.; Woolf, D. K.; Walker, P.; Findlay, H. S.; Upstill-Goddard, R. C.; Donlon, C. J.

    2013-12-01

    We applied coincident Earth observation data collected during 2008 and 2009 from multiple sensors (RA2, AATSR and MERIS, mounted on the European Space Agency satellite Envisat) to characterise environmental conditions and integrated sea-air fluxes of CO2 in three Arctic seas (Greenland, Barents, Kara). We assessed net CO2 sink sensitivity due to changes in temperature, salinity and sea ice duration arising from future climate scenarios. During the study period the Greenland and Barents seas were net sinks for atmospheric CO2, with integrated sea-air fluxes of -36 ± 14 and -11 ± 5 Tg C yr-1, respectively, and the Kara Sea was a weak net CO2 source with an integrated sea-air flux of +2.2 ± 1.4 Tg C yr-1. The combined integrated CO2 sea-air flux from all three was -45 ± 18 Tg C yr-1. In a sensitivity analysis we varied temperature, salinity and sea ice duration. Variations in temperature and salinity led to modification of the transfer velocity, solubility and partial pressure of CO2 taking into account the resultant variations in alkalinity and dissolved organic carbon (DOC). Our results showed that warming had a strong positive effect on the annual integrated sea-air flux of CO2 (i.e. reducing the sink), freshening had a strong negative effect and reduced sea ice duration had a small but measurable positive effect. In the climate change scenario examined, the effects of warming in just over a decade of climate change up to 2020 outweighed the combined effects of freshening and reduced sea ice duration. Collectively these effects gave an integrated sea-air flux change of +4.0 Tg C in the Greenland Sea, +6.0 Tg C in the Barents Sea and +1.7 Tg C in the Kara Sea, reducing the Greenland and Barents sinks by 11% and 53%, respectively, and increasing the weak Kara Sea source by 81%. Overall, the regional integrated flux changed by +11.7 Tg C, which is a 26% reduction in the regional sink. In terms of CO2 sink strength, we conclude that the Barents Sea is the most

  16. Diagnostic sea ice predictability in the pan-Arctic and U.S. Arctic regional seas

    NASA Astrophysics Data System (ADS)

    Cheng, Wei; Blanchard-Wrigglesworth, Edward; Bitz, Cecilia M.; Ladd, Carol; Stabeno, Phyllis J.

    2016-11-01

    This study assesses sea ice predictability in the pan-Arctic and U.S. Arctic regional (Bering, Chukchi, and Beaufort) seas with a purpose of understanding regional differences from the pan-Arctic perspective and how predictability might change under changing climate. Lagged correlation is derived using existing output from the Community Earth System Model Large Ensemble (CESM-LE), Pan-Arctic Ice-Ocean Modeling and Assimilation System, and NOAA Coupled Forecast System Reanalysis models. While qualitatively similar, quantitative differences exist in Arctic ice area lagged correlation in models with or without data assimilation. On regional scales, modeled ice area lagged correlations are strongly location and season dependent. A robust feature in the CESM-LE is that the pan-Arctic melt-to-freeze season ice area memory intensifies, whereas the freeze-to-melt season memory weakens as climate warms, but there are across-region variations in the sea ice predictability changes with changing climate.

  17. Hypsometry and volume of the Arctic Ocean and its constituent seas

    NASA Astrophysics Data System (ADS)

    Jakobsson, Martin

    2002-05-01

    This paper presents an analysis of the Arctic Ocean and its constituent seas for seafloor area distribution versus depth and ocean volume. The bathymetry from the International Bathymetric Chart of the Arctic Ocean (IBCAO) is used together with limits defining this ocean and its constituent seas from the International Hydrographic Organization (IHO) as well as redefined limits constructed to confine the seas to the shallow shelves. IBCAO is a bathymetric grid model with a resolution of 2.5 × 2.5 km, which significantly improved the portrayal of the Arctic Ocean seafloor through incorporation of newly released bathymetric data including echo soundings from U.S. and British navies, scientific nuclear submarine cruises, and icebreaker cruises. This analysis of seafloor area and ocean volume is the first for the Arctic Ocean based on this new and improved portrayal of the seafloor as represented by IBCAO. The seafloor area and volume are calculated for different depths starting from the present sea level and progressing in increments of 10 m to a depth of 500 m and in increments of 50 m from 550 m down to the deepest depth within each of the analyzed seas. Hypsometric curves expressed as simple histograms of the frequencies in different depth bins and depth plotted against cumulative area for each of the analyzed seas are presented. The area and volume calculations show that the entire IHO-defined Arctic Ocean makes up ~4.3% of the total ocean area but only ~1.4% of the volume. Furthermore, the IHO Arctic Ocean is the shallowest (mean depth 1201 m) of all the major oceans and their adjacent seas. The continental shelf area, from the coasts out to the shelf break, make up as much as ~52.9% of the total area in the Arctic Ocean, defined in this work as consisting of the oceanic deep Arctic Ocean Basin; the broad continental shelves of the Barents, Kara, Laptev, East Siberian, Chukchi, and Beaufort Seas; the White Sea; and the narrow continental shelf off both the

  18. On the mechanism of wind-induced transformation of a river runoff water lens in the Kara Sea

    NASA Astrophysics Data System (ADS)

    Zatsepin, A. G.; Zavialov, P. O.; Baranov, V. I.; Kremenetskiy, V. V.; Nedospasov, A. A.; Poyarkov, S. G.; Ocherednik, V. V.

    2017-01-01

    The paper describes a possible mechanism for the transformation of a desalinated water lens in the Kara Sea under the action of vertical turbulent mixing induced by wind. Using a simple one-dimensional model, we show that the strongest transformation occurs at the edge of the lens—its frontal zone, where the thickness of the desalinated layer is the smallest. Because of the strong (cubic) nonlinear dependence of the turbulent energy flux on the wind speed, significant transformation of the frontal zone of the lens occurs during storm events. A series of consecutive storms can cause horizontal lens fragmentation into several zones in which the salinity increases spasmodically towards the edge of the lens.

  19. Arctic and Antarctic sea ice and climate

    NASA Astrophysics Data System (ADS)

    Barreira, S.

    2014-12-01

    Principal Components Analysis in T-Mode Varimax rotated was performed on Antarctic and Arctic monthly sea ice concentration anomalies (SICA) fields for the period 1979-2014, in order to investigate which are the main spatial characteristics of sea ice and its relationship with atmospheric circulation. This analysis provides 5 patterns of sea ice for inter-spring period and 3 patterns for summer-autumn for Antarctica (69,2% of the total variance) and 3 different patterns for summer-autumn and 3 for winter-spring season for the Arctic Ocean (67,8% of the total variance).Each of these patterns has a positive and negative phase. We used the Monthly Polar Gridded Sea Ice Concentrations database derived from satellite information generated by NASA Team algorithm. To understand the links between the SICA and climate trends, we extracted the mean pressure and, temperature field patterns for the months with high loadings (positive or negative) of the sea ice patterns that gave distinct atmospheric structures associated with each one. For Antarctica, the first SICA spatial winter-spring pattern in positive phase shows a negative SICA centre over the Drake Passage and north region of Bellingshausen and Weddell Seas together with another negative SICA centre over the East Indian Ocean. Strong positive centres over the rest of the Atlantic and Indian Oceans basins and the Amundsen Sea are also presented. A strong negative pressure anomaly covers most of the Antarctic Continent centered over the Bellingshausen Sea accompanied by three positive pressure anomalies in middle-latitudes. During recent years, the Arctic showed persistent associations of sea-ice and climate patterns principally during summer. Our strongest summer-autumn pattern in negative phase showed a marked reduction on SICA over western Arctic, primarily linked to an overall increase in Arctic atmospheric temperature most pronounced over the Beaufort, Chukchi and East Siberian Seas, and a positive anomaly of

  20. Early 2016 Winter Storm Melts Arctic Sea Ice

    NASA Image and Video Library

    Arctic sea ice grows during the winter months, reaching its largest extent sometime in March. When something disrupts the cold, dry, winter Arctic atmosphere, sea ice can feel the effects, and thes...

  1. Variability and Trends in the Arctic Sea Ice Cover: Results from Different Techniques

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.; Meier, Walter N.; Gersten, Robert

    2017-01-01

    Variability and trend studies of sea ice in the Arctic have been conducted using products derived from the same raw passive microwave data but by different groups using different algorithms. This study provides consistency assessment of four of the leading products, namely, Goddard Bootstrap (SB2), Goddard NASA Team (NT1), EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI-SAF 1.2), and Hadley HadISST 2.2 data in evaluating variability and trends in the Arctic sea ice cover. All four provide generally similar ice patterns but significant disagreements in ice concentration distributions especially in the marginal ice zone and adjacent regions in winter and meltponded areas in summer. The discrepancies are primarily due to different ways the four techniques account for occurrences of new ice and meltponding. However, results show that the different products generally provide consistent and similar representation of the state of the Arctic sea ice cover. Hadley and NT1 data usually provide the highest and lowest monthly ice extents, respectively. The Hadley data also show the lowest trends in ice extent and ice area at negative 3.88 percent decade and negative 4.37 percent decade, respectively, compared to an average of negative 4.36 percent decade and negative 4.57 percent decade for all four. Trend maps also show similar spatial distribution for all four with the largest negative trends occurring at the Kara/Barents Sea and Beaufort Sea regions, where sea ice has been retreating the fastest. The good agreement of the trends especially with updated data provides strong confidence in the quantification of the rate of decline in the Arctic sea ice cover.

  2. A 21-Year Record of Arctic Sea Ice Extents and Their Regional, Seasonal, and Monthly Variability and Trends

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.; Cavalieri, Donald J.; Zukor, Dorothy J. (Technical Monitor)

    2001-01-01

    Satellite passive-microwave data have been used to calculate sea ice extents over the period 1979-1999 for the north polar sea ice cover as a whole and for each of nine regions. Over this 21-year time period, the trend in yearly average ice extents for the ice cover as a whole is -32,900 +/- 6,100 sq km/yr (-2.7 +/- 0.5 %/decade), indicating a reduction in sea ice coverage that has decelerated from the earlier reported value of -34,000 +/- 8,300 sq km/yr (-2.8 +/- 0.7 %/decade) for the period 1979-1996. Regionally, the reductions are greatest in the Arctic Ocean, the Kara and Barents Seas, and the Seas of Okhotsk and Japan, whereas seasonally, the reductions are greatest in summer, for which season the 1979-1999 trend in ice extents is -41,600 +/- 12,900 sq km/ yr (-4.9 +/- 1.5 %/decade). On a monthly basis, the reductions are greatest in July and September for the north polar ice cover as a whole, in September for the Arctic Ocean, in June and July for the Kara and Barents Seas, and in April for the Seas of Okhotsk and Japan. Only two of the nine regions show overall ice extent increases, those being the Bering Sea and the Gulf of St. Lawrence.For neither of these two regions is the increase statistically significant, whereas the 1079 - 1999 ice extent decreases are statistically significant at the 99% confidence level for the north polar region as a whole, the Arctic Ocean, the Seas of Okhotsk and Japan, and Hudson Bay.

  3. Changes in the Areal Extent of Arctic Sea Ice: Observations from Satellites

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.

    2000-01-01

    Wintertime sea ice covers 15 million square kilometers of the north polar region, an area exceeding one and a half times the area of the U. S. Even at the end of the summer melt season, sea ice still covers 7 million square kilometers. This vast ice cover is an integral component of the climate system, being moved around by winds and waves, restricting heat and other exchanges between the ocean and atmosphere, reflecting most of the solar radiation incident on it, transporting cold, relatively fresh water equatorward, and affecting the overturning of ocean waters underneath, with impacts that can be felt worldwide. Sea ice also is a major factor in the Arctic ecosystem, affecting life forms ranging from minute organisms living within the ice, sometimes to the tune of millions in a single ice floe, to large marine mammals like walruses that rely on sea ice as a platform for resting, foraging, social interaction, and breeding. Since 1978, satellite technology has allowed the monitoring of the vast Arctic sea ice cover on a routine basis. The satellite observations reveal that, overall, the areal extent of Arctic sea ice has been decreasing since 1978, at an average rate of 2.7% per decade through the end of 1998. Through 1998, the greatest rates of decrease occurred in the Seas of Okhotsk and Japan and the Kara and Barents Seas, with most other regions of the Arctic also experiencing ice extent decreases. The two regions experiencing ice extent increases over this time period were the Bering Sea and the Gulf of St. Lawrence. Furthermore, the satellite data reveal that the sea ice season shortened by over 25 days per decade in the central Sea of Okhotsk and the eastern Barents Sea, and by lesser amounts throughout much of the rest of the Arctic seasonal sea ice region, although not in the Bering Sea or the Gulf of St. Lawrence. Concern has been raised that if the trends toward shortened sea ice seasons and lesser sea ice coverage continue, this could entail major

  4. Changes in the Areal Extent of Arctic Sea Ice: Observations from Satellites

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.

    2000-01-01

    Wintertime sea ice covers 15 million square kilometers of the north polar region, an area exceeding one and a half times the area of the U. S. Even at the end of the summer melt season, sea ice still covers 7 million square kilometers. This vast ice cover is an integral component of the climate system, being moved around by winds and waves, restricting heat and other exchanges between the ocean and atmosphere, reflecting most of the solar radiation incident on it, transporting cold, relatively fresh water equatorward, and affecting the overturning of ocean waters underneath, with impacts that can be felt worldwide. Sea ice also is a major factor in the Arctic ecosystem, affecting life forms ranging from minute organisms living within the ice, sometimes to the tune of millions in a single ice floe, to large marine mammals like walruses that rely on sea ice as a platform for resting, foraging, social interaction, and breeding. Since 1978, satellite technology has allowed the monitoring of the vast Arctic sea ice cover on a routine basis. The satellite observations reveal that, overall, the areal extent of Arctic sea ice has been decreasing since 1978, at an average rate of 2.7% per decade through the end of 1998. Through 1998, the greatest rates of decrease occurred in the Seas of Okhotsk and Japan and the Kara and Barents Seas, with most other regions of the Arctic also experiencing ice extent decreases. The two regions experiencing ice extent increases over this time period were the Bering Sea and the Gulf of St. Lawrence. Furthermore, the satellite data reveal that the sea ice season shortened by over 25 days per decade in the central Sea of Okhotsk and the eastern Barents Sea, and by lesser amounts throughout much of the rest of the Arctic seasonal sea ice region, although not in the Bering Sea or the Gulf of St. Lawrence. Concern has been raised that if the trends toward shortened sea ice seasons and lesser sea ice coverage continue, this could entail major

  5. Massive phytoplankton blooms under Arctic sea ice.

    PubMed

    Arrigo, Kevin R; Perovich, Donald K; Pickart, Robert S; Brown, Zachary W; van Dijken, Gert L; Lowry, Kate E; Mills, Matthew M; Palmer, Molly A; Balch, William M; Bahr, Frank; Bates, Nicholas R; Benitez-Nelson, Claudia; Bowler, Bruce; Brownlee, Emily; Ehn, Jens K; Frey, Karen E; Garley, Rebecca; Laney, Samuel R; Lubelczyk, Laura; Mathis, Jeremy; Matsuoka, Atsushi; Mitchell, B Greg; Moore, G W K; Ortega-Retuerta, Eva; Pal, Sharmila; Polashenski, Chris M; Reynolds, Rick A; Schieber, Brian; Sosik, Heidi M; Stephens, Michael; Swift, James H

    2012-06-15

    Phytoplankton blooms over Arctic Ocean continental shelves are thought to be restricted to waters free of sea ice. Here, we document a massive phytoplankton bloom beneath fully consolidated pack ice far from the ice edge in the Chukchi Sea, where light transmission has increased in recent decades because of thinning ice cover and proliferation of melt ponds. The bloom was characterized by high diatom biomass and rates of growth and primary production. Evidence suggests that under-ice phytoplankton blooms may be more widespread over nutrient-rich Arctic continental shelves and that satellite-based estimates of annual primary production in these waters may be underestimated by up to 10-fold.

  6. Warm Rivers Play Role in Arctic Sea Ice Melt Animation

    NASA Image and Video Library

    2014-03-05

    This frame from a NASA MODIS animation depicts warming sea surface temperatures in the Arctic Beaufort Sea after warm waters from Canada Mackenzie River broke through a shoreline sea ice barrier in summer 2012, enhancing the melting of sea ice.

  7. Box model of radionuclide dispersion and radiation risk estimation for population in case of radioactivity release from nuclear submarine {number_sign}601 dumped in the Kara Sea

    SciTech Connect

    Yefimov, E.I.; Pankratov, D.V.; Ignatiev, S.V.

    1997-12-31

    When ships with nuclear reactors or nuclear materials aboard suffer shipwreck or in the case of burial or dumping of radioactive wastes, atmospheric fallout, etc., radionuclides may be released and spread in the sea, contaminating the sea water and the sea bottom. When a nuclear submarine (NS) is dumped this spread of activity may occur due to gradual core destruction by corrosion over many years. The objective of this paper is to develop a mathematical model of radionuclide dispersion and to assess the population dose and radiation risk for radionuclide release from the NS No. 601, with Pb-Bi coolant that was dumped in the Kara Sea.

  8. The impact of poleward moisture and sensible heat flux on Arctic winter sea-ice variability.

    NASA Astrophysics Data System (ADS)

    Park, H. S.; Lee, S.; Son, S. W.; Feldstein, S. B.; Kosaka, Y.

    2015-12-01

    The surface warming in recent decades has been most rapid in the Arctic, especially during the winter. Here, by utilizing global reanalysis and satellite datasets, we show that the northward flux of moisture into the Arctic during the winter strengthens the downward infrared radiation (IR) by 30-40 W m-2 over 1-2 weeks. This is followed by a decline of up to 10% in sea ice concentration over the Greenland, Barents and Kara Seas. A climate model simulation indicates that the wind-induced sea-ice drift leads the decline of sea-ice thickness during the early stage of the strong downward IR events, but that within one week the cumulative downward IR effect appears to be dominant. Further analysis indicates that strong downward IR events are preceded several days earlier by enhanced convection over the tropical Indian-western Pacific Ocean. This finding suggests that sea-ice predictions can benefit from an improved understanding of tropical convection and ensuing planetary wave dynamics.

  9. Interaction of oil with arctic sea ice

    SciTech Connect

    Thomas, D.R.

    1983-02-01

    The purpose of the paper is to summarize relavant knowledge about the interactions between arctic sea ice and oil. The completion of further experimental oil spill studies, along with recent laboratory studies of the interaction of oil and sea ice and studies of environmental conditions, makes an updating of those works desirable. An attempt is made to identify the major factors in the interaction between oil and arctic sea ice and to present them in a way that defines the scope of the problem. Generally, the paper is restricted to factors that can be expected to play a major role in the sequence of events following a large under-ice blowout in the Beaufort Sea during winter.

  10. Regional variability of acidification in the Arctic: a sea of contrasts

    NASA Astrophysics Data System (ADS)

    Popova, E. E.; Yool, A.; Aksenov, Y.; Coward, A. C.; Anderson, T. R.

    2014-01-01

    The Arctic Ocean is a region that is particularly vulnerable to the impact of ocean acidification driven by rising atmospheric CO2, with potentially negative consequences for calcifying organisms such as coccolithophorids and foraminiferans. In this study, we use an ocean-only general circulation model, with embedded biogeochemistry and a comprehensive description of the ocean carbon cycle, to study the response of pH and saturation states of calcite and aragonite to rising atmospheric pCO2 and changing climate in the Arctic Ocean. Particular attention is paid to the strong regional variability within the Arctic, and, for comparison, simulation results are contrasted with those for the global ocean. Simulations were run to year 2099 using the RCP8.5 (an Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) scenario with the highest concentrations of atmospheric CO2). The separate impacts of the direct increase in atmospheric CO2 and indirect effects via impact of climate change (changing temperature, stratification, primary production and freshwater fluxes) were examined by undertaking two simulations, one with the full system and the other in which atmospheric CO2 was prevented from increasing beyond its preindustrial level (year 1860). Results indicate that the impact of climate change, and spatial heterogeneity thereof, plays a strong role in the declines in pH and carbonate saturation (Ω) seen in the Arctic. The central Arctic, Canadian Arctic Archipelago and Baffin Bay show greatest rates of acidification and Ω decline as a result of melting sea ice. In contrast, areas affected by Atlantic inflow including the Greenland Sea and outer shelves of the Barents, Kara and Laptev seas, had minimal decreases in pH and Ω because diminishing ice cover led to greater vertical mixing and primary production. As a consequence, the projected onset of undersaturation in respect to aragonite is highly variable regionally within the Arctic, occurring

  11. The footprints of 16 year trends of Arctic springtime cloud and radiation properties on September sea ice retreat

    NASA Astrophysics Data System (ADS)

    Huang, Yiyi; Dong, Xiquan; Xi, Baike; Dolinar, Erica K.; Stanfield, Ryan E.

    2017-02-01

    The most prominent September Arctic sea ice decline over the period of 2000-2015 occurs over the Siberian Sea, Laptev Sea, and Kara Sea. The satellite observed and retrieved sea ice concentration (SIC) and cloud/radiation properties over the Arctic (70°-90°N) have been used to investigate the impact of springtime cloud and radiation properties on September SIC variation. Positive trends of cloud fractions, cloud water paths, and surface downward longwave flux at the surface over the September sea ice retreat areas are found over the period of 1 March to 14 May, while negative trends are found over the period of 15 May to 28 June. The spatial distributions of correlations between springtime cloud/radiation properties and September SIC have been calculated, indicating that increasing cloud fractions and downward longwave flux during springtime tend to enhance sea ice melting due to strong cloud warming effect. Surface downward and upward shortwave fluxes play an important role from May to June when the onset of sea ice melting occurs. The comparison between linearly detrended and nondetrended of each parameter indicates that significant impact of cloud and radiation properties on September sea ice retreat occurs over the Chukchi/Beaufort Sea at interannual time scale, especially over the period of 31 March to 29 April, while strongest climatological trends are found over the Laptev/Siberian Sea.

  12. Fluorescence of dissolved organic matter as a marker for distribution of desalinated waters in the Kara Sea and bays of Novaya Zemlya archipelago

    NASA Astrophysics Data System (ADS)

    Drozdova, A. N.; Patsaeva, S. V.; Khundzhua, D. A.

    2017-01-01

    The optical properties and distribution of dissolved organic matter in the surface waters of the Kara Sea and bays of Novaya Zemlya archipelago were studied during the 63th cruise of the R/V Akademik Mstislav Keldysh. The fluorescence of dissolved organic matter has been studied over wide excitation (230-550 nm) and emission (240-650 nm) wavelength ranges. Based on the results of fluorescence measurements, we propose a simple technique for estimating the relative content of humic compounds entering the Kara Sea shelf region with Ob and Yenisei river runoff. We have found that the blue shift parameters of the DOM fluorescence are Δ270-310 = 28 ± 2 nm and Δ355-310 = 29 ± 2 nm. The highest contents of humic compounds in surface waters were measured on the transect across the desalinated layer of the Kara Sea, near the continental slope on the transect along the St. Anna Trough, and in the area of Sedova, Oga and Tsivol'ki bays. Traces of labile terrigenous organic matter were found in the region of the Voronin Trough, in the bays of the Severny Island of Novaya Zemlya, as well as in some freshwater reservoirs and ice samples of the archipelago. We established a conservative distribution of dissolved organic matter, whose content in water varied from 1.25 to 8.55 mg/L.

  13. Virio- and bacterioplankton in the estuary zone of the Ob River and adjacent regions of the Kara Sea shelf

    NASA Astrophysics Data System (ADS)

    Kopylov, A. I.; Sazhin, A. F.; Zabotkina, E. A.; Romanenko, A. V.; Romanova, N. D.

    2017-01-01

    The distribution of structural and functional characteristics of virioplankton in the north of the Ob River estuary and the adjacent Kara Sea shelf (between latitudes 71°44'44″ N and 73°45'24″ N) was studied with consideration of the spatial variations in the number ( N B) and productivity ( P B) of bacteria and water properties (temperature, salinity, density) by analyzing samples taken in September 2013. The number of plankton viruses ( N V), the occurrence of visible infected bacteria cells, virus-induced mortality of bacteria, and virioplankton production in the studied region varied within (214-2917) × 103 particles/mL, 0.3-5.6% of NB, 2.2-64.4% of P B, and (6-17248) × 103 particles/(mL day), respectively. These parameters were the highest in water layers with a temperature of +7.3-7.5°C, salinity of 3.75-5.41 psu, and conventional density (στ) of 2.846-4.144. The number of bacterioplankton was (614-822) × 103 cells/mL, and the N V/ N B ratio was 1.1-4.5. A large amount of virus particles were attached to bacterial cells and suspended matter. The data testify to the considerable role of viruses in controlling the number and production of heterotrophic bacterioplankton in the interaction zone of river and sea waters.

  14. Duration of the Arctic sea ice melt season: Regional and interannual variability, 1979-2001

    USGS Publications Warehouse

    Belchansky, G.I.; Douglas, D.C.; Platonov, N.G.

    2004-01-01

    Melt onset dates, freeze onset dates, and melt season duration were estimated over Arctic sea ice, 1979–2001, using passive microwave satellite imagery and surface air temperature data. Sea ice melt duration for the entire Northern Hemisphere varied from a 104-day minimum in 1983 and 1996 to a 124-day maximum in 1989. Ranges in melt duration were highest in peripheral seas, numbering 32, 42, 44, and 51 days in the Laptev, Barents-Kara, East Siberian, and Chukchi Seas, respectively. In the Arctic Ocean, average melt duration varied from a 75-day minimum in 1987 to a 103-day maximum in 1989. On average, melt onset in annual ice began 10.6 days earlier than perennial ice, and freeze onset in perennial ice commenced 18.4 days earlier than annual ice. Average annual melt dates, freeze dates, and melt durations in annual ice were significantly correlated with seasonal strength of the Arctic Oscillation (AO). Following high-index AO winters (January–March), spring melt tended to be earlier and autumn freeze later, leading to longer melt season durations. The largest increases in melt duration were observed in the eastern Siberian Arctic, coincident with cyclonic low pressure and ice motion anomalies associated with high-index AO phases. Following a positive AO shift in 1989, mean annual melt duration increased 2–3 weeks in the northern East Siberian and Chukchi Seas. Decreasing correlations between consecutive-year maps of melt onset in annual ice during 1979–2001 indicated increasing spatial variability and unpredictability in melt distributions from one year to the next. Despite recent declines in the winter AO index, recent melt distributions did not show evidence of reestablishing spatial patterns similar to those observed during the 1979–88 low-index AO period. Recent freeze distributions have become increasingly similar to those observed during 1979–88, suggesting a recurrent spatial pattern of freeze chronology under low-index AO conditions.

  15. Arctic geodynamics: Arctic science and ERS-1 satellite altimetry

    NASA Technical Reports Server (NTRS)

    Anderson, Allen Joel; Sandwell, David T.

    1994-01-01

    A detailed gravity field map of the mid Arctic Ocean, spreading ridge system was produced on the basis of ERS-1 satellite altimetry data. Areas of special concern, the Barents and Kara Seas, and areas surrounding the islands of Svalbard, Frans Josef Land and Novoya Zemlya are reviewed. ERS-1 altimetry covers unique Arctic and Antarctic latitudes above 72 degrees. Before ERS-1 it was not possible to study these areas with satellite altimetry. Gravity field solutions for the Barents Sea, portions of the Arctic Ocean and the Norwegian sea are shown. The largest gravity anomalies occur along the Greenland fracture zone as well as along transform faults near Svalbard.

  16. Arctic geodynamics: Arctic science and ERS-1 satellite altimetry

    NASA Technical Reports Server (NTRS)

    Anderson, Allen Joel; Sandwell, David T.

    1994-01-01

    A detailed gravity field map of the mid Arctic Ocean, spreading ridge system was produced on the basis of ERS-1 satellite altimetry data. Areas of special concern, the Barents and Kara Seas, and areas surrounding the islands of Svalbard, Frans Josef Land and Novoya Zemlya are reviewed. ERS-1 altimetry covers unique Arctic and Antarctic latitudes above 72 degrees. Before ERS-1 it was not possible to study these areas with satellite altimetry. Gravity field solutions for the Barents Sea, portions of the Arctic Ocean and the Norwegian sea are shown. The largest gravity anomalies occur along the Greenland fracture zone as well as along transform faults near Svalbard.

  17. Radiocarbon content of pre-bomb marine mollusks and variations in the 14C Reservoir age for coastal areas of the Barents and Kara Seas, Russia

    NASA Astrophysics Data System (ADS)

    Forman, Steven L.; Polyak, Leonid

    Fourteen mollusks, collected alive between 1900 and 1945 from the Russian Barents and Kara seas, were analyzed by AMS 14C dating to evaluate variations in the 14C marine reservoir for arctic coastal sites, which is important for correcting ages in paleoenvironmental time-series and advancing understanding of the exchange of carbon. The 14C ages on the mollusks reveal a range of marine reservoir values (R(t)) from 159 14C yr to 764 14C yr. The oldest R(t) values of 764 to 620 14C yr are for the bivalve Portlandia arctica, which often inhabit cold and low salinity waters and muddy substrates. The depleted 14C content for this bivalve reflects possibly the incorporation of old carbon from freshwater inputs and/or the consumption of old organic matter from the underlying sediments and pore waters. Other mollusks with sessile habitats and pelagic food sources gave significantly lower R(t) values between 159 and 344 14C yr. The youngest R(t) values indicate enrichment in 14C and may partially reflect enhanced transfer of 14C-enriched CO2 from the atmosphere to the ocean surface with wind-generated wave agitation. This study underscores that a variety of processes can lead to variable 14C depletion and enrichment of surface waters yielding a ca. 600 year age span for contemporaneous arctic mollusks. There may be added uncertainty in the 14C reservoir correction for deposit-feeder species such as Portlandia sp. and perhaps for certain benthic foraminifera (e.g. Nonion labradoricum) because these taxa often incorporate old organic matter from the substrate. A reservoir correction of ≥700 years may be more appropriate for infaunal, deposit-eater species, particularly in glacier-dominated environments. Mollusks and foraminifera with sessile habits and pelagic food sources should be selected preferentially for 14C dating, because their shells may more closely reflect the 14C content of the global-ocean mixed layer.

  18. Radionuclides in the Arctic seas from the former Soviet Union: Potential health and ecological risks

    SciTech Connect

    Layton, D W; Edson, R; Varela, M; Napier, B

    1999-11-15

    The primary goal of the assessment reported here is to evaluate the health and environmental threat to coastal Alaska posed by radioactive-waste dumping in the Arctic and Northwest Pacific Oceans by the FSU. In particular, the FSU discarded 16 nuclear reactors from submarines and an icebreaker in the Kara Sea near the island of Novaya Zemlya, of which 6 contained spent nuclear fuel (SNF); disposed of liquid and solid wastes in the Sea of Japan; lost a {sup 90}Sr-powered radioisotope thermoelectric generator at sea in the Sea of Okhotsk; and disposed of liquid wastes at several sites in the Pacific Ocean, east of the Kamchatka Peninsula. In addition to these known sources in the oceans, the RAIG evaluated FSU waste-disposal practices at inland weapons-development sites that have contaminated major rivers flowing into the Arctic Ocean. The RAIG evaluated these sources for the potential for release to the environment, transport, and impact to Alaskan ecosystems and peoples through a variety of scenarios, including a worst-case total instantaneous and simultaneous release of the sources under investigation. The risk-assessment process described in this report is applicable to and can be used by other circumpolar countries, with the addition of information about specific ecosystems and human life-styles. They can use the ANWAP risk-assessment framework and approach used by ONR to establish potential doses for Alaska, but add their own specific data sets about human and ecological factors. The ANWAP risk assessment addresses the following Russian wastes, media, and receptors: dumped nuclear submarines and icebreaker in Kara Sea--marine pathways; solid reactor parts in Sea of Japan and Pacific Ocean--marine pathways; thermoelectric generator in Sea of Okhotsk--marine pathways; current known aqueous wastes in Mayak reservoirs and Asanov Marshes--riverine to marine pathways; and Alaska as receptor. For these waste and source terms addressed, other pathways, such as

  19. Sea Ice, Hydrocarbon Extraction, Rain-on-Snow and Tundra Reindeer Nomadism in Arctic Russia

    NASA Astrophysics Data System (ADS)

    Forbes, B. C.; Kumpula, T.; Meschtyb, N.; Laptander, R.; Macias-Fauria, M.; Zetterberg, P.; Verdonen, M.

    2015-12-01

    It is assumed that retreating sea ice in the Eurasian Arctic will accelerate hydrocarbon development and associated tanker traffic along Russia's Northern Sea Route. However, oil and gas extraction along the Kara and Barents Sea coasts will likely keep developing rapidly regardless of whether the Northwest Eurasian climate continues to warm. Less certain are the real and potential linkages to regional biota and social-ecological systems. Reindeer nomadism continues to be a vitally important livelihood for indigenous tundra Nenets and their large herds of semi-domestic reindeer. Warming summer air temperatures over the NW Russian Arctic have been linked to increases in tundra productivity, longer growing seasons, and accelerated growth of tall deciduous shrubs. These temperature increases have, in turn, been linked to more frequent and sustained summer high-pressure systems over West Siberia, but not to sea ice retreat. At the same time, winters have been warming and rain-on-snow (ROS) events have become more frequent and intense, leading to record-breaking winter and spring mortality of reindeer. What is driving this increase in ROS frequency and intensity is not clear. Recent modelling and simulation have found statistically significant near-surface atmospheric warming and precipitation increases during autumn and winter over Arctic coastal lands in proximity to regions of sea-ice loss. During the winter of 2013-14 an extensive and lasting ROS event led to the starvation of 61,000 reindeer out of a population of ca. 300,000 animals on Yamal Peninsula, West Siberia. Historically, this is the region's largest recorded mortality episode. More than a year later, participatory fieldwork with nomadic herders during spring-summer 2015 revealed that the ecological and socio-economic impacts from this extreme event will unfold for years to come. There is an urgent need to understand whether and how ongoing Barents and Kara Sea ice retreat may affect the region's ancient

  20. Changes in Arctic Melt Season and Implications for Sea Ice Loss

    NASA Technical Reports Server (NTRS)

    Stroeve, J. C.; Markus, T.; Boisvert, L.; Miller, J.; Barrett, A.

    2014-01-01

    The Arctic-wide melt season has lengthened at a rate of 5 days dec-1 from 1979 to 2013, dominated by later autumn freeze-up within the Kara, Laptev, East Siberian, Chukchi and Beaufort seas between 6 and 11 days dec(exp -1). While melt onset trends are generally smaller, the timing of melt onset has a large influence on the total amount of solar energy absorbed during summer. The additional heat stored in the upper ocean of approximately 752MJ m(exp -2) during the last decade, increases sea surface temperatures by 0.5 to 1.5 C and largely explains the observed delays in autumn freeze-up within the Arctic Ocean's adjacent seas. Cumulative anomalies in total absorbed solar radiation from May through September for the most recent pentad locally exceed 300-400 MJ m(exp -2) in the Beaufort, Chukchi and East Siberian seas. This extra solar energy is equivalent to melting 0.97 to 1.3 m of ice during the summer.

  1. Record Arctic Sea Ice Loss in 2007

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This image of the Arctic was produced from sea ice observations collected by the Advanced Microwave Scanning Radiometer (AMSR-E) Instrument on NASA's Aqua satellite on September 16, overlaid on the NASA Blue Marble. The image captures ice conditions at the end of the melt season. Sea ice (white, image center) stretches across the Arctic Ocean from Greenland to Russia, but large areas of open water were apparent as well. In addition to record melt, the summer of 2007 brought an ice-free opening though the Northwest Passage that lasted several weeks. The Northeast Passage did not open during the summer of 2007, however, as a substantial tongue of ice remained in place north of the Russian coast. According to the National Snow and Ice Data Center (NSIDC), on September 16, 2007, sea ice extent dropped to 4.13 million square kilometers (1.59 million square miles)--38 percent below average and 24 percent below the 2005 record.

  2. Record Arctic Sea Ice Loss in 2007

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This image of the Arctic was produced from sea ice observations collected by the Advanced Microwave Scanning Radiometer (AMSR-E) Instrument on NASA's Aqua satellite on September 16, overlaid on the NASA Blue Marble. The image captures ice conditions at the end of the melt season. Sea ice (white, image center) stretches across the Arctic Ocean from Greenland to Russia, but large areas of open water were apparent as well. In addition to record melt, the summer of 2007 brought an ice-free opening though the Northwest Passage that lasted several weeks. The Northeast Passage did not open during the summer of 2007, however, as a substantial tongue of ice remained in place north of the Russian coast. According to the National Snow and Ice Data Center (NSIDC), on September 16, 2007, sea ice extent dropped to 4.13 million square kilometers (1.59 million square miles)--38 percent below average and 24 percent below the 2005 record.

  3. Spatial and temporal patterns of sea ice variations in Vilkitsky strait, Russian High Arctic

    NASA Astrophysics Data System (ADS)

    Ci, T.; Cheng, X.; Hui, F.

    2013-12-01

    The Arctic Ocean has been greatly affected by climate change. Future predications show an even more drastic reduction of the ice cap which will open new areas for the exploration of natural resources and maritime transportation.Shipping through the Arctic Ocean via the Northern Sea Route (NSR) could save about 40% of the sailing distance from Asia (Yokohama) to Europe (Rotterdam) compared to the traditional route via the Suez Canal. Vilkitsky strait is the narrowest and northest portion of the Northern Sea Route with heaviest traffic between the Taimyr Peninsular and the Severnaya Zemlya archipelago. The preliminary results of sea ice variations are presented by using moderate-resolution imaging spectro radiometer(MODIS) data with 250-m resolution in the Vilkitsky strait during 2009-2012. Temporally, the first rupture on sea ice in Vilkitsky strait usually comes up in April and sea ice completely break into pieces in early June. The strait would be ice-free between August and late September. The frequency of ice floes grows while temperature falls down in October. There are always one or two months suitable for transport. Spatially, Sea ice on Laptev sea side breaks earlier than that of Kara sea side while sea ice in central of strait breaks earlier than in shoreside. The phenomena are directly related with the direction of sea wind and ocean current. In summmary, study on Spatial and temporal patterns in this area is significant for the NSR. An additional research issue to be tackled is to seeking the trends of ice-free duration in the context of global warming. Envisat ASAR data will also be used in this study.

  4. Warm Rivers Play Role in Arctic Sea Ice Melt

    NASA Image and Video Library

    2014-03-05

    Beaufort Sea surface temperatures where Canada Mackenzie River discharges into the Arctic Ocean, measured by NASA MODIS instrument; warm river waters had broken through a shoreline sea ice barrier to enhance sea ice melt.

  5. Summer Arctic Sea Ice Retreat: May - August 2013

    NASA Image and Video Library

    The melting of sea ice in the Arctic is well on its way toward its annual "minimum," that time when the floating ice cap covers less of the Arctic Ocean than at any other period during the year. 20...

  6. Approaching the 2015 Arctic Sea Ice Minimum

    NASA Image and Video Library

    2017-09-28

    As the sun sets over the Arctic, the end of this year’s melt season is quickly approaching and the sea ice cover has already shrunk to the fourth lowest in the satellite record. With possibly some days of melting left, the sea ice extent could still drop to the second or third lowest on record. Arctic sea ice, which regulates the planet’s temperature by bouncing solar energy back to space, has been on a steep decline for the last two decades. This animation shows the evolution of Arctic sea ice in 2015, from its annual maximum wintertime extent, reached on February 25, to September 6. Credit: NASA Scientific Visualization Studio DOWNLOAD THIS VIDEO HERE: svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11999 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

  7. Distribution of bacterioplankton with active metabolism in waters of the St. Anna Trough, Kara Sea, in autumn 2011

    NASA Astrophysics Data System (ADS)

    Mosharova, I. V.; Mosharov, S. A.; Ilinskiy, V. V.

    2017-01-01

    The distribution of bacterioplankton with active electron transport chains, as well as bacteria with intact cell membranes, was investigated for the first time in the region of St. Anna Trough in the Kara Sea. The average number of bacteria with active electron transport chains in the waters of the St. Anna Trough was 15.55 × 103 cells mL-1 (the limits of variation were 1.06-92.17 × 103 cells mL-1). The average number of bacteria with intact membranes was 33.46 × 103 cells mL-1 (the limits of variation were 6.78 to 103.18 × 103 cells mL-1). Almost all bacterioplankton microorganisms in the studied area were potentially viable, and the average share of bacteria with intact membranes was 92.1% of the total number of bacterioplankton (TNB) (the limits of variation were 76.2 to 98.4%). The share of bacteria with active metabolisms was 38.2% of the TNB (the limits of variation were 5.6-93.4%). The shares of the bacteria with active metabolisms were maximum in areas with the most stable environmental conditions (on the shelf and in deep water), whereas on the slope, where the gradients of water temperature and salinity were maximum, these values were lower.

  8. Estimated inventory of radionuclides in Former Soviet Union Naval Reactors dumped in the Kara Sea and their associated health risk

    SciTech Connect

    Mount, M.E.; Layton, D.W.; Schwertz, N.L.; Anspaugh, L.R.; Robison, W.L.

    1993-05-01

    Radionuclide inventories have bin estimated for the reactor cores, reactor components, and primary system corrosion products in the former Soviet Union naval reactors dumped at the Abrosimov Inlet, Tsivolka Inlet, Stepovoy Inlet, Techeniye Inlet, and Novaya Zemlya Depression sites in the Kara Sea between 1965 and 1988. For the time of disposal, the inventories are estimated at 17 to 66 kCi of actinides plus daughters and 1695 to 4782 kCi of fission products in the reactor cores, 917 to 1127 kCi of activation products in the reactor components, and 1.4 to 1.6 kCi of activation products in the primary system corrosion products. At the present time, the inventories are estimated to have decreased to 6 to 24 kCi of actinides plus daughters and 492 to 540 kCi of fission products in the reactor cores, 124 to 126 kCi of activation products in the reactor components, and 0.16 to 0.17 kCi of activation products in the primary system corrosion products. All actinide activities are estimated to be within a factor of two.

  9. Improvement in Simulation of Eurasian Winter Climate Variability with a Realistic Arctic Sea Ice Condition in an Atmospheric GCM

    NASA Technical Reports Server (NTRS)

    Lim, Young-Kwon; Ham, Yoo-Geun; Jeong, Jee-Hoon; Kug, Jong-Seong

    2012-01-01

    The present study investigates how much a realistic Arctic sea ice condition can contribute to improve simulation of the winter climate variation over the Eurasia region. Model experiments are set up using different sea ice boundary conditions over the past 24 years (i.e., 1988-2011). One is an atmospheric model inter-comparison (AMIP) type of run forced with observed sea-surface temperature (SST), sea ice, and greenhouse gases (referred to as Exp RSI), and the other is the same as Exp RSI except for the sea ice forcing, which is a repeating climatological annual cycle (referred to as Exp CSI). Results show that Exp RSI produces the observed dominant pattern of Eurasian winter temperatures and their interannual variation better than Exp CSI (correlation difference up to approx. 0.3). Exp RSI captures the observed strong relationship between the sea ice concentration near the Barents and Kara seas and the temperature anomaly across Eurasia, including northeastern Asia, which is not well captured in Exp CSI. Lagged atmospheric responses to sea ice retreat are examined using observations to understand atmospheric processes for the Eurasian cooling response including the Arctic temperature increase, sea-level pressure increase, upper-level jet weakening and cold air outbreak toward the mid-latitude. The reproducibility of these lagged responses by Exp RSI is also evaluated.

  10. The role of declining Arctic sea ice in recent decreasing terrestrial Arctic snow depths

    NASA Astrophysics Data System (ADS)

    Park, Hotaek; Walsh, John E.; Kim, Yongwon; Nakai, Taro; Ohata, Tetsuo

    2013-06-01

    The dramatic decline in Arctic sea ice cover is anticipated to influence atmospheric temperatures and circulation patterns. These changes will affect the terrestrial climate beyond the boundary of the Arctic, consequently modulating terrestrial snow cover. Therefore, an improved understanding of the relationship between Arctic sea ice and snow depth over the terrestrial Arctic is warranted. We examined responses of snow depth to the declining Arctic sea ice extent in September, during the period of 1979-2006. The major reason for a focus on snow depth, rather than snow cover, is because its variability has a climatic memory that impacts hydrothermal processes during the following summer season. Analyses of combined data sets of satellite measurements of sea ice extent and snow depth, simulated by a land surface model (CHANGE), suggested that an anomalously larger snow depth over northeastern Siberia during autumn and winter was significantly correlated to the declining September Arctic sea ice extent, which has resulted in cooling temperatures, along with an increase in precipitation. Meanwhile, the reduction of Arctic sea ice has amplified warming temperatures in North America, which has readily offset the input of precipitation to snow cover, consequently further decreasing snow depth. However, a part of the Canadian Arctic recorded an increase in snow depth driven locally by the diminishing September Arctic sea ice extent. Decreasing snow depth at the hemispheric scale, outside the northernmost regions (i.e., northeastern Siberia and Canadian Arctic), indicated that Arctic amplification related to the diminishing Arctic sea ice has already impacted the terrestrial Arctic snow depth. The strong reduction in Arctic sea ice anticipated in the future also suggests a potential long-range impact on Arctic snow cover. Moreover, the snow depth during the early snow season tends to contribute to the warming of soil temperatures in the following summer, at least in the

  11. Impact of declining Arctic sea ice on recent decreasing terrestrial Arctic snow depths

    NASA Astrophysics Data System (ADS)

    PARK, H.; Walsh, J. E.; Kim, Y.; Nakai, T.; Ohata, T.

    2012-12-01

    The dramatic decline in Arctic sea ice cover is anticipated to influence atmospheric temperatures and circulation patterns. These changes will affect the terrestrial climate beyond the boundary of the Arctic, consequently modulating terrestrial snow cover. Therefore, an improved understanding of the relationship between Arctic sea ice and snow depth over the terrestrial Arctic is warranted. We examined responses of snow depth to the declining Arctic sea ice extent in September, during the period of 1979-2006. The major reason for a focus on snow depth, rather than snow cover, is because its variability has a climatic memory that impacts hydrothermal processes during the following summer season. Analyses of combined data sets of satellite measurements of sea ice extent and snow depth, simulated by a land surface model (CHANGE), suggested that an anomalously larger snow depth over northeastern Siberia during autumn and winter was significantly correlated to the declining September Arctic sea ice extent, which has resulted in cooling temperatures, along with an increase in precipitation. Meanwhile, the reduction of Arctic sea ice has amplified warming temperatures in North America, which has readily offset the input of precipitation to snow cover, consequently further decreasing snow depth. However, a part of the Canadian Arctic recorded an increase in snow depth driven locally by the diminishing September Arctic sea ice extent. Decreasing snow depth at the hemispheric scale, outside the northernmost regions (i.e., northeastern Siberia and Canadian Arctic), indicated that Arctic amplification related to the diminishing Arctic sea ice has already impacted the terrestrial Arctic snow depth. The strong reduction in Arctic sea ice anticipated in the future also suggests a potential long-range impact on Arctic snow cover. Moreover, the snow depth during the early snow season tends to contribute to the warming of soil temperatures in the following summer, at least in the

  12. The Last Arctic Sea Ice Refuge

    NASA Astrophysics Data System (ADS)

    Pfirman, S. L.; Tremblay, B.; Newton, R.; Fowler, C.

    2010-12-01

    Summer sea ice may persist along the northern flank of Canada and Greenland for decades longer than the rest of the Arctic, raising the possibility of a naturally formed refugium for ice-associated species. Observations and models indicate that some ice in this region forms locally, while some is transported to the area by winds and ocean currents. Depending on future changes in melt patterns and sea ice transport rates, both the central Arctic and Siberian shelf seas may be sources of ice to the region. An international system of monitoring and management of the sea ice refuge, along with the ice source regions, has the potential to maintain viable habitat for ice-associated species, including polar bears, for decades into the future. Issues to consider in developing a strategy include: + the likely duration and extent of summer sea ice in this region based on observations, models and paleoenvironmental information + the extent and characteristics of the “ice shed” contributing sea ice to the refuge, including its dynamics, physical and biological characteristics as well as potential for contamination from local or long-range sources + likely assemblages of ice-associated species and their habitats + potential stressors such as transportation, tourism, resource extraction, contamination + policy, governance, and development issues including management strategies that could maintain the viability of the refuge.

  13. Stratospheric Impacts on Arctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Reichler, Thomas

    2016-04-01

    Long-term circulation change in the stratosphere can have substantial effects on the oceans and their circulation. In this study we investigate whether and how sea ice at the ocean surface responds to intraseasonal stratospheric variability. Our main question is whether the surface impact of stratospheric sudden warmings (SSWs) is strong and long enough to affect sea ice. A related question is whether the increased frequency of SSWs during the 2000s contributed to the rapid decrease in Arctic sea ice during this time. To this end we analyze observations of sea ice, NCEP/NCAR reanalysis, and a long control integration with a stratospherically-enhanced version of the GFDL CM2.1 climate model. From both observations and the model we find that stratospheric extreme events have a demonstrable impact on the distribution of Arctic sea ice. The areas most affected are near the edge of the climatological ice line over the North Atlantic, North Pacific, and the Arctic Ocean. The absolute changes in sea ice coverage amount to +/-10 %. Areas and magnitudes of increase and decrease are about the same. It is thus unlikely that the increased SSW frequency during the 2000s contributed to the decline of sea ice during that period. The sea ice changes are consistent with the impacts of a negative NAO at the surface and can be understood in terms of (1) dynamical change due to altered surface wind stress and (2) thermodynamical change due to altered temperature advection. Both dynamical and thermodynamical change positively reinforce each other in producing sea change. A simple advection model is used to demonstrate that most of the sea ice change can be explained from the sea ice drift due to the anomalous surface wind stress. Changes in the production or melt of sea ice by thermodynamical effects are less important. Overall, this study adds to an increasing body of evidence that the stratosphere not only impacts weather and climate of the atmosphere but also the surface and

  14. Circulation in the northwest Laptev Sea in the eastern Arctic Ocean: Crossroads between Siberian river water, Atlantic water and polynya-formed dense water

    NASA Astrophysics Data System (ADS)

    Janout, Markus; Hölemann, Jens; Timokhov, Leonid; Gutjahr, Oliver; Heinemann, Günther

    2017-04-01

    This paper investigates new unique observations from the poorly understood region between the Kara and Laptev Seas in the Eastern Arctic Ocean. We discuss relevant circulation features including riverine freshwater, Atlantic-derived water, and polynya-formed dense water, and emphasize Vilkitsky Strait (VS) as an important Kara Sea gateway (mean volume transport: 0.55 Sv), and the role of the adjacent 350 km-long submarine Vilkitsky Trough (VT) for the Arctic boundary current. Expeditions in 2013 and 2014 operated closely-spaced hydrographic transects and one year-long oceanographic mooring near VT's southern slope, and found persistent flow towards the Nansen Basin. The upper-ocean circulation is dominated by surface-intensified flow carrying Kara Sea freshwater along VT's southern edge with baroclinic volume and freshwater transports of 0.28 Sv and 16 mSv, respectively, though total transports may be substantially larger. The sub-surface features a steep front separating warm (-0.5°C) Atlantic-derived waters in central VT from cold (<-1.5°C) shelf waters, which episodically migrates as indicated by current reversals and temperature fluctuations. Shelf-transformed waters dominate above VT's slope measuring near-freezing temperatures throughout the water column at a wide salinity range (34-35). These dense waters are vigorously advected toward the Basin and characterize VT as a conduit for near-freezing waters that could potentially supply the Arctic Ocean's lower halocline, cool Atlantic water, and ventilate the deeper Arctic Ocean. Our observations highlight a topographically-complex region with multiple water masses, narrow fronts, polynyas and topographically-channeled storms as shown by a high-resolution (5-15 km) atmospheric model, which underlines the benefits of high-resolution circulation models.

  15. SWIFT Observations in the Arctic Sea State DRI

    DTIC Science & Technology

    2015-09-30

    to understand the role of waves and sea state in the Arctic Ocean , such that forecast models are improved and a robust climatology is defined...OBJECTIVES The objectives are to: develop a sea state climatology for the Arctic Ocean , improve wave forecasting in the presence of sea ice, improve...heat and mass fluxes in the air–sea–ice system. APPROACH The technical approach is to measure waves, winds, and turbulence in the Arctic Ocean

  16. Sea ice occurrence predicts genetic isolation in the Arctic fox.

    PubMed

    Geffen, Eli; Waidyaratne, Sitara; Dalén, Love; Angerbjörn, Anders; Vila, Carles; Hersteinsson, Pall; Fuglei, Eva; White, Paula A; Goltsman, Michael; Kapel, Christian M O; Wayne, Robert K

    2007-10-01

    Unlike Oceanic islands, the islands of the Arctic Sea are not completely isolated from migration by terrestrial vertebrates. The pack ice connects many Arctic Sea islands to the mainland during winter months. The Arctic fox (Alopex lagopus), which has a circumpolar distribution, populates numerous islands in the Arctic Sea. In this study, we used genetic data from 20 different populations, spanning the entire distribution of the Arctic fox, to identify barriers to dispersal. Specifically, we considered geographical distance, occurrence of sea ice, winter temperature, ecotype, and the presence of red fox and polar bear as nonexclusive factors that influence the dispersal behaviour of individuals. Using distance-based redundancy analysis and the BIOENV procedure, we showed that occurrence of sea ice is the key predictor and explained 40-60% of the genetic distance among populations. In addition, our analysis identified the Commander and Pribilof Islands Arctic populations as genetically unique suggesting they deserve special attention from a conservation perspective.

  17. Can regional climate engineering save the summer Arctic sea ice?

    NASA Astrophysics Data System (ADS)

    Tilmes, S.; Jahn, Alexandra; Kay, Jennifer E.; Holland, Marika; Lamarque, Jean-Francois

    2014-02-01

    Rapid declines in summer Arctic sea ice extent are projected under high-forcing future climate scenarios. Regional Arctic climate engineering has been suggested as an emergency strategy to save the sea ice. Model simulations of idealized regional dimming experiments compared to a business-as-usual greenhouse gas emission simulation demonstrate the importance of both local and remote feedback mechanisms to the surface energy budget in high latitudes. With increasing artificial reduction in incoming shortwave radiation, the positive surface albedo feedback from Arctic sea ice loss is reduced. However, changes in Arctic clouds and the strongly increasing northward heat transport both counteract the direct dimming effects. A 4 times stronger local reduction in solar radiation compared to a global experiment is required to preserve summer Arctic sea ice area. Even with regional Arctic dimming, a reduction in the strength of the oceanic meridional overturning circulation and a shut down of Labrador Sea deep convection are possible.

  18. Sea ice, rain-on-snow and tundra reindeer nomadism in Arctic Russia

    PubMed Central

    Kumpula, Timo; Meschtyb, Nina; Laptander, Roza; Macias-Fauria, Marc; Zetterberg, Pentti; Verdonen, Mariana; Kim, Kwang-Yul; Boisvert, Linette N.; Stroeve, Julienne C.; Bartsch, Annett

    2016-01-01

    Sea ice loss is accelerating in the Barents and Kara Seas (BKS). Assessing potential linkages between sea ice retreat/thinning and the region's ancient and unique social–ecological systems is a pressing task. Tundra nomadism remains a vitally important livelihood for indigenous Nenets and their large reindeer herds. Warming summer air temperatures have been linked to more frequent and sustained summer high-pressure systems over West Siberia, Russia, but not to sea ice retreat. At the same time, autumn/winter rain-on-snow (ROS) events have become more frequent and intense. Here, we review evidence for autumn atmospheric warming and precipitation increases over Arctic coastal lands in proximity to BKS ice loss. Two major ROS events during November 2006 and 2013 led to massive winter reindeer mortality episodes on the Yamal Peninsula. Fieldwork with migratory herders has revealed that the ecological and socio-economic impacts from the catastrophic 2013 event will unfold for years to come. The suggested link between sea ice loss, more frequent and intense ROS events and high reindeer mortality has serious implications for the future of tundra Nenets nomadism. PMID:27852939

  19. Sea ice, rain-on-snow and tundra reindeer nomadism in Arctic Russia.

    PubMed

    Forbes, Bruce C; Kumpula, Timo; Meschtyb, Nina; Laptander, Roza; Macias-Fauria, Marc; Zetterberg, Pentti; Verdonen, Mariana; Skarin, Anna; Kim, Kwang-Yul; Boisvert, Linette N; Stroeve, Julienne C; Bartsch, Annett

    2016-11-01

    Sea ice loss is accelerating in the Barents and Kara Seas (BKS). Assessing potential linkages between sea ice retreat/thinning and the region's ancient and unique social-ecological systems is a pressing task. Tundra nomadism remains a vitally important livelihood for indigenous Nenets and their large reindeer herds. Warming summer air temperatures have been linked to more frequent and sustained summer high-pressure systems over West Siberia, Russia, but not to sea ice retreat. At the same time, autumn/winter rain-on-snow (ROS) events have become more frequent and intense. Here, we review evidence for autumn atmospheric warming and precipitation increases over Arctic coastal lands in proximity to BKS ice loss. Two major ROS events during November 2006 and 2013 led to massive winter reindeer mortality episodes on the Yamal Peninsula. Fieldwork with migratory herders has revealed that the ecological and socio-economic impacts from the catastrophic 2013 event will unfold for years to come. The suggested link between sea ice loss, more frequent and intense ROS events and high reindeer mortality has serious implications for the future of tundra Nenets nomadism. © 2016 The Authors.

  20. Arctic Sea Ice : Trends, Stability and Variability

    NASA Astrophysics Data System (ADS)

    Moon, W.; Wettlaufer, J. S.

    2014-12-01

    A stochastic Arctic sea-ice model is derived and analysed in detail to interpret the recent decay and associated variability of Arctic sea-ice under changes in radiative forcing. The approach begins from a deterministic model of the heat flux balance through the air/sea/ice system, which uses observed monthly-averaged heat fluxesto drive a time evolution of sea-ice thickness. This model reproduces the observed seasonal cycle of the ice cover and it is to this that stochastic noise--representing high frequency variability--is introduced.The model takes the form of a single periodic non-autonomous stochastic ordinary differential equation. The value of such a model is that it provides a relatively simple framework to examine the role of noise in the basic nonlinear interactions at play as transitions in the state of the ice cover (e.g., from perennial to seasonal) are approached. Moreover, the stability and the noise conspire to underlie the inter annual variability and how that variability changes as one approaches the deterministic bifurcations in the system.

  1. Marine Transportation Implications of the Last Arctic Sea Ice Refuge

    NASA Astrophysics Data System (ADS)

    Brigham, L. W.

    2010-12-01

    Marine access is increasing throughout the Arctic Ocean and the 'Last Arctic Sea Ice Refuge' may have implications for governance and marine use in the region. Arctic marine transportation is increasing due to natural resource developemnt, increasing Arctic marine tourism, expanded Arctic marine research, and a general linkage of the Arctic to the gloabl economy. The Arctic Council recognized these changes with the release of the Arctic Marine Shipping Assessment of 2009. This key study (AMSA)can be viewed as a baseline assessment (using the 2004 AMSA database), a strategic guide for a host of stakeholders and actors, and as a policy document of the Arctic Council. The outcomes of AMSA of direct relevance to the Ice Refuge are within AMSA's 17 recommendations provided under three themes: Enhancing Arctic Marine Safety, Protecting Arctic People and the Environment, and Building the Arctic Marine Infrastructure. Selected recommendations of importance to the Ice Refuge include: a mandatory polar navigation code; identifying areas of heightened ecological and cultural significance; potential designation of special Arctic marine areas; enhancing the tracking and monitoring of Arctic marine traffic; improving circumpolar environmental response capacity; developing an Arctic search and rescue agreement; and, assessing the effects of marine transportation on marine mammals. A review will be made of the AMSA outcomes and how they can influence the governance, marine use, and future protection of this unique Arctic marine environment.

  2. Comparative Views of Arctic Sea Ice Growth

    NASA Technical Reports Server (NTRS)

    2000-01-01

    NASA researchers have new insights into the mysteries of Arctic sea ice, thanks to the unique abilities of Canada's Radarsat satellite. The Arctic is the smallest of the world's four oceans, but it may play a large role in helping scientists monitor Earth's climate shifts.

    Using Radarsat's special sensors to take images at night and to peer through clouds, NASA researchers can now see the complete ice cover of the Arctic. This allows tracking of any shifts and changes, in unprecedented detail, over the course of an entire winter. The radar-generated, high-resolution images are up to 100 times better than those taken by previous satellites.

    The two images above are separated by nine days (earlier image on the left). Both images represent an area (approximately 96 by 128 kilometers; 60 by 80 miles)located in the Baufort Sea, north of the Alaskan coast. The brighter features are older thicker ice and the darker areas show young, recently formed ice. Within the nine-day span, large and extensive cracks in the ice cover have formed due to ice movement. These cracks expose the open ocean to the cold, frigid atmosphere where sea ice grows rapidly and thickens.

    Using this new information, scientists at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., can generate comprehensive maps of Arctic sea ice thickness for the first time. 'Before we knew only the extent of the ice cover,' said Dr. Ronald Kwok, JPL principal investigator of a project called Sea Ice Thickness Derived From High Resolution Radar Imagery. 'We also knew that the sea ice extent had decreased over the last 20 years, but we knew very little about ice thickness.'

    'Since sea ice is very thin, about 3 meters (10 feet) or less,'Kwok explained, 'it is very sensitive to climate change.'

    Until now, observations of polar sea ice thickness have been available for specific areas, but not for the entire polar region.

    The new radar mapping technique has also given scientists a close look at

  3. Comparative Views of Arctic Sea Ice Growth

    NASA Technical Reports Server (NTRS)

    2000-01-01

    NASA researchers have new insights into the mysteries of Arctic sea ice, thanks to the unique abilities of Canada's Radarsat satellite. The Arctic is the smallest of the world's four oceans, but it may play a large role in helping scientists monitor Earth's climate shifts.

    Using Radarsat's special sensors to take images at night and to peer through clouds, NASA researchers can now see the complete ice cover of the Arctic. This allows tracking of any shifts and changes, in unprecedented detail, over the course of an entire winter. The radar-generated, high-resolution images are up to 100 times better than those taken by previous satellites.

    The two images above are separated by nine days (earlier image on the left). Both images represent an area (approximately 96 by 128 kilometers; 60 by 80 miles)located in the Baufort Sea, north of the Alaskan coast. The brighter features are older thicker ice and the darker areas show young, recently formed ice. Within the nine-day span, large and extensive cracks in the ice cover have formed due to ice movement. These cracks expose the open ocean to the cold, frigid atmosphere where sea ice grows rapidly and thickens.

    Using this new information, scientists at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., can generate comprehensive maps of Arctic sea ice thickness for the first time. 'Before we knew only the extent of the ice cover,' said Dr. Ronald Kwok, JPL principal investigator of a project called Sea Ice Thickness Derived From High Resolution Radar Imagery. 'We also knew that the sea ice extent had decreased over the last 20 years, but we knew very little about ice thickness.'

    'Since sea ice is very thin, about 3 meters (10 feet) or less,'Kwok explained, 'it is very sensitive to climate change.'

    Until now, observations of polar sea ice thickness have been available for specific areas, but not for the entire polar region.

    The new radar mapping technique has also given scientists a close look at

  4. The Timing of Arctic Sea Ice Advance and Retreat as an Indicator of Ice-Dependent Marine Mammal Habitat

    NASA Astrophysics Data System (ADS)

    Stern, H. L.; Laidre, K. L.

    2013-12-01

    The Arctic is widely recognized as the front line of climate change. Arctic air temperature is rising at twice the global average rate, and the sea-ice cover is shrinking and thinning, with total disappearance of summer sea ice projected to occur in a matter of decades. Arctic marine mammals such as polar bears, seals, walruses, belugas, narwhals, and bowhead whales depend on the sea-ice cover as an integral part of their existence. While the downward trend in sea-ice extent in a given month is an often-used metric for quantifying physical changes in the ice cover, it is not the most relevant measure for characterizing changes in the sea-ice habitat of marine mammals. Species that depend on sea ice are behaviorally tied to the annual retreat of sea ice in the spring and advance in the fall. Changes in the timing of the spring retreat and the fall advance are more relevant to Arctic marine species than changes in the areal sea-ice coverage in a particular month of the year. Many ecologically important regions of the Arctic are essentially ice-covered in winter and ice-free in summer, and will probably remain so for a long time into the future. But the dates of sea-ice retreat in spring and advance in fall are key indicators of climate change for ice-dependent marine mammals. We use daily sea-ice concentration data derived from satellite passive microwave sensors to calculate the dates of sea-ice retreat in spring and advance in fall in 12 regions of the Arctic for each year from 1979 through 2013. The regions include the peripheral seas around the Arctic Ocean (Beaufort, Chukchi, East Siberian, Laptev, Kara, Barents), the Canadian Arctic Archipelago, and the marginal seas (Okhotsk, Bering, East Greenland, Baffin Bay, Hudson Bay). We find that in 11 of the 12 regions (all except the Bering Sea), sea ice is retreating earlier in spring and advancing later in fall. Rates of spring retreat range from -5 to -8 days/decade, and rates of fall advance range from +5 to +9

  5. Anthropogenic radioactivity in the Arctic Ocean--review of the results from the joint German project.

    PubMed

    Nies, H; Harms, I H; Karcher, M J; Dethleff, D; Bahe, C

    1999-09-30

    The paper presents the results of the joint project carried out in Germany in order to assess the consequences in the marine environment from the dumping of nuclear wastes in the Kara and Barents Seas. The project consisted of experimental work on measurements of radionuclides in samples from the Arctic marine environment and numerical modelling of the potential pathways and dispersion of contaminants in the Arctic Ocean. Water and sediment samples were collected for determination of radionuclide such as 137Cs, 90Sr, 239 + 240Pu, 238Pu, and 241Am and various organic micropollutants. In addition, a few water and numerous surface sediment samples collected in the Kara Sea and from the Kola peninsula were taken by Russian colleagues and analysed for artificial radionuclide by the BSH laboratory. The role of transport by sea ice from the Kara Sea into the Arctic Ocean was assessed by a small subgroup at GEOMAR. This transport process might be considered as a rapid contribution due to entrainment of contaminated sediments into sea ice, following export from the Kara Sea into the transpolar ice drift and subsequent release in the Atlantic Ocean in the area of the East Greenland Current. Numerical modelling of dispersion of pollutants from the Kara and Barents Seas was carried out both on a local scale for the Barents and Kara Seas and for long range dispersion into the Arctic and Atlantic Oceans. Three-dimensional baroclinic circulation models were applied to trace the transport of pollutants. Experimental results were used to validate the model results such as the discharges from the nuclear reprocessing plant at Sellafield and subsequent contamination of the North Sea up the Arctic Seas.

  6. Arctic Sea Ice Predictability and the Sea Ice Prediction Network

    NASA Astrophysics Data System (ADS)

    Wiggins, H. V.; Stroeve, J. C.

    2014-12-01

    Drastic reductions in Arctic sea ice cover have increased the demand for Arctic sea ice predictions by a range of stakeholders, including local communities, resource managers, industry and the public. The science of sea-ice prediction has been challenged to keep up with these developments. Efforts such as the SEARCH Sea Ice Outlook (SIO; http://www.arcus.org/sipn/sea-ice-outlook) and the Sea Ice for Walrus Outlook have provided a forum for the international sea-ice prediction and observing community to explore and compare different approaches. The SIO, originally organized by the Study of Environmental Change (SEARCH), is now managed by the new Sea Ice Prediction Network (SIPN), which is building a collaborative network of scientists and stakeholders to improve arctic sea ice prediction. The SIO synthesizes predictions from a variety of methods, including heuristic and from a statistical and/or dynamical model. In a recent study, SIO data from 2008 to 2013 were analyzed. The analysis revealed that in some years the predictions were very successful, in other years they were not. Years that were anomalous compared to the long-term trend have proven more difficult to predict, regardless of which method was employed. This year, in response to feedback from users and contributors to the SIO, several enhancements have been made to the SIO reports. One is to encourage contributors to provide spatial probability maps of sea ice cover in September and the first day each location becomes ice-free; these are an example of subseasonal to seasonal, local-scale predictions. Another enhancement is a separate analysis of the modeling contributions. In the June 2014 SIO report, 10 of 28 outlooks were produced from models that explicitly simulate sea ice from dynamic-thermodynamic sea ice models. Half of the models included fully-coupled (atmosphere, ice, and ocean) models that additionally employ data assimilation. Both of these subsets (models and coupled models with data

  7. Spatial patterns of water quality parameters in upper layer of the Kara Sea in summer 2016 based on laser remote sensing

    NASA Astrophysics Data System (ADS)

    Osokina, Varvara; Pelevin, Vadim; Shatravin, Alexander; Belyaev, Nikolay; Demidov, Andrey; Redzhepova, Zuleyha

    2017-04-01

    The paper represents results of remote sensing by means of Laser Induced Fluorescence LiDAR during the expedition in Kara Sea in summer 2016. The expedition took place in Western and Southern parts of Kara Sea including Ob and Yenisei areas from June, 14 to August, 20 2016. The LiDAR observations were obtained from the research vessel Mstislav Keldysh and included 4600 km of almost continuous measurements and 94 complex stations. As a result now there is a vast LiDAR database available for scientific purposes. The data were processed and recalculated providing a set of high resolution maps of distribution of main oceanographic water quality parameters including chlorophyll "a", total organic carbon and total suspended matter in surface layer. The proceeded maps give a precise information about the location of frontal zones between Ob and Yenisei waters and Kara Sea waters, provide a detailed picture of complex surface water structure in central Kara Sea and other locations and present data about spatial distinction of concentrations of measured water parameters. The LiDAR measurements were afterwards compared to data, obtained by underway flow-through CTD measuring system and satellite images providing adjunct information on water parameters' distribution features. The instruments of UFL (Ultraviolet fluorescent LiDAR) series were developed by the Shirshov Institute of Oceanology, Moscow, Russia, and have been successfully used in lots of scientific expeditions in different water areas. UFL LiDARs take measurements with sampling rate up to 2 Hz from the vessel under way in any weather or sunlight conditions. The measurements are linked to a GPS, and so all data are geo-tagged and can be used to create interpolated maps of the measured parameters. The instrument analyses backward signal from dual excitation (355, 532 nm) laser pulses emitted at 2 Hz. The signal is detected across 11 bands in series (355, 385, 404, 424, 440, 460, 499, 532, 620, 651, 685 nm) on

  8. Swell and Sea in the Emerging Arctic Ocean

    DTIC Science & Technology

    2014-01-01

    GeophysicalResearchLetters RESEARCHLETTER 10.1002/2014GL059983 Key Points: • Surface waves in the Arctic Ocean increase during periods of sea ice ...fetch in the Arctic , because the swell is regionally driven. This suggests that further reductions in seasonal ice cover in the future will result in... ice sea swell Figure 2. Time series of Arctic Ocean wave conditions. Hourly values for (a) significant wave height, (b) wind speed at 10 m reference

  9. Collective doses to man from dumping of radioactive waste in the Arctic Seas.

    PubMed

    Nielsen, S P; Iosjpe, M; Strand, P

    1997-08-25

    A box model for the dispersion of radionuclides in the marine environment covering the Arctic Ocean and the North Atlantic Ocean has been constructed. Collective doses from ingestion pathways have been calculated from unit releases of the radionuclides 3H, 60Co, 63Ni, 90Sr, 129I, 137Cs, 239Pu and 241Am into a fjord on the east coast of NovayaZemlya. The results show that doses for the shorter-lived radionuclides (e.g. 137Cs) are derived mainly from seafood production in the Barents Sea. Doses from the longer-lived radionuclides (e.g. 239Pu) are delivered through marine produce further away from the Arctic Ocean. Collective doses were calculated for two release scenarios, both of which are based on information of the dumping of radioactive waste in the Barents and Kara Seas by the former Soviet Union and on preliminary information from the International Arctic Sea Assessment Programme. A worst-case scenario was assumed according to which all radionuclides in liquid and solid radioactive waste were available for dispersion in the marine environment at the time of dumping. Release of radionuclides from spent nuclear fuel was assumed to take place by direct corrosion of the fuel ignoring the barriers that prevent direct contact between the fuel and the seawater. The second scenario selected assumed that releases of radionuclides from spent nuclear fuel do not occur until after failure of the protective barriers. All other liquid and solid radioactive waste was assumed to be available for dispersion at the time of discharge in both scenarios. The estimated collective dose for the worst-case scenario was about 9 manSv and that for the second scenario was about 3 manSv. In both cases, 137Cs is the radionuclide predicted to dominate the collective doses as well as the peak collective dose rates.

  10. Annual Cycles of Multiyear Sea Ice Coverage of the Arctic Ocean: 1999-2003

    NASA Technical Reports Server (NTRS)

    Kwok, R.

    2004-01-01

    For the years 1999-2003, we estimate the time-varying perennial ice zone (PIZ) coverage and construct the annual cycles of multiyear (MY, including second year) ice coverage of the Arctic Ocean using QuikSCAT backscatter, MY fractions from RADARSAT, and the record of ice export from satellite passive microwave observations. An area balance approach extends the winter MY coverage from QuikSCAT to the remainder of the year. From these estimates, the coverage of MY ice at the beginning of each year is 3774 x 10(exp 3) sq km (2000), 3896 x 10(exp 3) sq km (2001), 4475 x 10(exp 3) sq km (2002), and 4122 x 10(exp 3) sq km (2003). Uncertainties in coverage are approx.150 x 10(exp 3) sq km. In the mean, on 1 January, MY ice covers approx.60% of the Arctic Ocean. Ice export reduces this coverage to approx.55% by 1 May. From the multiple annual cycles, the area of first-year (FY) ice that survives the intervening summers are 1192 x 10(exp 3) sq km (2000), 1509 x 10(exp 3) sq km (2001), and 582 x 10(exp 3) sq km (2002). In order for the MY coverage to remain constant from year to year, these replenishment areas must balance the overall area export and melt during the summer. The effect of the record minimum in Arctic sea ice area during the summer of 2002 is seen in the lowest area of surviving FY ice of the three summers. In addition to the spatial coverage, the location of the PIZ is important. One consequence of the unusual location of the PIZ at the end of the summer of 2002 is the preconditioning for enhanced export of MY ice into the Barents and Kara seas. Differences between the minimums in summer sea ice coverage from our estimates and passive microwave observations are discussed.

  11. SWIFT Observations in the Arctic Sea State DRI

    DTIC Science & Technology

    2014-09-30

    Arctic Sea State DRI Jim Thomson 1013 NE 40th St, Seattle WA 98105 phone: (206) 616-0858 fax: (206) 616-5467 email: jthomson@apl.uw.edu Award...goal is to understand the role of waves and sea state in the Arctic Ocean, such that forecast models are improved and a robust climatology is defined...OBJECTIVES The objectives are to: develop a sea state climatology for the Arctic Ocean, improve wave forecasting in the presence of sea ice, improve

  12. New data about seismicity and crustal velocity structure of the "continent-ocean" transition zone of the Barents-Kara region in the Arctic

    NASA Astrophysics Data System (ADS)

    Morozov, Alexey N.; Vaganova, Natalya V.; Konechnaya, Yana V.; Asming, Vladimir E.

    2015-01-01

    The recent (2011) installation of seismic station Zemlya Franca-Iocifa (ZFI) on Alexander Island in the Franz Josef Land Archipelago allows new seismic monitoring of the "continent-ocean" transition zone of the Barents-Kara Sea region. The region is seismically active, and we hypothesize that the prevailing geodynamic factor responsible for the occurrence of weak earthquakes is isostatic compensation of avalanche sedimentation in the "continent-ocean" transition zone. The crustal velocity structure beneath ZFI was determined using receiver functions. Crustal thickness is 30 km, based on an observed Moho discontinuity with underlying mantle velocities being Vp = 8.15 km/s and Vs = 4.5 km/s The model indicates a mid-crustal boundary at a depth of about 17 km with a velocity contrast between the upper ( Vp = 6.1 km/s, Vs = 3.6 km/s) and lower ( Vp = 6.8 km/s, Vs = 3.9 km/s) layers. In addition, the upper crustal sedimentary layer is about 4 km thick with Vp = 4.3 km/s and Vs = 2.36 km/s.

  13. Observing Arctic Sea Ice from Bow to Screen: Introducing Ice Watch, the Data Network of Near Real-Time and Historic Observations from the Arctic Shipborne Sea Ice Standardization Tool (ASSIST)

    NASA Astrophysics Data System (ADS)

    Orlich, A.; Hutchings, J. K.; Green, T. M.

    2013-12-01

    The Ice Watch Program is an open source forum to access in situ Arctic sea ice conditions. It provides the research community and additional stakeholders a convenient resource to monitor sea ice and its role in understanding the Arctic as a system by implementing a standardized observation protocol and hosting a multi-service data portal. International vessels use the Arctic Shipborne Sea Ice Standardization Tool (ASSIST) software to report near-real time sea ice conditions while underway. Essential observations of total ice concentration, distribution of multi-year ice and other ice types, as well as their respective stage of melt are reported. These current and historic sea ice conditions are visualized on interactive maps and in a variety of statistical analyses, and with all data sets available to download for further investigation. The summer of 2012 was the debut of the ASSIST software and the Ice Watch campaign, with research vessels from six nations reporting from a wide spatio-temporal scale spanning from the Beaufort Sea, across the North Pole and Arctic Basin, the coast of Greenland and into the Kara and Barents Seas during mid-season melt and into the first stages of freeze-up. The 2013 summer field season sustained the observation and data archiving record, with participation from some of the same cruises as well as other geographic and seasonal realms covered by new users. These results are presented to illustrate the evolution of the program, increased participation and critical statistics of ice regime change and record of melt and freeze processes revealed by the data. As an ongoing effort, Ice Watch/ASSIST aims to standardize observations of Arctic-specific sea ice features and conditions while utilizing nomenclature and coding based on the World Meteorological Organization (WMO) standards and the Antarctic Sea Ice and Processes & Climate (ASPeCt) protocol. Instigated by members of the CliC Sea Ice Working Group, the program has evolved with

  14. Source identification of the Arctic sea ice proxy IP25

    NASA Astrophysics Data System (ADS)

    Brown, T. A.; Belt, S. T.; Tatarek, A.; Mundy, C. J.

    2014-06-01

    Analysis of the organic geochemical biomarker IP25 in marine sediments is an established method for carrying out palaeo sea ice reconstructions for the Arctic. Such reconstructions cover timescales from decades back to the early Pleistocene, and are critical for understanding past climate conditions on Earth and for informing climate prediction models. Key attributes of IP25 include its strict association with Arctic sea ice together with its ubiquity and stability in underlying marine sediments; however, the sources of IP25 have remained undetermined. Here we report the identification of IP25 in three (or four) relatively minor (<5%) sea ice diatoms isolated from mixed assemblages collected from the Canadian Arctic. In contrast, IP25 was absent in the dominant taxa. Chemical and taxonomical investigations suggest that the IP25-containing taxa represent the majority of producers and are distributed pan-Arctic, thus establishing the widespread applicability of the IP25 proxy for palaeo Arctic sea ice reconstruction.

  15. Observing the Cloud Response to Arctic Sea Ice Loss

    NASA Astrophysics Data System (ADS)

    Morrison, Ariel L.; Kay, Jennifer E.; Chepfer, Helene; Guzman, Rodrigo

    2017-04-01

    Observed sea ice loss since 1979 is the most visible signal of anthropogenic Arctic warming. While the influence of clouds on Arctic sea ice is known, the influence of sea ice loss on Arctic clouds is challenging to detect and has never been isolated. Here, we use 8 years (2008 - 2015) of spaceborne lidar observations from the CALIPSO satellite to isolate the cloud response to sea ice loss from cloud changes due to atmospheric circulation. We focus on the liquid cloud response to observed sea ice loss because liquid-containing clouds are the most important cloud type for sea ice melt and growth. There is no observed change in liquid clouds in response to sea ice loss during summer. The absence of a summer cloud response indicates that a summer cloud-sea ice feedback cannot be relied upon to slow the rate of sea ice loss. In contrast, we find more liquid clouds over open water than over sea ice during fall. Thus, human-caused sea ice loss is increasing fall clouds over the Arctic Ocean. Since we robustly isolate the cloud response to sea ice loss, we can for the first time attribute an Arctic cloud change to human activities.

  16. Preferred atmospheric circulation patterns of winter Arctic sea ice decline

    NASA Astrophysics Data System (ADS)

    Luo, Binhe; Luo, Dehai; Zhong, Linhao; Wu, Lixin

    2017-04-01

    In this paper, the impact of the Ural blocking (UB) with the positive North Atlantic Oscillation (NAO+), negative NAO (NAO-) and neutral NAO on the sea ice variability over the Barents-Kara Sea (BKS) is examined, respectively, to understand what type of atmospheric circulation patterns can lead to the strongest sea ice decline. A water vapor reservoir as a richest moisture region is found to exist over the mid-latitude North Atlantic south of the Gulf Stream Extension due to strong positive sea surface temperature anomalies for the NAO+ winter. When the UB occurs together with the NAO+, the strongest BKS ice decline is seen due to the strongest BKS warming associated with the strongest moisture intrusion because the combined UB and NAO+ pattern is an optimal circulation pattern that favors the moisture intrusion into the BKS from the mid-latitude North Atlantic, as revealed from the trajectory tracking method.

  17. Spatial variability of concentrations of chlorophyll a, dissolved organic matter and suspended particles in the surface layer of the Kara Sea in September 2011 from lidar data

    NASA Astrophysics Data System (ADS)

    Pelevin, V. V.; Zavjalov, P. O.; Belyaev, N. A.; Konovalov, B. V.; Kravchishina, M. D.; Mosharov, S. A.

    2017-01-01

    The article presents results of underway remote laser sensing of the surface water layer in continuous automatic mode using the UFL-9 fluorescent lidar onboard the R/V Akademik Mstislav Keldysh during cruise 59 in the Kara Sea in 2011. The description of the lidar, the approach to interpreting seawater fluorescence data, and certain methodical aspects of instrument calibration and measurement are presented. Calibration of the lidar is based on laboratory analysis of water samples taken from the sea surface during the cruise. Spatial distribution of chlorophyll a, total organic carbon and suspended matter concentrations in the upper quasi-homogeneous layer are mapped and the characteristic scales of the variability are estimated. Some dependencies between the patchiness of the upper water layer and the atmospheric forcing and freshwater runoff are shown.

  18. Arctic Sea Ice Decline: Observations, Projections, Mechanisms, and Implications

    NASA Astrophysics Data System (ADS)

    DeWeaver, Eric T.; Bitz, Cecilia M.; Tremblay, L.-Bruno

    This volume addresses the rapid decline of Arctic sea ice, placing recent sea ice decline in the context of past observations, climate model simulations and projections, and simple models of the climate sensitivity of sea ice. 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 ice conditions prior to human observations, based on proxy data from sediments; • A modeling approach for assessing the impact of sea ice 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 ice decline will become (or has already become) irreversible, including an examination of the role of the small ice cap instability in global warming simulations; • A significant summertime atmospheric response to sea ice 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 ice, model projections of future sea ice loss, and the consequences of sea ice loss for the natural and human systems of the Arctic.

  19. Arctic Sea Ice: Trends, Stability and Variability

    NASA Astrophysics Data System (ADS)

    Moon, Woosok

    A stochastic Arctic sea-ice model is derived and analyzed in detail to interpret the recent decay and associated variability of Arctic sea-ice under changes in greenhouse gas forcing widely referred to as global warming. The approach begins from a deterministic model of the heat flux balance through the air/sea/ice system, which uses observed monthly-averaged heat fluxes to drive a time evolution of sea-ice thickness. This model reproduces the observed seasonal cycle of the ice cover and it is to this that stochastic noise---representing high frequency variability---is introduced. The model takes the form of a single periodic non-autonomous stochastic ordinary differential equation. Following an introductory chapter, the two that follow focus principally on the properties of the deterministic model in order to identify the main properties governing the stability of the ice cover. In chapter 2 the underlying time-dependent solutions to the deterministic model are analyzed for their stability. It is found that the response time-scale of the system to perturbations is dominated by the destabilizing sea-ice albedo feedback, which is operative in the summer, and the stabilizing long wave radiative cooling of the ice surface, which is operative in the winter. This basic competition is found throughout the thesis to define the governing dynamics of the system. In particular, as greenhouse gas forcing increases, the sea-ice albedo feedback becomes more effective at destabilizing the system. Thus, any projections of the future state of Arctic sea-ice will depend sensitively on the treatment of the ice-albedo feedback. This in turn implies that the treatment a fractional ice cover as the ice areal extent changes rapidly, must be handled with the utmost care. In chapter 3, the idea of a two-season model, with just winter and summer, is revisited. By breaking the seasonal cycle up in this manner one can simplify the interpretation of the basic dynamics. Whereas in the fully

  20. Atmospheric circulation and Arctic sea ice: Forcing of sea ice loss by remote teleconnnections and central Arctic responses / feedbacks

    NASA Astrophysics Data System (ADS)

    Wettstein, J. J.; Deser, C.

    2012-12-01

    Continued declines in Arctic sea ice volume and summer sea ice extent are generally anticipated for the coming decades, based upon their trajectory in available observations and within a wide variety of model projections. Substantial uncertainty regarding the magnitude of twenty-first century ice loss remains, however. Two studies focused on processes leading to uncertainty in 21st century Arctic sea ice loss projections are presented: 1) the role of large-scale atmospheric teleconnections in forcing Arctic sea ice loss and 2) coupled thermodynamic and dynamic atmospheric responses to and feedbacks on Arctic sea ice loss. A fully-coupled 39-member ensemble initialized by identical ocean, land and ice conditions and slightly different atmospheric initial conditions is the primary dataset used in these studies. Observations, reanalyses and other coupled and uncoupled simulations corroborate and add context to the large ensemble results. Internal variability is a leading factor influencing the magnitude of 21st century Arctic sea ice loss. Internal variability in ice loss is linked to a large-scale pattern of atmospheric circulation variability over the Pacific. A Rossby wavetrain emanates from the tropical Pacific and extends all the way into an ``Arctic Dipole'' sea level pressure pattern over the central Arctic. A trans-polar drift in ice velocity and ice advection out of the central Arctic through Fram Strait result. These physical ``forcing'' associations are qualitatively consistent across a wide range of time scales, in observations and in other coupled models. Arctic sea ice loss is also associated with two coupled ice-ocean-atmosphere responses and feedbacks. The first feedback involves upper ocean heating resulting from increased solar absorption directly beneath anomalous summer sea ice loss. Some of the anomalous ocean heat melts the overlying sea ice and delays winter freeze-up. A second coupled thermodynamic / dynamic feedback results because much of the

  1. Quantifying model uncertainty in seasonal Arctic sea-ice forecasts

    NASA Astrophysics Data System (ADS)

    Blanchard-Wrigglesworth, Edward; Barthélemy, Antoine; Chevallier, Matthieu; Cullather, Richard; Fučkar, Neven; Massonnet, François; Posey, Pamela; Wang, Wanqiu; Zhang, Jinlun; Ardilouze, Constantin; Bitz, Cecilia; Vernieres, Guillaume; Wallcraft, Alan; Wang, Muyin

    2017-04-01

    Dynamical model forecasts in the Sea Ice Outlook (SIO) of September Arctic sea-ice extent over the last decade have shown lower skill than that found in both idealized model experiments and hindcasts of previous decades. Additionally, it is unclear how different model physics, initial conditions or post-processing techniques contribute to SIO forecast uncertainty. In this work, we have produced a seasonal forecast of 2015 Arctic summer sea ice using SIO dynamical models initialized with identical sea-ice thickness in the central Arctic. Our goals are to calculate the relative contribution of model uncertainty and irreducible error growth to forecast uncertainty and assess the importance of post-processing, and to contrast pan-Arctic forecast uncertainty with regional forecast uncertainty. We find that prior to forecast post-processing, model uncertainty is the main contributor to forecast uncertainty, whereas after forecast post-processing forecast uncertainty is reduced overall, model uncertainty is reduced by an order of magnitude, and irreducible error growth becomes the main contributor to forecast uncertainty. While all models generally agree in their post-processed forecasts of September sea-ice volume and extent, this is not the case for sea-ice concentration. Additionally, forecast uncertainty of sea-ice thickness grows at a much higher rate along Arctic coastlines relative to the central Arctic ocean. Potential ways of offering spatial forecast information based on the timescale over which the forecast signal beats the noise are also explored.

  2. The effect of Arctic sea-ice extent on the absorbed (net) solar flux at the surface, based on ISCCP-D2 cloud data for 1983-2007

    NASA Astrophysics Data System (ADS)

    Matsoukas, C.; Hatzianastassiou, N.; Fotiadi, A.; Pavlakis, K. G.; Vardavas, I.

    2010-01-01

    We estimate the effect of the Arctic sea ice on the absorbed (net) solar flux using a radiative transfer model. Ice and cloud input data to the model come from satellite observations, processed by the International Satellite Cloud Climatology Project (ISCCP) and span the period July 1983-June 2007. The sea-ice effect on the solar radiation fluctuates seasonally with the solar flux and decreases interannually in synchronisation with the decreasing sea-ice extent. A disappearance of the Arctic ice cap during the sunlit period of the year would radically reduce the local albedo and cause an annually averaged 19.7 W m-2 increase in absorbed solar flux at the Arctic Ocean surface, or equivalently an annually averaged 0.55 W m-2 increase on the planetary scale. In the clear-sky scenario these numbers increase to 34.9 and 0.97 W m-2, respectively. A meltdown only in September, with all other months unaffected, increases the Arctic annually averaged solar absorption by 0.32 W m-2. We examined the net solar flux trends for the Arctic Ocean and found that the areas absorbing the solar flux more rapidly are the North Chukchi and Kara Seas, Baffin and Hudson Bays, and Davis Strait. The sensitivity of the Arctic absorbed solar flux on sea-ice extent and cloud amount was assessed. Although sea ice and cloud affect jointly the solar flux, we found little evidence of strong non-linearities.

  3. Arctic sea-ice extent and its effect on the absorbed (net) solar flux at the surface, based on ISCCP-D2 cloud data for 1983-2007

    NASA Astrophysics Data System (ADS)

    Matsoukas, C.; Hatzianastassiou, N.; Fotiadi, A.; Pavlakis, K. G.; Vardavas, I.

    2009-10-01

    We estimate the effect of the Arctic sea ice on the absorbed (net) solar flux using a radiation transfer model. Ice and cloud input data to the model come from satellite observations, processed by the International Satellite Cloud Climatology Project (ISCCP) and span the period July 1983-June 2007. The sea-ice effect on the solar radiation fluctuates seasonally with the solar flux and decreases interannually in synchronisation with the decreasing sea-ice extent. A disappearance of the Arctic ice cap during the sunlit period of the year would radically reduce the local albedo and cause a 19.7 W m-2 increase in absorbed solar flux at the Arctic Ocean surface, or equivalently a 0.55 W m-2 increase on the planetary scale. In the clear-sky scenario these numbers increase to 34.9 and 0.97 W m-2, respectively. A meltdown only in September, with all other months unaffected, increases the Arctic annually averaged solar absorption by 0.32 W m-2. We examined the net solar flux trends for the Arctic Ocean and found that the areas absorbing the solar flux more rapidly are the North Chukchi and Kara Seas, Buffin and Hudson Bays, and Davis Strait. The sensitivity of the Arctic absorbed solar flux on sea-ice extent and cloud amount was assessed. Although sea ice and cloud affect jointly the solar flux, we found little evidence of strong non-linearities.

  4. The role of zooplankton in the transformation of the organic matter in the Ob estuary, on the shelf, and in the deep regions of the Kara Sea

    NASA Astrophysics Data System (ADS)

    Arashkevich, E. G.; Flint, M. V.; Nikishina, A. B.; Pasternak, A. F.; Timonin, A. G.; Vasilieva, J. V.; Mosharov, S. A.; Soloviev, K. A.

    2010-10-01

    The data for the present study were collected at 20 sampling stations in the Kara Sea along the transect from the Ob estuary to the deep sea St. Anna Trough in September 2007. Based on the hydrophysical features, the distribution of the Chl a, and the primary production, we distinguished six habitats: the river, estuary, inner and outer shelf, continental slope, and trough. The impact of the small-size (<0.5 mm) and large-size (>0.5 mm) fractions of the zooplankton on the phytoplankton’s organic carbon in the different regions of the Kara Sea was estimated. The ingestion rate was assessed using the analysis of the gut fluorescence content and the gut evacuation rate. The zooplankton grazed 1-2% of the phytoplankton biomass in the river and estuary; 3.5% over the shelf; and 6 and 10% in the regions of the trough and slope, respectively. The grazing impact of the small-sized zooplankton increased from the river zone to the deep regions (from 1 to 90%) along with their share in the total zooplankton abundance (from 18 to 95%). From 72 to 86% of the primary production was grazed over the shelf and slope. The primary production did not cover the feeding requirements of the zooplankton in the estuarine regions and St. Anna Trough in the autumn. In the estuarine regions, the major portion of the organic matter settles on the bottom due to the strong inflow of the allochthonous matter and the relatively low zooplankton grazing.

  5. Arctic Daily Sea Ice, March 2012 to Feb. 2013

    NASA Image and Video Library

    This animation shows the seasonal change in the extent of the Arctic sea ice between March 1, 2012 and February 28, 2013. The annual cycle starts with the maximum extent reached on March 15, 2012. ...

  6. Arctic moisture source for Eurasian snow cover variations in autumn

    NASA Astrophysics Data System (ADS)

    Wegmann, Martin; Orsolini, Yvan; Vázquez Dominguez, Marta; Gimeno Presa, Luis; Nieto, Raquel; Buligyna, Olga; Jaiser, Ralf; Handorf, Dörthe; Rinke, Anette; Dethloff, Klaus; Sterin, Alexander; Brönnimann, Stefan

    2015-04-01

    Global warming is enhanced at high northern latitudes where the Arctic surface air temperature has risen at twice the rate of the global average in recent decades - a feature called Arctic amplification. This recent Arctic warming signal likely results from several factors such as the albedo feedback due to a diminishing cryosphere, enhanced poleward atmospheric and oceanic transport, and change in humidity. The reduction in Arctic sea ice is without doubt substantial and a key factor. Arctic summer sea-ice extent has declined by more than 10% per decade since the start of the satellite era (e.g. Stroeve et al., 2012), culminating in a new record low in September 2012, with the long-term trend largely attributed to anthropogenic global warming. Eurasian snow cover changes have been suggested as a driver for changes in the Arctic Oscillation and might provide a link between sea ice decline in the Arctic during summer and atmospheric circulation in the following winter. However, the mechanism connecting snow cover in Eurasia to sea ice decline in autumn is still under debate. Our analysis focuses at sea ice decline in the Barents-Kara Sea region, which allows us to specify regions of interest for FLEXPART forward and backwards moisture trajectories. Based on Eularian and Lagrangian diagnostics from ERA-INTERIM, we can address the origin and cause of late autumn snow depth variations in a dense (snow observations from 820 land stations), unutilized observational datasets over the Commonwealth of Independent States. Open waters in the Barents and Kara Sea have been shown to increase the diabatic heating of the atmosphere, which amplifies baroclinic cyclones and might induce a remote atmospheric response by triggering stationary Rossby waves (Honda et al. 2009). In agreement with these studies, our results show enhanced storm activity originating at the Barents and Kara with disturbances entering the continent through a small sector from the Barents and Kara Seas

  7. Environmental Oceanography of the Arctic Ocean and Its Marginal Seas

    DTIC Science & Technology

    2007-11-02

    the understanding of biogeochemical cycles in the high Arctic Ocean. The first Russian, US naval joint cruise failed to survey the Northern Sea of... Okhotsk , however, assisted by SakhNIRO, Salhaline, Russia, we have been able to continue the vital investigation of this fascinating ocean. Our...publication focused on the productivity, eddy formation in the Arctic Basin and the Okhotsk Sea’s dichothermal layer.

  8. Internal tide in the Kara Gates Strait

    NASA Astrophysics Data System (ADS)

    Morozov, E. G.; Kozlov, I. E.; Shchuka, S. A.; Frey, D. I.

    2017-01-01

    We observed strong internal tidal waves in the Kara Gates Strait. Internal tides are superimposed over a system of mean currents from the Barents to the Kara Sea. Field studies of internal tides in the Kara Gates were performed in 1997, 2007, and 2015. In 2015, we analyzed data from towed CTD measurements, numerical model calculations, and satellite images in the region. An internal tidal wave with a period of 12.4 h is generated due to the interaction between the currents of the barotropic tide and the bottom relief on the slopes of a ridge that crosses the strait from Novaya Zemlya to the continent. The depths of the ridge crest are 30-40 m. A constant current of relatively warm water flows from the Barents to the Kara Sea. An internal wave propagates in both directions from the ridge. In the Barents Sea, internal waves are intensified by the current from the Barents to the Kara Sea. Internal bores followed by a packet of short-period internal waves are found in both directions from the strait. Satellite images show that short-period internal waves are generated after the internal bore. A hydraulic jump was found on the eastern side of the strait. Numerical modeling agrees with the experimental results.

  9. The influence of regional Arctic sea-ice decline on stratospheric and tropospheric circulation

    NASA Astrophysics Data System (ADS)

    McKenna, Christine; Bracegirdle, Thomas; Shuckburgh, Emily; Haynes, Peter

    2016-04-01

    region (one perturbation experiment combines all regions). These regions correspond to sea-ice loss hotspots such as the Barents-Kara Seas and the Bering Sea. The differences between the control and perturbation runs yields the effects of the imposed sea-ice loss on the polar vortex. To detect and count SSWs for each run, we use the World Meteorological Organisation's definition of an SSW (a reversal in zonal mean zonal wind at 10 hPa and 60° N, and a reversal in zonal mean meridional temperature gradient at 10 hPa between 60° N and 90° N). The poster will present and discuss the initial results of this study. Implications of the results for future change in the lower latitude mid-troposphere will be discussed. References Sun, L., C. Deser, and R. A. Tomas, 2015: Mechanisms of Stratospheric and Tropospheric Circulation Response to Projected Arctic Sea Ice Loss. J. Climate, 28, 7824-7845, doi: http://dx.doi.org/10.1175/JCLI-D-15-0169.1.

  10. Natural Variability of Arctic Sea Ice Over the Holocene

    NASA Astrophysics Data System (ADS)

    Fisher, David; Dyke, Art; Koerner, Roy; Bourgeois, Jocelyne; Kinnard, Christophe; Zdanowicz, Christian; de Vernal, Anne; Hillaire-Marcel, Claude; Savelle, James; Rochon, André

    2006-07-01

    The area and volume of sea ice in the ArcticOcean is decreasing, with some predictingice-free summers by 2100 A.D. Johannessenet al., 2004. The implications ofthese trends for transportation and ecosystemsare profound; for example, summershipping through the Northwest Passagecould be possible, while loss of sea icecould cause stress for polar bears. Moreover,global climate may be affected throughalbedo feedbacks and increased sea ice productionand export. With more open water,more new sea ice forms in winter, whichmelts and/or gets exported out of the Arctic.

  11. Skillful regional prediction of Arctic sea ice on seasonal timescales

    NASA Astrophysics Data System (ADS)

    Bushuk, Mitchell; Msadek, Rym; Winton, Michael; Vecchi, Gabriel A.; Gudgel, Rich; Rosati, Anthony; Yang, Xiaosong

    2017-05-01

    Recent Arctic sea ice seasonal prediction efforts and forecast skill assessments have primarily focused on pan-Arctic sea ice extent (SIE). In this work, we move toward stakeholder-relevant spatial scales, investigating the regional forecast skill of Arctic sea ice in a Geophysical Fluid Dynamics Laboratory (GFDL) seasonal prediction system. Using a suite of retrospective initialized forecasts spanning 1981-2015 made with a coupled atmosphere-ocean-sea ice-land model, we show that predictions of detrended regional SIE are skillful at lead times up to 11 months. Regional prediction skill is highly region and target month dependent and generically exceeds the skill of an anomaly persistence forecast. We show for the first time that initializing the ocean subsurface in a seasonal prediction system can yield significant regional skill for winter SIE. Similarly, as suggested by previous work, we find that sea ice thickness initial conditions provide a crucial source of skill for regional summer SIE.

  12. Examining Differences in Arctic and Antarctic Sea Ice Change

    NASA Astrophysics Data System (ADS)

    Nghiem, S. V.; Rigor, I. G.; Clemente-Colon, P.; Neumann, G.; Li, P.

    2015-12-01

    The paradox of the rapid reduction of Arctic sea ice versus the stability (or slight increase) of Antarctic sea ice remains a challenge in the cryospheric science research community. Here we start by reviewing a number of explanations that have been suggested by different researchers and authors. One suggestion is that stratospheric ozone depletion may affect atmospheric circulation and wind patterns such as the Southern Annular Mode, and thereby sustaining the Antarctic sea ice cover. The reduction of salinity and density in the near-surface layer may weaken the convective mixing of cold and warmer waters, and thus maintaining regions of no warming around the Antarctic. A decrease in sea ice growth may reduce salt rejection and upper-ocean density to enhance thermohalocline stratification, and thus supporting Antarctic sea ice production. Melt water from Antarctic ice shelves collects in a cool and fresh surface layer to shield the surface ocean from the warmer deeper waters, and thus leading to an expansion of Antarctic sea ice. Also, wind effects may positively contribute to Antarctic sea ice growth. Moreover, Antarctica lacks of additional heat sources such as warm river discharge to melt sea ice as opposed to the case in the Arctic. Despite of these suggested explanations, factors that can consistently and persistently maintains the stability of sea ice still need to be identified for the Antarctic, which are opposed to factors that help accelerate sea ice loss in the Arctic. In this respect, using decadal observations from multiple satellite datasets, we examine differences in sea ice properties and distributions, together with dynamic and thermodynamic processes and interactions with land, ocean, and atmosphere, causing differences in Arctic and Antarctic sea ice change to contribute to resolving the Arctic-Antarctic sea ice paradox.

  13. Long-Range Forecasting of Arctic Sea Ice

    DTIC Science & Technology

    2010-06-01

    19 1. Sea Ice Concentrations from Nimbus -7 SMMR and DMSP SSM/I Passive...LEFT BLANK 19 II. DATA AND METHODS A. DATA SETS 1. Sea Ice Concentrations from Nimbus -7 SMMR and DMSP SSM/I Passive Microwave Data The sea ice...for Arctic sea ice research in the past. (e.g., Deser and Teng 2008). The data set is generated from brightness temperature derived from Nimbus -7

  14. Arctic sea ice in 2016: A preview of the future

    NASA Astrophysics Data System (ADS)

    Stroeve, Julienne; Serreze, Mark; Ornaheim, Ingrid; Holland, Marika; Vavrus, Stephen; Meier, Walt; Scambos, Ted; Fetterer, Florence

    2017-04-01

    The Arctic is warming twice as fast as the global average, resulting in dramatic thinning and shrinkage of the Arctic sea ice cover. In recent years the ice loss has accelerated and the 10 lowest summer sea ice extents have all occurred within the last 10 years, leading to the real possibility that the Arctic Ocean will become ice-free during summer by about mid-century. This ice loss has profound consequences for ecosystems in the Arctic and economic activities. The prospect of longer open water periods has led to an urgent need to predict sea ice conditions at the pan-Arctic and regional scales. However, as the Arctic Ocean heads towards seasonally ice-free conditions, a period of large variability is expected, making it more difficult to forecast ice conditions. This year saw the largest departures yet from the long-term mean, with each month falling more than 2 standard deviations below the long-term mean, and several months more than 3. This was unprecedented and resulted in 2016 having the lowest annual sea ice extent recorded during the satellite and historical sea ice data record. These large departures from climatology coincide with increased variability in late summer and autumn ice conditions observed since 2007. Together with climate model simulations from the CESM Large Ensemble (LE) we evaluate whether or not the observed increase in variance foreshadows a shift to seasonal ice-free conditions.

  15. Observations of atmospheric methane and its stable isotope ratio (δ13C) over the Russian Arctic seas from ship cruises in the summer and autumn of 2015

    NASA Astrophysics Data System (ADS)

    Skorokhod, A. I.; Pankratova, N. V.; Belikov, I. B.; Thompson, R. L.; Novigatsky, A. N.; Golitsyn, G. S.

    2016-10-01

    The results of experimental measurements of atmospheric methane concentrations and its isotopic composition in the Russian Arctic seas in the summer and autumn of 2015 are discussed. The Keeling plot method and inverse number simulation were used for revealing the factors responsible for elevated methane concentrations over the sea surface. Its maximum concentrations (up to 2050 ppb) were measured over the Kara and Laptev seas, as well as in the port area of Arkhangel'sk. It is shown that tundra and bog ecosystems of Siberia serve as the main sources of methane in the measurement zone (except for the area adjacent to large ports). As a whole, the share of methane from microbiological sources is as high as approximately 43% of the total methane concentrations along the ship route.

  16. The impact of the Arctic Sea Ice retreat on extratropical cyclones and anticyclones over Northern Eurasia: atmospheric model simulations

    NASA Astrophysics Data System (ADS)

    Akperov, Mirseid; Semenov, Vladimir; Mokhov, Igor; Lupo, Antony

    2015-04-01

    The Arctic region has been warming more than twice as fast as the other parts of the world during the last few decades. The rapid Arctic warming is accompanied with the dramatic change of Arctic sea ice cover. Recently, it has been suggested that such climatic changes might have led to the increase of anomalous weather events in winter over Northern Eurasia. One example is anomalous cold winters over Northern Eurasia associated with atmospheric blocking events. However, a large uncertainty remains concerning robustness of the observed relationship and associated mechanisms of impact. The main goal of this research is to explore the connection between the declining Arctic sea ice (most strongly expressed in the Barents-Kara Seas region) in the cold season and the change of cyclonic and anti-cyclonic activity over Northern Eurasia using simulations with atmospheric general circulation model (AGCM). The simulations were performed with the ECHAM5 AGCM using identical sea surface temperature climatology but different sea ice concentrations (SIC) for the periods corresponding to the high (1966-1969), low (1990-1995) and very low (2005-2012) SIC regimes in the Arctic as well as for the mean climatological SIC for 1971-2000. The duration of each simulation was 50 years. For the regimes with high and very low SIC, a statistically significant increase in the number of long-living anticyclones (with lifetime of more than 5 days) over Northern Eurasia was found. Long-living cyclones exhibited different changes in their number depending on their intensity. The analysis of the spatial patterns of cyclonic and anti-cyclonic activity over Eurasia was performed. We found an increase of the frequency of cyclones over the central region of the European part of Russia (EPR) and anticyclones over the northern region of the EPR for the regimes with a high sea ice concentration in the Arctic. For the regime with very low SIC the shift of the frequency of cyclones and anticyclones towards

  17. Implications of Arctic Sea Ice Reduction on Arctic Tropospheric Chemical Change (Invited)

    NASA Astrophysics Data System (ADS)

    Nghiem, S. V.

    2009-12-01

    We examine the drastic reduction of Arctic sea ice in this decade and discuss the potential implications on bromine, ozone, and mercury change in the Arctic troposphere. We are witnessing extraordinary change in the Arctic sea ice cover. In the context of a half century change, perennial sea ice, the class of thicker and older ice important to the stability of Arctic sea ice, has been declining precipitously in this decade. Perennial ice extent declines at rate of 0.5 million km2 per decade in the 1970s-1990s while there is no discernable trend in the 1950s-1960s. Abruptly, the rate of decrease has tripled to 1.5 million km2 per decade in the 2000s. A record was set in the reduction of Arctic perennial ice extent in winter 2008. By 1 March 2008, perennial ice extent was reduced by one million km2 compared to that at the same time in 2007, which continued the precipitous declining trend observed in this decade. While the record low of total ice extent in summer 2007 is a historical mark of sea ice loss, the distribution and extent of different sea ice classes in spring (March-May) are critical information to understand the implications of sea ice reduction on photochemical processes, such as bromine explosions, ozone depletion episodes (ODEs), gaseous elementary mercury depletion episodes (MDEs), which occur at the time of polar sunrise. In this regard, the drastic reduction of perennial ice means that the Arctic becomes dominated by seasonal ice consisting of thinner ice, more leads, polynyas, frost flowers, and salty snow (due to seawater spray from open water), representing the overall saltier condition of the Arctic sea ice cover conducive to ice-mediated chemical processes leading to Arctic tropospheric ODEs and MDEs. To date (2009), the extent of perennial sea ice remains low and the extent of the thinner and saltier seasonal ice continues to dominate the Arctic sea ice cover. The shift of the state of Arctic sea ice cover to the dominance domain of seasonal

  18. Arctic Sea Ice and Its Changes during the Satellite Period

    NASA Astrophysics Data System (ADS)

    Wang, X.; Liu, Y.; Key, J. R.

    2009-12-01

    Sea ice is a very important indicator and an effective modulator of regional and global climate change. Changes in sea ice will significantly affect the complex exchanges of momentum, heat, and mass between sea and the atmosphere, along with profound socio-economic influences due to its role in transportation, fisheries, hunting, polar animal habitat. Over the last two decades of the 20th century, the Arctic underwent significant changes in sea ice as part of the accelerated global warming of that period. More accurate, consistent, and detailed ice thickness, extent, and volume data are critical for a wide range of applications including climate change detection, climate modeling, and operational applications such as shipping and hazard mitigation. Satellite data provide an unprecedented opportunity to estimate and monitor Arctic sea ice routinely with relatively high spatial and temporal resolutions. In this study, a One-dimensional Thermodynamic Ice Model (OTIM) has been developed to estimate sea ice thickness based on the surface energy balance at a thermo-equilibrium state, containing all components of the surface energy balance. The OTIM has been extensively validated against submarine Upward-Looking Sonar (ULS) measurements, meteorological station measurements, and comprehensive numerical model simulations. Overall, OTIM-estimated sea ice thickness is accurate to within about 20% error when compared to submarine ULS ice thickness measurements and Canadian meteorological station measurements for ice less than 3 m. Along with sea ice extent information from the SSM/I, the Arctic sea ice volume can be estimated for the satellite period from 1984 to 2004. The OTIM has been used with satellite data from the extended Advanced Very High Resolution Radiometer (AVHRR) Polar Pathfinder (APP-x) products for the Arctic sea ice thickness, and sequentially sea ice volume estimations, and following statistical analysis of spatial and temporal distribution and trends in sea

  19. Attribution of the Recent Winter Arctic warming and Sea-Ice Decline with Observation-based Data and Coupled Climate Model Simulations

    NASA Astrophysics Data System (ADS)

    Lee, S.; Park, D. S. R.; Feldstein, S. B.; Franzke, C. L. E.

    2015-12-01

    Wintertime Arctic sea ice extent has been declining since the late 20th century, particularly over the Atlantic sector that encompasses the Barents-Kara Seas and Baffin Bay. This sea-ice decline is attributable to various Arctic environmental changes, such as enhanced downward infrared radiation (IR), preseason sea-ice reduction, enhanced inflow of warm Atlantic water into the Arctic Ocean, and sea-ice export. However, their relative contributions are uncertain. Utilizing ERA-Interim reanalysis and satellite-based data, it is shown here that a positive trend of downward IR accounts for nearly half of the sea-ice concentration (SIC) decline during the 1979-2011 winter over the Atlantic sector. Furthermore, we find that the Arctic downward IR increase is driven by horizontal atmospheric water flux and warm air advection into the Arctic, and not by evaporation and surface heat flux from the Arctic Ocean. These horizontal heat fluxes are linked to La-Nina-like tropical convection. In all CMIP5 climate models that are analyzed here, high pattern correlations are found between the surface air temperature trend and downward IR trend. However, there are two groups of CMIP5 models: one with small correlations between the Arctic surface air temperature trend and the surface heat flux trend (Group 1), and the other with large correlations (Group 2) between the same two variables. There is evidence that the Group 1 models are consistent with the aforementioned observation-based finding that the Arctic warming is closely related to large-scale circulation changes. In contrast, the Group 2 models are at odds with this observation in that their Arctic warming is more closely tied to surface heat fluxes than with the large-scale circulation change. Interestingly, while Group 1 models have a warm or weak bias, Group 2 models have large cold biases in the Arctic. This difference suggests that deficiencies that cause the cold bias of the mean state may contribute to the surface heat

  20. EOS Aqua AMSR-E Arctic Sea Ice Validation Program: Arctic2003 Aircraft Campaign Flight Report

    NASA Technical Reports Server (NTRS)

    Cavalieri, D. J.; Markus,T.

    2003-01-01

    In March 2003 a coordinated Arctic sea ice validation field campaign using the NASA Wallops P-3B aircraft was successfully completed. This campaign was part of the program for validating the Earth Observing System (EOS) Aqua Advanced Microwave Scanning Radiometer (AMSR-E) sea ice products. The AMSR-E, designed and built by the Japanese National Space Development Agency for NASA, was launched May 4, 2002 on the EOS Aqua spacecraft. The AMSR-E sea ice products to be validated include sea ice concentration, sea ice temperature, and snow depth on sea ice. This flight report describes the suite of instruments flown on the P-3, the objectives of each of the seven flights, the Arctic regions overflown, and the coordination among satellite, aircraft, and surface-based measurements. Two of the seven aircraft flights were coordinated with scientists making surface measurements of snow and ice properties including sea ice temperature and snow depth on sea ice at a study area near Barrow, AK and at a Navy ice camp located in the Beaufort Sea. Two additional flights were dedicated to making heat and moisture flux measurements over the St. Lawrence Island polynya to support ongoing air-sea-ice processes studies of Arctic coastal polynyas. The remaining flights covered portions of the Bering Sea ice edge, the Chukchi Sea, and Norton Sound.

  1. Multi-fractal structure in Arctic sea ice satellite data

    NASA Astrophysics Data System (ADS)

    Moon, W.; Wettlaufer, J. S.

    2011-12-01

    Since 21th century, Arctic sea ice has shown significant decrease especially during summer season. These decline has been considered by climate scientists as a critical sign of the effect of global warming. Especially, IPCC global climate models confirmed the recent decline of Arctic sea ice and predict the more decline in the near future. Even with rather significant amount of inter-model variability in climate models, satellite data during around 30 years support the results of climate models. However, the decline of Arctic sea ice is confirmed based on monthly averaged data and linear regression after erasing seasonal cycle. Even with strong conjecture of the real decline of Arctic sea ice, we cannot exclude one part of natural oscillations affecting Arctic sea ice physics due to strong non-stationarity. It is also possible not to make any conclusive statements using the monthly averaged data due to a lack of data or multi-fractal structure of data excluded in the data. Here, we will use MF-DFA (Multi-Fractal Detrended Fluctuation Analysis) to determine the multi-scale structure of Arctic sea ice area and albedo using AVHRR Polar Pathfinder Twice-Daily 5km EASE-grid composites, which is expected to decide whether the decline shown in the linear regression of the monthly averaged data can be considered as the real decline caused by global warming or not. Also, the multi-scale structure information drawn from this analysis is expected to give us the guideline for selecting significant physics for low-order Arctic sea ice

  2. Arctic and Antarctic Sea Ice Changes and Impacts (Invited)

    NASA Astrophysics Data System (ADS)

    Nghiem, S. V.

    2013-12-01

    The extent of springtime Arctic perennial sea ice, important to preconditioning summer melt and to polar sunrise photochemistry, continues its precipitous reduction in the last decade marked by a record low in 2012, as the Bromine, Ozone, and Mercury Experiment (BROMEX) was conducted around Barrow, Alaska, to investigate impacts of sea ice reduction on photochemical processes, transport, and distribution in the polar environment. In spring 2013, there was further loss of perennial sea ice, as it was not observed in the ocean region adjacent to the Alaskan north coast, where there was a stretch of perennial sea ice in 2012 in the Beaufort Sea and Chukchi Sea. In contrast to the rapid and extensive loss of sea ice in the Arctic, Antarctic sea ice has a trend of a slight increase in the past three decades. Given the significant variability in time and in space together with uncertainties in satellite observations, the increasing trend of Antarctic sea ice may arguably be considered as having a low confidence level; however, there was no overall reduction of Antarctic sea ice extent anywhere close to the decreasing rate of Arctic sea ice. There exist publications presenting various factors driving changes in Arctic and Antarctic sea ice. After a short review of these published factors, new observations and atmospheric, oceanic, hydrological, and geological mechanisms contributed to different behaviors of sea ice changes in the Arctic and Antarctic are presented. The contribution from of hydrologic factors may provide a linkage to and enhance thermal impacts from lower latitudes. While geological factors may affect the sensitivity of sea ice response to climate change, these factors can serve as the long-term memory in the system that should be exploited to improve future projections or predictions of sea ice changes. Furthermore, similarities and differences in chemical impacts of Arctic and Antarctic sea ice changes are discussed. Understanding sea ice changes and

  3. Multifractals, random walks and Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Agarwal, Sahil; Wettlaufer, John

    We examine the long-term correlations and multifractal properties of daily satellite retrievals of Arctic sea ice albedo, extent, and ice velocity for decadal periods. The approach harnesses a recent development called Multifractal Temporally Weighted Detrended Fluctuation Analysis (MF-TWDFA), which exploits the intuition that points closer in time are more likely to be related than distant points. In both data sets we extract multiple crossover times, as characterized by generalized Hurst exponents, ranging from synoptic to decadal. The method goes beyond treatments that assume a single decay scale process, such as a first-order autoregression, which cannot be justifiably fit to these observations. The ice extent data exhibits white noise behavior from seasonal to bi-seasonal time scales, whereas the clear fingerprints of the short (weather) and long (~ 7 and 9 year) time scales remain, the latter associated with the recent decay in the ice cover. Thus, long term persistence is reentrant beyond the seasonal scale and it is not possible to distinguish whether a given ice extent minimum/maximum will be followed by a minimum/maximum that is larger or smaller in magnitude. The ice velocity data show long term persistence in auto covariance. NASA Grant NNH13ZDA001N-CRYO and Swedish Research Council Grant No. 638-2013-9243.

  4. Impact of declining Arctic sea ice on winter snowfall.

    PubMed

    Liu, Jiping; Curry, Judith A; Wang, Huijun; Song, Mirong; Horton, Radley M

    2012-03-13

    While the Arctic region has been warming strongly in recent decades, anomalously large snowfall in recent winters has affected large parts of North America, Europe, and east Asia. Here we demonstrate that the decrease in autumn Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation that have some resemblance to the negative phase of the winter Arctic oscillation. However, the atmospheric circulation change linked to the reduction of sea ice shows much broader meridional meanders in midlatitudes and clearly different interannual variability than the classical Arctic oscillation. This circulation change results in more frequent episodes of blocking patterns that lead to increased cold surges over large parts of northern continents. Moreover, the increase in atmospheric water vapor content in the Arctic region during late autumn and winter driven locally by the reduction of sea ice provides enhanced moisture sources, supporting increased heavy snowfall in Europe during early winter and the northeastern and midwestern United States during winter. We conclude that the recent decline of Arctic sea ice has played a critical role in recent cold and snowy winters.

  5. North Pacific climate variability and Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Linkin, Megan E.

    Boreal winter North Pacific climate variability strongly influences North American hydroclimate and Arctic sea ice distribution in the marginal Arctic seas. Two modes of atmospheric variability explaining 53% of the variance in the Pacific Ocean sea level pressure (SLP) field are extracted and identified: the Pacific-North American (PNA) teleconnection and the North Pacific Oscillation/West Pacific (NPO/WP) teleconnection. The NPO/WP, a dipole in North Pacific SLP and geopotential heights, is affiliated with latitudinal displacements of the Asian Pacific jet and an intensification of the Pacific stormtrack. The North American hydroclimate impacts of the NPO/WP are substantial; its impact on Alaska, Pacific Northwest and Great Plains precipitation is more influential than both the PNA and the El Nino-Southern Oscillation (ENSO). The NPO/WP is also strongly associated with a contemporaneous extension of the marginal ice zone (MIZ) in the western Bering Sea and Sea of Okhotsk and MIZ retreat in the eastern Bering Sea. Wintertime climate variability also significantly impacts the distribution of Arctic sea ice during the subsequent summer months, due to the hysteretic nature of the ice cap. The North Atlantic Oscillation (NAO) is known for its effects on summer sea ice distribution; this study extends into the Pacific and finds that circulation anomalies related to Pacific sea surface temperature (SST) variability also strongly impact summer Arctic sea ice. The NAO and ENSO are related to sea ice decline in the Eastern Siberian Sea, where the linear trend since 1979 is 25% per decade. PDV affects sea ice in the eastern Arctic, a region which displays no linear trend since 1979. The low frequency of PDV variability and the persistent positive NAO during the 1980s and 1990s results in natural variability being aliased into the total linear trend in summer sea ice calculated from satellite-based sea ice concentration. Since 1979, natural variability accounts for 30% of

  6. Sea ice data for all: NSIDC's Arctic Sea Ice News & Analysis

    NASA Astrophysics Data System (ADS)

    Vizcarra, N.; Stroeve, J. C.; Serreze, M. C.; Scambos, T. A.; Meier, W.

    2014-12-01

    Arctic sea ice has long been recognized as a sensitive climate indicator and has undergone a dramatic decline over the past thirty years. The National Snow and Ice Data Center's Arctic Sea Ice News & Analysis blog continues to offer the public a transparent view of sea ice data and analysis. We have expanded our interactive sea ice graph to include Antarctic sea ice in response to increased attention from the public as a result of unexpected behavior of sea ice in the south. This poster explores the blog's new features and how other researchers, the media, and the public are currently using them.

  7. [Spectral features analysis of sea ice in the Arctic Ocean].

    PubMed

    Ke, Chang-qing; Xie, Hong-jie; Lei, Rui-bo; Li, Qun; Sun, Bo

    2012-04-01

    Sea ice in the Arctic Ocean plays an important role in the global climate change, and its quick change and impact are the scientists' focus all over the world. The spectra of different kinds of sea ice were measured with portable ASD FieldSpec 3 spectrometer during the long-term ice station of the 4th Chinese national Arctic Expedition in 2010, and the spectral features were analyzed systematically. The results indicated that the reflectance of sea ice covered by snow is the highest one, naked sea ice the second, and melted sea ice the lowest. Peak and valley characteristics of spectrum curves of sea ice covered by thick snow, thin snow, wet snow and snow crystal are very significant, and the reflectance basically decreases with the wavelength increasing. The rules of reflectance change with wavelength of natural sea ice, white ice and blue ice are basically same, the reflectance of them is medium, and that of grey ice is far lower than natural sea ice, white ice and blue ice. It is very significant for scientific research to analyze the spectral features of sea ice in the Arctic Ocean and to implement the quantitative remote sensing of sea ice, and to further analyze its response to the global warming.

  8. Interdecadal changes in snow depth on Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Webster, Melinda A.; Rigor, Ignatius G.; Nghiem, Son V.; Kurtz, Nathan T.; Farrell, Sinead L.; Perovich, Donald K.; Sturm, Matthew

    2014-08-01

    Snow plays a key role in the growth and decay of Arctic sea ice. In winter, it insulates sea ice from cold air temperatures, slowing sea ice growth. From spring to summer, the albedo of snow determines how much insolation is absorbed by the sea ice and underlying ocean, impacting ice melt processes. Knowledge of the contemporary snow depth distribution is essential for estimating sea ice thickness and volume, and for understanding and modeling sea ice thermodynamics in the changing Arctic. This study assesses spring snow depth distribution on Arctic sea ice using airborne radar observations from Operation IceBridge for 2009-2013. Data were validated using coordinated in situ measurements taken in March 2012 during the Bromine, Ozone, and Mercury Experiment (BROMEX) field campaign. We find a correlation of 0.59 and root-mean-square error of 5.8 cm between the airborne and in situ data. Using this relationship and IceBridge snow thickness products, we compared the recent results with data from the 1937, 1954-1991 Soviet drifting ice stations. The comparison shows thinning of the snowpack, from 35.1 ± 9.4 to 22.2 ± 1.9 cm in the western Arctic, and from 32.8 ± 9.4 to 14.5 ± 1.9 cm in the Beaufort and Chukchi seas. These changes suggest a snow depth decline of 37 ± 29% in the western Arctic and 56 ± 33% in the Beaufort and Chukchi seas. Thinning is negatively correlated with the delayed onset of sea ice freezeup during autumn.

  9. A Lagrangian analysis of sea ice dynamics in the Arctic

    NASA Astrophysics Data System (ADS)

    Szanyi, S.; Lukovich, J. V.; Haller, G.; Barber, D. G.

    2014-12-01

    Recent studies have highlighted acceleration in sea ice drift and deformation in the Arctic over the last several decades, underlining the need for improved understanding of sea ice dynamics and dispersion. In this study we present Lagrangian diagnostics to quantify changes in the dynamical characteristics of the Arctic sea ice cover from 1979 to 2012 during the transition from a predominantly multi-year to a first-year ice regime. Examined in particular is the evolution in finite-time Lyapunov exponents (FTLEs), which monitor the rate at which neighboring particle trajectories diverge, and stretching rates throughout the Arctic. In this analysis we compute FTLEs for the Arctic ice drift field using National Snow and Ice Data Centre (NSIDC) Polar Pathfinder Daily 25 km EASE-Grid weekly sea ice motion vectors for the annual cycle beginning both from the sea ice minimum in September, and maximum in March. Sensitivity analyses show that maximal FTLEs, or ridges, are robust even with the introduction of significant noise. Probability density functions and mean values of FTLEs show a trend towards higher FTLE values characteristic of increased mixing in the Arctic in the last decade, in keeping with a transition to a weaker, thinner ice cover.

  10. Export of algal biomass from the melting Arctic sea ice.

    PubMed

    Boetius, Antje; Albrecht, Sebastian; Bakker, Karel; Bienhold, Christina; Felden, Janine; Fernández-Méndez, Mar; Hendricks, Stefan; Katlein, Christian; Lalande, Catherine; Krumpen, Thomas; Nicolaus, Marcel; Peeken, Ilka; Rabe, Benjamin; Rogacheva, Antonina; Rybakova, Elena; Somavilla, Raquel; Wenzhöfer, Frank

    2013-03-22

    In the Arctic, under-ice primary production is limited to summer months and is restricted not only by ice thickness and snow cover but also by the stratification of the water column, which constrains nutrient supply for algal growth. Research Vessel Polarstern visited the ice-covered eastern-central basins between 82° to 89°N and 30° to 130°E in summer 2012, when Arctic sea ice declined to a record minimum. During this cruise, we observed a widespread deposition of ice algal biomass of on average 9 grams of carbon per square meter to the deep-sea floor of the central Arctic basins. Data from this cruise will contribute to assessing the effect of current climate change on Arctic productivity, biodiversity, and ecological function.

  11. Total and methylated mercury in Arctic multiyear sea ice.

    PubMed

    Beattie, Sarah A; Armstrong, Debbie; Chaulk, Amanda; Comte, Jérôme; Gosselin, Michel; Wang, Feiyue

    2014-05-20

    Mercury is one of the primary contaminants of concern in the Arctic marine ecosystem. While considerable efforts have been directed toward understanding mercury cycling in the Arctic, little is known about mercury dynamics within Arctic multiyear sea ice, which is being rapidly replaced with first-year ice. Here we report the first study on the distribution and potential methylation of mercury in Arctic multiyear sea ice. Based on three multiyear ice cores taken from the eastern Beaufort Sea and McClure Strait, total mercury concentrations ranged from 0.65 to 60.8 pM in bulk ice, with the highest values occurring in the topmost layer (∼40 cm) which is attributed to the dynamics of particulate matter. Methylated mercury concentrations ranged from below the method detection limit (<0.1 pM) to as high as 2.64 pM. The ratio of methylated to total mercury peaked, up to ∼40%, in the mid to bottom sections of the ice, suggesting the potential occurrence of in situ mercury methylation. The annual fluxes of total and methylated mercury into the Arctic Ocean via melt of multiyear ice are estimated to be 420 and 42 kg yr(-1), respectively, representing an important and changing source of mercury and methylmercury into the Arctic Ocean marine ecosystem.

  12. Warming in the Nordic Seas, North Atlantic storms and thinning Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Alexeev, Vladimir A.; Walsh, John E.; Ivanov, Vladimir V.; Semenov, Vladimir A.; Smirnov, Alexander V.

    2017-08-01

    Arctic sea ice 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 ice 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 ice growth or even melting. Our analysis indicates that the recently observed sea ice decline in the Nordic Seas during the cold season around Svalbard, 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 ice at the end of the winter. This change in the surface budget is an important contributing factor accelerating the thinning of Arctic sea ice.

  13. NASA Science Flights Target Melting Arctic Sea Ice

    NASA Image and Video Library

    2017-09-28

    This summer, with sea ice across the Arctic Ocean shrinking to below-average levels, a NASA airborne survey of polar ice just completed its first flights. Its target: aquamarine pools of melt water on the ice surface that may be accelerating the overall sea ice retreat. NASA’s Operation IceBridge completed the first research flight of its new 2016 Arctic summer campaign on July 13. The science flights, which continue through July 25, are collecting data on sea ice in a year following a record-warm winter in the Arctic. Read more: go.nasa.gov/29T6mxc Caption: A large pool of melt water over sea ice, as seen from an Operation IceBridge flight over the Beaufort Sea on July 14, 2016. During this summer campaign, IceBridge will map the extent, frequency and depth of melt ponds like these to help scientists forecast the Arctic sea ice yearly minimum extent in September. Credit: NASA/Operation IceBridge

  14. Interactions Between Arctic Sea Ice, Clouds, and the Circulation

    NASA Astrophysics Data System (ADS)

    Taylor, P. C.; Kato, S.; Xu, K. M.; Baker, N. C.

    2014-12-01

    The Arctic is one of the most climatically sensitive regions of the Earth. Climate models robustly project the Arctic to warm 2-3 times faster than the global mean surface temperature—termed polar warming amplification (PWA)—but also display the widest range of surface temperature projections in this region. The response of the Arctic to increased CO2 modulates the response in tropical and extra-tropical regions through teleconnections in the atmospheric circulation. An increased frequency of extreme precipitation events in the northern mid-latitudes, for example, has been linked to the change in the background equator-to-pole temperature gradient implied by PWA. Understanding the Arctic climate system is therefore important for predicting global climate change. The ice albedo feedback is the primary mechanism driving PWA, however cloud and dynamical feedbacks significantly contribute. These feedback mechanisms, however, do not operate independently. How do clouds respond to variations in sea ice? This critical question is addressed by combining sea ice, cloud, and radiation observations from satellites—including CERES, CloudSAT, CALIPSO, MODIS, and microwave radiometers—to investigate sea ice-cloud interactions at the interannual timescale in the Arctic. Cloud characteristics are strongly tied to the atmospheric dynamic and thermodynamic state. Therefore, the sensitivity of Arctic cloud characteristics—vertical distribution and optical properties—to sea ice anomalies is computed within atmospheric dynamic and thermodynamic regimes. Results indicate that the cloud response to changes in sea ice concentration differs significantly between atmospheric state regimes. This suggests that (1) the atmospheric dynamic and thermodynamic characteristics and (2) the characteristics of the marginal ice zone are important for determining the seasonal forcing by cloud on sea ice variability.

  15. Evaluation of Arctic Sea Ice Thickness Simulated by Arctic Ocean Model Intercomparison Project Models

    NASA Technical Reports Server (NTRS)

    Johnson, Mark; Proshuntinsky, Andrew; Aksenov, Yevgeny; Nguyen, An T.; Lindsay, Ron; Haas, Christian; Zhang, Jinlun; Diansky, Nikolay; Kwok, Ron; Maslowski, Wieslaw; Hakkinen, Sirpa; Ashik, Igor; De Cuevas, Beverly

    2012-01-01

    Six Arctic Ocean Model Intercomparison Project model simulations are compared with estimates of sea ice thickness derived from pan-Arctic satellite freeboard measurements (2004-2008); airborne electromagnetic measurements (2001-2009); ice draft data from moored instruments in Fram Strait, the Greenland Sea, and the Beaufort Sea (1992-2008) and from submarines (1975-2000); and drill hole data from the Arctic basin, Laptev, and East Siberian marginal seas (1982-1986) and coastal stations (1998-2009). Despite an assessment of six models that differ in numerical methods, resolution, domain, forcing, and boundary conditions, the models generally overestimate the thickness of measured ice thinner than approximately 2 mand underestimate the thickness of ice measured thicker than about approximately 2m. In the regions of flat immobile landfast ice (shallow Siberian Seas with depths less than 25-30 m), the models generally overestimate both the total observed sea ice thickness and rates of September and October ice growth from observations by more than 4 times and more than one standard deviation, respectively. The models do not reproduce conditions of fast ice formation and growth. Instead, the modeled fast ice is replaced with pack ice which drifts, generating ridges of increasing ice thickness, in addition to thermodynamic ice growth. Considering all observational data sets, the better correlations and smaller differences from observations are from the Estimating the Circulation and Climate of the Ocean, Phase II and Pan-Arctic Ice Ocean Modeling and Assimilation System models.

  16. Arctic temperature amplification and sea-ice melt

    NASA Astrophysics Data System (ADS)

    Graversen, R. G.; Kapsch, M.; Mauritzen, T.; Tjernström, M.

    2012-04-01

    In recent decades, Arctic temperatures increase more than the global average - this has become known as Arctic temperature amplification. At the same time, Arctic sea-ice extent is shrinking with a pace being largest in summer. Reanalysis data show Arctic temperature amplification in the free troposphere above the boundary layer. In summer this warming aloft cannot be attributed to surface processes. This is because the surface-air temperature trends are modest in the Arctic during summer, since the ice-melt keeps the temperatures close to the melting point. Rather the warming in the free troposphere could be due to changes of the heat advection into the Arctic and changes of the cloudiness. The warming aloft induces an increase of the energy flux towards the surface in terms of longwave radiation and turbulent fluxes, which contributes to the sea-ice melt during summer. When the ice melts, surface-based processes start acting, among them the surface-albedo feedback where the sea-ice reduction leads to an increase of absorption of solar radiation. During summer, the excess of energy at the surface is stored in the ocean, both internally as heat, and latently due to the ice melt. This energy is released during the following autumn and winter causing positive surface-air temperature in these seasons. The extreme ice melt in 2007 is an example of this chain of processes. During the summer of 2007 the Arctic sea ice shrank to the lowest extent ever observed. Using the state-of-the-art ERA-Interim reanalysis data, the role of the atmospheric energy transport in this extreme melt event is explored.

  17. EOS Aqua AMSR-E Arctic Sea Ice Validation Program

    NASA Technical Reports Server (NTRS)

    Cavalieri, D. J.; Markus, T.; Gasiewski, A.; Klein, M.; Maslanik, J.; Sturm, M.; Stroeve, J.; Heinrichs, J.

    2004-01-01

    A coordinated Arctic sea ice validation field campaign using the NASA Wallops P-3B aircraft was successfully completed in March 2003. This campaign was part of the program for validating the Earth Observing System (EOS) Aqua Advanced Microwave Scanning Radiometer (AMSR-E) sea ice products. The AMSR-E, designed and built by the Japanese National Space Development Agency for NASA, was launched May 4,2002 on the EOS Aqua spacecraft. The AMSR-E sea ice products include sea ice concentration, sea ice temperature, and snow depth on sea ice. The primary instrument on the P-3B aircraft was the NOAA ETL Polarimetric Scanning Radiometer (PSR) covering the same frequencies and polarizations as the AMSR-E. This paper describes the objectives of each of the seven flights, the Arctic regions overflown, and the coordination among satellite, aircraft, and surface-based measurements. Two of the seven aircraft flights were coordinated with scientists making surface measurements of snow and ice properties including sea ice temperature and snow depth on sea ice at a study area near Barrow, AK and at a Navy ice camp located in the Beaufort Sea. The remaining flights covered portions of the Bering Sea ice edge, the Chukchi Sea, and Norton Sound. Comparisons among the satellite and aircraft PSR data sets are presented.

  18. Increased snow contribution to Arctic sea ice mass balance

    NASA Astrophysics Data System (ADS)

    Granskog, M. A.; Rösel, A.; Provost, C.; Sennechael, N.; Dodd, P. A.; Martma, T.; Leng, M. J.

    2016-12-01

    Traditionally snow on Arctic sea ice has not been considered as a significant component of the mass balance of the (solid) ice cover, due to the low snow to ice thickness ratio. In contrast, snow contributes significantly to the mass balance of Antarctic sea ice due to thinner seasonal ice and thicker snow cover, similar to Arctic marginal seas, such as the Baltic and Okhotsk seas. Recent observations from the N-ICE2015 campaign, conducted in January-June 2015 in the rather thin ice pack north of Svalbard, imply that with a thinning of the Arctic ice pack, snow turned into ice, either as refrozen snow meltwater at the ice surface (superimposed ice) or snow-ice formed due to flooding of the bottom of the snow pack by seawater, can contribute significantly to Arctic sea ice mass balance. We provide evidence from both sea ice cores (from textural and isotope data) and ice mass balance buoys (IMB) with thermistor chains using a heating cycle to detect different media (air/snow/ice/water). Observations indicate that snow-ice or superimposed ice has formed in fall/winter likely when the ice was thin due to summer melt and heavy snow fall early in the freezing season. IMB records from winter/spring showcase the rapid formation of snow-ice due to flooding by seawater after re-adjustment of isostacy in response to: i) deformation events (likely related to changes in floe size) and ii) bottom ice melt over warmer Atlantic waters north of Svalbard. In summary the new data indicate that snow-ice or superimposed can contribute up to about 30% of total sea ice thickness, unprecedented from any earlier records in the high-Arctic.

  19. Global Fiducials Program - Arctic Buoy Sea Ice Studies

    NASA Astrophysics Data System (ADS)

    Wilson, E. M.; Wilds, S. R.; Friesen, B. A.; Sloan, J. L.

    2012-12-01

    The U.S. Geological Survey has utilized remotely sensed imagery to analyze Arctic Sea Ice since 1997, and has collected and created thousands of Literal Image Derived Products (LIDPS) at one meter resolution for public distribution. From 1997-2012, six static sea ice sites located in the Arctic Basin were selected and added to the Global Fiducial Library (GFL), to create an annual series of geographically referenced images to allow scientists to study seasonal changes in Arctic ice. In early 2009, a scientific group known as MEDEA (Measurements of Earth Data for Environmental Analysis) requested additional collections to track ice floe movements during the course of an entire summer (April through September), to better understand seasonal changes in the Arctic Sea Ice. In order to track and capture the same ice cover over time, USGS adopted a methodology to utilize buoys deployed at various locations across the Arctic by the International Arctic Buoy Program. The data buoys record and transmit hourly GPS positions, along with meteorologic and climatologic data associated with the sea ice in which they are anchored. Repeated imaging of the ice cover is guided by the data buoy GPS to help estimate travel direction and speed of the ice cover. Imagery is referenced by the MEDEA scientists to study ice fracture patterns, sea ice ridge heights, ice cover percentages, seasonal development and coverage of melt ponds, evolution of ice concentrations, floe size distribution, lateral melting, and other variables that are used for input to refine and develop climate models. These same ice floe images have been added to the GFL for various buoy locations from 2009 through 2011, and are being acquired for the 2012 summer season.

  20. Light Absorption in Arctic Sea Ice - Black Carbon vs Chlorophyll

    NASA Astrophysics Data System (ADS)

    Ogunro, O. O.; Wingenter, O. W.; Elliott, S.; Hunke, E. C.; Flanner, M.; Wang, H.; Dubey, M. K.; Jeffery, N.

    2015-12-01

    The fingerprint of climate change is more obvious in the Arctic than any other place on Earth. This is not only because the surface temperature there has increased at twice the rate of global mean temperature but also because Arctic sea ice extent has reached a record low of 49% reduction relative to the 1979-2000 climatology. Radiation absorption through black carbon (BC) deposited on Arctic snow and sea ice surface is one of the major hypothesized contributors to the decline. However, we note that chlorophyll-a absorption owing to increasing biology activity in this region could be a major competitor during boreal spring. Modeling of sea-ice physical and biological processes together with experiments and field observations promise rapid progress in the quality of Arctic ice predictions. Here we develop a dynamic ice system module to investigate discrete absorption of both BC and chlorophyll in the Arctic, using BC deposition fields from version 5 of Community Atmosphere Model (CAM5) and vertically distributed layers of chlorophyll concentrations from Sea Ice Model (CICE). To this point, our black carbon mixing ratios compare well with available in situ data. Both results are in the same order of magnitude. Estimates from our calculations show that sea ice and snow around the Canadian Arctic Archipelago and Baffin Bay has the least black carbon absorption while values at the ice-ocean perimeter in the region of the Barents Sea peak significantly. With regard to pigment concentrations, high amounts of chlorophyll are produced in Arctic sea ice by the bottom microbial community, and also within the columnar pack wherever substantial biological activity takes place in the presence of moderate light. We show that the percentage of photons absorbed by chlorophyll in the spring is comparable to the amount attributed to BC, especially in areas where the total deposition rates are decreasing with time on interannual timescale. We expect a continuous increase in

  1. Iodocarbons and Bromocarbons Associated with Arctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Roscoe, H. K.; Obbard, R. W.; Atkinson, H. M.; Hughes, C.; Liss, P. S.

    2015-12-01

    Short-lived halocarbons were measured in Arctic sea-ice brine, seawater and air above the Greenland and Norwegian seas at about 81°N in mid-summer, from a melting ice floe at the edge of the ice pack. In the ice floe, concentrations of C2H5I, 2-C3H7I and CH2Br2 showed significant enhancement in the sea ice brine, of average factors of 1.7, 1.4 and 2.5 times respectively, compared to the water underneath and after normalising to brine volume. Concentrations of mono-iodocarbons in air are the highest ever reported, and our calculations suggest increased fluxes of halocarbons to the atmosphere may result from their sea-ice enhancement. Laboratory measurements suggest that sea-ice diatoms produce iodocarbons in response to salinity stress. Concentrations of halocarbons in the Arctic ice were similar to those in earlier work in Antarctic sea ice that was similarly warm and porous. As climate warms and Arctic sea ice becomes more like that of the Antarctic, our results lead us to expect the production of iodocarbons and so of reactive iodine gases to increase.

  2. Pliocene palaeoceanography of the Arctic Ocean and subarctic seas.

    PubMed

    Matthiessen, Jens; Knies, Jochen; Vogt, Christoph; Stein, Ruediger

    2009-01-13

    The Pliocene is important in the geological evolution of the high northern latitudes. It marks the transition from restricted local- to extensive regional-scale glaciations on the circum-Arctic continents between 3.6 and 2.4Ma. Since the Arctic Ocean is an almost land-locked basin, tectonic activity and sea-level fluctuations controlled the geometry of ocean gateways and continental drainage systems, and exerted a major influence on the formation of continental ice sheets, the distribution of river run-off, and the circulation and water mass characteristics in the Arctic Ocean. The effect of a water mass exchange restricted to the Bering and Fram Straits on the oceanography is unknown, but modelling experiments suggest that this must have influenced the Atlantic meridional overturning circulation. Cold conditions associated with perennial sea-ice cover might have prevailed in the central Arctic Ocean throughout the Pliocene, whereas colder periods alternated with warmer seasonally ice-free periods in the marginal areas. The most pronounced oceanographic change occurred in the Mid-Pliocene when the circulation through the Bering Strait reversed and low-salinity waters increasingly flowed from the North Pacific into the Arctic Ocean. The excess freshwater supply might have facilitated sea-ice formation and contributed to a decrease in the Atlantic overturning circulation.

  3. Classification methods for monitoring Arctic sea ice using OKEAN passive/active two-channel microwave data

    USGS Publications Warehouse

    Belchansky, Gennady I.; Douglas, David C.

    2000-01-01

    This paper presents methods for classifying Arctic sea ice using both passive and active (2-channel) microwave imagery acquired by the Russian OKEAN 01 polar-orbiting satellite series. Methods and results are compared to sea ice classifications derived from nearly coincident Special Sensor Microwave Imager (SSM/I) and Advanced Very High Resolution Radiometer (AVHRR) image data of the Barents, Kara, and Laptev Seas. The Russian OKEAN 01 satellite data were collected over weekly intervals during October 1995 through December 1997. Methods are presented for calibrating, georeferencing and classifying the raw active radar and passive microwave OKEAN 01 data, and for correcting the OKEAN 01 microwave radiometer calibration wedge based on concurrent 37 GHz horizontal polarization SSM/I brightness temperature data. Sea ice type and ice concentration algorithms utilized OKEAN's two-channel radar and passive microwave data in a linear mixture model based on the measured values of brightness temperature and radar backscatter, together with a priori knowledge about the scattering parameters and natural emissivities of basic sea ice types. OKEAN 01 data and algorithms tended to classify lower concentrations of young or first-year sea ice when concentrations were less than 60%, and to produce higher concentrations of multi-year sea ice when concentrations were greater than 40%, when compared to estimates produced from SSM/I data. Overall, total sea ice concentration maps derived independently from OKEAN 01, SSM/I, and AVHRR satellite imagery were all highly correlated, with uniform biases, and mean differences in total ice concentration of less than four percent (sd<15%).

  4. Perspectives on the Arctic's shrinking sea-ice cover.

    PubMed

    Serreze, Mark C; Holland, Marika M; Stroeve, Julienne

    2007-03-16

    Linear trends in arctic sea-ice extent over the period 1979 to 2006 are negative in every month. This ice loss is best viewed as a combination of strong natural variability in the coupled ice-ocean-atmosphere system and a growing radiative forcing associated with rising concentrations of atmospheric greenhouse gases, the latter supported by evidence of qualitative consistency between observed trends and those simulated by climate models over the same period. Although the large scatter between individual model simulations leads to much uncertainty as to when a seasonally ice-free Arctic Ocean might be realized, this transition to a new arctic state may be rapid once the ice thins to a more vulnerable state. Loss of the ice cover is expected to affect the Arctic's freshwater system and surface energy budget and could be manifested in middle latitudes as altered patterns of atmospheric circulation and precipitation.

  5. Contrasts in Arctic shelf sea-ice regimes and some implications: Beaufort Sea versus Laptev Sea

    USGS Publications Warehouse

    Reimnitz, E.; Dethleff, D.; Nurnberg, D.

    1994-01-01

    The winter ice-regime of the 500 km) from the mainland than in the Beaufort Sea. As a result, the annual freeze-up does not incorporate old, deep-draft ice, and with a lack of compression, such deep-draft ice is not generated in situ, as on the Beaufort Sea shelf. The Laptev Sea has as much as 1000 km of fetch at the end of summer, when freezing storms move in and large (6 m) waves can form. Also, for the first three winter months, the polynya lies inshore at a water depth of only 10 m. Turbulence and freezing are excellent conditions for sediment entrainment by frazil and anchor ice, when compared to conditions in the short-fetched Beaufort Sea. We expect entrainment to occur yearly. Different from the intensely ice-gouged Beaufort Sea shelf, hydraulic bedforms probably dominate in the Laptev Sea. Corresponding with the large volume of ice produced, more dense water is generated in the Laptev Sea, possibly accompanied by downslope sediment transport. Thermohaline convection at the midshelf polynya, together with the reduced rate of bottom disruption by ice keels, may enhance benthic productivity and permit establishment of open-shelf benthic communities which in the Beaufort Sea can thrive only in the protection of barrier islands. Indirect evidence for high benthic productivity is found in the presence of walrus, who also require year-round open water. By contrast, lack of a suitable environment restricts walrus from the Beaufort Sea, although over 700 km farther to the south. We could speculate on other consequences of the different ice regimes in the Beaufort and Laptev Seas, but these few examples serve to point out the dangers of exptrapolating from knowledge gained in the North American Arctic to other shallow Arctic shelf settings. ?? 1994.

  6. Atmospheric CO2 balance: The role of Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Semiletov, Igor; Makshtas, Alexander; Akasofu, Syun-Ichi; Andreas, Edgar L.

    2004-03-01

    Climatic changes in the Northern Hemisphere have led to remarkable environmental changes in the Arctic Ocean, including significant shrinking of sea-ice cover in summer, increased time between sea-ice break-up and freeze-up, and Arctic surface water freshening and warming associated with melting sea-ice, thawing permafrost, and increased runoff [Carmack, 2000; Morison et al., 2000; Semiletov et al., 2000; Serreze et al., 2000]. These changes are commonly attributed to the greenhouse effect resulting from increased carbon dioxide (CO2) concentration. The greenhouse effect should be most pronounced in the Arctic where the largest air CO2 concentrations and winter-summer variations in the world for a clean background environment were detected [Conway et al., 1994; Climate Monitoring and Diagnostics Laboratory Data Archive, http://www.cmdl.noaa.gov/info/ftpdata.html]. Some increased seasonal variation may be a consequence of increasing summer CO2 assimilation by plants in response to higher temperature and longer growing season [Keeling et al., 1996]. Here we show that sea-ice melt ponds and open brine channels form an important spring/summer air CO2 sink that also must be included in any Arctic regional CO2 budget; both the direction and amount of CO2 transfer between air and sea during the open water season may be different from transfer during freezing and thawing, or during winter when CO2 accumulates beneath Arctic sea-ice.

  7. The Northern Bering Sea: An Arctic Ecosystem in Change

    NASA Astrophysics Data System (ADS)

    Grebmeier, J. M.; Cooper, L. W.

    2004-12-01

    Arctic systems can be rich and diverse habitats for marine life in spite of the extreme cold environment. Benthic faunal populations and associated biogeochemical cycling processes are influenced by sea-ice extent, seawater hydrography (nutrients, salinity, temperature, currents), and water column production. Benthic organisms on the Arctic shelves and margins are long-term integrators of overlying water column processes. Because these organisms have adapted to living at cold extremes, it is reasonable to expect that these communities will be among the most susceptible to climate warming. Recent observations show that Arctic sea ice in the North American Arctic is melting and retreating northward earlier in the season and the timing of these events can have dramatic impacts on the biological system. Changes in overlying primary production, pelagic-benthic coupling, and benthic production and community structure can have cascading effects to higher trophic levels, particularly benthic feeders such as walruses, gray whales, and diving seaducks. Recent indicators of contemporary Arctic change in the northern Bering Sea include seawater warming and reduction in ice extent that coincide with our time-series studies of benthic clam population declines in the shallow northern Bering shelf in the 1990's. In addition, declines in benthic amphipod populations have also likely influenced the movement of feeding gray whales to areas north of Bering Strait during this same time period. Finally a potential consequence of seawater warming and reduced ice extent in the northern Bering Sea could be the northward movement of bottom feeding fish currently in the southern Bering Sea that prey on benthic fauna. This would increase the feeding pressure on the benthic prey base and enhance competition for this food source for benthic-feeding marine mammals and seabirds. This presentation will outline recent biological changes observed in the northern Bering Sea ecosystem as documented in

  8. Trajectories of arctic sea ice under anthropogenic warming scenarios

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Steele, M.; Schweiger, A. J.

    2010-12-01

    A series of numerical experiments are conducted to study the possible trajectories of arctic sea ice in response to varying levels of future anthropogenic warming and climate variability using a sea ice-ocean model. A summer ice-free Arctic Ocean is likely by the mid-2040s if arctic surface air temperature (SAT) increases 4C by 2050 and climate variability is similar to the past relatively warm two decades. Summer ice volume decreases to very low levels (10-37% of the 1978-2009 summer mean) as early as 2025 and remains low in the following years, while summer ice extent continues to fluctuate annually. The rate of annual mean ice volume decrease relaxes approaching 2050. The causes of the reduced ice volume loss are examined.

  9. Data-driven Analysis and Prediction of Arctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Kondrashov, D. A.; Chekroun, M.; Ghil, M.; Yuan, X.; Ting, M.

    2015-12-01

    We present results of data-driven predictive analyses of sea ice over the main Arctic regions. Our approach relies on the Multilayer Stochastic Modeling (MSM) framework of Kondrashov, Chekroun and Ghil [Physica D, 2015] and it leads to prognostic models of sea ice concentration (SIC) anomalies on seasonal time scales.This approach is applied to monthly time series of leading principal components from the multivariate Empirical Orthogonal Function decomposition of SIC and selected climate variables over the Arctic. We evaluate the predictive skill of MSM models by performing retrospective forecasts with "no-look ahead" forup to 6-months ahead. It will be shown in particular that the memory effects included in our non-Markovian linear MSM models improve predictions of large-amplitude SIC anomalies in certain Arctic regions. Furtherimprovements allowed by the MSM framework will adopt a nonlinear formulation, as well as alternative data-adaptive decompositions.

  10. Empirical linkages between Arctic sea ice extents and northern hemisphere, mid-latitude column ozone levels

    SciTech Connect

    Marko, J.R.; Fissel, D.B.

    1993-01-08

    Statistically significant correlations are demonstrated between annual mean column ozone data collected at mid-latitude sites and mean annual and winter sea ice extents east of Greenland and in the Barents and Kara Seas. These results are discussed with reference to the locations of the correlated parameters relative to the Basic Pattern of stratosphere-solar flux correlations. Possibilities for underlying linkage mechanisms are considered and related to recent decreasing hemispheric ozone level trends. 19 refs., 2 figs., 2 tabs.

  11. Arctic Sea Ice Changes, Interactions, and Feedbacks on the Arctic Climate during the Satellite Era

    NASA Astrophysics Data System (ADS)

    Wang, X.; Key, J. R.; Liu, Y.

    2011-12-01

    Of all the components of the Earth climate system, the cryosphere is arguably the least understood even though it is a very important indicator and an effective modulator of regional and global climate change. Changes in sea ice will significantly affect exchanges of momentum, heat, and mass between the ocean and the atmosphere, and have profound socio-economic impacts on transportation, fisheries, hunting, polar animal habitat and more. In the last three decades, the Arctic underwent significant changes in sea ice as part of the accelerated global climate change. With the recently developed One-dimensional Thermodynamic Ice Model (OTIM), sea and lake ice thickness and trends can be reasonably estimated. The OTIM has been extensively validated against submarine and moored upward-looking sonar measurements, meteorological station measurements, and comprehensive numerical model simulations. The Extended AVHRR Polar Pathfinder (APP-x) dataset has 25 climate parameters covering surface, cloud, and sea ice properties as well as surface and top-of-atmosphere radiative fluxes for the period 1982 - 2004 over the Arctic and Antarctic at 25 km resolution. The OTIM has been used with APP-x dataset for Arctic sea ice thickness and volume estimation. Statistical analysis of spatial and temporal distributions and trends in sea ice extent, thickness, and volume over the satellite period has been performed, along with the temporal analysis of first year and multiple year sea ice extent changes. Preliminary results show clear evidence that Arctic sea ice has been experiencing significant changes over the last two decades of the 20th century. The Arctic sea ice has been shrinking unexpectedly fast with the declines in sea ice extent, thickness, and volume, most apparent in the fall season. Moreover, satellites provide an unprecedented opportunity to observe Arctic sea ice and its changes with high spatial and temporal coverage that is making it an ideal data source for mitigating

  12. Correlated declines in Pacific arctic snow and sea ice cover

    USGS Publications Warehouse

    Stone, Robert P.; Douglas, David C.; Belchansky, Gennady I.; Drobot, Sheldon

    2005-01-01

    Simulations of future climate suggest that global warming will reduce Arctic snow and ice cover, resulting in decreased surface albedo (reflectivity). Lowering of the surface albedo leads to further warming by increasing solar absorption at the surface. This phenomenon is referred to as “temperature–albedo feedback.” Anticipation of such a feedback is one reason why scientists look to the Arctic for early indications of global warming. Much of the Arctic has warmed significantly. Northern Hemisphere snow cover has decreased, and sea ice has diminished in area and thickness. As reported in the Arctic Climate Impact Assessment in 2004, the trends are considered to be outside the range of natural variability, implicating global warming as an underlying cause. Changing climatic conditions in the high northern latitudes have influenced biogeochemical cycles on a broad scale. Warming has already affected the sea ice, the tundra, the plants, the animals, and the indigenous populations that depend on them. Changing annual cycles of snow and sea ice also affect sources and sinks of important greenhouse gases (such as carbon dioxide and methane), further complicating feedbacks involving the global budgets of these important constituents. For instance, thawing permafrost increases the extent of tundra wetlands and lakes, releasing greater amounts of methane into the atmosphere. Variable sea ice cover may affect the hemispheric carbon budget by altering the ocean–atmosphere exchange of carbon dioxide. There is growing concern that amplification of global warming in the Arctic will have far-reaching effects on lower latitude climate through these feedback mechanisms. Despite the diverse and convincing observational evidence that the Arctic environment is changing, it remains unclear whether these changes are anthropogenically forced or result from natural variations of the climate system. A better understanding of what controls the seasonal distributions of snow and ice

  13. Analysis of WindSat Data over Arctic Sea Ice

    USDA-ARS?s Scientific Manuscript database

    The radiation of the 3rd and 4th Stokes components emitted by Arctic sea ice and observed by the spaceborne fully polarimetric radiometer WindSat is investigated. Two types of analysis are carried out, spatial (maps of different quadrants of azimuth look angles) and temporal (time series of daily av...

  14. Global warming releases microplastic legacy frozen in Arctic Sea ice

    NASA Astrophysics Data System (ADS)

    Obbard, Rachel W.; Sadri, Saeed; Wong, Ying Qi; Khitun, Alexandra A.; Baker, Ian; Thompson, Richard C.

    2014-06-01

    When sea ice forms it scavenges and concentrates particulates from the water column, which then become trapped until the ice melts. In recent years, melting has led to record lows in Arctic Sea ice extent, the most recent in September 2012. Global climate models, such as that of Gregory et al. (2002), suggest that the decline in Arctic Sea ice volume (3.4% per decade) will actually exceed the decline in sea ice extent, something that Laxon et al. (2013) have shown supported by satellite data. The extent to which melting ice could release anthropogenic particulates back to the open ocean has not yet been examined. Here we show that Arctic Sea ice from remote locations contains concentrations of microplastics at least two orders of magnitude greater than those that have been previously reported in highly contaminated surface waters, such as those of the Pacific Gyre. Our findings indicate that microplastics have accumulated far from population centers and that polar sea ice represents a major historic global sink of man-made particulates. The potential for substantial quantities of legacy microplastic contamination to be released to the ocean as the ice melts therefore needs to be evaluated, as do the physical and toxicological effects of plastics on marine life.

  15. Studies of Arctic Storms and Their Impacts on Arctic Winds and Sea Ice

    NASA Astrophysics Data System (ADS)

    Tao, Wei

    Storm activities have recently exhibited greater fluctuations and intensification in the Arctic, which impacts the air-ice-sea interactions and contributes to rapid changes in the Arctic climate system. In this study, the individual and collaborative impacts of troposphere and stratosphere thermal anomalies in the development of Arctic storms were first explored with the Weather Research and Forecasting (WRF) model. In a long-lasting Arctic storm, it is found that the stratosphere warm anomalies and the downward intrusion of tropopause polar vortex (TPV) play a decisive role in the storm's persistence. An out-of-phase occurrence in the maxima of the stratosphere warm and troposphere cold anomalies sustains the intensity of the potential vorticity anomalies around the tropopause, which in turn further supports the storm for an extended period. In a super-strong Arctic storm, thermal anomalies in both the troposphere and stratosphere are necessary for the storm's drastic development. The troposphere baroclinity along the Arctic Front Zone, as well as the enhanced TPV due to stratosphere warm anomalies contribute to a strong jet and accordingly accelerate the deepening rate of the surface low. Next, the storm activities and their impacts on the surface winds in the marginal ice zone of the Chukchi-Beaufort Seas were analyzed with the newly-developed Chukchi-Beaufort high-resolution atmospheric reanalysis and an improved storm identification and tracking algorithm. It is shown that more numerous yet weaker storms occur in the summer, while fewer but stronger storms occur in the winter in the study area. The relations between storm and surface winds demonstrate that the intensity of storm tends to produce a significant impact on the occurrence of strong wind events. Interplay between storms and the semi-permanent weather system Beaufort Sea High helps to shape extremely strong winds in the study area. Lastly, the impacts of Arctic storm activity on the Arctic summer sea

  16. Variability of Arctic Sea Ice as Determined from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.

    1999-01-01

    The compiled, quality-controlled satellite multichannel passive-microwave record of polar sea ice now spans over 18 years, from November 1978 through December 1996, and is revealing considerable information about the Arctic sea ice cover and its variability. The information includes data on ice concentrations (percent areal coverages of ice), ice extents, ice melt, ice velocities, the seasonal cycle of the ice, the interannual variability of the ice, the frequency of ice coverage, and the length of the sea ice season. The data reveal marked regional and interannual variabilities, as well as some statistically significant trends. For the north polar ice cover as a whole, maximum ice extents varied over a range of 14,700,000 - 15,900,000 sq km, while individual regions experienced much greater percent variations, for instance, with the Greenland Sea having a range of 740,000 - 1,110,000 sq km in its yearly maximum ice coverage. In spite of the large variations from year to year and region to region, overall the Arctic ice extents showed a statistically significant, 2.80% / decade negative trend over the 18.2-year period. Ice season lengths, which vary from only a few weeks near the ice margins to the full year in the large region of perennial ice coverage, also experienced interannual variability, along with spatially coherent overall trends. Linear least squares trends show the sea ice season to have lengthened in much of the Bering Sea, Baffin Bay, the Davis Strait, and the Labrador Sea, but to have shortened over a much larger area, including the Sea of Okhotsk, the Greenland Sea, the Barents Sea, and the southeastern Arctic.

  17. Variability of Arctic Sea Ice as Determined from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.

    1999-01-01

    The compiled, quality-controlled satellite multichannel passive-microwave record of polar sea ice now spans over 18 years, from November 1978 through December 1996, and is revealing considerable information about the Arctic sea ice cover and its variability. The information includes data on ice concentrations (percent areal coverages of ice), ice extents, ice melt, ice velocities, the seasonal cycle of the ice, the interannual variability of the ice, the frequency of ice coverage, and the length of the sea ice season. The data reveal marked regional and interannual variabilities, as well as some statistically significant trends. For the north polar ice cover as a whole, maximum ice extents varied over a range of 14,700,000 - 15,900,000 sq km, while individual regions experienced much greater percent variations, for instance, with the Greenland Sea having a range of 740,000 - 1,110,000 sq km in its yearly maximum ice coverage. In spite of the large variations from year to year and region to region, overall the Arctic ice extents showed a statistically significant, 2.80% / decade negative trend over the 18.2-year period. Ice season lengths, which vary from only a few weeks near the ice margins to the full year in the large region of perennial ice coverage, also experienced interannual variability, along with spatially coherent overall trends. Linear least squares trends show the sea ice season to have lengthened in much of the Bering Sea, Baffin Bay, the Davis Strait, and the Labrador Sea, but to have shortened over a much larger area, including the Sea of Okhotsk, the Greenland Sea, the Barents Sea, and the southeastern Arctic.

  18. Late Holocene Sea Ice and Productivity in the Western Chukchi Sea, Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Pearce, C.; Rattray, J.; Jakobsson, M.; O'Regan, M.; Barrientos, N.; Smittenberg, R.; Cronin, T. M.; Muschitiello, F.; Semiletov, I. P.

    2016-12-01

    The key to improving our understanding of Arctic sea ice cover and its response to external forcing is the reconstruction of past variability through paleo-records such as marine sediment cores. Although the observed recent sea ice loss seems to be the greatest of the last millennia, it is still uncertain whether the shift from perennial to seasonal ice cover expected for the near future was unprecedented during the current interglacial. High resolution sea ice reconstructions over longer time scales from the Arctic Ocean are rare, and specifically records from the Russian Arctic are underrepresented. In this study, we present results from marine sediment cores from the Herald Canyon in the western Chukchi Sea. This area is one of the major conduits of Pacific water entering the Arctic Ocean basin from the Bering Strait which plays an important role in regional warming and retreat of sea ice. Radiocarbon dating of mollusks indicates very high sedimentation rates at the coring sites which allowed for analyses at centennial up to decadal resolution in the late Holocene. Core samples were analyzed for sterols and the biomarker IP25, which is produced by diatoms living in sea ice and is used as a proxy of past seasonal sea ice concentrations. Preliminary results indicate the presence of seasonal sea ice during the entire Late Holocene and show a significant increase of sea ice concentrations during the last millennia.

  19. Radionuclide contamination of sediment deposits in the Ob and Yenisey estuaries and areas of the Kara Sea.

    PubMed

    Standring, W J F; Stepanets, O; Brown, J E; Dowdall, M; Borisov, A; Nikitin, A

    2008-04-01

    The Ob and Yenisey rivers are major contributors to total riverine discharge to the Arctic Ocean. Several large nuclear facilities discharge into these rivers, which could affect actual and potential discharges of radionuclides to the Arctic region. This article presents new radionuclide concentration and grain-size data resulting from analyses of several sediment samples collected during research cruises in the Ob and Yenisey estuaries and adjacent areas during 2000 and 2001. Results indicate that discharges from the main nuclear facilities do not constitute a major contribution to the level of radioactive contamination in the marine areas studied, though Co-60 was detected at low concentrations in some sediment horizons. However, the aggregate contamination from different sources is not radioecologically significant in sediments within the study area, maximum Cs-137 levels being approximately 80 Bq kg(-1) dry weight.

  20. Arctic Sea Ice Classification and Mapping for Surface Albedo Parameterization in Sea Ice Modeling

    NASA Astrophysics Data System (ADS)

    Nghiem, S. V.; Clemente-Colón, P.; Perovich, D. K.; Polashenski, C.; Simpson, W. R.; Rigor, I. G.; Woods, J. E.; Nguyen, D. T.; Neumann, G.

    2016-12-01

    A regime shift of Arctic sea ice from predominantly perennial sea ice (multi-year ice or MYI) to seasonal sea ice (first-year ice or FYI) has occurred in recent decades. This shift has profoundly altered the proportional composition of different sea ice classes and the surface albedo distribution pertaining to each sea ice class. Such changes impacts physical, chemical, and biological processes in the Arctic atmosphere-ice-ocean system. The drastic changes upset the traditional geophysical representation of surface albedo of the Arctic sea ice cover in current models. A critical science issue is that these profound changes must be rigorously and systematically observed and characterized to enable a transformative re-parameterization of key model inputs, such as ice surface albedo, to ice-ocean-atmosphere climate modeling in order to obtain re-analyses that accurately reproduce Arctic changes and also to improve sea ice and weather forecast models. Addressing this challenge is a strategy identified by the National Research Council study on "Seasonal to Decadal Predictions of Arctic Sea Ice - Challenges and Strategies" to replicate the new Arctic reality. We review results of albedo characteristics associated with different sea ice classes such as FYI and MYI. Then we demonstrate the capability for sea ice classification and mapping using algorithms developed by the Jet Propulsion Laboratory and by the U.S. National Ice Center for use with multi-sourced satellite radar data at L, C, and Ku bands. Results obtained with independent algorithms for different radar frequencies consistently identify sea ice classes and thereby cross-verify the sea ice classification methods. Moreover, field observations obtained from buoy webcams and along an extensive trek across Elson Lagoon and a sector of the Beaufort Sea during the BRomine, Ozone, and Mercury EXperiment (BROMEX) in March 2012 are used to validate satellite products of sea ice classes. This research enables the mapping

  1. Does Arctic sea ice reduction foster shelf-basin exchange?

    PubMed

    Ivanov, Vladimir; Watanabe, Eiji

    2013-12-01

    The recent shift in Arctic ice conditions from prevailing multi-year ice to first-year ice will presumably intensify fall-winter sea ice freezing and the associated salt flux to the underlying water column. Here, we conduct a dual modeling study whose results suggest that the predicted catastrophic consequences for the global thermohaline circulation (THC), as a result of the disappearance of Arctic sea ice, may not necessarily occur. In a warmer climate, the substantial fraction of dense water feeding the Greenland-Scotland overflow may form on Arctic shelves and cascade to the deep basin, thus replenishing dense water, which currently forms through open ocean convection in the sub-Arctic seas. We have used a simplified model for estimating how increased ice production influences shelf-basin exchange associated with dense water cascading. We have carried out case studies in two regions of the Arctic Ocean where cascading was observed in the past. The baseline range of buoyancy-forcing derived from the columnar ice formation was calculated as part of a 30-year experiment of the pan-Arctic coupled ice-ocean general circulation model (GCM). The GCM results indicate that mechanical sea ice divergence associated with lateral advection accounts for a significant part of the interannual variations in sea ice thermal production in the coastal polynya regions. This forcing was then rectified by taking into account sub-grid processes and used in a regional model with analytically prescribed bottom topography and vertical stratification in order to examine specific cascading conditions in the Pacific and Atlantic sectors of the Arctic Ocean. Our results demonstrate that the consequences of enhanced ice formation depend on geographical location and shelf-basin bathymetry. In the Pacific sector, strong density stratification in slope waters impedes noticeable deepening of shelf-origin water, even for the strongest forcing applied. In the Atlantic sector, a 1.5x increase of

  2. Simulating Arctic clouds during Arctic Radiation- IceBridge Sea and Ice Experiment (ARISE)

    NASA Astrophysics Data System (ADS)

    Bromwich, D. H.; Hines, K. M.; Wang, S. H.

    2015-12-01

    The representation within global and regional models of the extensive low-level cloud cover over polar oceans remains a critical challenge for quantitative studies and forecasts of polar climate. In response, the polar-optimized version of the Weather Research and Forecasting model (Polar WRF) is used to simulate the meteorology, boundary layer, and Arctic clouds during the September-October 2014 Arctic Radiation- IceBridge Sea and Ice Experiment (ARISE) project. Polar WRF was developed with several adjustments to the sea ice thermodynamics in WRF. ARISE was based out of Eielson Air Force Base near Fairbanks, Alaska and included multiple instrumented C-130 aircraft flights over open water and sea ice of the Beaufort Sea. Arctic boundary layer clouds were frequently observed within cold northeasterly flow over the open ocean and ice. Preliminary results indicate these clouds were primarily liquid water, with characteristics differing between open water and sea ice surfaces. Simulated clouds are compared to ARISE observations. Furthermore, Polar WRF simulations are run for the August-September 2008 Arctic Summer Cloud Ocean Study (ASCOS) for comparison to the ARISE. Preliminary analysis shows that simulated low-level water clouds over the sea ice are too extensive during the the second half of the ASCOS field program. Alternatives and improvements to the Polar WRF cloud schemes are considered. The goal is to use the ARISE and ASCOS observations to achieve an improved polar supplement to the WRF code for open water and sea ice that can be provided to the Polar WRF community.

  3. Arctic Sea Level During the Satellite Altimetry Era

    NASA Astrophysics Data System (ADS)

    Carret, A.; Johannessen, J. A.; Andersen, O. B.; Ablain, M.; Prandi, P.; Blazquez, A.; Cazenave, A.

    2016-11-01

    Results of the sea-level budget in the high latitudes (up to 80°N) and the Arctic Ocean during the satellite altimetry era. We investigate the closure of the sea-level budget since 2002 using two altimetry sea-level datasets based on the Envisat waveform retracking: temperature and salinity data from the ORAP5 reanalysis, and Gravity Recovery And Climate Experiment (GRACE) space gravimetry data to estimate the steric and mass components. Regional sea-level trends seen in the altimetry map, in particular over the Beaufort Gyre and along the eastern coast of Greenland, are of halosteric origin. However, in terms of regional average over the region ranging from 66°N to 80°N, the steric component contributes little to the observed sea-level trend, suggesting a dominant mass contribution in the Arctic region. This is confirmed by GRACE-based ocean mass time series that agree well with the altimetry-based sea-level time series. Direct estimate of the mass component is not possible prior to GRACE. Thus, we estimated the mass contribution from the difference between the altimetry-based sea level and the steric component. We also investigate the coastal sea level with tide gauge records. Twenty coupled climate models from the CMIP5 project are also used. The models lead us to the same conclusions concerning the halosteric origin of the trend patterns.

  4. Arctic Sea Level During the Satellite Altimetry Era

    NASA Astrophysics Data System (ADS)

    Carret, A.; Johannessen, J. A.; Andersen, O. B.; Ablain, M.; Prandi, P.; Blazquez, A.; Cazenave, A.

    2017-01-01

    Results of the sea-level budget in the high latitudes (up to 80°N) and the Arctic Ocean during the satellite altimetry era. We investigate the closure of the sea-level budget since 2002 using two altimetry sea-level datasets based on the Envisat waveform retracking: temperature and salinity data from the ORAP5 reanalysis, and Gravity Recovery And Climate Experiment (GRACE) space gravimetry data to estimate the steric and mass components. Regional sea-level trends seen in the altimetry map, in particular over the Beaufort Gyre and along the eastern coast of Greenland, are of halosteric origin. However, in terms of regional average over the region ranging from 66°N to 80°N, the steric component contributes little to the observed sea-level trend, suggesting a dominant mass contribution in the Arctic region. This is confirmed by GRACE-based ocean mass time series that agree well with the altimetry-based sea-level time series. Direct estimate of the mass component is not possible prior to GRACE. Thus, we estimated the mass contribution from the difference between the altimetry-based sea level and the steric component. We also investigate the coastal sea level with tide gauge records. Twenty coupled climate models from the CMIP5 project are also used. The models lead us to the same conclusions concerning the halosteric origin of the trend patterns.

  5. Regional variability in sea ice melt in a changing Arctic

    PubMed Central

    Perovich, Donald K.; Richter-Menge, Jacqueline A.

    2015-01-01

    In recent years, the Arctic sea ice cover has undergone a precipitous decline in summer extent. The sea ice mass balance integrates heat and provides insight on atmospheric and oceanic forcing. The amount of surface melt and bottom melt that occurs during the summer melt season was measured at 41 sites over the time period 1957 to 2014. There are large regional and temporal variations in both surface and bottom melting. Combined surface and bottom melt ranged from 16 to 294 cm, with a mean of 101 cm. The mean ice equivalent surface melt was 48 cm and the mean bottom melt was 53 cm. On average, surface melting decreases moving northward from the Beaufort Sea towards the North Pole; however interannual differences in atmospheric forcing can overwhelm the influence of latitude. Substantial increases in bottom melting are a major contributor to ice losses in the Beaufort Sea, due to decreases in ice concentration. In the central Arctic, surface and bottom melting demonstrate interannual variability, but show no strong temporal trends from 2000 to 2014. This suggests that under current conditions, summer melting in the central Arctic is not large enough to completely remove the sea ice cover. PMID:26032323

  6. Ocean farfield response to projected Arctic sea ice loss.

    NASA Astrophysics Data System (ADS)

    Jochum, Markus; Deser, Clara; Tomas, Robert

    2016-04-01

    An ensemble of 20 fully coupled CESM simulations is used to elucidate the ocean's role in shaping the global climate response to projected Arctic sea ice loss. The ensemble allows us to separate unambiguously between internal variability and forced changes. Thus, it is possible to identify the oceanic processes by which sea ice induced changes in Arctic and North Pacific sea level pressure are transmitted across the world ocean. Of particular interest is the Kelvin wave train that connects the North Atlantic with the equatorial Pacific. Within 10 years after the loss of sea ice the oceanic signal arrives in the Pacific and leads to a slow and steady deepening of the equatorial thermocline and, after another 5 decades, the subtropical thermocline. This suggests that the current Arctic sea ice loss already set into motion changes in tropical Pacific climate that will be felt several decades from now. We will dicuss these ocean induced changes in the mean climate as well as ENSO and explore possibilities of observational verification.

  7. Regional variability in sea ice melt in a changing Arctic.

    PubMed

    Perovich, Donald K; Richter-Menge, Jacqueline A

    2015-07-13

    In recent years, the Arctic sea ice cover has undergone a precipitous decline in summer extent. The sea ice mass balance integrates heat and provides insight on atmospheric and oceanic forcing. The amount of surface melt and bottom melt that occurs during the summer melt season was measured at 41 sites over the time period 1957 to 2014. There are large regional and temporal variations in both surface and bottom melting. Combined surface and bottom melt ranged from 16 to 294 cm, with a mean of 101 cm. The mean ice equivalent surface melt was 48 cm and the mean bottom melt was 53 cm. On average, surface melting decreases moving northward from the Beaufort Sea towards the North Pole; however interannual differences in atmospheric forcing can overwhelm the influence of latitude. Substantial increases in bottom melting are a major contributor to ice losses in the Beaufort Sea, due to decreases in ice concentration. In the central Arctic, surface and bottom melting demonstrate interannual variability, but show no strong temporal trends from 2000 to 2014. This suggests that under current conditions, summer melting in the central Arctic is not large enough to completely remove the sea ice cover.

  8. Arctic sea ice modeling with the material-point method.

    SciTech Connect

    Peterson, Kara J.; Bochev, Pavel Blagoveston

    2010-04-01

    Arctic sea ice plays an important role in global climate by reflecting solar radiation and insulating the ocean from the atmosphere. Due to feedback effects, the Arctic sea ice cover is changing rapidly. To accurately model this change, high-resolution calculations must incorporate: (1) annual cycle of growth and melt due to radiative forcing; (2) mechanical deformation due to surface winds, ocean currents and Coriolis forces; and (3) localized effects of leads and ridges. We have demonstrated a new mathematical algorithm for solving the sea ice governing equations using the material-point method with an elastic-decohesive constitutive model. An initial comparison with the LANL CICE code indicates that the ice edge is sharper using Materials-Point Method (MPM), but that many of the overall features are similar.

  9. Multi-system seasonal predictions of Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Merryfield, W. J.; Lee, W.-S.; Wang, W.; Chen, M.; Kumar, A.

    2013-04-01

    The utility of multi-system, coupled model-based seasonal predictions of Arctic sea ice area and extent is investigated for combined predictions from the Climate Forecast System version 2 (CFSv2) and Canadian Seasonal to Interannual Prediction System (CanSIPS) operational seasonal forecasting systems, which are among the first to have sea ice as a prognostic variable. Forecast skills for predictions of total anomalies and departures from long-term linear trends are examined both for the individual systems and the combined forecasts, and are compared against simple predictions such as damped anomaly persistence. Results indicate that the tendency for climate forecasts based on combined output from multiple prediction systems to outperform any one system, demonstrated previously for global variables such as temperature and precipitation, is realized for predictions of Arctic sea ice as well.

  10. Arctic Moisture Source for Eurasian Snow Cover Variations in Autumn

    NASA Astrophysics Data System (ADS)

    Wegmann, M.

    2015-12-01

    Global warming is enhanced at high northern latitudes where the Arctic surface airtemperature has risen at twice the rate of the global average in recent decades - afeature called Arctic amplification. This recent Arctic warming signal likely resultsfrom several factors such as the albedo feedback due to a diminishing cryosphere,enhanced poleward atmospheric and oceanic transport, and change in humidity. Moreover, Arcticsummer sea-ice extent has declined by more than 10% per decade since the start ofthe satellite era (e.g. Stroeve et al., 2012), culminating in a new record low inSeptember 2012.Eurasian snow cover changes have been suggested as a driver for changes in theArctic Oscillation and might provide a link between sea ice decline in the Arcticduring summer and atmospheric circulation in the following winter. However, themechanism connecting snow cover in Eurasia to sea ice decline in autumn is stillunder debate. Our analysis focuses on sea ice decline in the Barents-Kara Sea region, which allowsus to specify regions of interest for FLEXPART forward and backwards moisturetrajectories. Based on Eularian and Lagrangian diagnostics from ERA-INTERIM, wecan address the origin and cause of late autumn snow depth variations in a dense(snow observations from 820 land stations), unutilized observational datasets over theCommonwealth of Independent States.Open waters in the Barents and Kara Sea have been shown to increase the diabaticheating of the atmosphere, which amplifies baroclinic cyclones and might induce aremote atmospheric response by triggering stationary Rossby waves (Honda et al.2009).In agreement with these studies, our results show enhanced storm activity originatingat the Barents and Kara with disturbances entering the continent through a smallsector from the Barents and Kara Seas. Maxima in storm activity trigger increasing uplift, oftenaccompanied by positive snowfall and snow depth anomalies.We show that declining sea ice in the Barents and Kara Seas

  11. High Arctic sea ice conditions influence marine birds wintering in Low Arctic regions

    NASA Astrophysics Data System (ADS)

    McFarlane Tranquilla, Laura; Hedd, April; Burke, Chantelle; Montevecchi, William A.; Regular, Paul M.; Robertson, Gregory J.; Stapleton, Leslie Ann; Wilhelm, Sabina I.; Fifield, David A.; Buren, Alejandro D.

    2010-09-01

    Ocean climate change is having profound biological effects in polar regions. Such change can also have far-reaching downstream effects in sub-polar regions. This study documents an environmental relationship between High Arctic sea ice changes and mortality events of marine birds in Low Arctic coastal regions. During April 2007 and March 2009, hundreds of beached seabird carcasses and moribund seabirds were found along the east and northeast coasts of Newfoundland, Canada. These seabird "wrecks" (i.e. dead birds on beaches) coincided with a period of strong, persistent onshore winds and heavily-accumulated sea ice that blocked bays and trapped seabirds near beaches. Ninety-two percent of wreck seabirds were Thick-billed Murres ( Uria lomvia). Body condition and demographic patterns of wreck murres were compared to Thick-billed Murres shot in the Newfoundland murre hunt. Average body and pectoral masses of wreck carcasses were 34% and 40% lighter (respectively) than shot murres, indicating that wreck birds had starved. The acute nature of each wreck suggested that starvation and associated hypothermia occurred within 2-3 days. In 2007, first-winter murres (77%) dominated the wreck. In 2009, there were more adults (78%), mostly females (66%). These results suggest that spatial and temporal segregation in ages and sexes can play a role in differential survival when stochastic weather conditions affect discrete areas where these groups aggregate. In wreck years, southward movement of Arctic sea ice to Low Arctic latitudes was later and blocked bays longer than in most other years. These inshore conditions corresponded with recent climate-driven changes in High Arctic ice break-up and ice extent; coupled with local weather conditions, these ice conditions appeared to be the key environmental features that precipitated the ice-associated seabird wrecks in the Low Arctic region.

  12. Sea ice, erosion, and vulnerability of Arctic coasts

    NASA Astrophysics Data System (ADS)

    Barnhart, Katherine; Overeem, Irina; Kay, Jennifer; Anderson, Robert

    2015-04-01

    Coasts form the dynamic interface between the terrestrial and oceanic systems. In the Arctic, and in much of the world, the coast is a zone of relatively high population, infrastructure, biodiversity, and ecosystem services. A significant difference between Arctic and temperate coasts is the presence of sea ice. Sea ice influences Arctic coasts in two main ways: (1) the length of the sea ice-free season controls the length of time over which nearshore water can interact with the land, and (2) the location of the sea ice edge controls the fetch over which storm winds can blow over open water, resulting in changes in nearshore water level and wave field. The resulting nearshore hydrodynamic environment impacts all aspects of the coastal system. We first combine satellite records of sea ice with a simple model for wind-driven storm surge and waves to estimate how changes in the length and character of the sea ice-free season have impacted the nearshore hydrodynamic environment along Alaska's Beaufort Sea Coast for the period 1979-2012. This region has experienced some of the greatest changes in both sea ice cover and coastal erosion rates in the Arctic and is anticipated to experience significant change in the future. The median length of the 2012 open-water season along this stretch of coast, in comparison to 1979, expanded by 1.9 x. At the same time, coastal erosion rates increased from 8.7 m yr-1 to 19 m yr-1. At Drew Point, winds from the northwest result in increased water levels at the coast and control the process of submarine notch incision, the rate-limiting step of coastal retreat. When open-water conditions exist, the distance to the sea ice edge exerts control on the water level and wave field through its control on fetch. We find that the extreme values of water-level setup at Drew Point have increased consistently with increasing fetch. We then extend our analysis of the length of the open water season to the entire Arctic using both satellite

  13. Arctic Summer Sea-Ice Extent: How Free is Free?

    NASA Astrophysics Data System (ADS)

    Tremblay, B.; Cullather, R. I.; DeRepentigny, P.; Pfirman, S. L.; Newton, R.

    2015-12-01

    As Northern Hemisphere perennial sea ice cover continues a long-term downward trend, attention has begun to focus on the implications of the changing conditions. A summertime ice-free Arctic Ocean is frequently indicated as a signature milestone for these changes, however "ice-free" has a substantially different meaning among scientists and interested stakeholders. To climate scientists it may mean when there is so little sea ice that it plays a minimal role in the climate system. To those interested in development, it may mean a threshold where icebreaker support is not required. To coastal communities it may mean so little ice that hunting is not possible. To species dependent on sea ice, it may mean the point where they cannot find sufficient habitat to survive from spring until fall. In this contribution we document the projected seasonality of the sea ice retreat and address the following questions. For how long will the Arctic Ocean be ice free on average each year? What is the impact of such changes in the seasonality of the sea ice cover on species that are dependent on sea ice? To this end, we analyze the seasonal cycle in the sea-ice extent simulated by the Community Earth System Model 1 - Large Ensemble (CESM1-LE) output for the 21st century. CESM1-LE simulates a realistic late 20th, early 21st century Arctic climate with a seasonal cycle in sea ice extent and rate of decline in good agreement with observations. Results from this model show that even by the end of the 21st century, the length of the ice-free season is relatively short, with ice-free conditions mainly present for 2-3 months between August and October. The result is a much larger amplitude seasonal cycle when compared with the late 20th century climate.

  14. Impacts of Tropopause Polar Cyclones on Arctic Sea Ice Loss

    NASA Astrophysics Data System (ADS)

    Szapiro, N.; Cavallo, S. M.; Skamarock, W. C.; Park, S. H.

    2016-12-01

    Arctic sea ice exhibits considerable and potentially abrupt year to year variability, with changes amplified as the ice thins. Extremes of summer Arctic sea ice loss are intimately connected to the atmospheric forcing. On sub-seasonal to seasonal time scales, there are significant correlations between upper level heights, sea level pressure, and sea ice loss. Individual synoptic cyclones can also drive significant ice loss.Cyclonic tropopause polar vortices (TPVs) are common, coherent upper level potential vorticity anomalies with typical radii of 100 to 1000 km and lifetimes of days to months. Here, we test the hypothesis that TPVs have significant impacts on the evolution and predictability of summer sea ice loss.Historical TPV-based composites reveal coherent mass, momentum, and energy sea ice forcings under TPVs, with implications for pack ice maintenance and marginal ice loss. Coupled MPAS-CESM sensitivity experiments with strengthened and weakened TPVs quantify the sea ice response to these forcings at both short- and extended-range time scales. The coupling of forcings between TPVs and larger scales is seen to contribute to the significance of impacts. Since modelling systems exhibit systematic errors in the representation of TPVs, resolving these errors may realize the potential predictability associated with TPVs.

  15. Sea ice drift in the Arctic since the 1950s

    NASA Astrophysics Data System (ADS)

    Hakkinen, Sirpa; Proshutinsky, Andrey; Ashik, Igor

    2008-10-01

    Sea ice drift data (from Russian North Pole stations, various ice camps, and the International Arctic Buoy Program) and surface wind stress data from the NCAR/NCEP Reanalysis are analyzed to determine their long-term trends and causality. The study finds that both parameters (ice drift and wind stress) show gradual acceleration over last 50 years. Significant positive trends are present in both winter and summer data. The major cause of observed positive trends is increasing Arctic storm activity over the Transpolar Drift Stream caused by a shift of storm tracks toward higher latitudes. It is speculated, with some observational evidence, that the increased stirring of the ocean by winds could hasten the transition of the Arctic toward a weakly stratified ocean with a potential for deep convection and a new sink for atmospheric CO2.

  16. Nonlinear threshold behavior during the loss of Arctic sea ice.

    PubMed

    Eisenman, I; Wettlaufer, J S

    2009-01-06

    In light of the rapid recent retreat of Arctic sea ice, a number of studies have discussed the possibility of a critical threshold (or "tipping point") beyond which the ice-albedo feedback causes the ice cover to melt away in an irreversible process. The focus has typically been centered on the annual minimum (September) ice cover, which is often seen as particularly susceptible to destabilization by the ice-albedo feedback. Here, we examine the central physical processes associated with the transition from ice-covered to ice-free Arctic Ocean conditions. We show that although the ice-albedo feedback promotes the existence of multiple ice-cover states, the stabilizing thermodynamic effects of sea ice mitigate this when the Arctic Ocean is ice covered during a sufficiently large fraction of the year. These results suggest that critical threshold behavior is unlikely during the approach from current perennial sea-ice conditions to seasonally ice-free conditions. In a further warmed climate, however, we find that a critical threshold associated with the sudden loss of the remaining wintertime-only sea ice cover may be likely.

  17. Nonlinear threshold behavior during the loss of Arctic sea ice

    PubMed Central

    Eisenman, I.; Wettlaufer, J. S.

    2009-01-01

    In light of the rapid recent retreat of Arctic sea ice, a number of studies have discussed the possibility of a critical threshold (or “tipping point”) beyond which the ice–albedo feedback causes the ice cover to melt away in an irreversible process. The focus has typically been centered on the annual minimum (September) ice cover, which is often seen as particularly susceptible to destabilization by the ice–albedo feedback. Here, we examine the central physical processes associated with the transition from ice-covered to ice-free Arctic Ocean conditions. We show that although the ice–albedo feedback promotes the existence of multiple ice-cover states, the stabilizing thermodynamic effects of sea ice mitigate this when the Arctic Ocean is ice covered during a sufficiently large fraction of the year. These results suggest that critical threshold behavior is unlikely during the approach from current perennial sea-ice conditions to seasonally ice-free conditions. In a further warmed climate, however, we find that a critical threshold associated with the sudden loss of the remaining wintertime-only sea ice cover may be likely. PMID:19109440

  18. The Coastal Observing System for Northern and Arctic Seas (COSYNA)

    NASA Astrophysics Data System (ADS)

    Baschek, Burkard; Schroeder, Friedhelm; Brix, Holger; Riethmüller, Rolf; Badewien, Thomas H.; Breitbach, Gisbert; Brügge, Bernd; Colijn, Franciscus; Doerffer, Roland; Eschenbach, Christiane; Friedrich, Jana; Fischer, Philipp; Garthe, Stefan; Horstmann, Jochen; Krasemann, Hajo; Metfies, Katja; Merckelbach, Lucas; Ohle, Nino; Petersen, Wilhelm; Pröfrock, Daniel; Röttgers, Rüdiger; Schlüter, Michael; Schulz, Jan; Schulz-Stellenfleth, Johannes; Stanev, Emil; Staneva, Joanna; Winter, Christian; Wirtz, Kai; Wollschläger, Jochen; Zielinski, Oliver; Ziemer, Friedwart

    2017-05-01

    The Coastal Observing System for Northern and Arctic Seas (COSYNA) was established in order to better understand the complex interdisciplinary processes of northern seas and the Arctic coasts in a changing environment. Particular focus is given to the German Bight in the North Sea as a prime example of a heavily used coastal area, and Svalbard as an example of an Arctic coast that is under strong pressure due to global change.The COSYNA automated observing and modelling system is designed to monitor real-time conditions and provide short-term forecasts, data, and data products to help assess the impact of anthropogenically induced change. Observations are carried out by combining satellite and radar remote sensing with various in situ platforms. Novel sensors, instruments, and algorithms are developed to further improve the understanding of the interdisciplinary interactions between physics, biogeochemistry, and the ecology of coastal seas. New modelling and data assimilation techniques are used to integrate observations and models in a quasi-operational system providing descriptions and forecasts of key hydrographic variables. Data and data products are publicly available free of charge and in real time. They are used by multiple interest groups in science, agencies, politics, industry, and the public.

  19. Abnormal Winter Melting of the Arctic Sea Ice Cap Observed by the Spaceborne Passive Microwave Sensors

    NASA Astrophysics Data System (ADS)

    Lee, Seongsuk; Yi, Yu

    2016-12-01

    The spatial size and variation of Arctic sea ice 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 ice 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 ice and their causes. We investigated the variability of Arctic sea ice using the daily sea ice concentration data from passive microwave observations to identify the sea ice melting regions near the Arctic polar ice cap. We discovered the abnormal melting of the Arctic sea ice 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 ice. This hypothesis could be verified by the observation of warm water column structure below the melting or thinning arctic sea ice through the project such as Coriolis dataset for reanalysis (CORA).

  20. Biopolymers form a gelatinous microlayer at the air-sea interface when Arctic sea ice melts.

    PubMed

    Galgani, Luisa; Piontek, Judith; Engel, Anja

    2016-07-20

    The interface layer between ocean and atmosphere is only a couple of micrometers thick but plays a critical role in climate relevant processes, including the air-sea exchange of gas and heat and the emission of primary organic aerosols (POA). Recent findings suggest that low-level cloud formation above the Arctic Ocean may be linked to organic polymers produced by marine microorganisms. Sea ice harbors high amounts of polymeric substances that are produced by cells growing within the sea-ice brine. Here, we report from a research cruise to the central Arctic Ocean in 2012. Our study shows that microbial polymers accumulate at the air-sea interface when the sea ice melts. Proteinaceous compounds represented the major fraction of polymers supporting the formation of a gelatinous interface microlayer and providing a hitherto unrecognized potential source of marine POA. Our study indicates a novel link between sea ice-ocean and atmosphere that may be sensitive to climate change.

  1. Biopolymers form a gelatinous microlayer at the air-sea interface when Arctic sea ice melts

    NASA Astrophysics Data System (ADS)

    Galgani, Luisa; Piontek, Judith; Engel, Anja

    2016-07-01

    The interface layer between ocean and atmosphere is only a couple of micrometers thick but plays a critical role in climate relevant processes, including the air-sea exchange of gas and heat and the emission of primary organic aerosols (POA). Recent findings suggest that low-level cloud formation above the Arctic Ocean may be linked to organic polymers produced by marine microorganisms. Sea ice harbors high amounts of polymeric substances that are produced by cells growing within the sea-ice brine. Here, we report from a research cruise to the central Arctic Ocean in 2012. Our study shows that microbial polymers accumulate at the air-sea interface when the sea ice melts. Proteinaceous compounds represented the major fraction of polymers supporting the formation of a gelatinous interface microlayer and providing a hitherto unrecognized potential source of marine POA. Our study indicates a novel link between sea ice-ocean and atmosphere that may be sensitive to climate change.

  2. The problem of transfer of radionuclide pollution by sea ice.

    PubMed

    Pavlov, V K; Stanovoy, V V

    2001-04-01

    The problem of the radioactive pollution of the ice cover is discussed in this paper. An estimation of the possible transport of the radionuclides by drifting ice from the Kara Sea into the Arctic Ocean is presented. The conclusion about the importance of the contribution of drifting ice to the contamination of the Greenland coastal water is based on the comparison of estimates of the multiyear export of radioactive drifting ice from the Kara Sea with the observed concentrations of the radionuclides in the Greenland coastal water.

  3. Additional Arctic observations improve weather and sea-ice forecasts for the Northern Sea Route.

    PubMed

    Inoue, Jun; Yamazaki, Akira; Ono, Jun; Dethloff, Klaus; Maturilli, Marion; Neuber, Roland; Edwards, Patti; Yamaguchi, Hajime

    2015-11-20

    During ice-free periods, the Northern Sea Route (NSR) could be an attractive shipping route. The decline in Arctic sea-ice extent, however, could be associated with an increase in the frequency of the causes of severe weather phenomena, and high wind-driven waves and the advection of sea ice could make ship navigation along the NSR difficult. Accurate forecasts of weather and sea ice are desirable for safe navigation, but large uncertainties exist in current forecasts, partly owing to the sparse observational network over the Arctic Ocean. Here, we show that the incorporation of additional Arctic observations improves the initial analysis and enhances the skill of weather and sea-ice forecasts, the application of which has socioeconomic benefits. Comparison of 63-member ensemble atmospheric forecasts, using different initial data sets, revealed that additional Arctic radiosonde observations were useful for predicting a persistent strong wind event. The sea-ice forecast, initialised by the wind fields that included the effects of the observations, skilfully predicted rapid wind-driven sea-ice advection along the NSR.

  4. Additional Arctic observations improve weather and sea-ice forecasts for the Northern Sea Route

    PubMed Central

    Inoue, Jun; Yamazaki, Akira; Ono, Jun; Dethloff, Klaus; Maturilli, Marion; Neuber, Roland; Edwards, Patti; Yamaguchi, Hajime

    2015-01-01

    During ice-free periods, the Northern Sea Route (NSR) could be an attractive shipping route. The decline in Arctic sea-ice extent, however, could be associated with an increase in the frequency of the causes of severe weather phenomena, and high wind-driven waves and the advection of sea ice could make ship navigation along the NSR difficult. Accurate forecasts of weather and sea ice are desirable for safe navigation, but large uncertainties exist in current forecasts, partly owing to the sparse observational network over the Arctic Ocean. Here, we show that the incorporation of additional Arctic observations improves the initial analysis and enhances the skill of weather and sea-ice forecasts, the application of which has socioeconomic benefits. Comparison of 63-member ensemble atmospheric forecasts, using different initial data sets, revealed that additional Arctic radiosonde observations were useful for predicting a persistent strong wind event. The sea-ice forecast, initialised by the wind fields that included the effects of the observations, skilfully predicted rapid wind-driven sea-ice advection along the NSR. PMID:26585690

  5. On large outflows of Arctic sea ice into the Barents Sea

    NASA Technical Reports Server (NTRS)

    Kwok, Ron; Maslowski, Wieslaw; Laxon, Seymour W.

    2005-01-01

    Winter outflows of Arctic sea ice into the Barents Sea are estimated using a 10-year record of satellite ice motion and thickness. The mean winter volume export through the Svalbard/Franz Josef Land passage is 40 km3, and ranges from -280 km3 to 340 km3. A large outflow in 2003 is preconditioned by an unusually high concentration of thick perennial ice over the Nansen Basin at the end of the 2002 summer. With a deep atmospheric low situated over the eastern Barents Sea in winter, the result is an increased export of Arctic ice. The Oct-Mar ice area flux, at 110 x 10 to the third power km3, is not only unusual in magnitude but also remarkable in that >70% of the area is multiyear ice; the ice volume flux at340 km3 is almost one-fifth of the ice flux through the Fram Strait. Another large outflow of Arctic sea ice through this passage, comparable to that in 2003, is found in 1996. This southward flux of sea ice represents one of two major sources of freshwater in the Barents Sea; the other is the eastward flux of water via the Norwegian Coastal Current. The possible consequences of variable freshwater input on the Barents Sea hydrography and its impact on transformation of Atlantic Water en route to the Arctic Ocean are examined with a 25-year coupled ice-ocean model.

  6. On large outflows of Arctic sea ice into the Barents Sea

    NASA Technical Reports Server (NTRS)

    Kwok, Ron; Maslowski, Wieslaw; Laxon, Seymour W.

    2005-01-01

    Winter outflows of Arctic sea ice into the Barents Sea are estimated using a 10-year record of satellite ice motion and thickness. The mean winter volume export through the Svalbard/Franz Josef Land passage is 40 km3, and ranges from -280 km3 to 340 km3. A large outflow in 2003 is preconditioned by an unusually high concentration of thick perennial ice over the Nansen Basin at the end of the 2002 summer. With a deep atmospheric low situated over the eastern Barents Sea in winter, the result is an increased export of Arctic ice. The Oct-Mar ice area flux, at 110 x 10 to the third power km3, is not only unusual in magnitude but also remarkable in that >70% of the area is multiyear ice; the ice volume flux at340 km3 is almost one-fifth of the ice flux through the Fram Strait. Another large outflow of Arctic sea ice through this passage, comparable to that in 2003, is found in 1996. This southward flux of sea ice represents one of two major sources of freshwater in the Barents Sea; the other is the eastward flux of water via the Norwegian Coastal Current. The possible consequences of variable freshwater input on the Barents Sea hydrography and its impact on transformation of Atlantic Water en route to the Arctic Ocean are examined with a 25-year coupled ice-ocean model.

  7. Sea ice loss enhances wave action at the Arctic coast

    USGS Publications Warehouse

    Overeem, I.; Anderson, R. Scott; Wobus, C.W.; Clow, G.D.; Urban, F.E.; Matell, N.

    2011-01-01

    Erosion rates of permafrost coasts along the Beaufort Sea accelerated over the past 50 years synchronously with Arctic-wide declines in sea ice extent, suggesting a causal relationship between the two. A fetch-limited wave model driven by sea ice position and local wind data from northern Alaska indicates that the exposure of permafrost bluffs to seawater increased by a factor of 2.5 during 1979-2009. The duration of the open water season expanded from ???45 days to ???95 days. Open water expanded more rapidly toward the fall (???0.92 day yr-1), when sea surface temperatures are cooler, than into the mid-summer (???0.71 days yr-1).Time-lapse imagery demonstrates the relatively efficient erosive action of a single storm in August. Sea surface temperatures have already decreased significantly by fall, reducing the potential impact of thermal erosion due to fall season storm waves. Copyright 2011 by the American Geophysical Union.

  8. Sunlight, Sea Ice, and the Ice Albedo Feedback in a Changing Arctic Sea Ice Cover

    DTIC Science & Technology

    2013-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Sunlight, Sea Ice, and the Ice Albedo Feedback in a...ice age, and iv) onset dates of melt and freezeup. 4. Assess the magnitude of the contribution from ice- albedo feedback to the observed decrease of...COVERED 00-00-2013 to 00-00-2013 4. TITLE AND SUBTITLE Sunlight, Sea Ice, and the Ice Albedo Feedback in a Changing Arctic Sea Ice Cover 5a

  9. Arctic Intermediate Water in the Nordic Seas, 1991-2009

    NASA Astrophysics Data System (ADS)

    Jeansson, Emil; Olsen, Are; Jutterström, Sara

    2017-04-01

    The evolution of the different types of Arctic Intermediate Water (AIW) in the Nordic Seas are evaluated and compared, utilising hydro-chemical data between 1991 and 2009 from the GLODAPv2 data product. These waters have been suggested to be important components of the dense overflows to the North Atlantic, and thus it is important to understand how they vary in properties and distribution with time. The AIW from the Greenland and the Iceland Seas, show different degrees of variability during the studied period, but only the Greenland Sea AIW (GSAIW) shows increasing temperature and salinity during the 2000s that considerably changed the properties of this water mass, resulting in a more Atlantic-dominated water type in 2009. An optimum multiparameter (OMP) analysis performed to assess the sources of the Norwegian Sea AIW (NSAIW) show that both the Iceland Sea Arctic Intermediate Water (ISAIW) and the GSAIW contributes clearly to NSAIW, but at different densities, corresponding to their respective density range. This illustrates that they flow largely isopycnally from their source regions to the Norwegian Sea. The main source to the NSAIW, however, is the upper Polar Deep Water, which agrees with the lower concentrations of oxygen and chlorofluorocarbons, and higher salinity and silicate concentrations found in the NSAIW layer, compared to ISAIW and GSAIW. The analysis shows how vital it is to include chemical tracers to any water mass analysis to correctly assess the sources.

  10. Arctic spring ozone reduction associated with projected sea ice loss

    NASA Astrophysics Data System (ADS)

    Deser, C.; Sun, L.; Tomas, R. A.; Polvani, L. M.

    2013-12-01

    The impact of Arctic sea ice loss on the stratosphere is investigated using the Whole-Atmosphere Community Climate Model (WACCM), by prescribing the sea ice in the late 20th century and late 21st century, respectively. The localized Sea Surface Temperature (SST) change associated with sea ice 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 cap ozone reduction is up to 20 DU. Since the difference between these two runs lies only in the sea ice 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 ice loss. The reduction in propagation causes less wave dissipation and thus less zonal wind deceleration in the extratropical stratosphere.

  11. Melting Arctic Sea Ice Dries the American West

    NASA Astrophysics Data System (ADS)

    Sewall, J. O.; Sloan, L. C.

    2003-12-01

    Over the last century, Arctic sea ice cover has decreased dramatically and many researchers expect that future greenhouse warming will exacerbate this trend. The prospect of a warmer Arctic with less ice raises many environmental and economic questions, one of which is: How will reduced Arctic ice cover effect extrapolar climates? Using the fully coupled NCAR CCSM we completed a multi-century simulation of global climate responses to reduced Arctic sea ice cover. While the global average climate response is muted, regional responses to the imposed forcing are significant. One of the more striking regional responses is a shift in storm tracks that drives a 50-100% increase in annual evaporation minus precipitation over the American West, a region where limited water resources are already a significant problem. This result highlights two well-known aspects of climate change: (1) relatively small global changes can be composed of significant regional changes and (2) changes in one region can have a large impact on distant locations. Both of these facts will become increasingly important as researchers and policy makers attempt to untangle the looming thicket of climate change impacts and feedbacks.

  12. Springtime atmospheric transport controls Arctic summer sea-ice extent

    NASA Astrophysics Data System (ADS)

    Kapsch, Marie; Graversen, Rune; Tjernström, Michael

    2013-04-01

    The sea-ice extent in the Arctic has been steadily decreasing during the satellite remote sensing era, 1979 to present, with the highest rate of retreat found in September. Contributing factors causing the ice retreat are among others: changes in surface air temperature (SAT; Lindsay and Zhang, 2005), ice circulation in response to winds/pressure patterns (Overland et al., 2008) and ocean currents (Comiso et al., 2008), as well as changes in radiative fluxes (e.g. due to changes in cloud cover; Francis and Hunter, 2006; Maksimovich and Vihma, 2012) and ocean conditions. However, large interannual variability is superimposed onto the declining trend - the ice extent by the end of the summer varies by several million square kilometer between successive years (Serreze et al., 2007). But what are the processes causing the year-to-year ice variability? A comparison of years with an anomalously large September sea-ice extent (HIYs - high ice years) with years showing an anomalously small ice extent (LIYs - low ice years) reveals that the ice variability is most pronounced in the Arctic Ocean north of Siberia (which became almost entirely ice free in September of 2007 and 2012). Significant ice-concentration anomalies of up to 30% are observed for LIYs and HIYs in this area. Focusing on this area we find that the greenhouse effect associated with clouds and water-vapor in spring is crucial for the development of the sea ice during the subsequent months. In years where the end-of-summer sea-ice extent is well below normal, a significantly enhanced transport of humid air is evident during spring into the region where the ice retreat is encountered. The anomalous convergence of humidity increases the cloudiness, resulting in an enhancement of the greenhouse effect. As a result, downward longwave radiation at the surface is larger than usual. In mid May, when the ice anomaly begins to appear and the surface albedo therefore becomes anomalously low, the net shortwave radiation

  13. Reconstructing sea ice conditions in the Arctic and sub-Arctic prior to human observations

    NASA Astrophysics Data System (ADS)

    de Vernal, Anne; Hillaire-Marcel, Claude; Solignac, Sandrine; Radi, Taoufik; Rochon, André

    Sea ice is a sensitive parameter characterized by a high variability in space and time that can be reconstructed from paleoclimatological archives. The most direct indication of past sea ice cover is found in marine sediments, which contain various tracers or proxies of environments characterized by sea ice. They include sedimentary tracers of particles entrained and dispersed by sea ice, biogenic remains associated with production under/within sea ice or with ice-free conditions, in addition to geochemical and isotopic tracers of brine formation linked to sea ice growth. Reconstructing the extent of past sea ice is, however, difficult because proxies are only indirectly related to sea ice and require the use of transfer functions having inherent uncertainties. In particular, we have to assume a correspondence between sea ice cover values from modern observations and the sea ice proxies from surface sediment samples, which is a source of bias since the time intervals represented by modern observations (here 1954-2000) and surface sediments (100-103 years) are not equivalent. Moreover, suitable sedimentary sequences for reconstructing sea ice are rare, making the spatial resolution of reconstructions very patchy. Nevertheless, although fragmentary in time and space and despite uncertainties, available reconstructions reveal very large amplitude changes of sea ice in response to natural forcing during the recent geological past. For example, during the early Holocene, about 8000 years ago, data from dinocyst assemblages suggest reduced sea ice cover as compared to present in some subarctic basins (Labrador Sea, Baffin Bay, and Hudson Bay), whereas enhanced sea ice cover is reconstructed along the eastern Greenland margin and in the western Arctic, showing a pattern not unlike the dipole anomaly that was observed during the 20th century.

  14. Diminishing sea ice in the western Arctic Ocean

    USGS Publications Warehouse

    Stone, R.S.; Belchansky, G.I.; Drobot, Sheldon; Douglas, D.C.; Levinson, D.H.; Waple, A.M.

    2004-01-01

    Since the advent of satellite passive microwave radiometry (1978), variations in sea ice extent and concentration have been carefully monitored from space. An estimated 7.4% decrease in sea ice extent has occurred in the last 25 yr (Johannessen et al. 2004), with recent record minima (e.g., Maslanik et al. 1999; Serreze et al. 2003) accounting for much of the decline. Comparisons between the time series of Arctic sea ice melt dynamics and snowmelt dates at the NOAA–CMDL Barrow Observatory (BRW) reveal intriguing correlations.Melt-onset dates over sea ice (Drobot and Anderson 2001) were cross correlated with the melt-date time series from BRW, and a prominent region of high correlation between snowmelt onset over sea ice and the BRW record of melt dates was approximately aligned with the climatological center of the Beaufort Sea Anticyclone (BSA). The BSA induces anticyclonic ice motion in the region, effectively forcing the Beaufort gyre. A weak gyre caused by a breakdown of the BSA diminishes transport of multiyear ice into this region (Drobot and Maslanik 2003). Similarly, the annual snow cycle at BRW varies with the position and intensity of the BSA (Stone et al. 2002, their Fig. 6). Thus, variations in the BSA appear to have far-reaching effects on the annual accumulation and subsequent melt of snow over a large region of the western Arctic.A dramatic increase in melt season duration (Belchansky et al. 2004) was also observed within the same region of high correlation between onset of melt over the ice pack and snowmelt at BRW (Fig. 5.7). By inference, this suggests linkages between factors that modulate the annual cycle of snow on land and processes that influence melting of snow and ice in the western Arctic Ocean.

  15. Arctic Sea Ice Motion from Wavelet Analysis of Satellite Data

    NASA Technical Reports Server (NTRS)

    Liu, Antony K.; Zhao, Yunhe

    1998-01-01

    Wavelet analysis of DMSP SSM/I (Special Sensor Microwave/Imager) 85 GHz and 37 GHz radiance data, SMMR (Scanning Multichannel Microwave Radiometer) 37 GHz, and NSCAT (NASA Scatterometer) 13.9 GHZ data can be used to obtain daily sea ice drift information for both the northern and southern polar regions. The derived maps of sea ice drift provide both improved spatial coverage over the existing array of Arctic Ocean buoys and better temporal resolution over techniques utilizing data from satellite synthetic aperture radars (SAR). Examples of derived ice-drift maps in the Arctic illustrate large-scale circulation reversals within a period of a couple weeks. Comparisons with ice displacements derived from buoys show good quantitative agreement. NASA Scatterometer (NSCAT) 13.9 GHZ data have been also used for wavelet analysis to derive sea-ice drift. First, the 40' incidence-angle, sigma-zero (surface roughness) daily map of whole Arctic region with 25 km of pixel size from satellite's 600 km swath has been constructed. Then, the similar wavelet transform procedure to SSM/I data can be applied. Various scales of wavelet transform and threshold have been tested. By overlaying , neighbor filtering, and block-averaging the results of multiscale wavelet transforms, the final sea ice drift vectors are much smooth and representative to the sea ice motion. This wavelet analysis procedure is robust and can make a major contribution to the understanding of ice motion over large areas at relatively high temporal resolutions. The results of wavelet analysis of SSM/I and NSCAT images and buoy data can be merged by some data fusion techniques and will help to improve our current knowledge of sea ice drift and related processes through the data assimilation of ocean-ice numerical model.

  16. Arctic Sea Ice Motion from Wavelet Analysis of Satellite Data

    NASA Technical Reports Server (NTRS)

    Liu, Antony K.; Zhao, Yunhe

    1998-01-01

    Wavelet analysis of DMSP SSM/I (Special Sensor Microwave/Imager) 85 GHz and 37 GHz radiance data, SMMR (Scanning Multichannel Microwave Radiometer) 37 GHz, and NSCAT (NASA Scatterometer) 13.9 GHZ data can be used to obtain daily sea ice drift information for both the northern and southern polar regions. The derived maps of sea ice drift provide both improved spatial coverage over the existing array of Arctic Ocean buoys and better temporal resolution over techniques utilizing data from satellite synthetic aperture radars (SAR). Examples of derived ice-drift maps in the Arctic illustrate large-scale circulation reversals within a period of a couple weeks. Comparisons with ice displacements derived from buoys show good quantitative agreement. NASA Scatterometer (NSCAT) 13.9 GHZ data have been also used for wavelet analysis to derive sea-ice drift. First, the 40' incidence-angle, sigma-zero (surface roughness) daily map of whole Arctic region with 25 km of pixel size from satellite's 600 km swath has been constructed. Then, the similar wavelet transform procedure to SSM/I data can be applied. Various scales of wavelet transform and threshold have been tested. By overlaying , neighbor filtering, and block-averaging the results of multiscale wavelet transforms, the final sea ice drift vectors are much smooth and representative to the sea ice motion. This wavelet analysis procedure is robust and can make a major contribution to the understanding of ice motion over large areas at relatively high temporal resolutions. The results of wavelet analysis of SSM/I and NSCAT images and buoy data can be merged by some data fusion techniques and will help to improve our current knowledge of sea ice drift and related processes through the data assimilation of ocean-ice numerical model.

  17. Controls on Arctic sea ice from first-year and multi-year survival rates

    SciTech Connect

    Hunke, Jes

    2009-01-01

    The recent decrease in Arctic sea ice cover has transpired with a significant loss of multi year ice. The transition to an Arctic that is populated by thinner first year sea ice has important implications for future trends in area and volume. Here we develop a reduced model for Arctic sea ice with which we investigate how the survivability of first year and multi year ice control the mean state, variability, and trends in ice area and volume.

  18. Arctic sea ice melt leads to atmospheric new particle formation.

    PubMed

    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

    2017-06-12

    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 (Svalbard) 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 ice regions. The occurrence of such events across a full decade was anti-correlated with sea ice extent. New particles originating from open water and open pack ice increased the cloud condensation nuclei concentration background by at least ca. 20%, supporting a marine biosphere-climate link through sea ice 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.

  19. Data-Driven Modeling and Prediction of Arctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Kondrashov, Dmitri; Chekroun, Mickael; Ghil, Michael

    2016-04-01

    We present results of data-driven predictive analyses of sea ice over the main Arctic regions. Our approach relies on the Multilayer Stochastic Modeling (MSM) framework of Kondrashov, Chekroun and Ghil [Physica D, 2015] and it leads to probabilistic prognostic models of sea ice concentration (SIC) anomalies on seasonal time scales. This approach is applied to monthly time series of state-of-the-art data-adaptive decompositions of SIC and selected climate variables over the Arctic. We evaluate the predictive skill of MSM models by performing retrospective forecasts with "no-look ahead" for up to 6-months ahead. It will be shown in particular that the memory effects included intrinsically in the formulation of our non-Markovian MSM models allow for improvements of the prediction skill of large-amplitude SIC anomalies in certain Arctic regions on the one hand, and of September Sea Ice Extent, on the other. Further improvements allowed by the MSM framework will adopt a nonlinear formulation and explore next-generation data-adaptive decompositions, namely modification of Principal Oscillation Patterns (POPs) and rotated Multichannel Singular Spectrum Analysis (M-SSA).

  20. Polar Bears Across the Arctic Face Shorter Sea Ice Season

    NASA Image and Video Library

    2017-09-28

    Polar bears already face shorter ice seasons - limiting prime hunting and breeding opportunities. Nineteen separate polar bear subpopulations live throughout the Arctic, spending their winters and springs roaming on sea ice and hunting. The bears have evolved mainly to eat seals, which provide necessary fats and nutrients in the harsh Arctic environment. Polar bears can't outswim their prey, so instead they perch on the ice as a platform and ambush seals at breathing holes or break through the ice to access their dens. The total number of ice-covered days declined at the rate of seven to 19 days per decade between 1979 and 2014. The decline was even greater in the Barents Sea and the Arctic basin. Sea ice concentration during the summer months — an important measure because summertime is when some subpopulations are forced to fast on land — also declined in all regions, by 1 percent to 9 percent per decade. Read more: go.nasa.gov/2cIZSSc Photo credit: Mario Hoppmann

  1. Deglacial-Holocene short-term variability in sea-ice distribution on the Eurasian shelf (Arctic Ocean) - An IP25 biomarker reconstruction.

    NASA Astrophysics Data System (ADS)

    Hörner, Tanja; Stein, Ruediger; Fahl, Kirsten

    2016-04-01

    Four well-dated sediment cores from the Eurasian continental shelf, i.e., the Kara Sea (Cores BP99/07 and BP00/07) and Laptev Sea (Cores PS51/154 and PS51/159), were selected for high-resolution reconstruction of past Arctic environmental conditions during the deglacial-Holocene time interval. These marginal seas are strongly affected by the post-glacial sea-level rise of about 120m. The major focus of our study was the reconstruction of the paleo-sea-ice distribution as sea-ice plays a key role within the modern and past climate system. For reconstruction of paleo-sea ice, the sea-ice proxy IP25 in combination with open-water phytoplankton biomarkers was used (for approach see Belt et al., 2007; Müller et al., 2009, 2011). In addition, specific sterols were determined to reconstruct changes in river run-off and biological production. The post-glacial sea-level rise is especially reflected in prominent decrease in terrigenous biomarkers. Deglacial variations in sea-ice cover sustained for thousand of years, mostly following climatic changes like the Bølling/Allerød (14.7-12.9 ka), Younger Dryas (12.9-11.6 ka) and Holocene warm phase (10-8 ka). Superimposed on a (Late) Holocene cooling trend, short-term fluctuations in sea-ice cover (on centennial scale) are distinctly documented in the distal/off-shore Core BP00/07 from the Kara Sea, less pronounced in the proximal/near-shore Core PS99/07 and in the Laptev Sea cores. Interestingly, this short-term variability in sea-ice cover correlates quite well to changes in Siberian river run-off (e.g., Stein et al. 2004), pointing to a direct linkage between precipitation (atmospheric circulation) and sea-ice formation. References Belt, S.T., Massé, G., Rowland, S.J., Poulin, M., Michel, C., LeBlanc, B., 2007. A novel chemical fossil of palaeo sea ice: IP25. Organic Geochemistry 38, 16-27. Müller, J., Masse, G., Stein, R., Belt, S.T., 2009. Variability of sea-ice conditions in the Fram Strait over the past 30,000 years

  2. Aircraft measurements of microwave emission from Arctic Sea Ice

    NASA Technical Reports Server (NTRS)

    Wilheit, T. T.; Blinn, J.; Campbell, W. J.; Edgerton, A. T.; Nordberg, W.

    1971-01-01

    Measurements of the microwave emission from Arctic Sea ice were made with aircraft at 8 wavelengths ranging from 0.510 cm to 2.81 cm. The expected contrast in emissivities between ice and water was observed at all wavelengths. Distributions of sea ice and open water were mapped from altitudes up to 11 km in the presence of dense cloud cover. Different forms of ice also exhibited strong contrasts in emissivity. Emissivity differences of up to 0.2 were observed between two types of ice at 0.811 cm wavelength. The higher emissivity ice type is tentatively identified as having been formed more recently than the lower emissivity ice.

  3. Persistent organic pollutants in ringed seals from the Russian Arctic.

    PubMed

    Savinov, Vladimir; Muir, Derek C G; Svetochev, Vladislav; Svetocheva, Olga; Belikov, Stanislav; Boltunov, Andrey; Alekseeva, Ludmila; Reiersen, Lars-Otto; Savinova, Tatiana

    2011-06-15

    Organochlorine compounds total DDT (ΣDDT), total HCH isomers (ΣHCH), toxaphenes (sum of Parlar 26, 50, 62), mirex, endrin, methoxychlor, total chlorinated benzenes (ΣCBz), total chlordane compounds (ΣCHL), polychlorinated biphenyls (total of 56 congeners; ΣPCBs), polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), and polybrominated diphenyl ethers (sum of 7 tri- to hepta congeners; ΣPBDEs) were analysed in the blubber of adult ringed seals from the four areas of the Russian Arctic (White Sea, Barents Sea, Kara Sea and Chukchi Sea) collected in 2001-2005. Ringed seals from the south-western part of the Kara Sea (Dikson Island - Yenisei estuary) were the most contaminated with ΣDDTs, ΣPCBs, ΣCHL, and mirex as compared with those found in the other three areas of Russian Arctic, while the highest mean concentrations of ΣHCHs and PCDD/Fs were found in the blubber of ringed seals from the Chukchi Sea and the White Sea, respectively. Among all organochlorine compounds measured in ringed seals from the European part of the Russian Arctic, concentrations of ΣDDT and ΣPCBs only were higher as compared with the other Arctic regions. Levels of all other organochlorine compounds were similar or lower than in seals from Svalbard, Alaska, the Canadian Arctic and Greenland. ΣPBDEs were found in all ringed seal samples analysed. There were no significant differences between ΣPBDE concentrations found in the blubber of ringed seals from the three studied areas of the European part of the Russian Arctic, while PBDE contamination level in ringed seals from the Chukchi Sea was 30-50 times lower. ΣPBDE levels in the blubber of seals from the European part of the Russian Arctic are slightly higher than in ringed seals from the Canadian Arctic, Alaska, and western Greenland but lower compared to ringed seals from Svalbard and eastern Greenland.

  4. Arctic Sea Ice Is Losing Its Bulwark Against Warming Summers

    NASA Image and Video Library

    2017-09-28

    Arctic sea ice, 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 ice has either thinned or melted away, leaving the sea ice cap more vulnerable to the warming ocean and atmosphere. “What we’ve seen over the years is that the older ice is disappearing,” said Walt Meier, a sea ice researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This older, thicker ice is like the bulwark of sea ice: a warm summer will melt all the young, thin ice away but it can’t completely get rid of the older ice. But this older ice is becoming weaker because there’s less of it and the remaining old ice 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

  5. Arctic sea ice simulation in the PlioMIP ensemble

    NASA Astrophysics Data System (ADS)

    Howell, Fergus W.; Haywood, Alan M.; Otto-Bliesner, Bette L.; Bragg, Fran; Chan, Wing-Le; Chandler, Mark A.; Contoux, Camille; Kamae, Youichi; Abe-Ouchi, Ayako; Rosenbloom, Nan A.; Stepanek, Christian; Zhang, Zhongshi

    2016-03-01

    Eight general circulation models have simulated the mid-Pliocene warm period (mid-Pliocene, 3.264 to 3.025 Ma) as part of the Pliocene Modelling Intercomparison Project (PlioMIP). Here, we analyse and compare their simulation of Arctic sea ice for both the pre-industrial period and the mid-Pliocene. Mid-Pliocene sea ice thickness and extent is reduced, and the model spread of extent is more than twice the pre-industrial spread in some summer months. Half of the PlioMIP models simulate ice-free conditions in the mid-Pliocene. This spread amongst the ensemble is in line with the uncertainties amongst proxy reconstructions for mid-Pliocene sea ice extent. Correlations between mid-Pliocene Arctic temperatures and sea ice extents are almost twice as strong as the equivalent correlations for the pre-industrial simulations. The need for more comprehensive sea ice proxy data is highlighted, in order to better compare model performances.

  6. Decadal variability of Arctic sea ice in the Canada Basin

    NASA Astrophysics Data System (ADS)

    Connor, L. N.

    2015-12-01

    A series of spring Arctic flight campaigns surveying a region over the Canada Basin, from 2006 to 2015, has resulted in unique observations that reveal new details of sea ice leads and freeboard evolution, during a decade of significant interannual variability in the Arctic ice cover. The series began in 2006 with a joint NASA/NOAA airborne altimetry campaign over a 1300 km survey line northwest of the Canadian Archipelago extending into the northern Beaufort Sea. Operation IceBridge (OIB) took up this flight line again in 2009 and repeated it annually through 2012. Additional observations have been collected along a 1000+ km flight line, in the southern Canada Basin and eastern Beaufort Sea, between 2009 and 2015. Here we examine laser altimetry, snow radar data, and high-resolution visible imagery to better understand the frequency and distribution of leads and ice floes, the characteristics of first- and multi-year ice types in the survey region, and their impact on the derivation and accuracy of sea ice freeboard. We demonstrate a novel lead detection methodology that depends only upon laser altimeter measurements, and we quantify the impact of low lead frequencies on estimates of instantaneous sea surface height. The analysis reveals a variable springtime freeboard north of 78° N, significantly reduced after 2006, and a notable lead outbreak over the Canada Basin during 2010.

  7. Arctic Sea Ice Simulation in the PlioMIP Ensemble

    NASA Technical Reports Server (NTRS)

    Howell, Fergus W.; Haywood, Alan M.; Otto-Bliesner, Bette L.; Bragg, Fran; Chan, Wing-Le; Chandler, Mark A.; Contoux, Camille; Kamae, Youichi; Abe-Ouchi, Ayako; Rosenbloom, Nan A.; hide

    2016-01-01

    Eight general circulation models have simulated the mid-Pliocene warm period (mid-Pliocene, 3.264 to 3.025 Ma) as part of the Pliocene Modelling Intercomparison Project (PlioMIP). Here, we analyse and compare their simulation of Arctic sea ice for both the pre-industrial period and the mid-Pliocene. Mid-Pliocene sea ice thickness and extent is reduced, and the model spread of extent is more than twice the pre-industrial spread in some summer months. Half of the PlioMIP models simulate ice-free conditions in the mid-Pliocene. This spread amongst the ensemble is in line with the uncertainties amongst proxy reconstructions for mid-Pliocene sea ice extent. Correlations between mid-Pliocene Arctic temperatures and sea ice extents are almost twice as strong as the equivalent correlations for the pre-industrial simulations. The need for more comprehensive sea ice proxy data is highlighted, in order to better compare model performances.

  8. Arctic Sea Ice Simulation in the PlioMIP Ensemble

    NASA Technical Reports Server (NTRS)

    Howell, Fergus W.; Haywood, Alan M.; Otto-Bliesner, Bette L.; Bragg, Fran; Chan, Wing-Le; Chandler, Mark A.; Contoux, Camille; Kamae, Youichi; Abe-Ouchi, Ayako; Rosenbloom, Nan A.; Stepanek, Christian; Zhang, Zhongshi

    2016-01-01

    Eight general circulation models have simulated the mid-Pliocene warm period (mid-Pliocene, 3.264 to 3.025 Ma) as part of the Pliocene Modelling Intercomparison Project (PlioMIP). Here, we analyse and compare their simulation of Arctic sea ice for both the pre-industrial period and the mid-Pliocene. Mid-Pliocene sea ice thickness and extent is reduced, and the model spread of extent is more than twice the pre-industrial spread in some summer months. Half of the PlioMIP models simulate ice-free conditions in the mid-Pliocene. This spread amongst the ensemble is in line with the uncertainties amongst proxy reconstructions for mid-Pliocene sea ice extent. Correlations between mid-Pliocene Arctic temperatures and sea ice extents are almost twice as strong as the equivalent correlations for the pre-industrial simulations. The need for more comprehensive sea ice proxy data is highlighted, in order to better compare model performances.

  9. Comparing growth rates of Arctic Cod Boreogadus saida across the Chukchi and Beaufort Seas

    NASA Astrophysics Data System (ADS)

    Frothingham, A. M.; Norcross, B.

    2016-02-01

    Dramatic changes to the Arctic have highlighted the need for a greater understanding of the present ecosystem. Arctic Cod, Boreogadus saida, commonly dominate fish assemblages in the Arctic region and inhabit two geographically unique seas in the U.S. Due to the importance of Arctic Cod in the Arctic food web, establishing current benchmark information such as growth rates, will provide a better understanding as to how the species will adapt to the effects of climate change. To investigate differences in Arctic Cod life history across nearly 1500 km of vital habitat, growth rates were examined using a von Bertalanffy growth equation. Arctic Cod were collected from 2009 to 2014 from the Chukchi and Beaufort seas. Arctic Cod collected from the Chukchi Sea had an overall smaller maximum achievable length (210 mm) compared to the Beaufort Sea (253 mm) despite a larger sample size in the Chukchi Sea (n=1569) than the Beaufort Sea (n=1140). Growth rates indicated faster growth in the Chukchi Sea (K =0.33) than in the Beaufort Sea (K= 0.29). Arctic Cod collected from the Chukchi Sea had similar achievable maximum lengths throughout, but those collected from the southern Chukchi Sea grew at faster rates (K=0.45).Arctic Cod in the eastern Beaufort Sea region had a higher overall maximum achievable length (243 mm) than in the western Beaufort Sea region (186 mm). Knowledge about contemporary growth rates of Arctic Cod in the Chukchi and Beaufort Seas can be used in future comparisons to evaluate potential effects of increasing climate change and anthropogenic influences.

  10. The Kara and Ust-Kara impact structures (USSR) and their relevance to the K/T boundary event

    NASA Technical Reports Server (NTRS)

    Koeberl, Christian; Nazarov, M. A.; Harrison, T. M.; Sharpton, V. L.; Murali, A. V.; Burke, K.

    1988-01-01

    The Kara and Ust-Kara craters are twin impact structures situated at about 69 deg 10 min N; 65 deg 00 min E at the Kara Sea. For Kara a diameter of about 55 km would be a very conservative estimate, and field observations indicate a maximum current diameter of about 60 km. The diameter of Ust-Kara has to be larger than 16 km. A better estimate might be 25 km but in all likelihood it is even larger. Suevites and impactites from the Kara area have been known since the beginning of the century, but had been misidentified as glacial deposits. Only about 15 years ago the impact origin of the two structures was demonstrated, following the recognition of shock metamorphism in the area. The composition of the target rocks is mirrored by the composition of the clasts within the suevites. In the southern part of Kara, Permian shales and limestones are sometimes accompanied by diabasic dykes, similar to in the central uplift. Due to the high degree of shock metamorphism the shocked magmatic rocks are not easily identified, although most of them seem to be of diabasic or dioritic composition. The impact melts (tagamites) are grey to dark grey fine grained crystallized rocks showing very fine mineral components and are the product of shock-melting with later recrystallization. The impact glasses show a layered structure, inclusions, and vesicles, and have colors ranging from translucent white over brown and grey to black. A complete geochemical characterization of the Kara and Ust-Kara impact craters was attempted by analyzing more than 40 samples of target rocks, shocked rocks, suevites, impact melts, and impact glasses for major and trace elements.

  11. Geographical distribution of organochlorine pesticides (OCPs) in polar bears (Ursus maritimus) in the Norwegian and Russian Arctic

    USGS Publications Warehouse

    Lie, E.; Bernhoft, A.; Riget, F.; Belikov, Stanislav; Boltunov, Andrei N.; Derocher, A.E.; Garner, G.W.; Wiig, O.; Skaare, J.U.

    2003-01-01

    Geographical variation of organochlorine pesticides (OCPs) was studied in blood samples from 90 adult female polar bear (Ursus maritimus) from Svalbard, Franz Josef Land, Kara Sea, East-Siberian Sea and Chukchi Sea. In all regions, oxychlordane was the dominant OCP. Regional differences in mean levels of HCB, oxychlordane, trans-nonachlor, ??-HCH, ??-HCH and p,p???-DDE were found. The highest levels of oxychlordane, trans-nonachlor and DDE were found in polar bears from Franz Josef Land and Kara Sea. HCB level was lowest in polar bears from Svalbard. Polar bears from Chukchi Sea had the highest level of ??- and ??-HCH. The lowest ??-HCH concentration was found in bears from Kara Sea. In all the bears, ???HCHs was dominated by ??-HCH. The geographical variation in OCP levels and pattern may suggest regional differences in pollution sources and different feeding habits in the different regions. Polar bears from the Western Russian Arctic were exposed to higher levels of chlordanes and p,p???-DDE than polar bears from locations westwards and eastwards from this region. This may imply the presence of a significant pollution source in the Russian Arctic area. The study suggests that the western Russian Arctic is the most contaminated region of the Arctic and warrants further research. ?? 2002 Elsevier Science B.V. All rights reserved.

  12. Geographical distribution of organochlorine pesticides (OCPs) in polar bears (Ursus maritimus) in the Norwegian and Russian Arctic.

    PubMed

    Lie, E; Bernhoft, A; Riget, F; Belikov, S E; Boltunov, A N; Derocher, A E; Garner, G W; Wiig, Ø; Skaare, J U

    2003-05-01

    Geographical variation of organochlorine pesticides (OCPs) was studied in blood samples from 90 adult female polar bear (Ursus maritimus) from Svalbard, Franz Josef Land, Kara Sea, East-Siberian Sea and Chukchi Sea. In all regions, oxychlordane was the dominant OCP. Regional differences in mean levels of HCB, oxychlordane, trans-nonachlor, alpha-HCH, beta-HCH and p,p'-DDE were found. The highest levels of oxychlordane, trans-nonachlor and DDE were found in polar bears from Franz Josef Land and Kara Sea. HCB level was lowest in polar bears from Svalbard. Polar bears from Chukchi Sea had the highest level of alpha- and beta-HCH. The lowest alpha-HCH concentration was found in bears from Kara Sea. In all the bears, summation operator HCHs was dominated by beta-HCH. The geographical variation in OCP levels and pattern may suggest regional differences in pollution sources and different feeding habits in the different regions. Polar bears from the Western Russian Arctic were exposed to higher levels of chlordanes and p,p'-DDE than polar bears from locations westwards and eastwards from this region. This may imply the presence of a significant pollution source in the Russian Arctic area. The study suggests that the western Russian Arctic is the most contaminated region of the Arctic and warrants further research.

  13. Multi-model seasonal forecast of Arctic sea-ice: forecast uncertainty at pan-Arctic and regional scales

    NASA Astrophysics Data System (ADS)

    Blanchard-Wrigglesworth, E.; Barthélemy, A.; Chevallier, M.; Cullather, R.; Fučkar, N.; Massonnet, F.; Posey, P.; Wang, W.; Zhang, J.; Ardilouze, C.; Bitz, C. M.; Vernieres, G.; Wallcraft, A.; Wang, M.

    2016-10-01

    Dynamical model forecasts in the Sea Ice Outlook (SIO) of September Arctic sea-ice extent over the last decade have shown lower skill than that found in both idealized model experiments and hindcasts of previous decades. Additionally, it is unclear how different model physics, initial conditions or forecast post-processing (bias correction) techniques contribute to SIO forecast uncertainty. In this work, we have produced a seasonal forecast of 2015 Arctic summer sea ice using SIO dynamical models initialized with identical sea-ice thickness in the central Arctic. Our goals are to calculate the relative contribution of model uncertainty and irreducible error growth to forecast uncertainty and assess the importance of post-processing, and to contrast pan-Arctic forecast uncertainty with regional forecast uncertainty. We find that prior to forecast post-processing, model uncertainty is the main contributor to forecast uncertainty, whereas after forecast post-processing forecast uncertainty is reduced overall, model uncertainty is reduced by an order of magnitude, and irreducible error growth becomes the main contributor to forecast uncertainty. While all models generally agree in their post-processed forecasts of September sea-ice volume and extent, this is not the case for sea-ice concentration. Additionally, forecast uncertainty of sea-ice thickness grows at a much higher rate along Arctic coastlines relative to the central Arctic ocean. Potential ways of offering spatial forecast information based on the timescale over which the forecast signal beats the noise are also explored.

  14. Multi-model seasonal forecast of Arctic sea-ice: forecast uncertainty at pan-Arctic and regional scales

    NASA Astrophysics Data System (ADS)

    Blanchard-Wrigglesworth, E.; Barthélemy, A.; Chevallier, M.; Cullather, R.; Fučkar, N.; Massonnet, F.; Posey, P.; Wang, W.; Zhang, J.; Ardilouze, C.; Bitz, C. M.; Vernieres, G.; Wallcraft, A.; Wang, M.

    2017-08-01

    Dynamical model forecasts in the Sea Ice Outlook (SIO) of September Arctic sea-ice extent over the last decade have shown lower skill than that found in both idealized model experiments and hindcasts of previous decades. Additionally, it is unclear how different model physics, initial conditions or forecast post-processing (bias correction) techniques contribute to SIO forecast uncertainty. In this work, we have produced a seasonal forecast of 2015 Arctic summer sea ice using SIO dynamical models initialized with identical sea-ice thickness in the central Arctic. Our goals are to calculate the relative contribution of model uncertainty and irreducible error growth to forecast uncertainty and assess the importance of post-processing, and to contrast pan-Arctic forecast uncertainty with regional forecast uncertainty. We find that prior to forecast post-processing, model uncertainty is the main contributor to forecast uncertainty, whereas after forecast post-processing forecast uncertainty is reduced overall, model uncertainty is reduced by an order of magnitude, and irreducible error growth becomes the main contributor to forecast uncertainty. While all models generally agree in their post-processed forecasts of September sea-ice volume and extent, this is not the case for sea-ice concentration. Additionally, forecast uncertainty of sea-ice thickness grows at a much higher rate along Arctic coastlines relative to the central Arctic ocean. Potential ways of offering spatial forecast information based on the timescale over which the forecast signal beats the noise are also explored.

  15. Variability of Arctic Sea Ice as Viewed from Space

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.

    1998-01-01

    Over the past 20 years, satellite passive-microwave radiometry has provided a marvelous means for obtaining information about the variability of the Arctic sea ice cover and particularly about sea ice concentrations (% areal coverages) and from them ice extents and the lengths of the sea ice season. This ability derives from the sharp contrast between the microwave emissions of sea ice versus liquid water and allows routine monitoring of the vast Arctic sea ice cover, which typically varies in extent from a minimum of about 8,000,000 sq km in September to a maximum of about 15,000,000 sq km in March, the latter value being over 1.5 times the area of either the United States or Canada. The vast Arctic ice cover has many impacts, including hindering heat, mass, and y momentum exchanges between the oceans and the atmosphere, reducing the amount of solar radiation absorbed at the Earth's surface, affecting freshwater transports and ocean circulation, and serving as a vital surface for many species of polar animals. These direct impacts also lead to indirect impacts, including effects on local and perhaps global atmospheric temperatures, effects that are being examined in general circulation modeling studies, where preliminary results indicate that changes on the order of a few percent sea ice concentration can lead to temperature changes of 1 K or greater even in local areas outside of the sea ice region. Satellite passive-microwave data for November 1978 through December 1996 reveal marked regional and interannual variabilities in both the ice extents and the lengths of the sea ice season, as well as some statistically significant trends. For the north polar ice cover as a whole, maximum ice extents varied over a range of 14,700,000 - 15,900,000 km(2), while individual regions showed much greater percentage variations, e.g., with the Greenland Sea experiencing a range of 740,000 - 1,1110,000 km(2) in its yearly maximum ice coverage. Although variations from year to

  16. Variability of Arctic Sea Ice as Viewed from Space

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.

    1998-01-01

    Over the past 20 years, satellite passive-microwave radiometry has provided a marvelous means for obtaining information about the variability of the Arctic sea ice cover and particularly about sea ice concentrations (% areal coverages) and from them ice extents and the lengths of the sea ice season. This ability derives from the sharp contrast between the microwave emissions of sea ice versus liquid water and allows routine monitoring of the vast Arctic sea ice cover, which typically varies in extent from a minimum of about 8,000,000 sq km in September to a maximum of about 15,000,000 sq km in March, the latter value being over 1.5 times the area of either the United States or Canada. The vast Arctic ice cover has many impacts, including hindering heat, mass, and y momentum exchanges between the oceans and the atmosphere, reducing the amount of solar radiation absorbed at the Earth's surface, affecting freshwater transports and ocean circulation, and serving as a vital surface for many species of polar animals. These direct impacts also lead to indirect impacts, including effects on local and perhaps global atmospheric temperatures, effects that are being examined in general circulation modeling studies, where preliminary results indicate that changes on the order of a few percent sea ice concentration can lead to temperature changes of 1 K or greater even in local areas outside of the sea ice region. Satellite passive-microwave data for November 1978 through December 1996 reveal marked regional and interannual variabilities in both the ice extents and the lengths of the sea ice season, as well as some statistically significant trends. For the north polar ice cover as a whole, maximum ice extents varied over a range of 14,700,000 - 15,900,000 km(2), while individual regions showed much greater percentage variations, e.g., with the Greenland Sea experiencing a range of 740,000 - 1,1110,000 km(2) in its yearly maximum ice coverage. Although variations from year to

  17. Physical Characteristics and Geobiology of 'Rotten' Arctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Frantz, C. M.; Light, B.; Orellana, M. V.; Carpenter, S.; Junge, K.

    2015-12-01

    Arctic sea ice in its final stage of demise, "rotten ice", is characterized by seriously compromised structural integrity, making it difficult to collect and study. Consequently, little is known about the physical, chemical and biological properties of this ice type. Yet, as the Arctic melt season lengthens, this ice type will likely appear sooner and become more prevalent in the Arctic Ocean and its occurrence may be more common than satellite mapping and ice charts suggest (e.g., Barber et al., 2009). Here we present physical, chemical, biological, and optical measurements of first-year ice near Barrow, Alaska during the spring and summer of 2015. Samples represent a progression from solid, "springtime" shorefast ice (May); through melting, heavily melt-ponded, "summertime" shorefast ice (June); to the final stage of barely-intact, "rotten" ice collected from small floes Beaufort Sea (July). Results indicate that rotten ice exhibits low salinity, is well drained and has a lower density than its springtime counterpart. X-ray tomography of dimethyl phthalate-casted sea ice samples indicates differences in porosity and relative permeability in rotten ice vs. spring- and summertime ice. We also present a preliminary characterization of rotten sea ice as a microbial habitat using preliminary results of chemical measurements (nutrients, dissolved organic and inorganic carbon), and microbiological characterizations (concentrations and16S/18S rDNA-based identifications) from seawater vs. sea ice vs. sea ice brines. Optical measurements show that while decreased ice thickness and increased melt pond coverage cause an overall increase in solar radiation to the ocean as sea ice warms, rotten ice is actually less transparent to solar radiation than its spring- and summertime counterparts. These factors determine solar heating in the ocean and, ultimately, the potential for accelerated ice melting (e.g., Light et al., 2008). This work provides a foundation for understanding

  18. Quantifying Uncertainties in the Seasonal Cycle of Arctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Lucas, D. D.; Covey, C. C.; Klein, R.; Tannahill, J.; Ivanova, D. P.

    2013-12-01

    Many climate models project that the Arctic Ocean will be free of summertime sea ice within a century when forced with representative future greenhouse gas emission scenarios. To determine whether uncertainties in sea ice physics can also lead to an ice-free Arctic, we ran present-day ensemble simulations with the Community Climate System Model (CCSM4) that varied 7 parameters in the Community Ice Code (CICE4) over expert-provided ranges. The September minimum in sea ice extent computed by the ensemble ranges from 0.5 to 7.7 million km2, the lower end of which is significantly less than current observed values and lower than the models in the Coupled Model Intercomparison Project Phase 5 (CMIP5). CCSM4 can therefore simulate a summertime Arctic that is effectively free of sea ice either by increasing greenhouse gas forcing or by keeping the forcing constant and varying CICE4 parameters within recommended ranges. We identified three key CICE4 parameters related to radiative and thermal properties of snow that drive this extreme ensemble variability. Given observational data, machine learning algorithms were also used to quantify and constrain probability distribution functions for these parameters, which can be sampled to provide probabilistic assessments of sea ice characteristics simulated by CICE4. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was funded by the Uncertainty Quantification Strategic Initiative Laboratory Directed Research and Development Project at LLNL under project tracking code 10-SI-013 (UCRL LLNL-ABS-641752).

  19. Arctic Sea Ice Thickness - Past, Present And Future

    NASA Astrophysics Data System (ADS)

    Wadhams, P.

    2007-12-01

    In November 2005 the International Workshop on Arctic Sea Ice Thickness: Past, Present and Future was held at Rungstedgaard Conference Center, near Copenhagen, Denmark. The proceedings of the Workshop were subsequently published as a book by the European Commission. In this review we summarise the conclusions of the Workshop on the techniques which show the greatest promise for thickness monitoring on different spatial and temporal scales, and for different purposes. Sonic methods, EM techniques, buoys and satellite methods will be considered. Some copies of the book will be available at the lecture, and others can be ordered from the European Commission. The paper goes on to consider early results from some of the latest measurements on Arctic sea ice thickness done in 2007. These comprise a trans-Arctic voyage by a UK submarine, HMS "Tireless", equipped with a Kongsberg 3002 multibeam sonar which generates a 3-D digital terrain map of the ice underside; and experiments at the APLIS ice station in the Beaufort Sea carried out by the Gavia AUV equipped with a GeoSwath interferometric sonar. In both cases 3-D mapping of sea ice constitutes a new step forward in sea ice data collection, but in the case of the submarine the purpose is to map change in ice thickness (comparing results with a 2004 "Tireless" cruise and with US and UK data prior to 2000), while for the small AUV the purpose is intensive local mapping of a few ridges to improve our knowledge of their structure, as part of a multisensor programme

  20. How does sea ice influence δ18O of Arctic precipitation?

    NASA Astrophysics Data System (ADS)

    Faber, Anne-Katrine; Møllesøe Vinther, Bo; Sjolte, Jesper; Anker Pedersen, Rasmus

    2017-05-01

    This study investigates how variations in Arctic sea ice and sea surface conditions influence δ18O of present-day Arctic precipitation. This is done using the model isoCAM3, an isotope-equipped version of the National Center for Atmospheric Research Community Atmosphere Model version 3. Four sensitivity experiments and one control simulation are performed with prescribed sea surface temperature (SST) and sea ice. Each of the four experiments simulates the atmospheric and isotopic response to Arctic oceanic conditions for selected years after the beginning of the satellite era in 1979. Changes in sea ice extent and SSTs have different impacts in Greenland and the rest of the Arctic. The simulated changes in central Arctic sea ice do not influence δ18O of Greenland precipitation, only anomalies of Baffin Bay sea ice. However, this does not exclude the fact that simulations based on other sea ice and sea surface temperature distributions might yield changes in the δ18O of precipitation in Greenland. For the Arctic, δ18O of precipitation and water vapour is sensitive to local changes in sea ice and sea surface temperature and the changes in water vapour are surface based. Reduced sea ice extent yields more enriched isotope values, whereas increased sea ice extent yields more depleted isotope values. The distribution of the sea ice and sea surface conditions is found to be essential for the spatial distribution of the simulated changes in δ18O.

  1. Contaminants in arctic snow collected over northwest Alaskan sea ice

    USGS Publications Warehouse

    Garbarino, J.R.; Snyder-Conn, E.; Leiker, T.J.; Hoffman, G.L.

    2002-01-01

    Snow cores were collected over sea ice from four northwest Alaskan Arctic estuaries that represented the annual snowfall from the 1995-1996 season. Dissolved trace metals, major cations and anions, total mercury, and organochlorine compounds were determined and compared to concentrations in previous arctic studies. Traces (<4 nanograms per liter, ng L-1) of cis- and trans-chlordane, dimethyl 2,3,5,6-tetrachloroterephthalate, dieldrin, endosulfan II, and PCBs were detected in some samples, with endosulfan I consistently present. High chlorpyrifos concentrations (70-80 ng L-1) also were estimated at three sites. The snow was highly enriched in sulfates (69- 394 mg L-1), with high proportions of nonsea salt sulfates at three of five sites (9 of 15 samples), thus indicating possible contamination through long-distance transport and deposition of sulfate-rich atmospheric aerosols. Mercury, cadmium, chromium, molybdenum, and uranium were typically higher in the marine snow (n = 15) in relation to snow from arctic terrestrial studies, whereas cations associated with terrigenous sources, such as aluminum, frequently were lower over the sea ice. One Kasegaluk Lagoon site (Chukchi Sea) had especially high concentrations of total mercury (mean = 214 ng L-1, standard deviation = 5 ng L-1), but no methyl mercury was detected above the method detection limit (0.036 ng L-1) at any of the sites. Elevated concentrations of sulfate, mercury, and certain heavy metals might indicate mechanisms of contaminant loss from the arctic atmosphere over marine water not previously reported over land areas. Scavenging by snow, fog, or riming processes and the high content of deposited halides might facilitate the loss of such contaminants from the atmosphere. Both the mercury and chlorpyrifos concentrations merit further investigation in view of their toxicity to aquatic organisms at low concentrations.

  2. Coherent GNSS Reflections from Arctic Sea

    NASA Astrophysics Data System (ADS)

    Semmling, M.; Papke, J.; Helm, A.; Stosius, R.; Beyerle, G.; Yudanov, S.; Ribo, S.; Rius, A.; Rothacher, M.

    2009-04-01

    GNSS signals reflected from the earth surface can be used for remote sensing. In contrast to an active system a GNSS Reflectometry (GNSS-R) receiver is a passive device using GNSS signals of opportunity. Reflection tracks from multiple GNSS satellites will be distributed in the field of view. For applications of interest i.a. sea ice concentration a high coverage is important. An arrangement of several receivers would increase the surface coverage of reflection tracks. In this respect many approved, integrated GNSS-R receivers are needed. In collaboration with JAVAD GNSS we adapted a commercial GNSS receiver for Occultation, Reflectometry and Scatterometry (GORS) applications. To test the receiver a ground based experiment was set up. Within the GPS-SIDS (Sea Ice Dry Snow) project, the GORS receiver was installed at the coast in about 700m above sea level near Godhavn, Western Greenland. Continuous data was recorded in the winter period 2008/2009. The data includes the in-phase/quad-phase of the signal for frequencies L1 and L2. The observations were restricted to elevation angles below 15 degrees to obtain coherent reflections. The coherence yields an interference of the direct and reflected signal. We expect a difference in the coherent fraction between ice and water. In a first approach we aim to locate the boundary between water and appearing sea ice.

  3. Black Carbon Sources Constrained by Observations in the Russian High Arctic.

    PubMed

    Popovicheva, Olga B; Evangeliou, Nikolaos; Eleftheriadis, Konstantinos; Kalogridis, Athina C; Sitnikov, Nikolay; Eckhardt, Sabine; Stohl, Andreas

    2017-04-04

    Understanding the role of short-lived climate forcers such as black carbon (BC) at high northern latitudes in climate change is hampered by the scarcity of surface observations in the Russian Arctic. In this study, highly time-resolved Equivalent BC (EBC) measurements during a ship campaign in the White, Barents, and Kara Seas in October 2015 are presented. The measured EBC concentrations are compared with BC concentrations simulated with a Lagrangian particle dispersion model coupled with a recently completed global emission inventory to quantify the origin of the Arctic BC. EBC showed increased values (100-400 ng m(-3)) in the Kara Strait, Kara Sea, and Kola Peninsula and an extremely high concentration (1000 ng m(-3)) in the White Sea. Assessment of BC origin throughout the expedition showed that gas-flaring emissions from the Yamal-Khanty-Mansiysk and Nenets-Komi regions contributed the most when the ship was close to the Kara Strait, north of 70° N. Near Arkhangelsk (White Sea), biomass burning in mid-latitudes, surface transportation, and residential and commercial combustion from Central and Eastern Europe were found to be important BC sources. The model reproduced observed EBC concentrations efficiently, building credibility in the emission inventory for BC emissions at high northern latitudes.

  4. Physical characteristics of summer sea ice across the Arctic Ocean

    USGS Publications Warehouse

    Tucker, W. B.; Gow, A.J.; Meese, D.A.; Bosworth, H.W.; Reimnitz, E.

    1999-01-01

    Sea ice characteristics were investigated during July and August on the 1994 transect across the Arctic Ocean. Properties examined from ice cores included salinity, temperature, and ice structure. Salinities measured near zero at the surface, increasing to 3-4??? at the ice-water interface. Ice crystal texture was dominated by columnar ice, comprising 90% of the ice sampled. Surface albedos of various ice types, measured with radiometers, showed integrated shortwave albedos of 0.1 to 0.3 for melt ponds, 0.5 for bare, discolored ice, and 0.6 to 0.8 for a deteriorated surface or snow-covered ice. Aerial photography was utilized to document the distribution of open melt ponds, which decreased from 12% coverage of the ice surface in late July at 76??N to almost none in mid-August at 88??N. Most melt ponds were shallow, and depth bore no relationship to size. Sediment was pervasive from the southern Chukchi Sea to the north pole, occurring in bands or patches. It was absent in the Eurasian Arctic, where it had been observed on earlier expeditions. Calculations of reverse trajectories of the sediment-bearing floes suggest that the southernmost sediment was entrained during ice formation in the Beaufort Sea while more northerly samples probably originated in the East Siberian Sea, some as far west as the New Siberian Islands.

  5. Multiscale Models of Melting Arctic Sea Ice

    DTIC Science & Technology

    2013-09-30

    understanding the evolution of melt ponds and sea ice albedo remains a significant challenge to improving climate models. Our research is focused on...Mathematics, U. of Utah) Don Perovich ( Research Geophysicist, ERDC-CRREL) Tolga Tasdizen (Associate Professor, Department of Electrical and Computer...Chris Polashenski ( Research Geophysicist, ERDC-CRREL) Ivan Sudakov (Lorenz Postdoc in Mathematics of Climate, U. of Utah) Report Documentation

  6. The distribution of atmospheric black carbon in the marine boundary layer over the North Atlantic and the Russian Arctic Seas in July - October 2015

    NASA Astrophysics Data System (ADS)

    Shevchenko, Vladimir P.; Kopeikin, Vladimir M.; Evangeliou, Nikolaos; Novigatsky, Alexander N.; Pankratova, Natalia V.; Starodymova, Dina P.; Stohl, Andreas; Thompson, Rona

    2016-04-01

    Black carbon (BC) particles are highly efficient at absorbing visible light, which has a large potential impact on Arctic climate. However, measurement data on the distribution of BC in the atmosphere over the North Atlantic and the Russian Arctic Seas are scarce. We present measurement data on the distribution of atmospheric BC in the marine boundary layer of the North Atlantic and Baltic, North, Norwegian, Barents, White, Kara and Laptev Seas from research cruises during July 23 to October 6, 2015. During the 62nd and 63rd cruises of the RV "Akademik Mstislav Keldysh" air was filtered through Hahnemuhle fineart quarz-microfibre filters. The mass of BC on the filter was determined by measurement of the attenuation of a beam of light transmitted through the filter. Source areas were estimated by backwards trajectories of air masses calculated using NOAA's HYSPLIT model (http://www.arl.noaa.gov/ready.html) and FLEXPART model (http://www.flexpart.eu). During some parts of the cruises, air masses arrived from background areas of high latitudes, and the measured BC concentrations were low. During other parts of the cruise, air masses arrived from industrially developed areas with strong BC sources, and this led to substantially enhanced measured BC concentrations. Model-supported analyses are currently performed to use the measurement data for constraining the emission strength in these areas.

  7. Comparison of radar backscatter from Antarctic and Arctic sea ice

    NASA Technical Reports Server (NTRS)

    Hosseinmostafa, R.; Lytle, V.

    1992-01-01

    Two ship-based step-frequency radars, one at C-band (5.3 GHz) and one at Ku-band (13.9 GHz), measured backscatter from ice in the Weddell Sea. Most of the backscatter data were from first-year (FY) and second-year (SY) ice at the ice stations where the ship was stationary and detailed snow and ice characterizations were performed. The presence of a slush layer at the snow-ice interface masks the distinction between FY and SY ice in the Weddell Sea, whereas in the Arctic the separation is quite distinct. The effect of snow-covered ice on backscattering coefficients (sigma0) from the Weddell Sea region indicates that surface scattering is the dominant factor. Measured sigma0 values were compared with Kirchhoff and regression-analysis models. The Weibull power-density function was used to fit the measured backscattering coefficients at 45 deg.

  8. A Rapidly Declining Arctic Perennial Sea Ice Cover

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.; Koblinsky, Chester J. (Technical Monitor)

    2002-01-01

    The perennial sea ice cover in the Arctic is shown to be declining at -8.9 plus or minus 2.0% per decade, using 22 years of satellite data. A sustained decline at this rate would mean the disappearance of the multiyear ice cover during this century and drastic changes in the seasonal characteristics of the Arctic ice cover. An apparent increase in the fraction of second year ice in the 1990s is also inferred suggesting an overall thinning of the ice cover while co-registered satellite surface temperatures show a warming trend of 0.8 plus or minus 0.6 K per decade in summer and a good correlation with the perennial ice data.

  9. Regional dependence in the rapid loss of Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Close, Sally; Houssais, Marie-Noëlle; Herbaut, Christophe

    2016-04-01

    The accelerating rate of sea ice decline in the Arctic, particularly in the summer months, has been well documented by previous studies. However, the methods of analysis used to date have tended to employ pre-defined regions over which to determine sea ice loss, potentially masking regional variability within these regions. Similarly, evidence of acceleration has frequently been based on decade-to-decade comparisons that do not precisely quantify the timing of the increase in rate of decline. In this study, we address this issue by quantifying the onset time of rapid loss in sea ice concentration on a point-by-point basis, using an objective method applied to satellite passive microwave data. Seasonal maps of onset time are produced, and reveal strong regional dependency, with differences of up to 20 years in onset time between the various subregions of the Arctic. In certain cases, such as the Laptev Sea, strong spatial variability is found even at the regional scale, suggesting that caution should be employed in the use of geographically-based region definitions that may be misaligned with the physical response. The earliest onset times are found in the Pacific sector, where certain areas undergo a transition ca. 1992. In contrast, onset times in the Atlantic sector are much more recent. Rates of decline prior to and following the onset of rapid decline are calculated, and suggest that the post-onset rate of loss is weakest in the Pacific sector and greatest in the Barents Sea region. Coherency is noted in the season-to-season response, both at interannual and longer time scales. Our results describe a series of spatially self-consistent regional responses, and may be useful in understanding the primary drivers of recent sea ice loss.

  10. The emergence of modern sea ice cover in the Arctic Ocean.

    PubMed

    Knies, Jochen; Cabedo-Sanz, Patricia; Belt, Simon T; Baranwal, Soma; Fietz, Susanne; Rosell-Melé, Antoni

    2014-11-28

    Arctic sea ice coverage is shrinking in response to global climate change and summer ice-free conditions in the Arctic Ocean are predicted by the end of the century. The validity of this prediction could potentially be tested through the reconstruction of the climate of the Pliocene epoch (5.33-2.58 million years ago), an analogue of a future warmer Earth. Here we show that, in the Eurasian sector of the Arctic Ocean, ice-free conditions prevailed in the early Pliocene until sea ice expanded from the central Arctic Ocean for the first time ca. 4 million years ago. Amplified by a rise in topography in several regions of the Arctic and enhanced freshening of the Arctic Ocean, sea ice expanded progressively in response to positive ice-albedo feedback mechanisms. Sea ice reached its modern winter maximum extension for the first time during the culmination of the Northern Hemisphere glaciation, ca. 2.6 million years ago.

  11. Air-sea interactions during an Arctic storm

    NASA Astrophysics Data System (ADS)

    Long, Zhenxia; Perrie, Will

    2012-08-01

    The impacts of increased open water in the Beaufort Sea were investigated for a summer Arctic storm in 2008 using a coupled atmosphere-ice-ocean model. The storm originated in northern Siberia and slowly moved into the Beaufort Sea along the ice edge in late July. The maximum wind associated with the storm occurred when it was located over the open water near the Beaufort Sea coast, after it had moved over the Chukchi and Beaufort Seas. The coupled model system is shown to simulate the storm track, intensity, maximum wind speed and the ice cover well. The model simulations suggest that the lack of ice cover in the Beaufort Sea during the 2008 storm results in increased local surface wind and surface air temperature, compared to enhanced ice cover extents such as occurred in past decades. In addition, due to this increase of open water, the surface latent and sensible heat fluxes into the atmosphere are significantly increased. However, there were no significant impacts on the storm track. The expanded open water and the loss of the sea ice results in increases in the surface air temperature by as much as 8°C. Although the atmospheric warming mostly occurs in the boundary layer, there is increased atmospheric boundary turbulence and downward kinetic energy transport that reach to mid-levels of the troposphere and beyond. These changes result in enhanced surface winds, by as much as ˜4 m/s during the 2008 storm, compared to higher ice concentration conditions (typical of past decades). The dominant sea surface temperature response to the storm occurs over open water; storm-generated mixing in the upper ocean results in sea surface cooling of up to 2°C along the southern Beaufort Sea coastal waters. The Ekman divergence associated with the storm caused a decrease in the fresh water content in the central Beaufort Sea by about 11 cm.

  12. Mechanisms for low-frequency variability of summer Arctic sea ice extent

    PubMed Central

    Zhang, Rong

    2015-01-01

    Satellite observations reveal a substantial decline in September Arctic sea ice extent since 1979, which has played a leading role in the observed recent Arctic surface warming and has often been attributed, in large part, to the increase in greenhouse gases. However, the most rapid decline occurred during the recent global warming hiatus period. Previous studies are often focused on a single mechanism for changes and variations of summer Arctic sea ice extent, and many are based on short observational records. The key players for summer Arctic sea ice extent variability at multidecadal/centennial time scales and their contributions to the observed summer Arctic sea ice decline are not well understood. Here a multiple regression model is developed for the first time, to the author’s knowledge, to provide a framework to quantify the contributions of three key predictors (Atlantic/Pacific heat transport into the Arctic, and Arctic Dipole) to the internal low-frequency variability of Summer Arctic sea ice extent, using a 3,600-y-long control climate model simulation. The results suggest that changes in these key predictors could have contributed substantially to the observed summer Arctic sea ice decline. If the ocean heat transport into the Arctic were to weaken in the near future due to internal variability, there might be a hiatus in the decline of September Arctic sea ice. The modeling results also suggest that at multidecadal/centennial time scales, variations in the atmosphere heat transport across the Arctic Circle are forced by anticorrelated variations in the Atlantic heat transport into the Arctic. PMID:25825758

  13. Mechanisms for low-frequency variability of summer Arctic sea ice extent.

    PubMed

    Zhang, Rong

    2015-04-14

    Satellite observations reveal a substantial decline in September Arctic sea ice extent since 1979, which has played a leading role in the observed recent Arctic surface warming and has often been attributed, in large part, to the increase in greenhouse gases. However, the most rapid decline occurred during the recent global warming hiatus period. Previous studies are often focused on a single mechanism for changes and variations of summer Arctic sea ice extent, and many are based on short observational records. The key players for summer Arctic sea ice extent variability at multidecadal/centennial time scales and their contributions to the observed summer Arctic sea ice decline are not well understood. Here a multiple regression model is developed for the first time, to the author's knowledge, to provide a framework to quantify the contributions of three key predictors (Atlantic/Pacific heat transport into the Arctic, and Arctic Dipole) to the internal low-frequency variability of Summer Arctic sea ice extent, using a 3,600-y-long control climate model simulation. The results suggest that changes in these key predictors could have contributed substantially to the observed summer Arctic sea ice decline. If the ocean heat transport into the Arctic were to weaken in the near future due to internal variability, there might be a hiatus in the decline of September Arctic sea ice. The modeling results also suggest that at multidecadal/centennial time scales, variations in the atmosphere heat transport across the Arctic Circle are forced by anticorrelated variations in the Atlantic heat transport into the Arctic.

  14. CryoSat-2 Estimates of Sea Ice Freeboard in the Greenland Sea of Arctic

    NASA Astrophysics Data System (ADS)

    Zhang, S.

    2015-12-01

    Arctic region is one of the most important parts that contribute to the global climate system. As an important climatic indicator, sea ice has also undergone dramatic changes. Due to the limitations of poor geographical conditions and a lack of in-situ observations, knowledge about Arctic sea ice has not been explored well for a long time, furthermore it is especial difficult to get a high quality of Arctic Sea ice thickness information.Equipped with a Ku-band SIRAL, CryoSat-2 has been launched in 2010 as an important European Space Agency Earth Explorer Opportunity mission. CryoSat-2 has the advantage of measuring the thickness of polar sea ice and monitoring changes in the ice sheets that blanket Greenland and Antarctica with high precision. In this paper, the CryoSat-2/SIRAL radar altimeter data were used to retrieve the sea ice thickness in the Greenland Sea, Arctic, validated with the Ice, Cloud, and Land Elevation (ICESat) laser altimeter measurements from National Aeronautics and Space Administration (NASA) and Beaufort Gyre Experiment Program (BGEP) Upward Looking Sonar (ULS) measurements. Results show that the sea ice freeboard in Greenland Sea has a remarkable seasonal variation and presents an evident regional characteristics. As it show below, during the frozen season in autumn and winter the sea ice freeboard concentrated in around 0.23m , the average freeboard in Greenland Sea in June decreased to around 0.18m, the minimum freeboard 0.12m appeared in September. In the Western Greenland Sea near the Greenland and the Fram Strait with higher-latitude where multi-year ice occupy most has a larger freeboard around 0.3m in winter. In the south-eastern Greenland Sea with lower-latitude and shallow sea water, the freeboard composed by first-year ice concentrated in around 0.1m in winter. At the same time, the sea ice area also had seasonal variations, its maximum was in January and March, and minimum was in September.

  15. Wave Processes in Arctic Seas, Observed from TerraSAR-X

    DTIC Science & Technology

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. “ Wave Processes in Arctic Seas, Observed from TerraSAR-X...of the sea ice coverage during the boreal summer will lead to an increased importance of wind waves for the dynamic processes of the Arctic Seas...The large ice free areas lead to longer fetch and thus longer and higher sea state. Wind waves will enhance upper-ocean mixing, may affect the breakup

  16. The Arctic-Subarctic sea ice system is entering a seasonal regime: Implications for future Arctic amplification.

    PubMed

    Haine, Thomas W N; Martin, Torge

    2017-07-04

    The loss of Arctic sea ice is a conspicuous example of climate change. Climate models project ice-free conditions during summer this century under realistic emission scenarios, reflecting the increase in seasonality in ice cover. To quantify the increased seasonality in the Arctic-Subarctic sea ice system, we define a non-dimensional seasonality number for sea ice extent, area, and volume from satellite data and realistic coupled climate models. We show that the Arctic-Subarctic, i.e. the northern hemisphere, sea ice now exhibits similar levels of seasonality to the Antarctic, which is in a seasonal regime without significant change since satellite observations began in 1979. Realistic climate models suggest that this transition to the seasonal regime is being accompanied by a maximum in Arctic amplification, which is the faster warming of Arctic latitudes compared to the global mean, in the 2010s. The strong link points to a peak in sea-ice-related feedbacks that occurs long before the Arctic becomes ice-free in summer.

  17. Genome sequences of six Pseudoalteromonas strains isolated from Arctic sea ice.

    PubMed

    Bian, Fei; Xie, Bin-Bin; Qin, Qi-Long; Shu, Yan-Li; Zhang, Xi-Ying; Yu, Yong; Chen, Bo; Chen, Xiu-Lan; Zhou, Bai-Cheng; Zhang, Yu-Zhong

    2012-02-01

    Yu et al. (Polar Biol. 32:1539-1547, 2009) isolated 199 Pseudoalteromonas strains from Arctic sea ice. We sequenced the genomes of six of these strains, which are affiliated to different Pseudoalteromonas species based on 16S rRNA gene sequences, facilitating the study of physiology and adaptation of Arctic sea ice Pseudoalteromonas strains.

  18. Contribution of sea-ice loss to Arctic amplification is regulated by Pacific Ocean decadal variability

    NASA Astrophysics Data System (ADS)

    Screen, James A.; Francis, Jennifer A.

    2016-09-01

    The pace of Arctic warming is about double that at lower latitudes--a robust phenomenon known as Arctic amplification. Many diverse climate processes and feedbacks cause Arctic amplification, including positive feedbacks associated with diminished sea ice. However, the precise contribution of sea-ice loss to Arctic amplification remains uncertain. Through analyses of both observations and model simulations, we show that the contribution of sea-ice loss to wintertime Arctic amplification seems to be dependent on the phase of the Pacific Decadal Oscillation (PDO). Our results suggest that, for the same pattern and amount of sea-ice loss, consequent Arctic warming is larger during the negative PDO phase relative to the positive phase, leading to larger reductions in the poleward gradient of tropospheric thickness and to more pronounced reductions in the upper-level westerlies. Given the oscillatory nature of the PDO, this relationship has the potential to increase skill in decadal-scale predictability of the Arctic and sub-Arctic climate. Our results indicate that Arctic warming in response to the ongoing long-term sea-ice decline is greater (reduced) during periods of the negative (positive) PDO phase. We speculate that the observed recent shift to the positive PDO phase, if maintained and all other factors being equal, could act to temporarily reduce the pace of wintertime Arctic warming in the near future.

  19. New High-Resolution Images of Summer Arctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Kwok, Ronald; Untersteiner, Norbert

    2011-02-01

    In 1995 a group of government and academic scientists were appointed by the vice president of the United States to review and advise on acquisitions of imagery obtained by classified intelligence satellites (National Technical Means) and to recommend the declassification of certain data sets for the benefit of science. The group is called MEDEA and was first described by Richelson [1998]. MEDEA disbanded in 2000 but reassembled in 2008. On 15 June 2009, under the auspices of MEDEA, the U.S. Geological Survey (USGS) released to the public as Literal Image Derived Products (LIDPs) numerous images with 1-meter resolution acquired since 1999 at six locations in the Arctic Basin (Beaufort Sea, Canadian Arctic, Fram Strait, East Siberian Sea, Chukchi Sea, and Point Barrow). These locations are named “fiducial sites” to suggest that the collected imagery establishes a baseline data set for understanding recent and future changes. Data in the Global Fiducials Library (GFL) can be accessed via http://gfl.usgs.gov/. This data repository is updated by USGS as additional data become available.

  20. Arctic sea ice cover in connection with climate change

    NASA Astrophysics Data System (ADS)

    Alekseev, G. V.; Aleksandrov, E. I.; Glok, N. I.; Ivanov, N. E.; Smolyanitsky, V. M.; Kharlanenkova, N. E.; Yulin, A. V.

    2015-12-01

    Recently published studies on key issues in the evolution of Arctic sea ice cover are reviewed and attempts to answer disputable questions are made in the research part of the work. It is shown that climate warming, manifested in an increase in the surface air temperature, and reduction in the ice cover develop with a high degree of agreement in summer. Based on this fact, anomalies of the September ice-cover area have been retrieved from 1900. They show a significant decrease in the 1930-1940s, which is almost twice as low as in 2007-2012. The influence of fluctuations in the flow of warm and salty Atlantic water is noted in variations in the winter maximum of the ice-cover area in the Barents Sea. An accelerated positive trend has been ascertained for the air temperature in late autumn-early winter in 1993-2012 due to an increase in the open water area in late summer. Inherent regularities of the ice-cover-area variability made it possible to develop a prediction of the monthly values of sea-ice extent with a head time from 6 months to 2 years. Their strong correlation with summer air temperature is used to estimate the onset of summer ice clearance in the Arctic.

  1. Contrasting Trends in Arctic and Antarctic Sea Ice Coverage Since the Late 1970s

    NASA Astrophysics Data System (ADS)

    Parkinson, C. L.

    2016-12-01

    Satellite observations have allowed a near-continuous record of Arctic and Antarctic sea ice coverage since late 1978. This record has revealed considerable interannual variability in both polar regions but also significant long-term trends, with the Arctic losing, the Antarctic gaining, and the Earth as a whole losing sea ice coverage. Over the period 1979-2015, the trend in yearly average sea ice extents in the Arctic is -53,100 km2/yr (-4.3 %/decade) and in the Antarctic is 23,800 km2/yr (2.1 %/decade). For all 12 months, trends are negative in the Arctic and positive in the Antarctic, with the highest magnitude monthly trend being for September in the Arctic, at -85,300 km2/yr (-10.9 %/decade). The decreases in Arctic sea ice extents have been so dominant that not a single month since 1986 registered a new monthly record high, whereas 75 months registered new monthly record lows between 1987 and 2015 and several additional record lows were registered in 2016. The Antarctic sea ice record highs and lows are also out of balance, in the opposite direction, although not in such dramatic fashion. Geographic details on the changing ice covers, down to the level of individual pixels, can be seen by examining changes in the length of the sea ice season. Results reveal (and quantify) shortening ice seasons throughout the bulk of the Arctic marginal ice zone, the main exception being within the Bering Sea, and lengthening sea ice seasons through much of the Southern Ocean but shortening seasons in the Bellingshausen Sea, southern Amundsen Sea, and northwestern Weddell Sea. The decreasing Arctic sea ice coverage was widely anticipated and fits well with a large array of environmental changes in the Arctic, whereas the increasing Antarctic sea ice coverage was not widely anticipated and explaining it remains an area of active research by many scientists exploring a variety of potential explanations.

  2. Nordic Seas and Arctic Ocean CFC data in CARINA

    NASA Astrophysics Data System (ADS)

    Jeansson, E.; Olsson, K. A.; Tanhua, T.; Bullister, J. L.

    2010-02-01

    Water column data of carbon and carbon relevant hydrographic and hydrochemical parameters have been retrieved from a large number of cruises and collected into a new database called CARINA (CARbon IN the Atlantic). These data have been merged into three sets of files, one for each of the three CARINA regions; the Arctic Mediterranean Seas (AMS), the Atlantic (ATL) and the Southern Ocean (SO). The first part of the CARINA database consists of three files, one for each CARINA region, containing the original, non-adjusted cruise data sets, including data quality flags for each measurement. These data have then been subject to rigorous quality control (QC) in order to ensure highest possible quality and consistency. The data for most of the parameters included were examined in order to quantify systematic biases in the reported values, i.e. secondary quality control. Significant biases have been corrected for in the second part of the CARINA data product. This consists of three files, one for each CARINA region, which contain adjustments to the original data values based on recommendations from the CARINA QC procedures, along with calculated and interpolated values for some missing parameters. Here we present an overview of the QC of the CFC data for the AMS region, including the chlorofluorocarbons CFC-11, CFC-12 and CFC-113, as well as carbon tetrachloride (CCl4). The Arctic Mediterranean Seas is comprised of the Arctic Ocean and the Nordic Seas, and the quality control was carried out separately in these two areas. For the secondary QC of the CFCs we used a combination of tools, including the evaluation of depth profiles and CFC ratios, surface saturations and a crossover analysis. This resulted in a multiplicative adjustment of data from some cruises, while other data were flagged to be of questionable quality, which excluded them from the final data product.

  3. Fine-resolution simulation of surface current and sea ice in the Arctic Mediterranean Seas

    NASA Astrophysics Data System (ADS)

    Liu, Xiying; Zhang, Xuehong; Yu, Rucong; Liu, Hailong; Li, Wei

    2007-04-01

    A fine-resolution model is developed for ocean circulation simulation in the National Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Chinese Academy of Sciences, and is applied to simulate surface current and sea ice variations in the Arctic Mediterranean Seas. A dynamic sea ice model in elastic-viscous-plastic rheology and a thermodynamic sea ice model are employed. A 200-year simulation is performed and a dimatological average of a 10-year period (141st 150th) is presented with focus on sea ice concentration and surface current variations in the Arctic Mediterranean Seas. The model is able to simulate well the East Greenland Current, Beaufort Gyre and the Transpolar Drift, but the simulated West Spitsbergen Current is small and weak. In the March climatology, the sea ice coverage can be simulated well except for a bit more ice in east of Spitsbergen Island. The result is also good for the September scenario except for less ice concentration east of Greenland and greater ice concentration near the ice margin. The extra ice east of Spitsbergen Island is caused by sea ice current convergence forced by atmospheric wind stress.

  4. The central role of diminishing sea ice in recent Arctic temperature amplification.

    PubMed

    Screen, James A; Simmonds, Ian

    2010-04-29

    The rise in Arctic near-surface air temperatures has been almost twice as large as the global average in recent decades-a feature known as 'Arctic amplification'. Increased concentrations of atmospheric greenhouse gases have driven Arctic and global average warming; however, the underlying causes of Arctic amplification remain uncertain. The roles of reductions in snow and sea ice cover and changes in atmospheric and oceanic circulation, cloud cover and water vapour are still matters of debate. A better understanding of the processes responsible for the recent amplified warming is essential for assessing the likelihood, and impacts, of future rapid Arctic warming and sea ice loss. Here we show that the Arctic warming is strongest at the surface during most of the year and is primarily consistent with reductions in sea ice cover. Changes in cloud cover, in contrast, have not contributed strongly to recent warming. Increases in atmospheric water vapour content, partly in response to reduced sea ice cover, may have enhanced warming in the lower part of the atmosphere during summer and early autumn. We conclude that diminishing sea ice has had a leading role in recent Arctic temperature amplification. The findings reinforce suggestions that strong positive ice-temperature feedbacks have emerged in the Arctic, increasing the chances of further rapid warming and sea ice loss, and will probably affect polar ecosystems, ice-sheet mass balance and human activities in the Arctic.

  5. Climate models agree remarkably well on Arctic sea ice reductions

    NASA Astrophysics Data System (ADS)

    Christensen, Jens H.; Yang, Shuting; Langen, Peter L.; Thejl, Peter; Boberg, Fredrik

    2017-04-01

    Coupled global climate models have been used to provide future climate projections as major tools based on physical laws that govern the dynamics and thermodynamics of the climate system. However, while climate models in general predict declines in Arctic sea ice cover (i.e., ice extent and volume) from late 20th century through the next decades in response to increase of anthropogenic forcing, models show wide inter-model spread in hindcast with simulated sea ice extend as low as 50% or as high as 200% of the observed present day conditions. Likewise models show a wide range in the timing of projected sea ice decline, raising the question of uncertainty in model predicted polar climate and casting doubt on the robustness of the findings based on multi-model approaches, such as provided by the Coupled Model Intercomparison Project phase 5 (CMIP5). Constrained estimates of when global mean temperature pass a certain threshold leading to a new sea ice state in the Arctic with summer time open water conditions are in increasing demand both for scientific reasons, but also from policymakers and stakeholders in general. Climate models are used to pursue this, but due to model inadequacies or 'errors' mentioned above, as well as a wide spread in possible future projections, uncertainties due to model deficiencies have been seen as the main source of uncertainty in providing the demanded information with sufficient accuracy. As an effort within the ERC-Synergy project Ice2Ice, here we demonstrate that relating relative changes in sea ice area with global mean temperature change from individual models using all available information from the CMIP5 archives from historical and the RCP4.5 and RCP8.0 future scenarios, together with the observed variation from 1979-2015 shows that i) simulated and observed sea ice area cannot at the 95% level be seen as coming from different statistical populations; ii) the Arctic could as a combination of natural variability and anthropogenic

  6. 30-Year Satellite Record Reveals Accelerated Arctic Sea Ice Loss, Antarctic Sea Ice Trend Reversal

    NASA Technical Reports Server (NTRS)

    Cavalieri, Donald J.; Parkinson, C. L.; Vinnikov, K. Y.

    2003-01-01

    Arctic sea ice extent decreased by 0.30 plus or minus 0.03 x 10(exp 6) square kilometers per decade from 1972 through 2002, but decreased by 0.36 plus or minus 0.05 x 10(exp 6) square kilometers per decade from 1979 through 2002, indicating an acceleration of 20% in the rate of decrease. In contrast to the Arctic, the Antarctic sea ice extent decreased dramatically over the period 1973-1977, then gradually increased, with an overall 30-year trend of -0.15 plus or minus 0.08 x 10(exp 6) square kilometers per 10yr. The trend reversal is attributed to a large positive anomaly in Antarctic sea ice extent observed in the early 1970's.

  7. 30-Year Satellite Record Reveals Accelerated Arctic Sea Ice Loss, Antarctic Sea Ice Trend Reversal

    NASA Technical Reports Server (NTRS)

    Cavalieri, Donald J.; Parkinson, C. L.; Vinnikov, K. Y.

    2003-01-01

    Arctic sea ice extent decreased by 0.30 plus or minus 0.03 x 10(exp 6) square kilometers per decade from 1972 through 2002, but decreased by 0.36 plus or minus 0.05 x 10(exp 6) square kilometers per decade from 1979 through 2002, indicating an acceleration of 20% in the rate of decrease. In contrast to the Arctic, the Antarctic sea ice extent decreased dramatically over the period 1973-1977, then gradually increased, with an overall 30-year trend of -0.15 plus or minus 0.08 x 10(exp 6) square kilometers per 10yr. The trend reversal is attributed to a large positive anomaly in Antarctic sea ice extent observed in the early 1970's.

  8. Atmospheric Response to Variations in Arctic Sea Ice Conditions

    NASA Astrophysics Data System (ADS)

    Bhatt, U.; Alexander, M.; Walsh, J.; Timlin, M.; Miller, J.

    2001-12-01

    While it is generally accepted that changes in air temperature and circulation determine sea ice conditions, it is not understood how the atmosphere is influenced by changes in sea ice. We employ the NCAR CCM 3.6 with specified ice extent and sea surface temperatures (sst). The overarching question addressed in this study is: how do variations in sea ice influence the atmosphere? We are particularly interested in the summer time response to highlight this unique aspect of this research. A control experiment has been integrated for 55 years by repeating the mean annual cycle of observed sea ice extent (either 0% or 100% ice cover) and sst, based on the period 1979-99. Sets of 50 member ensemble experiments were constructed by integrating the CCM from October to April using climatological sst (same as control) and observed sea ice extent from the winters of 1982-83 (ice maximum) and 1995-96 (ice minimum). Similar summertime sensitivity experiments were performed using ice extent conditions from April to October during 1982 (maximum) and 1995 (minimum). While responses were found both in winter and summer, the results described below refer to the summer of 1995. A set of 50 ensembles was also integrated for the summer of 1995 using sea ice concentration instead of extent. During the summer of 1995, negative sea ice anomalies were particularly large in the Siberian Arctic. Sea ice reductions result in increased surface and air temperatures and enhanced latent, sensible, and longwave fluxes out of the ocean. However, the net heat flux out of the ocean decreases because the changes are dominated by increased absorption of solar radiation over the low-albedo ocean. Cloud feedbacks are important in the Arctic and the downwelling solar at the surface decreases. The total cloud amount decreases due to reductions in low level clouds, however, convective cloud amounts increased. The net cloud radiative (shortwave and longwave) forcing is smaller in the experiment than the

  9. Observed sea ice extent in the Russian Arctic, 1933-2006

    NASA Astrophysics Data System (ADS)

    Mahoney, Andrew R.; Barry, Roger G.; Smolyanitsky, Vasily; Fetterer, Florence

    2008-11-01

    We present a time series of sea ice extent in the Russian Arctic based on observational sea ice charts compiled by the Arctic and Antarctic Research Institute (AARI). These charts are perhaps the oldest operational sea ice data in existence and show that sea ice extent in the Russian Arctic has generally decreased since the beginning of the chart series in 1933. This retreat has not been continuous, however. For the Russian Arctic as a whole in summer, there have been two periods of retreat separated by a partial recovery between the mid-1950s and mid-1980s. The AARI charts, combined with air temperature records, suggest that the retreat in recent decades is pan-Arctic and year-round in some regions, whereas the early twentieth century retreat was only observed in summer in the Russian Arctic. The AARI ice charts indicate that a significant transition occurred in the Russian Arctic in the mid-1980s, when its sea ice cover began to retreat along with that of the rest of the Arctic. Summertime sea ice extents derived from the AARI data set agree with those derived from passive microwave, including the Hadley Centre's global sea ice coverage and sea surface temperature (HadISST) data set. The HadISST results do not indicate the 1980s transition or the partial recovery that took place before it. The AARI charts therefore add significantly to our understanding of the variability of Arctic sea ice over the last 8 decades, and we recommend their inclusion in future historical data sets of Arctic sea ice.

  10. The Role of the Barents Sea in the Arctic Climate System

    NASA Astrophysics Data System (ADS)

    Smedsrud, Lars H.; Esau, Igor; Ingvaldsen, Randi B.; Eldevik, Tor; Haugan, Peter M.; Li, Camille; Lien, Vidar S.; Olsen, Are; Omar, Abdirahman M.; Otterâ, Odd H.; Risebrobakken, Bjørg; Sandø, Anne B.; Semenov, Vladimir A.; Sorokina, Svetlana A.

    2013-09-01

    Present global warming is amplified in the Arctic and accompanied by unprecedented sea ice decline. Located along the main pathway of Atlantic Water entering the Arctic, the Barents Sea is the site of coupled feedback processes that are important for creating variability in the entire Arctic air-ice-ocean system. As warm Atlantic Water flows through the Barents Sea, it loses heat to the Arctic atmosphere. Warm periods, like today, are associated with high northward heat transport, reduced Arctic sea ice cover, and high surface air temperatures. The cooling of the Atlantic inflow creates dense water sinking to great depths in the Arctic Basins, and 60% of the Arctic Ocean carbon uptake is removed from the carbon-saturated surface this way. Recently, anomalously large ocean heat transport has reduced sea ice formation in the Barents Sea during winter. The missing Barents Sea winter ice makes up a large part of observed winter Arctic sea ice loss, and in 2050, the Barents Sea is projected to be largely ice free throughout the year, with 4°C summer warming in the formerly ice-covered areas. The heating of the Barents atmosphere plays an important role both in "Arctic amplification" and the Arctic heat budget. The heating also perturbs the large-scale circulation through expansion of the Siberian High northward, with a possible link to recent continental wintertime cooling. Large air-ice-ocean variability is evident in proxy records of past climate conditions, suggesting that the Barents Sea has had an important role in Northern Hemisphere climate for, at least, the last 2500 years.

  11. Abrupt Decline in the Arctic Winter Sea Ice Cover

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.

    2007-01-01

    Maximum ice extents in the Arctic in 2005 and 2006 have been observed to be significantly lower (by about 6%) than the average of those of previous years starting in 1979. Since the winter maxima had been relatively stable with the trend being only about -1.5% per decade (compared to about -10% per decade for the perennial ice area), this is a significant development since signals from greenhouse warming are expected to be most prominent in winter. Negative ice anomalies are shown to be dominant in 2005 and 2006 especially in the Arctic basin and correlated with winds and surface temperature anomalies during the same period. Progressively increasing winter temperatures in the central Arctic starting in 1997 is observed with significantly higher rates of increase in 2005 and 2006. The Atlantic Oscillation (AO) indices correlate weakly with the sea ice and surface temperature anomaly data but may explain the recent shift in the perennial ice cover towards the western region. Results suggest that the trend in winter ice is finally in the process of catching up with that of the summer ice cover.

  12. Arctic Sea Ice Thickness Distribution as an Indicator of Arctic Climate Change - Synthesis of Model Results and Observations

    NASA Astrophysics Data System (ADS)

    Maslowski, Wieslaw; Clement Kinney, Jaclyn; Jakacki, Jaromir; Osinski, Robert; Zwally, Jay

    2010-05-01

    The Arctic region is an integral part of the Earth's climate system through its influence on global surface energy and moisture fluxes and on atmospheric and oceanic circulation. Within the Arctic, its sea ice cover is possibly the most sensitive indicator of the polar amplified global warming and of the state of Arctic climate system as a whole. Hence changes in Arctic climate and the decline of multi-year sea ice cover have significant ramifications to the entire pan-Arctic region and beyond. Having the recorded average global surface temperature about 0.54°C (0.96°F) above the 20th Century average the decade of 2000-2009 has been the warmest of the 130-year record, with the maximum positive temperatures anomalies in the northern high latitude regions. Satellite records of the Arctic sea ice show a decreasing and accelerating trend in ice extent and concentration since the late 1979, as a result of the global warming. More importantly there is growing evidence that the Arctic sea ice thickness and volume have been decreasing at even faster rate. This means that our knowledge of the Arctic sea ice melt might be significantly biased due to the interpretation of 2-dimensional sea ice extent / concentration records only instead of ice thickness and volume. The rates of recent ice thickness and volume melt derived from our pan-Arctic coupled ice-ocean model results combined with recent remotely sensed data suggest an accelerating negative trend. This trend is robust and lends credence to the postulation that the Arctic not only might but it is likely to be ice-free during the summer in the near future. However, global climate models vary widely in their predictions of warming and the rate of Arctic ice melt, suggesting it may take anywhere from a couple of decades to more than a century to melt most of the summer sea ice cover. Also many regional models are limited in their representation of the rapid Arctic sea ice thinning and volume loss. The inability of models

  13. ICESat Observations of Arctic Sea Ice: A First Look

    NASA Technical Reports Server (NTRS)

    Kwok, Ron; Zwally, H. Jay; Yi, Dong-Hui

    2004-01-01

    Analysis of near-coincident ICESat and RADARSAT imagery shows that the retrieved elevations from the laser altimeter are sensitive to new openings (containing thin ice or open water) in the sea ice cover as well as to surface relief of old and first-year ice. The precision of the elevation estimates, measured over relatively flat sea ice, is approx. 2 cm Using the thickness of thin-ice in recent openings to estimate sea level references, we obtain the sea-ice free-board along the altimeter tracks. This step is necessitated by the large uncertainties in the time-varying sea surface topography compared to that required for accurate determination of free-board. Unknown snow depth introduces the largest uncertainty in the conversion of free-board to ice thickness. Surface roughness is also derived, for the first time, from the variability of successive elevation estimates along the altimeter track Overall, these ICESat measurements provide an unprecedented view of the Arctic Ocean ice cover at length scales at and above the spatial dimension of the altimeter footprint.

  14. ICESat Observations of Arctic Sea Ice: A First Look

    NASA Technical Reports Server (NTRS)

    Kwok, Ron; Zwally, H. Jay; Yi, Donghui

    2004-01-01

    Analysis of near-coincident ICESat and RADARSAT imagery shows that the retrieved elevations from the laser altimeter are sensitive to new openings (containing thin ice or open water) in the sea ice cover as well as to surface relief of old and first-year ice. The precision of the elevation estimates, measured over relatively flat sea ice, is approx. 2 cm. Using the thickness of thin-ice in recent openings to estimate sea level references, we obtain the sea-ice freeboard along the altimeter tracks. This step is necessitated by the large uncertainties in the sea surface topography compared to that required for accurate determination of freeboard. Unknown snow depth introduces the largest uncertainty in the conversion of freeboard to ice thickness. Surface roughness is also derived, for the first time, from the variability of successive elevation estimates along the altimeter track. Overall, these ICESat measurements provide an unprecedented view of the Arctic Ocean ice cover at length scales at and above the spatial dimension of the altimeter footprint of approx. 70 m.

  15. ICESat Observations of Arctic Sea Ice: A First Look

    NASA Technical Reports Server (NTRS)

    Kwok, Ron; Zwally, H. Jay; Yi, Donghui

    2004-01-01

    Analysis of near-coincident ICESat and RADARSAT imagery shows that the retrieved elevations from the laser altimeter are sensitive to new openings (containing thin ice or open water) in the sea ice cover as well as to surface relief of old and first-year ice. The precision of the elevation estimates, measured over relatively flat sea ice, is approx. 2 cm. Using the thickness of thin-ice in recent openings to estimate sea level references, we obtain the sea-ice freeboard along the altimeter tracks. This step is necessitated by the large uncertainties in the sea surface topography compared to that required for accurate determination of freeboard. Unknown snow depth introduces the largest uncertainty in the conversion of freeboard to ice thickness. Surface roughness is also derived, for the first time, from the variability of successive elevation estimates along the altimeter track. Overall, these ICESat measurements provide an unprecedented view of the Arctic Ocean ice cover at length scales at and above the spatial dimension of the altimeter footprint of approx. 70 m.

  16. Evaluation of Arctic Sea Ice Thickness Simulated by AOMIP Models

    NASA Technical Reports Server (NTRS)

    Johnson, Mark; Proshutinsky, Andrey; Aksenov, Yevgeny; Nguyen, An T.; Lindsay, Ron; Haas, Christian; Zhang, Jinlun; Diansky, Nimolay; Kwok, Ron; Maslowski, Wieslaw; Hakkinen, Sirpa; Ashik, Igor; de Cuevas, Beverly

    2011-01-01

    We compare results from six AOMIP model simulations with estimates of sea ice thickness obtained from ICESat, moored and submarine-based upward looking sensors, airborne electromagnetic measurements and drill holes. Our goal is to find patterns of model performance to guide model improvement. The satellite data is pan-arctic from 2004-2008, ice-draft data is from moored instruments in Fram Strait, the Greenland Sea and the Beaufort Sea from 1992-2008 and from submarines from 1975-2000. The drill hole data are from the Laptev and East Siberian marginal seas from 1982-1986 and from coastal stations from 1998-2009. While there are important caveats when comparing modeled results with measurements from different platforms and time periods such as these, the models agree well with moored ULS data. In general, the AOMIP models underestimate the thickness of measured ice thicker than about 2 m and overestimate thickness of ice thinner than 2 m. The simulated results are poor over the fast ice and marginal seas of the Siberian shelves. Averaging over all observational data sets, the better correlations and smaller differences from observed thickness are from the ECCO2 and UW models.

  17. Sea Ice Summer Camp: Bringing Together Arctic Sea Ice Modelers and Observers

    NASA Astrophysics Data System (ADS)

    Perovich, D. K.; Holland, M. M.

    2016-12-01

    The Arctic sea ice has undergone dramatic change and numerical models project this to continue for the foreseeable future. Understanding the mechanisms behind sea ice loss and its consequences for the larger Arctic and global systems is of critical importance if we are to anticipate and plan for the future. One impediment to progress is a disconnect between the observational and modeling communities. A sea ice summer camp was held in Barrow Alaska from 26 May to 1 June 2016 to overcome this impediment and better integrate the sea ice community. The 25 participants were a mix of modelers and observers from 13 different institutions at career stages from graduate student to senior scientist. The summer camp provided an accelerated program on sea ice observations and models and also fostered future collaborative interdisciplinary activities. Each morning was spent in the classroom with a daily lecture on an aspect of modeling or remote sensing followed by practical exercises. Topics included using models to assess sensitivity, to test hypotheses and to explore sources of uncertainty in future Arctic sea ice loss. The afternoons were spent on the ice making observations. There were four observational activities; albedo observations, ice thickness measurements, ice coring and physical properties, and ice morphology surveys. The last field day consisted of a grand challenge where the group formulated a hypothesis, developed an observational and modeling strategy to test the hypothesis, and then integrated the observations and model results. The impacts of changing sea ice are being felt today in Barrow Alaska. We opened a dialog with Barrow community members to further understand these changes. This included an evening discussion with two Barrow sea ice experts and a community presentation of our work in a public lecture at the Inupiat Heritage Center.

  18. Aircraft measurements of microwave emission from Arctic Sea ice

    USGS Publications Warehouse

    Wilheit, T.; Nordberg, W.; Blinn, J.; Campbell, W.; Edgerton, A.

    1971-01-01

    Measurements of the microwave emission from Arctic Sea ice were made with aircraft at 8 wavelengths ranging from 0.510 to 2.81 cm. The expected contrast in emissivities between ice and water was observed at all wavelengths. Distributions of sea ice and open water were mapped from altitudes up to 11 km in the presence of dense cloud cover. Different forms of ice also exhibited strong contrasts in emissivity. Emissivity differences of up to 0.2 were observed between two types of ice at the 0.811-cm wavelength. The higher emissivity ice type is tentatively identified as having been formed more recently than the lower emissivity ice. ?? 1971.

  19. Summer Arctic sea ice character from satellite microwave data

    NASA Technical Reports Server (NTRS)

    Carsey, F. D.

    1985-01-01

    It is pointed out that Arctic sea ice and its environment undergo a number of changes during the summer period. Some of these changes affect the ice cover properties and, in turn, their response to thermal and mechanical forcing throughout the year. The main objective of this investigation is related to the development of a method for estimating the areal coverage of exposed ice, melt ponds, and leads, which are the basic surface variables determining the local surface albedo. The study is based on data obtained in a field investigation conducted from Mould Bay (NWT), Nimbus 5 satellite data, and Seasat data. The investigation demonstrates that microwave data from satellites, especially microwave brightness temperature, provide good data for estimating important characteristics of summer sea ice cover.

  20. Top/bottom multisensor remote sensing of Arctic sea ice

    NASA Technical Reports Server (NTRS)

    Comiso, J. C.; Wadhams, P.; Krabill, W. B.; Swift, R. N.; Crawford, J. P.

    1991-01-01

    Results are presented on the Aircraft/Submarine Sea Ice Project experiment carried out in May 1987 to investigate concurrently the top and the bottom features of the Arctic sea-ice cover. Data were collected nearly simultaneously by instruments aboard two aircraft and a submarine, which included passive and active (SAR) microwave sensors, upward looking and sidescan sonars, a lidar profilometer, and an IR sensor. The results described fall into two classes of correlations: (1) quantitative correlations between profiles, such as ice draft (sonar), ice elevation (laser), SAR backscatter along the track line, and passive microwave brightness temperatures; and (2) qualitative and semiquantitative correlations between corresponding areas of imagery (i.e., passive microwave, AR, and sidescan sonar).

  1. Summer Arctic sea ice character from satellite microwave data

    NASA Technical Reports Server (NTRS)

    Carsey, F. D.

    1985-01-01

    It is pointed out that Arctic sea ice and its environment undergo a number of changes during the summer period. Some of these changes affect the ice cover properties and, in turn, their response to thermal and mechanical forcing throughout the year. The main objective of this investigation is related to the development of a method for estimating the areal coverage of exposed ice, melt ponds, and leads, which are the basic surface variables determining the local surface albedo. The study is based on data obtained in a field investigation conducted from Mould Bay (NWT), Nimbus 5 satellite data, and Seasat data. The investigation demonstrates that microwave data from satellites, especially microwave brightness temperature, provide good data for estimating important characteristics of summer sea ice cover.

  2. Propaganda, News, or Education: Reporting Changing Arctic Sea Ice Conditions

    NASA Astrophysics Data System (ADS)

    Leitzell, K.; Meier, W.

    2010-12-01

    The National Snow and Ice Data Center provides information on Arctic sea ice conditions via the Arctic Sea Ice News & Analysis (ASINA) website. As a result of this effort to explain climatic data to the general public, we have attracted a huge amount of attention from our readers. Sometimes, people write to thank us for the information and the explanation. But people also write to accuse us of bias, slant, or outright lies in our posts. The topic of climate change is a minefield full of political animosity, and even the most carefully written verbiage can appear incomplete or biased to some audiences. Our strategy has been to report the data and stick to the areas in which our scientists are experts. The ASINA team carefully edits our posts to make sure that all statements are based on the science and not on opinion. Often this means using some technical language that may be difficult for a layperson to understand. However, we provide concise definitions for technical terms where appropriate. The hope is that by communicating the data clearly, without an agenda, we can let the science speak for itself. Is this an effective strategy to communicate clearly about the changing climate? Or does it downplay the seriousness of climate change? By writing at a more advanced level and avoiding oversimplification, we require our readers to work harder. But we may also maintain the attention of skeptics, convincing them to read further and become more knowledgeable about the topic.

  3. Age characteristics in a multidecadal Arctic sea ice simulation

    SciTech Connect

    Hunke, Elizabeth C; Bitz, Cecllia M

    2008-01-01

    Results from adding a tracer for age of sea ice to a sophisticated sea ice model that is widely used for climate studies are presented. The consistent simulation of ice age, dynamics, and thermodynamics in the model shows explicitly that the loss of Arctic perennial ice has accelerated in the past three decades, as has been seen in satellite-derived observations. Our model shows that the September ice age average across the Northern Hemisphere varies from about 5 to 8 years, and the ice is much younger (about 2--3 years) in late winter because of the expansion of first-year ice. We find seasonal ice on average comprises about 5% of the total ice area in September, but as much as 1.34 x 10{sup 6} km{sup 2} survives in some years. Our simulated ice age in the late 1980s and early 1990s declined markedly in agreement with other studies. After this period of decline, the ice age began to recover, but in the final years of the simulation very little young ice remains after the melt season, a strong indication that the age of the pack will again decline in the future as older ice classes fail to be replenished. The Arctic ice pack has fluctuated between older and younger ice types over the past 30 years, while ice area, thickness, and volume all declined over the same period, with an apparent acceleration in the last decade.

  4. Floating ice-algal aggregates below melting arctic sea ice.

    PubMed

    Assmy, Philipp; Ehn, Jens K; Fernández-Méndez, Mar; Hop, Haakon; Katlein, Christian; Sundfjord, Arild; Bluhm, Katrin; Daase, Malin; Engel, Anja; Fransson, Agneta; Granskog, Mats A; Hudson, Stephen R; Kristiansen, Svein; Nicolaus, Marcel; Peeken, Ilka; Renner, Angelika H H; Spreen, Gunnar; Tatarek, Agnieszka; Wiktor, Jozef

    2013-01-01

    During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded within the mucous matrix. Aggregates maintained buoyancy and accumulated just above a strong pycnocline that separated meltwater and seawater layers. We were able, for the first time, to obtain quantitative abundance and biomass estimates of these aggregates. Although their biomass and production on a square metre basis was small compared to ice-algal blooms, the floating ice-algal aggregates supported high levels of biological activity on the scale of the individual aggregate. In addition they constituted a food source for the ice-associated fauna as revealed by pigments indicative of zooplankton grazing, high abundance of naked ciliates, and ice amphipods associated with them. During the Arctic melt season, these floating aggregates likely play an important ecological role in an otherwise impoverished near-surface sea ice environment. Our findings provide important observations and measurements of a unique aggregate-based habitat during the 2012 record sea ice minimum year.

  5. Floating Ice-Algal Aggregates below Melting Arctic Sea Ice

    PubMed Central

    Assmy, Philipp; Ehn, Jens K.; Fernández-Méndez, Mar; Hop, Haakon; Katlein, Christian; Sundfjord, Arild; Bluhm, Katrin; Daase, Malin; Engel, Anja; Fransson, Agneta; Granskog, Mats A.; Hudson, Stephen R.; Kristiansen, Svein; Nicolaus, Marcel; Peeken, Ilka; Renner, Angelika H. H.; Spreen, Gunnar; Tatarek, Agnieszka; Wiktor, Jozef

    2013-01-01

    During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded within the mucous matrix. Aggregates maintained buoyancy and accumulated just above a strong pycnocline that separated meltwater and seawater layers. We were able, for the first time, to obtain quantitative abundance and biomass estimates of these aggregates. Although their biomass and production on a square metre basis was small compared to ice-algal blooms, the floating ice-algal aggregates supported high levels of biological activity on the scale of the individual aggregate. In addition they constituted a food source for the ice-associated fauna as revealed by pigments indicative of zooplankton grazing, high abundance of naked ciliates, and ice amphipods associated with them. During the Arctic melt season, these floating aggregates likely play an important ecological role in an otherwise impoverished near-surface sea ice environment. Our findings provide important observations and measurements of a unique aggregate-based habitat during the 2012 record sea ice minimum year. PMID:24204642

  6. Evidence of Arctic sea ice thinning from direct observations

    NASA Astrophysics Data System (ADS)

    Renner, Angelika H. H.; Gerland, Sebastian; Haas, Christian; Spreen, Gunnar; Beckers, Justin F.; Hansen, Edmond; Nicolaus, Marcel; Goodwin, Harvey

    2014-07-01

    The Arctic sea ice cover is rapidly shrinking, but a direct, longer-term assessment of the ice thinning remains challenging. A new time series constructed from in situ measurements of sea ice thickness at the end of the melt season in Fram Strait shows a thinning by over 50% during 2003-2012. The modal and mean ice thickness along 79°N decreased at a rate of 0.3 and 0.2 m yr-1, respectively, with long-term averages of 2.5 and 3 m. Airborne observations reveal an east-west thickness gradient across the strait in spring but not in summer due to advection from more different source regions. There is no clear relationship between interannual ice thickness variability and the source regions of the ice. The observed thinning is therefore likely a result of Arctic-wide reduction in ice thickness with a potential shift in exported ice types playing a minor role.

  7. Observed Arctic sea-ice loss directly follows anthropogenic CO2 emission

    NASA Astrophysics Data System (ADS)

    Notz, Dirk; Stroeve, Julienne

    2016-11-01

    Arctic sea ice is retreating rapidly, raising prospects of a future ice-free Arctic Ocean during summer. Because climate-model simulations of the sea-ice loss differ substantially, we used a robust linear relationship between monthly-mean September sea-ice area and cumulative carbon dioxide (CO2) emissions to infer the future evolution of Arctic summer sea ice directly from the observational record. The observed linear relationship implies a sustained loss of 3 ± 0.3 square meters of September sea-ice area per metric ton of CO2 emission. On the basis of this sensitivity, Arctic sea ice will be lost throughout September for an additional 1000 gigatons of CO2 emissions. Most models show a lower sensitivity, which is possibly linked to an underestimation of the modeled increase in incoming longwave radiation and of the modeled transient climate response.

  8. Observed Arctic sea-ice loss directly follows anthropogenic CO2 emission.

    PubMed

    Notz, Dirk; Stroeve, Julienne

    2016-11-11

    Arctic sea ice is retreating rapidly, raising prospects of a future ice-free Arctic Ocean during summer. Because climate-model simulations of the sea-ice loss differ substantially, we used a robust linear relationship between monthly-mean September sea-ice area and cumulative carbon dioxide (CO2) emissions to infer the future evolution of Arctic summer sea ice directly from the observational record. The observed linear relationship implies a sustained loss of 3 ± 0.3 square meters of September sea-ice area per metric ton of CO2 emission. On the basis of this sensitivity, Arctic sea ice will be lost throughout September for an additional 1000 gigatons of CO2 emissions. Most models show a lower sensitivity, which is possibly linked to an underestimation of the modeled increase in incoming longwave radiation and of the modeled transient climate response.

  9. Predictability of large interannual Arctic sea-ice anomalies

    NASA Astrophysics Data System (ADS)

    Tietsche, Steffen; Notz, Dirk; Jungclaus, Johann H.; Marotzke, Jochem

    2013-11-01

    In projections of twenty-first century climate, Arctic sea ice declines and at the same time exhibits strong interannual anomalies. Here, we investigate the potential to predict these strong sea-ice anomalies under a perfect-model assumption, using the Max-Planck-Institute Earth System Model in the same setup as in the Coupled Model Intercomparison Project Phase 5 (CMIP5). We study two cases of strong negative sea-ice anomalies: a 5-year-long anomaly for present-day conditions, and a 10-year-long anomaly for conditions projected for the middle of the twenty-first century. We treat these anomalies in the CMIP5 projections as the truth, and use exactly the same model configuration for predictions of this synthetic truth. We start ensemble predictions at different times during the anomalies, considering lagged-perfect and sea-ice-assimilated initial conditions. We find that the onset and amplitude of the interannual anomalies are not predictable. However, the further deepening of the anomaly can be predicted for typically 1 year lead time if predictions start after the onset but before the maximal amplitude of the anomaly. The magnitude of an extremely low summer sea-ice minimum is hard to predict: the skill of the prediction ensemble is not better than a damped-persistence forecast for lead times of more than a few months, and is not better than a climatology forecast for lead times of two or more years. Predictions of the present-day anomaly are more skillful than predictions of the mid-century anomaly. Predictions using sea-ice-assimilated initial conditions are competitive with those using lagged-perfect initial conditions for lead times of a year or less, but yield degraded skill for longer lead times. The results presented here suggest that there is limited prospect of predicting the large interannual sea-ice anomalies expected to occur throughout the twenty-first century.

  10. Arctic sea ice concentration observed with SMOS during summer

    NASA Astrophysics Data System (ADS)

    Gabarro, Carolina; Martinez, Justino; Turiel, Antonio

    2017-04-01

    The Arctic Ocean is under profound transformation. Observations and model predictions show dramatic decline in sea ice extent and volume [1]. A retreating Arctic ice cover has a marked impact on regional and global climate, and vice versa, through a large number of feedback mechanisms and interactions with the climate system [2]. The launch of the Soil Moisture and Ocean Salinity (SMOS) mission, in 2009, marked the dawn of a new type of space-based microwave observations. Although the mission was originally conceived for hydrological and oceanographic studies [3,4], SMOS is also making inroads in the cryospheric sciences by measuring the thin ice thickness [5,6]. SMOS carries an L-band (1.4 GHz), passive interferometric radiometer (the so-called MIRAS) that measures the electromagnetic radiation emitted by the Earth's surface, at about 50 km spatial resolution, continuous multi-angle viewing, large wide swath (1200-km), and with a 3-day revisit time at the equator, but more frequently at the poles. A novel radiometric method to determine sea ice concentration (SIC) from SMOS is presented. The method uses the Bayesian-based Maximum Likelihood Estimation (MLE) approach to retrieve SIC. The advantage of this approach with respect to the classical linear inversion is that the former takes into account the uncertainty of the tie-point measured data in addition to the mean value, while the latter only uses a mean value of the tie-point data. When thin ice is present, the SMOS algorithm underestimates the SIC due to the low opacity of the ice at this frequency. However, using a synergistic approach with data from other satellite sensors, it is possible to obtain accurate thin ice thickness estimations with the Bayesian-based method. Despite its lower spatial resolution relative to SSMI or AMSR-E, SMOS-derived SIC products are little affected by the atmosphere and the snow (almost transparent at L-band). Moreover L-band measurements are more robust in front of the

  11. Regional variability of a projected sea ice-free Arctic during the summer months

    NASA Astrophysics Data System (ADS)

    Laliberté, F.; Howell, S. E. L.; Kushner, P. J.

    2016-01-01

    Climate projections of sea ice retreat under anthropogenic climate change at the regional scale and in summer months other than September have largely not been evaluated. Information at this level of detail is vital for future planning of safe Arctic marine activities. Here the timing of when Arctic waters will be reliably ice free across Arctic regions from June to October is presented. It is shown that during this century regions along the Northern Sea Route and Arctic Bridge will be more reliably ice free than regions along the Northwest Passage and the Transpolar Sea Route, which will retain substantial sea ice cover past midcentury. Moreover, ice-free conditions in the Arctic will likely be confined to September for several decades to come in many regions. Projections using a selection of models that accounts for agreement of models in each region and calendar month with observations yield similar conclusions.

  12. Multiyear study of the dependence of sea salt aerosol on wind speed and sea ice conditions in the coastal Arctic

    NASA Astrophysics Data System (ADS)

    May, N. W.; Quinn, P. K.; McNamara, S. M.; Pratt, K. A.

    2016-08-01

    Thinning of Arctic sea ice gives rise to ice fracturing and leads (areas of open water surrounded by sea ice) that are a potential source of sea salt aerosol. Atmospheric particle inorganic ion concentrations, local sea ice conditions, and meteorology at Barrow, AK, from 2006 to 2009, were combined to investigate the dependence of submicron (aerodynamic diameter < 1 µm) and supermicron (aerodynamic diameter 1-10 µm) sea salt mass concentrations on sea ice coverage and wind speed. Consistent with a wind-dependent source, supermicron sea salt mass concentrations increased in the presence of nearby leads and wind speeds greater than 4 m s-1. Increased supermicron and submicron sea salt chloride depletion was observed for periods of low winds or a lack of nearby open water, consistent with transported sea salt influence. Sea salt aerosol produced from leads has the potential to alter cloud formation, as well as the chemical composition of the Arctic atmosphere and snowpack.

  13. Tropical Pacific Variability and its Influence on Twenty-First Century Arctic Sea Ice Loss

    NASA Astrophysics Data System (ADS)

    Wettstein, J. J.; Deser, C.

    2014-12-01

    Large declines in Arctic sea ice volume and summer sea ice extent are generally anticipated for the coming decades, based upon their trajectory in available observations and from a wide variety of greenhouse gas-forced model projections. Substantial uncertainty remains, however, regarding the magnitude of twenty-first century Arctic sea ice loss. Two studies are presented that document and explore the existence of an atmospheric teleconnection between the tropical Pacific and the Arctic on time scales ranging from the interannual to the multi-decadal. In the first study, twenty-first-century summer Arctic sea ice loss and its relationship to the large-scale atmospheric circulation is investigated in a 39-member Community Climate System Model, version 3 (CCSM3) ensemble for the period 2000-2061. Each member is subject to an identical greenhouse gas emissions scenario and differs only in the atmospheric model component's initial condition. A surprisingly large factor of three range in the multi-decadal trends of Arctic sea ice loss is projected, which can only be attributed to internal variability. Higher rates of summer Arctic sea ice loss in CCSM3 are associated with enhanced transpolar drift and Fram Strait ice export driven by surface wind and sea level pressure patterns. Outside the Arctic, the internal variability in sea ice loss is associated with an atmospheric Rossby wave train concentrated over the Pacific sector. The structure of the atmospheric teleconnection pattern in CCSM3 suggests that the tropical Pacific modulates Arctic sea ice loss via the aforementioned Rossby wave train. The second study generally corroborates results in the first by documenting qualitatively similar relationships in a newer model version and across a Coupled Model Intercomparison Project (CMIP) ensemble. Hints of a similar tropical Pacific-Arctic sea ice variability relationship are also present in various reanalyses at the interannual time scale.

  14. Arctic sea ice volume and thickness: trends and observations

    NASA Astrophysics Data System (ADS)

    Kwok, Ronald

    The sea ice extent of the Northern Hemisphere has been declining at an average rate of ˜3% per decade over the satellite record (1978-present) and the summer decline seems to be accelerating (Comiso et al., 2008). In September 2007, the summer ice extent reached a record minimum of 4.2×106 km2, which was 1.6×106 km2 or 23% less than the previous record set in September 2005. The loss of old ice is occurring at an even higher rate of ˜10% per decade. In addition to these remarkable trends in summer ice coverage, combined submarine and satellite records show a parallel thinning of the central Arctic ice cover from a winter thickness of 3.64 m in 1980 to only 1.89 m by 2008, a net decrease of 1.75 m or 48% in thickness (Kwok and Rothrock, 2009). More than two-thirds of the Arctic is now covered by thinner seasonal ice. If current rates persist, both trajectories point to the potential of ice-free summers in the not too distant future. Recent thickness observations from ICESat-1 have also provided a short record of the total sea ice volume of the Arctic Ocean -an important indicator of the state of the sea ice system. However, sustaining a capability to construct a long-term climate record of thickness and volume is a challenge. At this writing, ICESat-1 is near the end of its mission life and CryoSat-2 is about to be launched. CryoSat-2 is designed to have a mission life of 3 years that would likely end prior to launch of ICESat-II in ˜2015. Cross-calibration of the ICESat and CryoSat-2 (and eventually ICESat-II) ice thickness estimates is needed for linking the two data sets to extend the record of the seasonal, interannual, and decadal trends in thickness and volume. This is crucial for understanding the trends, process studies, as well as for improvement of long-term climate projections. Through this decade, there will be gaps in observations that need to be bridged with airborne assets augmented perhaps other new approaches to measure sea ice thickness. In

  15. Biopolymers form a gelatinous microlayer at the air-sea interface when Arctic sea ice melts

    PubMed Central

    Galgani, Luisa; Piontek, Judith; Engel, Anja

    2016-01-01

    The interface layer between ocean and atmosphere is only a couple of micrometers thick but plays a critical role in climate relevant processes, including the air-sea exchange of gas and heat and the emission of primary organic aerosols (POA). Recent findings suggest that low-level cloud formation above the Arctic Ocean may be linked to organic polymers produced by marine microorganisms. Sea ice harbors high amounts of polymeric substances that are produced by cells growing within the sea-ice brine. Here, we report from a research cruise to the central Arctic Ocean in 2012. Our study shows that microbial polymers accumulate at the air-sea interface when the sea ice melts. Proteinaceous compounds represented the major fraction of polymers supporting the formation of a gelatinous interface microlayer and providing a hitherto unrecognized potential source of marine POA. Our study indicates a novel link between sea ice-ocean and atmosphere that may be sensitive to climate change. PMID:27435531

  16. Observed Nordic Sea ice-cover variability 1992-2008

    NASA Astrophysics Data System (ADS)

    Kern, Stefan; Kaleschke, Lars; Spreen, Gunnar

    We examined the sea-ice cover of the Arctic peripheral seas bordering the Northern North Atlantic: Irminger, Greenland, Barents, Kara, and White/Pechora Sea using daily sea-ice con-centration data obtained with the ASI algorithm at a grid resolution of 12.5 km × 12.5 km from Special Sensor Microwave/Imager 85 GHz brightness temperature measurements for 1992-2008. The obtained annual cycles of monthly average ice area and extent indicate, in agreement with previous studies, an increase of the length of the melt season and reductions in the mean maxi-mum and minimum ice-cover in all regions between 1992-1999 and 2000-2008, with wintertime changes of between 5-10% (Greenland Sea, White/Pechora Sea) and 15-20% (Irminger and Barents Sea), and summertime changes between 30% (Kara Sea) and up to 55% (Irminger and Barents Sea). Monthly mean ice-area and -extent anomalies relative to the average annual cycle are calculated and indicate pronounced differences between the Barents Sea and the other regions. A lag-correlation analysis between all ice-area and -extent anomalies is carried out. The main results are: i) Barents Sea ice-area and -extent anomalies are significantly auto-correlated for a two-fold longer period of time than respective anomalies in the other regions. ii) Fall/early winter Irminger Sea ice-area and -extent anomalies are significantly correlated with respective summer/fall Greenland Sea anomalies; the average time-lag is 2-3 months, the average (max-imum) duration is 2 (8) months. iii) Barents and Kara Sea ice-area and -extent anomalies are significantly correlated with each other during summer/fall. We found also a significant correlation between Barents Sea Dec. to July and Kara Sea July to Sep./Nov. ice-area and -extent anomalies with an average duration of 2-3 months. We have investigated the relationship between anomalies in ice-area flux between the Arctic Ocean and the considered peripheral seas and the ice-area and -extent anomalies in these

  17. Active microwave measurements of Arctic sea ice under summer conditions

    NASA Technical Reports Server (NTRS)

    Onstott, R. G.; Gogineni, S. P.

    1985-01-01

    Radar provides a valuable tool in the study of sea-ice conditions and the solution of sea-ice operational problems. For this reason, the U.S. and Canada have conducted studies to define a bilateral synthetic aperture radar (SAR) satellite program. The present paper is concerned with work which has been performed to explore the needs associated with the study of sea-ice-covered waters. The design of a suitable research or operational spaceborne SAR or real aperture radar must be based on an adequate knowledge of the backscatter coefficients of the ice features which are of interest. In order to obtain the needed information, studies involving the use of a helicopter were conducted. In these studies L-C-X-Ku-band calibrated radar data were acquired over areas of Arctic first-year and multiyear ice during the first half of the summer of 1982. The results show that the microwave response in the case of sea ice is greatly influenced by summer melt, which produces significant changes in the properties of the snowpack and ice sheet.

  18. Sea Ice Drift in the Arctic Ocean. Seasonal Variability and Long-Term Changes

    NASA Astrophysics Data System (ADS)

    Pavlov, V.; Pavlova, O.

    2010-12-01

    Variability in the drift of sea ice in the Arctic Ocean is an important parameter that can be used to characterise the thermodynamic processes in the Arctic. Knowledge of the features of sea ice drift in the Arctic Ocean is necessary for climate research, for an improved understanding of polar ecology and as an aid to human activity in the Arctic Ocean. Monthly mean sea ice drift velocities, computed from Advanced Very High Resolution Radiometer (AVHRR), Scanning Multichannel Microwave Radiometer (SMMR), Special Sensor Microwave/Imager (SSM/I), and International Arctic Buoy Programme (IABP) buoy data, are used to investigate the spatial and temporal variability of ice motion in the Arctic Ocean and Nordic Seas from 1979. Sea ice drift in the Arctic Ocean is characterized by strong seasonal and inter-annual variability. The results of combined statistical analysis of sea ice velocities and wind fields over the Arctic Ocean suggest that the seasonal changes of local wind are a predominant factor in the formation of the sea ice velocities annual cycle. Sea ice drift velocities mirror seasonal changes of the wind in the Arctic, reaching a maximum in December, with a minimum in June. In the central part of the Arctic Ocean and in the area near the Canadian shore the amplitude of this variation is not more than 2 cm/ sec. The maximum amplitudes are found in the Fram Strait (9-10 cm/sec), Beaufort Gyre (6-7 cm/sec) and the northern part of Barents Sea (5-6 cm/sec). Low frequency variations of sea ice drift velocities, with periods of 2.0-2.5 yrs and 5.0-6.0 yrs, are related to reorganization of the atmospheric circulation over the Arctic. There is evidence that the average sea ice velocity for the whole of the Arctic Ocean is increasing, with a positive trend for the period of last three decades. Trends of the monthly mean ice drift velocities are positive almost everywhere in the Arctic Ocean. In the Baffin Bay, Fram Strait and Barents Sea regions, sea ice velocities

  19. Arctic Ocean sea ice cover during the penultimate glacial and the last interglacial.

    PubMed

    Stein, Ruediger; Fahl, Kirsten; Gierz, Paul; Niessen, Frank; Lohmann, Gerrit

    2017-08-29

    Coinciding with global warming, Arctic sea ice has rapidly decreased during the last four decades and climate scenarios suggest that sea ice may completely disappear during summer within the next about 50-100 years. Here we produce Arctic sea ice biomarker proxy records for the penultimate glacial (Marine Isotope Stage 6) and the subsequent last interglacial (Marine Isotope Stage 5e). The latter is a time interval when the high latitudes were significantly warmer than today. We document that even under such warmer climate conditions, sea ice existed in the central Arctic Ocean during summer, whereas sea ice was significantly reduced along the Barents Sea continental margin influenced by Atlantic Water inflow. Our proxy reconstruction of the last interglacial sea ice cover is supported by climate simulations, although some proxy data/model inconsistencies still exist. During late Marine Isotope Stage 6, polynya-type conditions occurred off the major ice sheets along the northern Barents and East Siberian continental margins, contradicting a giant Marine Isotope Stage 6 ice shelf that covered the entire Arctic Ocean.Coinciding with global warming, Arctic sea ice has rapidly decreased during the last four decades. Here, using biomarker records, the authors show that permanent sea ice was still present in the central Arctic Ocean during the last interglacial, when high latitudes were warmer than present.

  20. Dumping of radioactive waste in the Artic Seas - The International Arctic Seas Assessment Project (IASAP)

    SciTech Connect

    Linsley, G.S.; Sjoeblom, K.L.

    1994-12-31

    The IAEA has initiated the International Arctic Seas Assessment Project (IASAP) to address the widespread concern over the possible health and environmental impacts of the dumped radioactive wastes in the shallow waters the Arctic seas. The work is being carried out as part of IAEA responsibilities to the London Convention 1972. It is envisaged that the project will last for four years and be run by the IAEA in co-operation with the Norwegian and Russian Governments and with the involvement, through the IAEA, of experts from relevant IAEA member states. The project is aimed at producing an assessment of the potential radiological implications of the dumping and at addressing the question of possible remedial measures. At the same time, it is intended to provide a focus for the reporting of national research and assessment work and a mechanism for encouraging international co-operation and collaboration.

  1. Northern Barents Sea Evolution Linked to the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Minakov, A.; Mjelde, R.; Faleide, J. I.; Huismans, R. S.; Dannowski, A.; Flueh, E. R.; Glebovsky, V.; Keers, H.; Podladchikov, Y. Y.

    2010-12-01

    The current effort represents a systematic regional study of the vast and poorly sampled area, linking the Barents Sea and the Arctic Ocean. The deep structure of the Northern Barents Sea was examined by means of integration various geophysical techniques, including numerical geodynamic modeling. Ocean Bottom Seismometers data have been acquired east of Svalbard and processed using a seismic refraction/reflection tomography method. A series of crustal-scale geotransects, illustrating the architecture of the Cenozoic Northern Barents Sea margin were constructed using gravity modeling, sparse seismic reflection profiles and depth to magnetic sources estimates. The structure of the Mesozoic passive margin, facing to the Amerasia Basin, was inferred based on a similar technique, involving plate reconstructions. Numerical simulations of the lithosphere extension, leading to formation of the Eurasia Basin, was performed using the finite element method. The velocity structure east of Svalbard exhibits evidences of Cretaceous magmatism. In particular, funnel-shaped high-velocity anomalies, reaching 10% relative to the 1D background model, are interpreted as Early Cretaceous magmatic intrusions. Further to the north, a narrow and steep continent-ocean transition was observed. The conjugate northern (and eastern) Barents Sea - Lomonosov Ridge margins are symmetric and narrow whereas the continent-ocean transition on the Podvodnikov Basin's side of the Lomonosov Ridge is broad. On the continental side, the Northern Barents Sea margin is underlain by Paleozoic-Early Mesozoic deep sedimentary basins separated from the oceanic side by the marginal basement uplift. The Northern Barents Sea, including Svalbard, was not affected by the major Late Jurassic - Early Cretaceous rifting which gave rise to deep basins in the South Western Barents Sea. However, the area experienced widespread Early Cretaceous magmatism. The emplacement of mafic magmas was controlled by Paleozoic rift

  2. Selected physical, biological and biogeochemical implications of a rapidly changing Arctic Marginal Ice Zone

    NASA Astrophysics Data System (ADS)

    Barber, David G.; Hop, Haakon; Mundy, Christopher J.; Else, Brent; Dmitrenko, Igor A.; Tremblay, Jean-Eric; Ehn, Jens K.; Assmy, Philipp; Daase, Malin; Candlish, Lauren M.; Rysgaard, Søren

    2015-12-01

    The Marginal Ice Zone (MIZ) of the Arctic Ocean is changing rapidly due to a warming Arctic climate with commensurate reductions in sea ice extent and thickness. This Pan-Arctic review summarizes the main changes in the Arctic ocean-sea ice-atmosphere (OSA) interface, with implications for primary- and secondary producers in the ice and the underlying water column. Changes in the Arctic MIZ were interpreted for the period 1979-2010, based on best-fit regressions for each month. Trends of increasingly open water were statistically significant for each month, with quadratic fit for August-November, illustrating particularly strong seasonal feedbacks in sea-ice formation and decay. Geographic interpretations of physical and biological changes were based on comparison of regions with significant changes in sea ice: (1) The Pacific Sector of the Arctic Ocean including the Canada Basin and the Beaufort, Chukchi and East Siberian seas; (2) The Canadian Arctic Archipelago; (3) Baffin Bay and Hudson Bay; and (4) the Barents and Kara seas. Changes in ice conditions in the Barents sea/Kara sea region appear to be primarily forced by ocean heat fluxes during winter, whereas changes in the other sectors appear to be more summer-autumn related and primarily atmospherically forced. Effects of seasonal and regional changes in OSA-system with regard to increased open water were summarized for photosynthetically available radiation, nutrient delivery to the euphotic zone, primary production of ice algae and phytoplankton, ice-associated fauna and zooplankton, and gas exchange of CO2. Changes in the physical factors varied amongst regions, and showed direct effects on organisms linked to sea ice. Zooplankton species appear to be more flexible and likely able to adapt to variability in the onset of primary production. The major changes identified for the ice-associated ecosystem are with regard to production timing and abundance or biomass of ice flora and fauna, which are related to

  3. Methane excess in Arctic surface water-triggered by sea ice formation and melting.

    PubMed

    Damm, E; Rudels, B; Schauer, U; Mau, S; Dieckmann, G

    2015-11-10

    Arctic amplification of global warming has led to increased summer sea ice retreat, which influences gas exchange between the Arctic Ocean and the atmosphere where sea ice previously acted as a physical barrier. Indeed, recently observed enhanced atmospheric methane concentrations in Arctic regions with fractional sea-ice cover point to unexpected feedbacks in cycling of methane. We report on methane excess in sea ice-influenced water masses in the interior Arctic Ocean and provide evidence that sea ice is a potential source. We show that methane release from sea ice into the ocean occurs via brine drainage during freezing and melting i.e. in winter and spring. In summer under a fractional sea ice cover, reduced turbulence restricts gas transfer, then seawater acts as buffer in which methane remains entrained. However, in autumn and winter surface convection initiates pronounced efflux of methane from the ice covered ocean to the atmosphere. Our results demonstrate that sea ice-sourced methane cycles seasonally between sea ice, sea-ice-influenced seawater and the atmosphere, while the deeper ocean remains decoupled. Freshening due to summer sea ice retreat will enhance this decoupling, which restricts the capacity of the deeper Arctic Ocean to act as a sink for this greenhouse gas.

  4. Methane excess in Arctic surface water- triggered by sea ice formation and melting

    PubMed Central

    Damm, E.; Rudels, B.; Schauer, U.; Mau, S.; Dieckmann, G.

    2015-01-01

    Arctic amplification of global warming has led to increased summer sea ice retreat, which influences gas exchange between the Arctic Ocean and the atmosphere where sea ice previously acted as a physical barrier. Indeed, recently observed enhanced atmospheric methane concentrations in Arctic regions with fractional sea-ice cover point to unexpected feedbacks in cycling of methane. We report on methane excess in sea ice-influenced water masses in the interior Arctic Ocean and provide evidence that sea ice is a potential source. We show that methane release from sea ice into the ocean occurs via brine drainage during freezing and melting i.e. in winter and spring. In summer under a fractional sea ice cover, reduced turbulence restricts gas transfer, then seawater acts as buffer in which methane remains entrained. However, in autumn and winter surface convection initiates pronounced efflux of methane from the ice covered ocean to the atmosphere. Our results demonstrate that sea ice-sourced methane cycles seasonally between sea ice, sea-ice-influenced seawater and the atmosphere, while the deeper ocean remains decoupled. Freshening due to summer sea ice retreat will enhance this decoupling, which restricts the capacity of the deeper Arctic Ocean to act as a sink for this greenhouse gas. PMID:26553610

  5. Shifting El Niño inhibits summer Arctic warming and Arctic sea-ice melting over the Canada Basin

    PubMed Central

    Hu, Chundi; Yang, Song; Wu, Qigang; Li, Zhenning; Chen, Junwen; Deng, Kaiqiang; Zhang, Tuantuan; Zhang, Chengyang

    2016-01-01

    Arctic climate changes include not only changes in trends and mean states but also strong interannual variations in various fields. Although it is known that tropical-extratropical teleconnection is sensitive to changes in flavours of El Niño, whether Arctic climate variability is linked to El Niño, in particular on interannual timescale, remains unclear. Here we demonstrate for the first time a long-range linkage between central Pacific (CP) El Niño and summer Arctic climate. Observations show that the CP warming related to CP El Niño events deepens the tropospheric Arctic polar vortex and strengthens the circumpolar westerly wind, thereby contributing to inhibiting summer Arctic warming and sea-ice melting. Atmospheric model experiments can generally capture the observed responses of Arctic circulation and robust surface cooling to CP El Niño forcing. We suggest that identification of the equator-Arctic teleconnection, via the ‘atmospheric bridge', can potentially contribute to improving the skill of predicting Arctic climate. PMID:27251873

  6. Shifting El Niño inhibits summer Arctic warming and Arctic sea-ice melting over the Canada Basin

    NASA Astrophysics Data System (ADS)

    Hu, Chundi; Yang, Song; Wu, Qigang; Li, Zhenning; Chen, Junwen; Deng, Kaiqiang; Zhang, Tuantuan; Zhang, Chengyang

    2016-06-01

    Arctic climate changes include not only changes in trends and mean states but also strong interannual variations in various fields. Although it is known that tropical-extratropical teleconnection is sensitive to changes in flavours of El Niño, whether Arctic climate variability is linked to El Niño, in particular on interannual timescale, remains unclear. Here we demonstrate for the first time a long-range linkage between central Pacific (CP) El Niño and summer Arctic climate. Observations show that the CP warming related to CP El Niño events deepens the tropospheric Arctic polar vortex and strengthens the circumpolar westerly wind, thereby contributing to inhibiting summer Arctic warming and sea-ice melting. Atmospheric model experiments can generally capture the observed responses of Arctic circulation and robust surface cooling to CP El Niño forcing. We suggest that identification of the equator-Arctic teleconnection, via the `atmospheric bridge', can potentially contribute to improving the skill of predicting Arctic climate.

  7. Shifting El Niño inhibits summer Arctic warming and Arctic sea-ice melting over the Canada Basin.

    PubMed

    Hu, Chundi; Yang, Song; Wu, Qigang; Li, Zhenning; Chen, Junwen; Deng, Kaiqiang; Zhang, Tuantuan; Zhang, Chengyang

    2016-06-02

    Arctic climate changes include not only changes in trends and mean states but also strong interannual variations in various fields. Although it is known that tropical-extratropical teleconnection is sensitive to changes in flavours of El Niño, whether Arctic climate variability is linked to El Niño, in particular on interannual timescale, remains unclear. Here we demonstrate for the first time a long-range linkage between central Pacific (CP) El Niño and summer Arctic climate. Observations show that the CP warming related to CP El Niño events deepens the tropospheric Arctic polar vortex and strengthens the circumpolar westerly wind, thereby contributing to inhibiting summer Arctic warming and sea-ice melting. Atmospheric model experiments can generally capture the observed responses of Arctic circulation and robust surface cooling to CP El Niño forcing. We suggest that identification of the equator-Arctic teleconnection, via the 'atmospheric bridge', can potentially contribute to improving the skill of predicting Arctic climate.

  8. A Pan-Arctic Network to Study Past, Present, and Future Sea Ice Trends

    NASA Astrophysics Data System (ADS)

    Wegner, Carolyn; Frey, Karen E.; Michel, Christine

    2011-03-01

    Arctic in Rapid Transition Implementation Workshop; Winnipeg, Manitoba, Canada, 18-20 October 2010 ; Rapid transitions in Arctic sea ice and the associated global integrated Earth system impacts and socioeconomic consequences have brought the Arctic Ocean to the top of national and international geophysical and political agendas. Alarmingly, there is a persistent mismatch between observed and predicted patterns, which speaks to the complexity of planning adaptation and mitigation activities in the Arctic. Predicting future conditions of Arctic marine ecosystems for climate change requires interdisciplinary and pan-Arctic characterization and understanding of past and present trends. The Arctic in Rapid Transition (ART) initiative is an integrative, international, interdisciplinary, pan-Arctic network to study spatial and temporal changes in sea ice cover and ocean circulation over broad time scales to better understand and forecast the impact of these changes on Arctic marine ecosystems and biogeochemistry. The ART initiative began in October 2008 and is still led by early-career scientists. The ART science plan, developed after the ART initiation workshop in November 2009, was endorsed by the Arctic Ocean Sciences Board, which is now the Marine Working Group of the International Arctic Science Committee.

  9. Peopling of the high Arctic - induced by sea ice?

    NASA Astrophysics Data System (ADS)

    Funder, Svend

    2010-05-01

    'We travelled in the winter after the return of daylight and did not go into fixed camp until spring, when the ice broke up. There was good hunting on the way, seals, beluga, walrus, bear.' (From Old Merkrusârk's account of his childhood's trek from Baffin Island to Northwest Greenland, told to Knud Rasmussen on Saunders Island in 1904) Five thousand years ago people moving eastwards from Beringia spread over the barrens of the Canadian high Arctic. This was the first of three waves of prehistoric Arctic 'cultures', which eventually reached Greenland. The passage into Greenland has to go through the northernmost and most hostile part of the country with a 5 month Polar night, and to understand this extraordinary example of human behaviour and endurance, it has been customary to invoke a more favourable (warmer) climate. This presentation suggests that land-fast sea ice, i.e. stationary sea ice anchored to the coast, is among the most important environmental factors behind the spread of prehistoric polar cultures. The ice provides the road for travelling and social communion - and access to the most important source of food, the ocean. In the LongTerm Project (2006 and 2007) we attempted to establish a Holocene record for sea ice variations along oceanic coasts in northernmost Greenland. Presently the coasts north of 80° N are beleaguered by year-round sea ice - for ten months this is land-fast ice, and only for a period in the stormy autumn months are the coasts exposed to pack-ice. This presentation Land-fast ice - as opposed to pack-ice - is a product of local temperatures, but its duration over the year, and especially into the daylight season, is also conditioned by other factors, notably wind strength. In the geological record we recognize long lasting land-fast ice by two absences: absence of traces of wave action (no beach formation), which, however, can also be a result of pack-ice along the coast; - and absence of driftwood on the shore (land-fast ice

  10. How sea ice could be the cold beating heart of European weather

    NASA Astrophysics Data System (ADS)

    Margrethe Ringgaard, Ida; Yang, Shuting; Hesselbjerg Christensen, Jens; Kaas, Eigil

    2017-04-01

    The possibility that the ongoing rapid demise of Arctic sea ice may instigate abrupt changes is, however, not tackled by current research in general. Ice cores from the Greenland Ice Sheet (GIS) show clear evidence of past abrupt warm events with up to 15 degrees warming in less than a decade, most likely triggered by rapid disappearance of Nordic Seas sea ice. At present, both Arctic Sea ice and the GIS are in strong transformation: Arctic sea-ice cover has been retreating during most of the satellite era and in recent years, Arctic sea ice experienced a dramatic reduction and the summer extent was in 2012 and 2016 only half of the 1979-2000 average. With such dramatic change in the current sea ice coverage as a point of departure, several studies have linked reduction in wintertime sea ice in the Barents-Kara seas to cold weather anomalies over Europe and through large scale tele-connections to regional warming elsewhere. Here we aim to investigate if, and how, Arctic sea ice impacts European weather, i.e. if the Arctic sea ice works as the 'cold heart' of European weather. To understand the effects of the sea ice reduction on the full climate system, a fully-coupled global climate model, EC-Earth, is used. A new energy-conserving method for assimilating sea ice using the sensible heat flux is implemented in the coupled climate model and compared to the traditional, non-conserving, method of assimilating sea ice. Using this new method, experiments are performed with reduced sea ice cover in the Barents-Kara seas under both warm and cold conditions in Europe. These experiments are used to evaluate how the Arctic sea ice modulates European winter weather under present climate conditions with a view towards favouring both relatively cold and warm conditions.

  11. The missing Northern European winter cooling response to Arctic sea ice loss

    NASA Astrophysics Data System (ADS)

    Screen, James A.

    2017-03-01

    Reductions in Arctic sea ice may promote the negative phase of the North Atlantic Oscillation (NAO-). It has been argued that NAO-related variability can be used an as analogue to predict the effects of Arctic sea ice loss on mid-latitude weather. As NAO- events are associated with colder winters over Northern Europe, a negatively shifted NAO has been proposed as a dynamical pathway for Arctic sea ice loss to cause Northern European cooling. This study uses large-ensemble atmospheric simulations with prescribed ocean surface conditions to examine how seasonal-scale NAO- events are affected by Arctic sea ice loss. Despite an intensification of NAO- events, reflected by more prevalent easterly flow, sea ice loss does not lead to Northern European winter cooling and daily cold extremes actually decrease. The dynamical cooling from the changed NAO is `missing', because it is offset (or exceeded) by a thermodynamical effect owing to advection of warmer air masses.

  12. The missing Northern European winter cooling response to Arctic sea ice loss.

    PubMed

    Screen, James A

    2017-03-06

    Reductions in Arctic sea ice may promote the negative phase of the North Atlantic Oscillation (NAO-). It has been argued that NAO-related variability can be used an as analogue to predict the effects of Arctic sea ice loss on mid-latitude weather. As NAO- events are associated with colder winters over Northern Europe, a negatively shifted NAO has been proposed as a dynamical pathway for Arctic sea ice loss to cause Northern European cooling. This study uses large-ensemble atmospheric simulations with prescribed ocean surface conditions to examine how seasonal-scale NAO- events are affected by Arctic sea ice loss. Despite an intensification of NAO- events, reflected by more prevalent easterly flow, sea ice loss does not lead to Northern European winter cooling and daily cold extremes actually decrease. The dynamical cooling from the changed NAO is 'missing', because it is offset (or exceeded) by a thermodynamical effect owing to advection of warmer air masses.

  13. Loitering of the retreating sea ice edge in the Arctic Seas.

    PubMed

    Steele, Michael; Ermold, Wendy

    2015-12-01

    Each year, the arctic sea ice edge retreats from its winter maximum extent through the Seasonal Ice Zone (SIZ) to its summer minimum extent. On some days, this retreat happens at a rapid pace, while on other days, parts of the pan-arctic ice edge hardly move for periods of days up to 1.5 weeks. We term this stationary behavior "ice edge loitering," and identify areas that are more prone to loitering than others. Generally, about 20-25% of the SIZ area experiences loitering, most often only one time at any one location during the retreat season, but sometimes two or more times. The main mechanism controlling loitering is an interaction between surface winds and warm sea surface temperatures in areas from which the ice has already retreated. When retreat happens early enough to allow atmospheric warming of this open water, winds that force ice floes into this water cause melting. Thus, while individual ice floes are moving, the ice edge as a whole appears to loiter. The time scale of loitering is then naturally tied to the synoptic time scale of wind forcing. Perhaps surprisingly, the area of loitering in the arctic seas has not changed over the past 25 years, even as the SIZ area has grown. This is because rapid ice retreat happens most commonly late in the summer, when atmospheric warming of open water is weak. We speculate that loitering may have profound effects on both physical and biological conditions at the ice edge during the retreat season.

  14. Use of {sup 59}Ni, {sup 99}Tc, and {sup 236}U to monitor the release of radionuclides from objects containing spent nuclear fuel dumped in the Kara Sea

    SciTech Connect

    Mount, M.E.; Layton, D.W.; Lynn, N.M.; Hamilton, T.F.

    1998-04-01

    Between 1965 and 1981, five objects - six naval reactor pressure vessels (RPVs) from four former Soviet Union submarines and a special containers from the icebreaker Lenin, each of which contained damaged spent nuclear fuel (SNF) - were dumped in a variety of containments, using a number of sealing methods, at four sites in the Kara Sea. All objects were dumped at sites that varied in depth from 12 to 300 m. This paper examines the use of the long-lived radionuclides {sup 59}Ni, {sup 99}Tc, and {sup 236}U encased within these objects to monitor the breakdown of the containments due to corrosion. Included are discussions of the radionuclide inventory and their release rate model, the estimated radionuclide mass in a typical seawater sample, and the potential for radionuclide measurement via Accelerator Mass Spectrometry (AMS).

  15. EOS Aqua AMSR-E Arctic Sea-Ice Validation Program: Arctic2006 Aircraft Campaign Flight Report

    NASA Technical Reports Server (NTRS)

    Cavalieri, D. J.; Markus, T.

    2006-01-01

    In March 2006, a coordinated Arctic sea-ice validation field campaign using the NASA Wallops P-3B aircraft was successfully completed. This campaign was the second Alaskan Arctic field campaign for validating the Earth Observing System (EOS) Aqua Advanced Microwave Scanning Radiometer (AMSR-E) sea-ice products. The first campaign was completed in March 2003. The AMSR-E, designed and built by the Japanese Space Agency for NASA, was launched May 4, 2002 on the EOS Aqua spacecraft. The AMSR-E sea-ice products to be validated include sea-ice concentration, sea-ice temperature, and snow depth on sea ice. The focus of this campaign was on the validation of snow depth on sea ice and sea-ice temperature. This flight report describes the suite of instruments flown on the P-3, the objectives of each of the six flights, the Arctic regions overflown, and the coordination among satellite, aircraft, and surface-based measurements.

  16. The application of ERTS imagery to monitoring Arctic sea ice. [mapping ice in Bering Sea, Beaufort Sea, Canadian Archipelago, and Greenland Sea

    NASA Technical Reports Server (NTRS)

    Barnes, J. C. (Principal Investigator); Bowley, C. J.

    1974-01-01

    The author has identified the following significant results. Because of the effect of sea ice on the heat balance of the Arctic and because of the expanding economic interest in arctic oil and minerals, extensive monitoring and further study of sea ice is required. The application of ERTS data for mapping ice is evaluated for several arctic areas, including the Bering Sea, the eastern Beaufort Sea, parts of the Canadian Archipelago, and the Greenland Sea. Interpretive techniques are discussed, and the scales and types of ice features that can be detected are described. For the Bering Sea, a sample of ERTS-1 imagery is compared with visual ice reports and aerial photography from the NASA CV-990 aircraft. The results of the investigation demonstrate that ERTS-1 imagery has substantial practical application for monitoring arctic sea ice. Ice features as small as 80-100 m in width can be detected, and the combined use of the visible and near-IR imagery is a powerful tool for identifying ice types. Sequential ERTS-1 observations at high latitudes enable ice deformations and movements to be mapped. Ice conditions in the Bering Sea during early March depicted in ERTS-1 images are in close agreement with aerial ice observations and photographs.

  17. Effect of retreating sea ice on Arctic cloud cover in simulated recent global warming

    NASA Astrophysics Data System (ADS)

    Abe, Manabu; Nozawa, Toru; Ogura, Tomoo; Takata, Kumiko

    2016-11-01

    This study investigates the effect of sea ice reduction on Arctic cloud cover in historical simulations with the coupled atmosphere-ocean general circulation model MIROC5. Arctic sea ice has been substantially retreating since the 1980s, particularly in September, under simulated global warming conditions. The simulated sea ice reduction is consistent with satellite observations. On the other hand, Arctic cloud cover has been increasing in October, with about a 1-month lag behind the sea ice reduction. The delayed response leads to extensive sea ice reductions because the heat and moisture fluxes from the underlying open ocean into the atmosphere are enhanced. Sensitivity experiments with the atmospheric part of MIROC5 clearly show that sea ice reduction causes increases in cloud cover. Arctic cloud cover increases primarily in the lower troposphere, but it decreases in the near-surface layers just above the ocean; predominant temperature rises in these near-surface layers cause drying (i.e., decreases in relative humidity), despite increasing moisture flux. Cloud radiative forcing due to increases in cloud cover in autumn brings an increase in the surface downward longwave radiation (DLR) by approximately 40-60 % compared to changes in clear-sky surface DLR in fall. These results suggest that an increase in Arctic cloud cover as a result of reduced sea ice coverage may bring further sea ice retreat and enhance the feedback processes of Arctic warming.

  18. Development, sensitivity analysis, and uncertainty quantification of high-fidelity arctic sea ice models.

    SciTech Connect

    Peterson, Kara J.; Bochev, Pavel Blagoveston; Paskaleva, Biliana S.

    2010-09-01

    Arctic sea ice is an important component of the global climate system and due to feedback effects the Arctic ice cover is changing rapidly. Predictive mathematical models are of paramount importance for accurate estimates of the future ice trajectory. However, the sea ice components of Global Climate Models (GCMs) vary significantly in their prediction of the future state of Arctic sea ice and have generally underestimated the rate of decline in minimum sea ice extent seen over the past thirty years. One of the contributing factors to this variability is the sensitivity of the sea ice to model physical parameters. A new sea ice model that has the potential to improve sea ice predictions incorporates an anisotropic elastic-decohesive rheology and dynamics solved using the material-point method (MPM), which combines Lagrangian particles for advection with a background grid for gradient computations. We evaluate the variability of the Los Alamos National Laboratory CICE code and the MPM sea ice code for a single year simulation of the Arctic basin using consistent ocean and atmospheric forcing. Sensitivities of ice volume, ice area, ice extent, root mean square (RMS) ice speed, central Arctic ice thickness, and central Arctic ice speed with respect to ten different dynamic and thermodynamic parameters are evaluated both individually and in combination using the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA). We find similar responses for the two codes and some interesting seasonal variability in the strength of the parameters on the solution.

  19. Reconstructed changes in Arctic sea ice over the past 1,450 years.

    PubMed

    Kinnard, Christophe; Zdanowicz, Christian M; Fisher, David A; Isaksson, Elisabeth; de Vernal, Anne; Thompson, Lonnie G

    2011-11-23

    Arctic sea ice extent is now more than two million square kilometres less than it was in the late twentieth century, with important consequences for the climate, the ocean and traditional lifestyles in the Arctic. Although observations show a more or less continuous decline for the past four or five decades, there are few long-term records with which to assess natural sea ice variability. Until now, the question of whether or not current trends are potentially anomalous has therefore remained unanswerable. Here we use a network of high-resolution terrestrial proxies from the circum-Arctic region to reconstruct past extents of summer sea ice, and show that-although extensive uncertainties remain, especially before the sixteenth century-both the duration and magnitude of the current decline in sea ice seem to be unprecedented for the past 1,450 years. Enhanced advection of warm Atlantic water to the Arctic seems to be the main factor driving the decline of sea ice extent on multidecadal timescales, and may result from nonlinear feedbacks between sea ice and the Atlantic meridional overturning circulation. These results reinforce the assertion that sea ice is an active component of Arctic climate variability and that the recent decrease in summer Arctic sea ice is consistent with anthropogenically forced warming.

  20. Arctic Sea Ice Trafficability - New Strategies for a Changing Icescape

    NASA Astrophysics Data System (ADS)

    Dammann, Dyre Oliver

    Sea ice is an important part of the Arctic social-environmental system, in part because it provides a platform for human transportation and for marine flora and fauna that use the ice as a habitat. Sea ice loss projected for coming decades is expected to change ice conditions throughout the Arctic, but little is known about the nature and extent of anticipated changes and in particular potential implications for over-ice travel and ice use as a platform. This question has been addressed here through an extensive effort to link sea ice use and key geophysical properties of sea ice, drawing upon extensive field surveys around on-ice operations and local and Indigenous knowledge for the widely different ice uses and ice regimes of Utqiagvik, Kotzebue, and Nome, Alaska.. A set of nine parameters that constrain landfast sea ice use has been derived, including spatial extent, stability, and timing and persistence of landfast ice. This work lays the foundation for a framework to assess and monitor key ice-parameters relevant in the context of ice-use feasibility, safety, and efficiency, drawing on different remote-sensing techniques. The framework outlines the steps necessary to further evaluate relevant parameters in the context of user objectives and key stakeholder needs for a given ice regime and ice use scenario. I have utilized this framework in case studies for three different ice regimes, where I find uses to be constrained by ice thickness, roughness, and fracture potential and develop assessment strategies with accuracy at the relevant spatial scales. In response to the widely reported importance of high-confidence ice thickness measurements, I have developed a new strategy to estimate appropriate thickness compensation factors. Compensation factors have the potential to reduce risk of misrepresenting areas of thin ice when using point-based in-situ assessment methods along a particular route. This approach was tested on an ice road near Kotzebue, Alaska, where

  1. Polar bear and walrus response to the rapid decline in Arctic sea ice

    USGS Publications Warehouse

    Oakley, K.; Whalen, M.; Douglas, D.; Udevitz, M.; Atwood, T.; Jay, C.

    2012-01-01

    The Arctic is warming faster than other regions of the world due to positive climate feedbacks associated with loss of snow and ice. One highly visible consequence has been a rapid decline in Arctic sea ice over the past 3 decades - a decline projected to continue and result in ice-free summers likely as soon as 2030. The polar bear (Ursus maritimus) and the Pacific walrus (Odobenus rosmarus divergens) are dependent on sea ice over the continental shelves of the Arctic Ocean's marginal seas. The continental shelves are shallow regions with high biological productivity, supporting abundant marine life within the water column and on the sea floor. Polar bears use sea ice as a platform for hunting ice seals; walruses use sea ice as a resting platform between dives to forage for clams and other bottom-dwelling invertebrates. How have sea ice changes affected polar bears and walruses? How will anticipated changes affect them in the future?

  2. SMOS sea surface salinity maps of the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Gabarro, Carolina; Olmedo, Estrella; Turiel, Antonio; Ballabrera-Poy, Joaquim; Martinez, Justino; Portabella, Marcos

    2016-04-01

    years of SMOS data acquisitions. The second is the modification of the filtering criterion to account for the statistical distributions of SSS at each ocean grid point. This allows retrieving a value of SSS which is less affected by outliers originated from RFI and other effects. We will provide an assessment of the quality of these new SSS products in the Arctic, as well as illustrate the potential of these maps to monitor the main river discharges to the Arctic Ocean. [1] Font, J.; Camps, A.; Borges, A.; Martín-Neira, M.; Boutin, J.; Reul, N.; Kerr, Y.; Hahne, A. & Mecklenburg, S. SMOS: The Challenging Sea Surface Salinity Measurement From Space Proceedings of the IEEE, 2010, 98, 649 -665

  3. Force balance and deformation characteristics of anisotropic Arctic sea ice (a high resolution study)

    NASA Astrophysics Data System (ADS)

    Feltham, D. L.; Heorton, H. D.; Tsamados, M.

    2016-12-01

    The spatial distribution of Arctic sea ice arises from its deformation, driven by external momentum forcing, thermodynamic growth and melt. The deformation of Arctic sea ice is observed to have structural alignment on a broad range of length scales. By considering the alignment of diamond-shaped sea ice floes, an anisotropic rheology (known as the Elastic Anisotropic Plastic, EAP, rheology) has been developed for use in a climate sea ice model. Here we present investigations into the role of anisotropy in determining the internal ice stress gradient and the complete force balance of Arctic sea ice using a state-of-the-art climate sea ice model. Our investigations are focused on the link between external imposed dynamical forcing, predominantly the wind stress, and the emergent properties of sea ice, including its drift speed and thickness distribution. We analyse the characteristics of deformation events for different sea ice states and anisotropic alignment over different regions of the Arctic Ocean. We present the full seasonal stress balance and sea ice state over the Arctic ocean. We have performed 10 km basin-scale simulations over a 30-year time scale, and 2 km and 500 m resolution simulations in an idealised configuration. The anisotropic EAP sea ice rheology gives higher shear stresses than the more customary isotropic EVP rheology, and these reduce ice drift speed and mechanical thickening, particularly important in the Archipelago. In the central Arctic the circulation of sea ice is reduced allowing it to grow thicker thermodynamically. The emergent stress-strain rate correlations from the EAP model suggest that it is possible to characterise the internal ice stresses of Arctic sea ice from observable basin-wide deformation and drift patterns.

  4. The impact of lower sea-ice extent on Arctic greenhouse-gas exchange

    USGS Publications Warehouse

    Parmentier, Frans-Jan W.; Christensen, Torben R.; Sørensen, Lise Lotte; Rysgaard, Søren; McGuire, A. David; Miller, Paul A.; Walker, Donald A.

    2013-01-01

    In September 2012, Arctic sea-ice extent plummeted to a new record low: two times lower than the 1979–2000 average. Often, record lows in sea-ice cover are hailed as an example of climate change impacts in the Arctic. Less apparent, however, are the implications of reduced sea-ice cover in the Arctic Ocean for marine–atmosphere CO2 exchange. Sea-ice decline has been connected to increasing air temperatures at high latitudes. Temperature is a key controlling factor in the terrestrial exchange of CO2 and methane, and therefore the greenhouse-gas balance of the Arctic. Despite the large potential for feedbacks, many studies do not connect the diminishing sea-ice extent with changes in the interaction of the marine and terrestrial Arctic with the atmosphere. In this Review, we assess how current understanding of the Arctic Ocean and high-latitude ecosystems can be used to predict the impact of a lower sea-ice cover on Arctic greenhouse-gas exchange.

  5. Filamentous phages prevalent in Pseudoalteromonas spp. confer properties advantageous to host survival in Arctic sea ice

    PubMed Central

    Yu, Zi-Chao; Chen, Xiu-Lan; Shen, Qing-Tao; Zhao, Dian-Li; Tang, Bai-Lu; Su, Hai-Nan; Wu, Zhao-Yu; Qin, Qi-Long; Xie, Bin-Bin; Zhang, Xi-Ying; Yu, Yong; Zhou, Bai-Cheng; Chen, Bo; Zhang, Yu-Zhong

    2015-01-01

    Sea ice is one of the most frigid environments for marine microbes. In contrast to other ocean ecosystems, microbes in permanent sea ice are space confined and subject to many extreme conditions, which change on a seasonal basis. How these microbial communities are regulated to survive the extreme sea ice environment is largely unknown. Here, we show that filamentous phages regulate the host bacterial community to improve survival of the host in permanent Arctic sea ice. We isolated a filamentous phage, f327, from an Arctic sea ice Pseudoalteromonas strain, and we demonstrated that this type of phage is widely distributed in Arctic sea ice. Growth experiments and transcriptome analysis indicated that this phage decreases the host growth rate, cell density and tolerance to NaCl and H2O2, but enhances its motility and chemotaxis. Our results suggest that the presence of the filamentous phage may be beneficial for survival of the host community in sea ice in winter, which is characterized by polar night, nutrient deficiency and high salinity, and that the filamentous phage may help avoid over blooming of the host in sea ice in summer, which is characterized by polar day, rich nutrient availability, intense radiation and high concentration of H2O2. Thus, while they cannot kill the host cells by lysing them, filamentous phages confer properties advantageous to host survival in the Arctic sea ice environment. Our study provides a foremost insight into the ecological role of filamentous phages in the Arctic sea ice ecosystem. PMID:25303713

  6. Filamentous phages prevalent in Pseudoalteromonas spp. confer properties advantageous to host survival in Arctic sea ice.

    PubMed

    Yu, Zi-Chao; Chen, Xiu-Lan; Shen, Qing-Tao; Zhao, Dian-Li; Tang, Bai-Lu; Su, Hai-Nan; Wu, Zhao-Yu; Qin, Qi-Long; Xie, Bin-Bin; Zhang, Xi-Ying; Yu, Yong; Zhou, Bai-Cheng; Chen, Bo; Zhang, Yu-Zhong

    2015-03-17

    Sea ice is one of the most frigid environments for marine microbes. In contrast to other ocean ecosystems, microbes in permanent sea ice are space confined and subject to many extreme conditions, which change on a seasonal basis. How these microbial communities are regulated to survive the extreme sea ice environment is largely unknown. Here, we show that filamentous phages regulate the host bacterial community to improve survival of the host in permanent Arctic sea ice. We isolated a filamentous phage, f327, from an Arctic sea ice Pseudoalteromonas strain, and we demonstrated that this type of phage is widely distributed in Arctic sea ice. Growth experiments and transcriptome analysis indicated that this phage decreases the host growth rate, cell density and tolerance to NaCl and H2O2, but enhances its motility and chemotaxis. Our results suggest that the presence of the filamentous phage may be beneficial for survival of the host community in sea ice in winter, which is characterized by polar night, nutrient deficiency and high salinity, and that the filamentous phage may help avoid over blooming of the host in sea ice in summer, which is characterized by polar day, rich nutrient availability, intense radiation and high concentration of H2O2. Thus, while they cannot kill the host cells by lysing them, filamentous phages confer properties advantageous to host survival in the Arctic sea ice environment. Our study provides a foremost insight into the ecological role of filamentous phages in the Arctic sea ice ecosystem.

  7. Response of Arctic sea level and hydrography to hydrological regime change over boreal catchments

    NASA Astrophysics Data System (ADS)

    Tourian, Mohammad J.; Sneeuw, Nico; Losch, Martin; Rabe, Benjamin

    2016-04-01

    Changes in freshwater influx into the Arctic Ocean are a key driver of regional dynamics and sea level change in the Arctic waters. Low-salinity surface waters maintain a strong stratification in the Arctic. This halocline largely shields the cool polar surface water and sea ice from the warmer waters of Atlantic origin below and, hence, inhibits vertical heat fluxes of heat, salt and nutrients. Recently observed changes in the freshwater content of the upper Arctic Ocean raise the question of the effect of these changes on the region. Changes in the freshwater budget affect regional steric sea level, but also the modified ocean dynamics may change sea level through mass transports within the Arctic. One component of the freshwater budget is continental runoff. The hydrological regime of river runoff appears to be non-stationary. There is both interannual variability and a significantly positive trend since the 1970s. The decreasing Arctic sea-ice cover may be a possible reason for the non-stationary behavior of runoff, especially in coastal and marginal seas. The decrease of sea ice due to global warming would lead to cloud formation and, indeed, increased precipitation. During the warmer season, increased precipitation would lead to more discharge of freshwater to the Arctic shelves and basins. The observational record of discharge into the Arctic Ocean, however, is still too sparse to address important science questions about the long-term behavior and development of Arctic sea level and climate. Given the insufficient monitoring from in situ gauge networks, and without any outlook of improvement, spaceborne approaches are currently being investigated. In this contribution we assess the long-term behavior of monthly runoff time series obtained from hydro-geodetic approaches and explore the effects of interannual runoff variability and long term trends on ocean model simulations.

  8. Analysis of the Warmest Arctic Winter, 2015-2016

    NASA Technical Reports Server (NTRS)

    Cullather, Richard I.; Lim, Young-Kwon; Boisvert, Linette N.; Brucker, Ludovic; Lee, Jae N.; Nowicki, Sophie M. J.

    2016-01-01

    December through February 2015-2016 defines the warmest winter season over the Arctic in the observational record. Positive 2m temperature anomalies were focused over regions of reduced sea ice cover in the Kara and Barents Seas and southwestern Alaska. A third region is found over the ice-covered central Arctic Ocean. The period is marked by a strong synoptic pattern which produced melting temperatures in close proximity to the North Pole in late December and anomalous high pressure near the Taymyr Peninsula. Atmospheric teleconnections from the Atlantic contributed to warming over Eurasian high-latitude land surfaces, and El Niño-related teleconnections explain warming over southwestern Alaska and British Columbia, while warm anomalies over the central Arctic are associated with physical processes including the presence of enhanced atmospheric water vapor and an increased downwelling longwave radiative flux. Preconditioning of sea ice conditions by warm temperatures affected the ensuing spring extent.

  9. Analysis of the warmest Arctic winter, 2015-2016

    NASA Astrophysics Data System (ADS)

    Cullather, Richard I.; Lim, Young-Kwon; Boisvert, Linette N.; Brucker, Ludovic; Lee, Jae N.; Nowicki, Sophie M. J.

    2016-10-01

    December through February 2015-2016 defines the warmest winter season over the Arctic in the observational record. Positive 2 m temperature anomalies were focused over regions of reduced sea ice cover in the Kara and Barents Seas and southwestern Alaska. A third region is found over the ice-covered central Arctic Ocean. The period is marked by a strong synoptic pattern which produced melting temperatures in close proximity to the North Pole in late December and anomalous high pressure near the Taymyr Peninsula. Atmospheric teleconnections from the Atlantic contributed to warming over Eurasian high-latitude land surfaces, and El Niño-related teleconnections explain warming over southwestern Alaska and British Columbia, while warm anomalies over the central Arctic are associated with physical processes including the presence of enhanced atmospheric water vapor and an increased downwelling longwave radiative flux. Preconditioning of sea ice conditions by warm temperatures affected the ensuing spring extent.

  10. Sensitivity of Arctic warming to sea ice concentration

    NASA Astrophysics Data System (ADS)

    Yim, Bo Young; Min, Hong Sik; Kim, Baek-Min; Jeong, Jee-Hoon; Kug, Jong-Seong

    2016-06-01

    We examine the sensitivity of Arctic amplification (AA) to background sea ice concentration (SIC) under greenhouse warming by analyzing the data sets of the historical and Representative Concentration Pathway 8.5 runs of the Coupled Model Intercomparison Project Phase 5. To determine whether the sensitivity of AA for a given radiative forcing depends on background SIC state, we examine the relationship between the AA trend and mean SIC on moving 30 year windows from 1960 to 2100. It is found that the annual mean AA trend varies depending on the mean SIC condition. In particular, some models show a highly variable AA trend in relation to the mean SIC clearly. In these models, the AA trend tends to increase until the mean SIC reaches a critical level (i.e., 20-30%), and the maximum AA trend is almost 3 to 5 times larger than the trend in the early stage of global warming (i.e., 50-60%, 60-70%). However, the AA trend tends to decrease after that. Further analysis shows that the sensitivity of AA trend to mean SIC condition is closely related to the feedback processes associated with summer surface albedo and winter turbulent heat flux in the Arctic Ocean.

  11. Sediments in Arctic sea ice: Implications for entrainment, transport and release

    USGS Publications Warehouse

    Nurnberg, D.; Wollenburg, I.; Dethleff, D.; Eicken, H.; Kassens, H.; Letzig, T.; Reimnitz, E.; Thiede, Jorn

    1994-01-01

    Despite the Arctic sea ice cover's recognized sensitivity to environmental change, the role of sediment inclusions in lowering ice albedo and affecting ice ablation is poorly understood. Sea ice sediment inclusions were studied in the central Arctic Ocean during the Arctic 91 expedition and in the Laptev Sea (East Siberian Arctic Region Expedition 1992). Results from these investigations are here combined with previous studies performed in major areas of ice ablation and the southern central Arctic Ocean. This study documents the regional distribution and composition of particle-laden ice, investigates and evaluates processes by which sediment is incorporated into the ice cover, and identifies transport paths and probable depositional centers for the released sediment. In April 1992, sea ice in the Laptev Sea was relatively clean. The sediment occasionally observed was distributed diffusely over the entire ice column, forming turbid ice. Observations indicate that frazil and anchor ice formation occurring in a large coastal polynya provide a main mechanism for sediment entrainment. In the central Arctic Ocean sediments are concentrated in layers within or at the surface of ice floes due to melting and refreezing processes. The surface sediment accumulation in central Arctic multi-year sea ice exceeds by far the amounts observed in first-year ice from the Laptev Sea in April 1992. Sea ice sediments are generally fine grained, although coarse sediments and stones up to 5 cm in diameter are observed. Component analysis indicates that quartz and clay minerals are the main terrigenous sediment particles. The biogenous components, namely shells of pelecypods and benthic foraminiferal tests, point to a shallow, benthic, marine source area. Apparently, sediment inclusions were resuspended from shelf areas before and incorporated into the sea ice by suspension freezing. Clay mineralogy of ice-rafted sediments provides information on potential source areas. A smectite

  12. Revisiting Observations of Arctic Sea-ice Motion and Deformation To Investigate Bounds of Sea-ice Variability.

    NASA Astrophysics Data System (ADS)

    Heil, P.

    The Arctic sea ice is an important part of the northern polar climate system. Individual records of sea-ice drift in the Arctic were obtained through the last century. Observa- tions with high spatial or temporal coverage start in the 1970's when remote observa- tions of sea-ice motion are available from satellite-based instruments and in situ from drifting buoys. In the climatology of Arctic sea-ice drift the clockwise Beaufort Gyre, a northward motion off the Siberian Coast, and a south-eastward drift from the North Pole towards Fram Strait, have been identified. During recent decades this picture of Arctic ice motion has shifted away from the baseline state in response to changed at- mospheric conditions. Here we investigate high-resolution time-series of ice motion derived from IABP drifting buoys to identify further patterns of preferred ice motion in the Arctic. These can be associated with atmospheric regimes by correlating the two- dimensional variance of the buoy-derived ice velocities with the horizontal gradient of the mean sea-level pressure. Changes in the spatial pattern of regional meander coeffi- cients for the sea-ice motion provide further evidence for repeated transitions between patterns of ice motion in dependence to the atmospheric forcing. This is supported by dynamic frequency spectra of sea-ice divergence, which suggest damping of subdaily deformation cycles during low AO years. For regions with persistent buoy coverage (e.g., the western Arctic) time-series of sea-ice motion and deformation characteris- tics have been constructed. The identification of a dominant spatial pattern of sea-ice motion and deformation in response to changing atmospheric forcing is then used to explain the variability seen in Arctic ice extent and volume.

  13. Eastern-western Arctic sea ice analysis, 1993

    SciTech Connect

    1993-12-31

    This publication is the 20th edition of the annual Arctic sea-ice atlases prepared by the JIC. The atlas contains weekly charts depicting Northern Hemisphere ice conditions and extent. The significant use of high resolution satellite imagery, combined with valuable ice reconnaissance data from various sources, has greatly improved the accuracy of these analyses. The purpose of this atlas is to provide the user with reliable weekly hemispheric ice analyses. These charts are prepared by experienced Navy and NOAA ice analysts who plot and evaluate numerous data sources: (a) Conventional shore station, ship, and aerial reconnaissance observations; and (b) Satellite data from various sensors. Table I, located on the inside back cover, lists these sensors and their availability. A final product is synthesized from the inputs described above. When insufficient data is available, estimated boundaries are plotted, using meteorological data and computer generated ice drift vectors to determine estimated ice position.

  14. SEA-ICE INFLUENCE ON ARCTIC COASTAL RETREAT.

    USGS Publications Warehouse

    Reimnitz, Erk; Barnes, P.W.

    1987-01-01

    Recent studies document the effectiveness of sea ice in reshaping the seafloor of the inner shelf into sharp-relief features, including ice gouges with jagged flanking ridges, ice-wallow relief, and 2- to 6-m-deep strudel-scour craters. These ice-related relief forms are in disequilibrium with classic open-water hydraulic processes and thus are smoothed over by waves and currents in one to two years. Such alternate reworking of the shelf by ice and currents - two diverse types of processes, which in the case of ice wallow act in unison-contributes to sediment mobility and, thus, to sediment loss from the coast and inner shelf. The bulldozing action by ice results in coast-parallel sediment displacement. Additionally, suspension of sediment by frazil and anchor ice, followed by ice rafting, can move large amounts of bottom-derived materials. Our understanding of all these processes is insufficient to model Arctic coastal processes.

  15. Influence of Sea Ice on Arctic Marine Sulfur Biogeochemistry in the Community Climate System Model

    SciTech Connect

    Deal, Clara; Jin, Meibing

    2013-06-30

    Global climate models (GCMs) have not effectively considered how responses of arctic marine ecosystems to a warming climate will influence the global climate system. A key response of arctic marine ecosystems that may substantially influence energy exchange in the Arctic is a change in dimethylsulfide (DMS) emissions, because DMS emissions influence cloud albedo. This response is closely tied to sea ice through its impacts on marine ecosystem carbon and sulfur cycling, and the ice-albedo feedback implicated in accelerated arctic warming. To reduce the uncertainty in predictions from coupled climate simulations, important model components of the climate system, such as feedbacks between arctic marine biogeochemistry and climate, need to be reasonably and realistically modeled. This research first involved model development to improve the representation of marine sulfur biogeochemistry simulations to understand/diagnose the control of sea-ice-related processes on the variability of DMS dynamics. This study will help build GCM predictions that quantify the relative current and possible future influences of arctic marine ecosystems on the global climate system. Our overall research objective was to improve arctic marine biogeochemistry in the Community Climate System Model (CCSM, now CESM). Working closely with the Climate Ocean Sea Ice Model (COSIM) team at Los Alamos National Laboratory (LANL), we added 1 sea-ice algae and arctic DMS production and related biogeochemistry to the global Parallel Ocean Program model (POP) coupled to the LANL sea ice model (CICE). Both CICE and POP are core components of CESM. Our specific research objectives were: 1) Develop a state-of-the-art ice-ocean DMS model for application in climate models, using observations to constrain the most crucial parameters; 2) Improve the global marine sulfur model used in CESM by including DMS biogeochemistry in the Arctic; and 3) Assess how sea ice influences DMS dynamics in the arctic marine

  16. Community-based sea ice thickness observatories in the Arctic

    NASA Astrophysics Data System (ADS)

    Gearheard, S.; Mahoney, A. R.; Huntington, H.; Oshima, T.; Qillaq, T.; Barry, R. G.

    2007-12-01

    The thickness of sea ice is a fundamental diagnostic variable for assessing the state of the ice cover. At the scale of the Arctic Basin, the ice thickness distribution determines the volume of the ice pack and its susceptibility to a warming climate as well as affecting the exchange of heat between the ocean and atmosphere. At the local scale, it dictates where and when it is safe to travel on the ice or through the water. Measuring the thickness of sea ice is challenging both technically and logistically and any measurement program strikes a balance between cost and coverage accordingly. Accurately measuring the thickness of large areas of sea ice generally requires airplanes, ice breakers or submarines and electromagnetic or acoustic devices. In this study, we use one of the least technical methods combined with support from remote communities to establish a set of sea ice observation stations in Barrow (Alaska), Clyde River (Baffin Island, Nunavut) and Qaanaaq (northwest Greenland). We employ hunters from these communities, who are experts in traveling and working on the ice, and train them to deploy ice observation stations and take measurements. Each station consists of snow stakes and hot-wire ice thickness gauges and the local observers take measurements on a weekly basis. Involvement of the community is fundamental to the success of these measurement programs and ensures the data collected are relevant to the local use of the sea ice. Community elders and hunters chose the station locations according to where they hunt and travel and to be representative of local variability. As partners in research, the scientists and local hunters are able to share and synthesize their knowledge; the scientific community gains a better understanding of the extraordinary depth of traditional knowledge and the communities improve their understanding of global changes and ability to adapt. Here we present data from observation stations near Clyde River and Qaanaaq. At Clyde

  17. Shallow methylmercury production in the marginal sea ice zone of the central Arctic Ocean.

    PubMed

    Heimbürger, Lars-Eric; Sonke, Jeroen E; Cossa, Daniel; Point, David; Lagane, Christelle; Laffont, Laure; Galfond, Benjamin T; Nicolaus, Marcel; Rabe, Benjamin; van der Loeff, Michiel Rutgers

    2015-05-20

    Methylmercury (MeHg) is a neurotoxic compound that threatens wildlife and human health across the Arctic region. Though much is known about the source and dynamics of its inorganic mercury (Hg) precursor, the exact origin of the high MeHg concentrations in Arctic biota remains uncertain. Arctic coastal sediments, coastal marine waters and surface snow are known sites for MeHg production. Observations on marine Hg dynamics, however, have been restricted to the Canadian Archipelago and the Beaufort Sea (<79 °N). Here we present the first central Arctic Ocean (79-90 °N) profiles for total mercury (tHg) and MeHg. We find elevated tHg and MeHg concentrations in the marginal sea ice zone (81-85 °N). Similar to other open ocean basins, Arctic MeHg concentration maxima also occur in the pycnocline waters, but at much shallower depths (150-200 m). The shallow MeHg maxima just below the productive surface layer possibly result in enhanced biological uptake at the base of the Arctic marine food web and may explain the elevated MeHg concentrations in Arctic biota. We suggest that Arctic warming, through thinning sea ice, extension of the seasonal sea ice zone, intensified surface ocean stratification and shifts in plankton ecodynamics, will likely lead to higher marine MeHg production.

  18. Shallow methylmercury production in the marginal sea ice zone of the central Arctic Ocean

    PubMed Central

    Heimbürger, Lars-Eric; Sonke, Jeroen E.; Cossa, Daniel; Point, David; Lagane, Christelle; Laffont, Laure; Galfond, Benjamin T.; Nicolaus, Marcel; Rabe, Benjamin; van der Loeff, Michiel Rutgers

    2015-01-01

    Methylmercury (MeHg) is a neurotoxic compound that threatens wildlife and human health across the Arctic region. Though much is known about the source and dynamics of its inorganic mercury (Hg) precursor, the exact origin of the high MeHg concentrations in Arctic biota remains uncertain. Arctic coastal sediments, coastal marine waters and surface snow are known sites for MeHg production. Observations on marine Hg dynamics, however, have been restricted to the Canadian Archipelago and the Beaufort Sea (<79°N). Here we present the first central Arctic Ocean (79–90°N) profiles for total mercury (tHg) and MeHg. We find elevated tHg and MeHg concentrations in the marginal sea ice zone (81–85°N). Similar to other open ocean basins, Arctic MeHg concentration maxima also occur in the pycnocline waters, but at much shallower depths (150–200 m). The shallow MeHg maxima just below the productive surface layer possibly result in enhanced biological uptake at the base of the Arctic marine food web and may explain the elevated MeHg concentrations in Arctic biota. We suggest that Arctic warming, through thinning sea ice, extension of the seasonal sea ice zone, intensified surface ocean stratification and shifts in plankton ecodynamics, will likely lead to higher marine MeHg production. PMID:25993348

  19. Quaternary Sea-ice history in the Arctic Ocean based on a new Ostracode sea-ice proxy

    USGS Publications Warehouse

    Cronin, T. M.; Gemery, L.; Briggs, W.M.; Jakobsson, M.; Polyak, L.; Brouwers, E.M.

    2010-01-01

    Paleo-sea-ice history in the Arctic Ocean was reconstructed using the sea-ice dwelling ostracode Acetabulastoma arcticum from late Quaternary sediments from the Mendeleyev, Lomonosov, and Gakkel Ridges, the Morris Jesup Rise and the Yermak Plateau. Results suggest intermittently high levels of perennial sea ice in the central Arctic Ocean during Marine Isotope Stage (MIS) 3 (25-45 ka), minimal sea ice during the last deglacial (16-11 ka) and early Holocene thermal maximum (11-5 ka) and increasing sea ice during the mid-to-late Holocene (5-0 ka). Sediment core records from the Iceland and Rockall Plateaus show that perennial sea ice existed in these regions only during glacial intervals MIS 2, 4, and 6. These results show that sea ice exhibits complex temporal and spatial variability during different climatic regimes and that the development of modern perennial sea ice may be a relatively recent phenomenon. ?? 2010.

  20. Arctic dipole anomaly and its contribution to sea ice export from the Arctic Ocean in the 20th century

    NASA Astrophysics Data System (ADS)

    Watanabe, Eiji; Wang, Jia; Sumi, Akimasa; Hasumi, Hiroyasu

    2006-12-01

    The winter dipole anomaly (DA) in the Arctic atmosphere and its contribution to sea ice export are investigated by using a high-resolution coupled global general circulation model. The spatial distributions of the first two leading EOF modes of winter mean sea level pressure (SLP) and geopotential height at 500 hPa north of 70°N obtained by the long-term simulation (1900-2010) are highly similar to those derived from the National Center for Environmental Prediction and the National Center for the Atmospheric Research (NCEP/NCAR) reanalysis datasets (1948-2004). The first-leading mode corresponds to the Arctic Oscillation (AO). The DA is defined as the second-leading mode. The AO and DA account for 59% and 19% of the total variance, respectively. Composite spatial patterns of SLP, sea ice thickness and velocity in the extreme years when both the absolute values of principal component (PC1 and PC2) exceed 1.0 standard deviation indicate that the DA plays a great important role in sea ice export from the Arctic Ocean to the Greenland Sea due to its strong meridionality. Sea ice export is highly promoted (restricted) in the positive (negative) DA phase. The dependence of sea ice export on the DA is comparable to or rather larger than that on the AO.