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Sample records for naturener glacier wind

  1. 78 FR 26770 - NaturEner Wind Watch, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission NaturEner Wind Watch, LLC; Supplemental Notice That Initial Market-Based... above-referenced proceeding of NaturEner Wind Watch, LLC's application for market-based rate...

  2. 76 FR 69720 - NaturEner Rim Rock Wind Energy, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission NaturEner Rim Rock Wind Energy, LLC; Supplemental Notice That Initial Market... in the above-referenced proceeding of NaturEner Rim Rock Wind Energy, LLC's application for...

  3. 76 FR 62791 - Combined Notice of Filings #2

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-11

    ..., October 19, 2011. Docket Numbers: ER11-4666-000. Applicants: NaturEner Glacier Wind Energy 1, LLC. Description: NaturEner Glacier Wind Energy 1, LLC submits tariff filing per 35.1: Baseline Filing of Market.... Applicants: NaturEner Glacier Wind Energy 2, LLC. Description: NaturEner Glacier Wind Energy 2, LLC...

  4. 77 FR 62504 - Combined Notice of Filings #1

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-15

    ...-001. Applicants: NaturEner Glacier Wind Energy 1, LLC, NaturEner Glacier Wind Energy 2, LLC, NaturEner...Ener Glacier Wind Energy 1, LLC, et al. Filed Date: 10/1/12. Accession Number: 20121001-5470....

  5. Glaciers

    NASA Astrophysics Data System (ADS)

    Hambrey, Michael; Alean, Jürg

    2004-12-01

    Glaciers are among the most beautiful natural wonders on Earth, as well as the least known and understood, for most of us. Michael Hambrey describes how glaciers grow and decay, move and influence human civilization. Currently covering a tenth of the Earth's surface, glacier ice has shaped the landscape over millions of years by scouring away rocks and transporting and depositing debris far from its source. Glacier meltwater drives turbines and irrigates deserts, and yields mineral-rich soils as well as a wealth of valuable sand and gravel. However, glaciers also threaten human property and life. Our future is indirectly connected with the fate of glaciers and their influence on global climate and sea level. Including over 200 stunning photographs, the book takes the reader from the High-Arctic through North America, Europe, Asia, Africa, New Zealand and South America to the Antarctic. Michael Hambrey is Director of the Centre for Glaciology at the University of Wales, Aberystwyth. A past recipient of the Polar Medal, he was also given the Earth Science Editors' Outstanding Publication Award for the first edition of Glaciers (Cambridge, 1995). Hambrey is also the author of Glacial Environments (British Columbia, 1994). JÜrg Alean is Professor of Geography at the Kantonsschule ZÜrcher Unterland in BÜlach, Switzerland.

  6. GLACIER VARIABILITY IN WYOMING’S WIND RIVER RANGE AND TETON RANGE

    NASA Astrophysics Data System (ADS)

    Thompson, D.; Bell, J. E.; Edmunds, J.; Tootle, G. A.; Kerr, G.

    2009-12-01

    The Wind River Range (WRR) in west central Wyoming is host to 63 glaciers, while the Teton Range (TR) is host to 10 named glaciers. These glaciers serve as natural water reservoirs, and the continued recession of glaciers will impact agricultural water supply in the region. Glacier area changes in the WRR were estimated for 44 glaciers using un-rectified high resolution (1 m) aerial photography from 1966 to 2006. Additionally, glacier area was also developed for ten of the 44 glaciers using resampled aerial photography at 10 m (SPOT), 15 m (ASTER), 22.5 m (IRS-LISS) and 30 m (Landsat) resolutions for 1966 and 2006. The total surface area of the 44 glaciers was calculated to be 45.9 ± 0.13 km2 in 1966 and 28.5 ± 0.11 km2 in 2006, an average decrease of 38% over the 40 year period. Small glaciers experienced noticeably more area reduction than large glaciers. Of the 44 glaciers analyzed, 22 had an area of greater than 0.5 km2 in 1966, while 22 were less than 0.5 km2 in 1966. The glaciers with a surface area less than 0.5 km2 experienced an average surface area loss (fraction of 1966 surface area) of 47%, while the larger glaciers (greater than 0.5 km2) experienced an average surface area loss of 36% in 2006. Of the ten glaciers analyzed by resampling, the total surface area (fraction of 1966 surface area) decreased by 36.8% using aerial photographs, 36.5% using SPOT images, 36.6% using ASTER images, 36.0% using IRS-LISS images and 37.1% using Landsat images. Glacier area changes in the TR were estimated for three glaciers using un-rectified aerial photography from 1967 to 2006. The total surface area of the three glaciers was calculated to be 0.53 ± 0.13 km2 in 1967 and 0.40 ± 0.10 km2 in 2006, an average decrease of 34% over the 39 year period. The smallest glacier Teepe experienced the most noticeable lost, losing 60% while the Teton glacier lost 17%. Applying area-volume scaling relationships for Teton, Middle Teton, and Teepe glaciers, volume loss was

  7. 77 FR 48509 - Combined Notice of Filings #3

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-14

    ... following electric rate filings: Docket Numbers: ER12-2057-000. Applicants: NaturEner Glacier Wind Energy 1, LLC. Description: Amendment to Filing of NaturEner Glacier Wind Energy 1, LLC. Filed Date:...

  8. 77 FR 38044 - Combined Notice of Filings #1

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-26

    ...: 5 p.m. ET 7/9/12. Docket Numbers: EG12-79-000. Applicants: NaturEner Glacier Wind Energy 1, LLC. Description: Notice of Self-Certification of Exempt Wholesale Generator Status of NaturEner Glacier Wind.... Comments Due: 5 p.m. ET 7/9/12. Docket Numbers: ER12-2057-000. Applicants: NaturEner Glacier Wind Energy...

  9. 78 FR 64488 - Combined Notice of Filings #2

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-29

    ...: 20131017-5104. Comments Due: 5 p.m. ET 11/7/13. Docket Numbers: ER14-118-000. Applicants: NaturEner Glacier Wind Energy 1, LLC. Description: NaturEner Glacier Wind Energy 1, LLC submits tariff filing per...

  10. A study of turbulent fluxes and their measurement errors for different wind regimes over the tropical Zongo glacier (16° S) during the dry season

    NASA Astrophysics Data System (ADS)

    Litt, M.; Sicart, J.-E.; Helgason, W.

    2015-01-01

    Over glaciers in the outer tropics, during the dry winter season, turbulent fluxes are an important sink of melt energy due to high sublimation rates, but measurements in stable surface layers, in remote and complex terrains remain challenging. Eddy-covariance (EC) and bulk-aerodynamic (BA) methods were used to estimate surface turbulent heat fluxes of sensible (H) and latent heat (LE) in the ablation zone of the tropical Zongo glacier, Bolivia (16° S, 5080 m a.s.l.), from 22 July to 1 September 2007. We studied the turbulent fluxes and their associated random and systematic measurement errors under the three most frequent wind regimes. For nightly, density-driven katabatic flows, and for strong downslope flows related to large-scale forcing, H generally heats the surface (i.e., is positive), while LE cools it down (i.e., is negative). On average, both fluxes exhibit similar magnitudes and cancel each other out. Most energy losses through turbulence occur for daytime upslope flows, when H is weak due to small temperature gradients and LE is strongly negative due to very dry air. Mean random errors of the BA method (6% on net H + LE fluxes) originated mainly from large uncertainties in roughness lengths. For EC fluxes, mean random errors were due mainly to poor statistical sampling of large-scale outer-layer eddies (12%). The BA method is highly sensitive to the method used to derive surface temperature from long-wave radiation measurements and underestimates fluxes due to vertical flux divergence at low heights and nonstationarity of turbulent flow. The EC method also probably underestimates the fluxes, but to a lesser extent, due to underestimation of vertical wind speed and to vertical flux divergence. For both methods, when H and LE compensate each other in downslope fluxes, biases tend to cancel each other out or remain small. When the net turbulent fluxes (H + LE) are the largest in upslope flows, nonstationarity effects and underestimations of the vertical

  11. A study of turbulent fluxes and their measurement errors for different wind regimes over the tropical Zongo Glacier (16° S) during the dry season

    NASA Astrophysics Data System (ADS)

    Litt, M.; Sicart, J.-E.; Helgason, W.

    2015-08-01

    Over glaciers in the outer tropics, during the dry winter season, turbulent fluxes are an important sink of melt energy due to high sublimation rates, but measurements in stable surface layers in remote and complex terrains remain challenging. Eddy-covariance (EC) and bulk-aerodynamic (BA) methods were used to estimate surface turbulent heat fluxes of sensible (H) and latent heat (LE) in the ablation zone of the tropical Zongo Glacier, Bolivia (16° S, 5080 m a.s.l.), from 22 July to 1 September 2007. We studied the turbulent fluxes and their associated random and systematic measurement errors under the three most frequent wind regimes. For nightly, density-driven katabatic flows, and for strong downslope flows related to large-scale forcing, H generally heats the surface (i.e. is positive), while LE cools it down (i.e. is negative). On average, both fluxes exhibit similar magnitudes and cancel each other out. Most energy losses through turbulence occur for daytime upslope flows, when H is weak due to small temperature gradients and LE is strongly negative due to very dry air. Mean random errors of the BA method (6 % on net H + LE fluxes) originated mainly from large uncertainties in roughness lengths. For EC fluxes, mean random errors were due mainly to poor statistical sampling of large-scale outer-layer eddies (12 %). The BA method is highly sensitive to the method used to derive surface temperature from longwave radiation measurements and underestimates fluxes due to vertical flux divergence at low heights and nonstationarity of turbulent flow. The EC method also probably underestimates the fluxes, albeit to a lesser extent, due to underestimation of vertical wind speed and to vertical flux divergence. For both methods, when H and LE compensate each other in downslope fluxes, biases tend to cancel each other out or remain small. When the net turbulent fluxes (H + LE) are the largest in upslope flows, nonstationarity effects and underestimations of the vertical

  12. Alaska Glaciers and Rivers

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image on October 7, 2007, showing the Alaska Mountains of south-central Alaska already coated with snow. Purple shadows hang in the lee of the peaks, giving the snow-clad land a crumpled appearance. White gives way to brown on the right side of the image where the mountains yield to the lower-elevation Susitna River Valley. The river itself cuts a silver, winding path through deep green forests and brown wetlands and tundra. Extending from the river valley, are smaller rivers that originated in the Alaska Mountains. The source of these rivers is evident in the image. Smooth white tongues of ice extend into the river valleys, the remnants of the glaciers that carved the valleys into the land. Most of the water flowing into the Gulf of Alaska from the Susitna River comes from these mountain glaciers. Glacier melt also feeds glacier lakes, only one of which is large enough to be visible in this image. Immediately left of the Kahiltna River, the aquamarine waters of Chelatna Lake stand out starkly against the brown and white landscape.

  13. Glacier microseismicity

    USGS Publications Warehouse

    West, Michael E.; Larsen, Christopher F.; Truffer, Martin; O'Neel, Shad; LeBlanc, Laura

    2010-01-01

    We present a framework for interpreting small glacier seismic events based on data collected near the center of Bering Glacier, Alaska, in spring 2007. We find extremely high microseismicity rates (as many as tens of events per minute) occurring largely within a few kilometers of the receivers. A high-frequency class of seismicity is distinguished by dominant frequencies of 20–35 Hz and impulsive arrivals. A low-frequency class has dominant frequencies of 6–15 Hz, emergent onsets, and longer, more monotonic codas. A bimodal distribution of 160,000 seismic events over two months demonstrates that the classes represent two distinct populations. This is further supported by the presence of hybrid waveforms that contain elements of both event types. The high-low-hybrid paradigm is well established in volcano seismology and is demonstrated by a comparison to earthquakes from Augustine Volcano. We build on these parallels to suggest that fluid-induced resonance is likely responsible for the low-frequency glacier events and that the hybrid glacier events may be caused by the rush of water into newly opening pathways.

  14. Jakobshavn Glacier

    Atmospheric Science Data Center

    2013-04-17

    article title:  Greenland's Coast in Holiday Colors     View ... the area surrounding the Jakobshavn Glacier on the western coast of Greenland. The image is a false-color (near-infrared, green, blue) ... the ocean currents and pose hazards for shipping along the coast. The Multi-angle Imaging SpectroRadiometer (MISR) views the daylit ...

  15. Pine Island Glacier, Antarctica

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This pair of MISR images of the Pine Island Glacier in western Antarctica was acquired on December 12, 2000 during Terra orbit 5246. At left is a conventional, true-color image from the downward-looking (nadir) camera. The false-color image at right is a composite of red band data taken by the MISR forward 60-degree, nadir, and aftward 60-degree cameras, displayed in red, green, and blue colors, respectively. Color variations in the left (true-color) image highlight spectral differences. In the multi-angle composite, on the other hand, color variations act as a proxy for differences in the angular reflectance properties of the scene. In this representation, clouds show up as light purple. Blue to orange gradations on the surface indicate a transition in ice texture from smooth to rough. For example, the bright orange 'carrot-like' features are rough crevasses on the glacier's tongue. In the conventional nadir view, the blue ice labeled 'rough crevasses' and 'smooth blue ice' exhibit similar coloration, but the multi-angle composite reveals their different textures, with the smoother ice appearing dark purple instead of orange. This could be an indicator of different mechanisms by which this ice is exposed. The multi-angle view also reveals subtle roughness variations on the frozen sea ice between the glacier and the open water in Pine Island Bay.

    To the left of the 'icebergs' label are chunks of floating ice. Additionally, smaller icebergs embedded in the frozen sea ice are visible below and to the right of the label. These small icebergs are associated with dark streaks. Analysis of the illumination geometry suggests that these streaks are surface features, not shadows. Wind-driven motion and thinning of the sea ice in the vicinity of the icebergs is one possible explanation.

    Recently, Robert Bindschadler, a glaciologist at the NASA Goddard Space Flight Center discovered in Landsat 7 imagery a newly-formed crack traversing the Pine Island Glacier. This crack

  16. Antarctic Peninsula Tidewater Glacier Dynamics

    NASA Astrophysics Data System (ADS)

    Pettit, E. C.; Scambos, T. A.; Haran, T. M.; Wellner, J. S.; Domack, E. W.; Vernet, M.

    2015-12-01

    The northern Antarctic Peninsula (nAP, north of 66°S) is a north-south trending mountain range extending transverse across the prevailing westerly winds of the Southern Ocean resulting in an extreme west-to-east precipitation gradient. Snowfall on the west side of the AP is one to two orders of magnitude higher than the east side. This gradient drives short, steep, fast-flowing glaciers into narrow fjords on the west side, while longer lower-sloping glaciers flow down the east side into broader fjord valleys. This pattern in ice dynamics affects ice-ocean interaction on timescales of decades to centuries, and shapes the subglacial topography and submarine bathymetry on timescales of glacial cycles. In our study, we calculate ice flux for the western and eastern nAP using a drainage model that incorporates the modern ice surface topography, the RACMO-2 precipitation estimate, and recent estimates of ice thinning. Our results, coupled with observed rates of ice velocity from InSAR (I. Joughin, personal communication) and Landsat 8 -derived flow rates (this study), provide an estimate of ice thickness and fjord depth in grounded-ice areas for the largest outlet glaciers. East-side glaciers either still terminate in or have recently terminated in ice shelves. Sedimentary evidence from the inner fjords of the western glaciers indicates they had ice shelves during LIA time, and may still have transient floating ice tongues (tabular berg calvings are observed). Although direct oceanographic evidence is limited, the high accumulation rate and rapid ice flux implies cold basal ice for the western nAP glaciers and therefore weak subglacial discharge relative to eastern nAP glaciers and or other tidewater fjord systems such as in Alaska. Finally, despite lower accumulation rates on the east side, the large elongate drainage basins result in a greater ice flux funneled through fewer deeper glaciers. Due to the relation between ice flux and erosion, these east-side glaciers

  17. Alpine Glaciers

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 27 August 2003

    This image shows part of the western flank of Arsia Mons, the southernmost of the three great Tharsis Montes. The surface shows parallel ridges more reminiscent of a Zen garden than any typical geological feature. These ridges are not typical of lava flow fronts, so a different explanation has been proposed by Mars scientists. These ridges may instead be ancient signs of previously existing glaciers that formed high on the volcano's flank. As glaciers retreat with the seasons and shifting climate, they leave behind a mound of debris along their receding edge. Successive retreats can produce a series of parallel ridges similar to those seen here.

    Image information: VIS instrument. Latitude -6.9, Longitude 230.5 East (129.5 West). 19 meter/pixel resolution.

  18. 77 FR 56834 - Notice of Effectiveness of Exempt Wholesale Generator Status

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-14

    ... LLC. O.L.S. Energy-Agnews, Inc EG12-75-000 NRG Solar Avra Valley LLC EG12-76-000 Spearville 3, LLC EG12-77-000 NaturEner Rim Rock Wind Energy, LLC.... EG12-78-000 NaturEner Glacier Wind Energy 1, LLC... EG12-79-000 Flat Ridge 2 Wind Energy LLC EG12-80-000 Blue Sky East, LLC EG12-81-000 Meadow...

  19. Principles of Glacier Mechanics

    NASA Astrophysics Data System (ADS)

    Waddington, Edwin D.

    Glaciers are awesome in size and move at a majestic pace, and they frequently occupy spectacular mountainous terrain. Naturally, many Earth scientists are attracted to glaciers. Some of us are even fortunate enough to make a career of studying glacier flow. Many others work on the large, flat polar ice sheets where there is no scenery. As a leader of one of the foremost research projects now studying the flow of mountain glaciers (Storglaciaren, Norway), Roger Hooke is well qualified to describe the principles of glacier mechanics. Principles of Glacier Mechanics is written for upper-level undergraduate students and graduate students with an interest in glaciers and the landforms that glaciers produce. While most of the examples in the text are drawn from valley glacier studies, much of the material is also relevant to “glacier flatland” on the polar ice sheets.

  20. Glaciers of North America - Glaciers of Alaska

    USGS Publications Warehouse

    Molnia, Bruce F.

    2008-01-01

    Glaciers cover about 75,000 km2 of Alaska, about 5 percent of the State. The glaciers are situated on 11 mountain ranges, 1 large island, an island chain, and 1 archipelago and range in elevation from more than 6,000 m to below sea level. Alaska's glaciers extend geographically from the far southeast at lat 55 deg 19'N., long 130 deg 05'W., about 100 kilometers east of Ketchikan, to the far southwest at Kiska Island at lat 52 deg 05'N., long 177 deg 35'E., in the Aleutian Islands, and as far north as lat 69 deg 20'N., long 143 deg 45'W., in the Brooks Range. During the 'Little Ice Age', Alaska's glaciers expanded significantly. The total area and volume of glaciers in Alaska continue to decrease, as they have been doing since the 18th century. Of the 153 1:250,000-scale topographic maps that cover the State of Alaska, 63 sheets show glaciers. Although the number of extant glaciers has never been systematically counted and is thus unknown, the total probably is greater than 100,000. Only about 600 glaciers (about 1 percent) have been officially named by the U.S. Board on Geographic Names (BGN). There are about 60 active and former tidewater glaciers in Alaska. Within the glacierized mountain ranges of southeastern Alaska and western Canada, 205 glaciers (75 percent in Alaska) have a history of surging. In the same region, at least 53 present and 7 former large ice-dammed lakes have produced jokulhlaups (glacier-outburst floods). Ice-capped volcanoes on mainland Alaska and in the Aleutian Islands have a potential for jokulhlaups caused by subglacier volcanic and geothermal activity. Because of the size of the area covered by glaciers and the lack of large-scale maps of the glacierized areas, satellite imagery and other satellite remote-sensing data are the only practical means of monitoring regional changes in the area and volume of Alaska's glaciers in response to short- and long-term changes in the maritime and continental climates of the State. A review of the

  1. Glaciers of South America

    USGS Publications Warehouse

    Williams, Richard S.; Ferrigno, Jane G.

    1998-01-01

    Landsat images, together with maps and aerial photographs, have been used to produce glacier inventories, define glacier locations, and study glacier dynamics in the countries of South America, along with the Andes Mountains. In Venezuela, Colombia, Ecuador, and Bolivia, the small glaciers have been undergoing extensive glacier recession since the late 1800's. Glacier-related hazards (outburst floods, mud flows, and debris avalanches) occur in Colombia, in Ecuador, and associated with the more extensive (2,600 km2) glaciers of Peru. The largest area of glacier ice is found in Argentina and Chile, including the northern Patagonian ice field (about 4,200 km2) and the southern Patagonian ice field (about 13,000 km2), the largest glacier in the Southern Hemisphere outside Antarctica.

  2. Glaciers of Europe

    USGS Publications Warehouse

    Williams, Richard S.; Ferrigno, Jane G.

    1993-01-01

    ALPS: AUSTRIAN: An overview is provided on the occurrence of the glaciers in the Eastern Alps of Austria and on the climatic conditions in this area, Historical documents on the glaciers have been available since the Middle Ages. Special glaciological observations and topographic surveys of individual glaciers were initiated as early as 1846. Recent data in an inventory based on aerial photographs taken in 1969 show 925 glaciers in the Austrian Alps with a total area of 542 square kilometers. Present research topics include studies of mass and energy balance, relations of glaciers and climate, physical glaciology, a complete inventory of the glaciers, and testing of remote sensing methods. The location of the glacier areas is shown on Landsat multispectral scanner images; the improved capabilities of the Landsat thematic mapper are illustrated with an example from the Oztaler Alpen group. ALPS: SWISS: According to a glacier inventory published in 1976, which is based on aerial photography of 1973, there are 1,828 glacier units in the Swiss Alps that cover a total area of 1fl42 square kilometers. The Rhonegletscher, currently the ninth largest in the country, was one of the first to be studied in detail. Its surface has been surveyed repeatedly; velocity profiles were measured, and the fluctuations of its terminus were mapped and recorded from 1874 to 1914. Recent research on the glacier has included climatological, hydrological, and massbalance studies. Glaciological research has been conducted on various other glaciers in Switzerland concerning glacier hydrology, glacier hazards, fluctuations of glacier termini, ice mechanics, ice cores, and mass balance. Good maps are available showing the extent of glaciers from the latter decades of the 19th century. More recently, the entire country has been mapped at scales of 1:25,000, 1:50,000, 1:100,000, 1:200,000, and 1:500,000. The 1:25,000-scale series very accurately represents the glaciers as well as locates

  3. Pine Island Glacier

    Atmospheric Science Data Center

    2013-04-16

    article title:  Pine Island Glacier, Antarctica     View ... Imaging SpectroRadiometer (MISR) images of the Pine Island Glacier in western Antarctica was acquired on December 12, 2000 during ... sea ice between the glacier and the open water in Pine Island Bay. To the left of the "icebergs" label are chunks of floating ice. ...

  4. Glacier Ecosystems of Himalaya

    NASA Astrophysics Data System (ADS)

    Kohshima, S.; Yoshimura, Y.; Takeuchi, N.; Segawa, T.; Uetake, J.

    2012-12-01

    Biological activity on glaciers has been believed to be extremely limited. However, we found various biotic communities specialized to the glacier environment in various part of the world, such as Himalaya, Patagonia and Alaska. Some of these glacier hosted biotic communities including various cold-tolerant insects, annelids and copepods that were living in the glacier by feeding on algae and bacteria growing in the snow and ice. Thus, the glaciers are simple and relatively closed ecosystems sustained by the primary production in the snow and ice. In this presentation, we will briefly introduce glacier ecosystems in Himalaya; ecology and behavior of glacier animals, altitudinal zonation of snow algal communities, and the structure of their habitats in the glacier. Since the microorganisms growing on the glacier surface are stored in the glacial strata every year, ice-core samples contain many layers with these microorganisms. We showed that the snow algae in the ice-core are useful for ice core dating and could be new environmental signals for the studies on past environment using ice cores. These microorganisms in the ice core will be important especially in the studies of ice core from the glaciers of warmer regions, in which chemical and isotopic contents are often heavily disturbed by melt water percolation. Blooms of algae and bacteria on the glacier can reduce the surface albedo and significantly affect the glacier melting. For example, the surface albedo of some Himalayan glaciers was significantly reduced by a large amount of dark-colored biogenic material (cryoconite) derived from snow algae and bacteria. It increased the melting rates of the surfaces by as much as three-fold. Thus, it was suggested that the microbial activity on the glacier could affect the mass balance and fluctuation of the glaciers.

  5. Glaciers of Asia

    USGS Publications Warehouse

    Williams, Richard S., Jr.; Ferrigno, Jane G.

    2010-01-01

    This chapter is the ninth to be released in U.S. Geological Survey Professional Paper 1386, Satellite Image Atlas of Glaciers of the World, a series of 11 chapters. In each of the geographic area chapters, remotely sensed images, primarily from the Landsat 1, 2, and 3 series of spacecraft, are used to analyze the specific glacierized region of our planet under consideration and to monitor glacier changes. Landsat images, acquired primarily during the middle to late 1970s and early 1980s, were used by an international team of glaciologists and other scientists to study various geographic regions and (or) to discuss related glaciological topics. In each glacierized geographic region, the present areal distribution of glaciers is compared, wherever possible, with historical information about their past extent. The atlas provides an accurate regional inventory of the areal extent of glacier ice on our planet during the 1970s as part of a growing international scientific effort to measure global environmental change on the Earth?s surface. The chapter is divided into seven geographic parts and one topical part: Glaciers of the Former Soviet Union (F-1), Glaciers of China (F-2), Glaciers of Afghanistan (F?3), Glaciers of Pakistan (F-4), Glaciers of India (F-5), Glaciers of Nepal (F?6), Glaciers of Bhutan (F-7), and the Paleoenvironmental Record Preserved in Middle-Latitude, High-Mountain Glaciers (F-8). Each geographic section describes the glacier extent during the 1970s and 1980s, the benchmark time period (1972-1981) of this volume, but has been updated to include more recent information. Glaciers of the Former Soviet Union are located in the Russian Arctic and various mountain ranges of Russia and the Republics of Georgia, Kyrgyzstan, Tajikistan, and Kazakstun. The Glacier Inventory of the USSR and the World Atlas of Ice and Snow Resources recorded a total of 28,881 glaciers covering an area of 78,938 square kilometers (km2). China includes many of the mountain-glacier

  6. Afghanistan Glacier Diminution

    NASA Astrophysics Data System (ADS)

    Shroder, J. F.; Bishop, M.; Haritashya, U.; Olsenholler, J.

    2008-12-01

    Glaciers in Afghanistan represent a late summer - early fall source of melt water for late season crop irrigation in a chronically drought-torn region. Precise river discharge figures associated with glacierized drainage basins are generally unavailable because of the destruction of hydrological gauging stations built in pre-war times although historic discharge data and prior (1960s) mapped glacier regions offer some analytical possibilities. The best satellite data sets for glacier-change detection are declassified Cornona and Keyhole satellite data sets, standard Landsat sources, and new ASTER images assessed in our GLIMS (Global Land Ice Measurements from Space) Regional Center for Southwest Asia (Afghanistan and Pakistan). The new hyperspectral remote sensing survey of Afghanistan completed by the US Geological Survey and the Afghanistan Ministry of Mines offers potential for future detailed assessments. Long-term climate change in southwest Asia has decreased precipitation for millennia so that glaciers, rivers and lakes have all declined from prehistoric and historic highs. As many glaciers declined in ice volume, they increased in debris cover until they were entirely debris-covered or became rock glaciers, and the ice was protected thereby from direct solar radiation, to presumably reduce ablation rates. We have made a preliminary assessment of glacier location and extent for the country, with selected, more-detailed, higher-resolution studies underway. In the Great Pamir of the Wakhan Corridor where the largest glaciers occur, we assessed fluctuations of a randomly selected 30 glaciers from 1976 to 2003. Results indicate that 28 glacier-terminus positions have retreated, and the largest average retreat rate was 36 m/yr. High albedo, non-vegetated glacier forefields formed prior to 1976, and geomorphological evidence shows apparent glacier-surface downwasting after 1976. Climatic conditions and glacier retreat have resulted in disconnection of tributary

  7. The thermophysics of glaciers

    SciTech Connect

    Zotikov, I.A.

    1986-01-01

    This volume presents the results of experimental and theoretical work on the thermodynamics of ice sheets and glaciers. The author has carried out extensive field work in both the Soviet Union and Antarctica over the last 25 years and has contributed to the understanding of the thermophysics of glaciers. The topics covered in this volume embrace heat flow measurement and temperature distributions in glaciers, the thermal drilling of glaciers, the melting and freezing of ice sheets, and other thermophysical problems. Also included are topics of relevance to glacial engineering.

  8. The thickness of glaciers

    NASA Astrophysics Data System (ADS)

    Faraoni, Valerio; Vokey, Marshall W.

    2015-09-01

    Basic formulae and results of glacier physics appearing in glaciology textbooks can be derived from first principles introduced in algebra-based first year physics courses. We discuss the maximum thickness of alpine glaciers and ice sheets and the relation between maximum thickness and length of an ice sheet. Knowledge of ordinary differential equations allows one to derive also the local ice thickness.

  9. HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. HALF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. HALF DOME AT CENTER REAR. SAME VIEW AT CA-157-2. LOOKING NNE. GIS: N-37' 43 44.3 / W-119 34 14.1 - Glacier Point Road, Between Chinquapin Flat & Glacier Point, Yosemite Village, Mariposa County, CA

  10. 2. HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. HALF DOME AT CENTER REAR. LOOKING NNE. GIS N-37 43 44.3 / W-119 34 14.1 - Glacier Point Road, Between Chinquapin Flat & Glacier Point, Yosemite Village, Mariposa County, CA

  11. Ablation of Martian glaciers

    NASA Technical Reports Server (NTRS)

    Moore, Henry J.; Davis, Philip A.

    1987-01-01

    Glacier like landforms are observed in the fretted terrain of Mars in the latitude belts near + or - 42 deg. It was suggested that sublimation or accumulation-ablation rates could be estimated for these glaciers if their shapes were known. To this end, photoclinometric profiles were obtained of a number of these landforms. On the basis of analyses of these profiles, it was concluded that ice is chiefly ablating from these landforms that either are inactive rock-glaciers or have materials within them that are moving exceedingly slowly at this time. These conclusions are consistent with other geologic information. The analyses were performed using a two-dimensional model of an isothermal glacier.

  12. A strategy for monitoring glaciers

    USGS Publications Warehouse

    Fountain, Andrew G.; Krimmel, Robert M.; Trabant, Dennis C.

    1997-01-01

    Glaciers are important features in the hydrologic cycle and affect the volume, variability, and water quality of runoff. Assessing and predicting the effect of glaciers on water resources require a monitoring program to provide basic data for this understanding. The monitoring program of the U.S. Geological Survey employs a nested approach whereby an intensively studied glacier is surrounded by less intensively studied glaciers and those monitored solely by remote sensing. Ideally, each glacierized region of the United States would have such a network of glaciers. The intensively studied glacier provides a detailed understanding of the physical processes and their temporal changes that control the mass exchange of the glaciers in that region. The less intensively studied glaciers are used to assess the variability of such processes within the region.

  13. Water, ice, and meteorological measurements at South Cascade glacier, Washington, balance year 2003

    USGS Publications Warehouse

    Bidlake, William R.; Josberger, Edward G.; Savoca, Mark E.

    2005-01-01

    Winter snow accumulation and summer snow and ice ablation were measured at South Cascade Glacier, Washington, to estimate glacier mass-balance quantities for balance year 2003. The 2003 glacier-average maximum winter snow balance was 2.66 meters water equivalent, which was about equal to the average of such balances for the glacier since balance year 1959. The 2003 glacier summer balance (-4.76 meters water equivalent) was the most negative reported for the glacier, and the 2003 net balance (-2.10 meters water equivalent), was the second-most negative reported. The glacier 2003 annual (water year) balance was -1.89 meters water equivalent. The area of the glacier near the end of the balance year was 1.89 square kilometers, a decrease of 0.03 square kilometer from the previous year. The equilibrium-line altitude was higher than any part of the glacier; however, because snow remained along part of one side of the upper glacier, the accumulation-area ratio was 0.07. During September 13, 2002-September 13, 2003, the glacier terminus retreated at a rate of about 15 meters per year. Average speed of surface ice, computed using a series of vertical aerial photographs dating back to 2001, ranged from 2.2 to 21.8 meters per year. Runoff from the subbasin containing the glacier and from an adjacent non-glacierized basin was gaged during part of water year 2003. Air temperature, precipitation, atmospheric water-vapor pressure, wind speed, and incoming solar radiation were measured at selected locations on and near the glacier. Summer 2003 at the glacier was among the warmest for which data are available.

  14. Isotopic composition of ice cores and meltwater from upper fremont glacier and Galena Creek rock glacier, Wyoming

    USGS Publications Warehouse

    DeWayne, Cecil L.; Green, J.R.; Vogt, S.; Michel, R.; Cottrell, G.

    1998-01-01

    Meltwater runoff from glaciers can result from various sources, including recent precipitation and melted glacial ice. Determining the origin of the meltwater from glaciers through isotopic analysis can provide information about such things as the character and distribution of ablation on glaciers. A 9.4 m ice core and meltwater were collected in 1995 and 1996 at the glacigenic Galena Creek rock glacier in Wyoming's Absaroka Mountains. Measurements of chlorine-36 (36Cl), tritium (3H), sulphur-35 (35S), and delta oxygen-18 (??18O) were compared to similar measurements from an ice core taken from the Upper Fremont Glacier in the Wind River Range of Wyoming collected in 1991-95. Meltwater samples from three sites on the rock glacier yielded 36Cl concentrations that ranged from 2.1 ?? 1.0 X 106 to 5.8??0.3 X 106 atoms/l. The ice-core 36Cl concentrations from Galena Creek ranged from 3.4??0.3 X 105 to 1.0??0.1 X 106 atoms/l. Analysis of an ice core from the Upper Fremont Glacier yielded 36Cl concentrations of 1.2??0.2 X 106 and 5.2??0.2 X 106 atoms/l for pre- 1940 ice and between 2 X 106 and 3 X 106 atoms/l for post-1980 ice. Purdue's PRIME Lab analyzed the ice from the Upper Fremont Glacier. The highest concentration of 36Cl in the ice was 77 ?? 2 X 106 atoms/l and was deposited during the peak of atmospheric nuclear weapons testing in the late 1950s. This is an order of magnitude greater than the largest measured concentration from both the Upper Fremont Glacier ice core that was not affected by weapons testing fallout and the ice core collected from the Galena Creek rock glacier. Tritium concentrations from the rock glacier ranged from 9.2??0.6 to 13.2??0.8 tritium units (TU) in the meltwater to -1.3??1.3 TU in the ice core. Concentrations of 3H in the Upper Fremont Glacier ice core ranged from 0 TU in the ice older than 50 years to 6-12 TU in the ice deposited in the last 10 years. The maximum 3H concentration in ice from the Upper Fremont Glacier deposited in the

  15. 2008 Wind Energy Projects, Wind Powering America (Poster)

    SciTech Connect

    Not Available

    2009-01-01

    The Wind Powering America program produces a poster at the end of every calendar year that depicts new U.S. wind energy projects. The 2008 poster includes the following projects: Stetson Wind Farm in Maine; Dutch Hill Wind Farm in New York; Grand Ridge Wind Energy Center in Illinois; Hooper Bay, Alaska; Forestburg, South Dakota; Elbow Creek Wind Project in Texas; Glacier Wind Farm in Montana; Wray, Colorado; Smoky Hills Wind Farm in Kansas; Forbes Park Wind Project in Massachusetts; Spanish Fork, Utah; Goodland Wind Farm in Indiana; and the Tatanka Wind Energy Project on the border of North Dakota and South Dakota.

  16. The Glaciers of HARMONIE

    NASA Astrophysics Data System (ADS)

    Mottram, Ruth; Gleeson, Emily; Pagh Nielsen, Kristian

    2016-04-01

    Developed by the large ALADIN-HIRLAM consortium, the numerical weather prediction (NWP) model system HARMONIE is run by a large number of national weather services and research institutions in Europe, the Middle East and North Africa for weather forecasting. It is now being adopted for climate research purposes as a limited area model in a form known as HCLIM. It is currently run for a number of domains, mostly in Europe but also including Greenland, at a very high resolution (~2.5 km). HARMONIE is a convection permitting non-hydrostatic model that includes the multi-purpose SURFEX surface model. By improving the characterization of glacier surfaces within SURFEX we show that weather forecast errors over both the Greenland ice sheet and over Icelandic glaciers can be significantly reduced. The improvements also facilitate increasingly accurate ice melt and runoff computations, which are important both for ice surface mass balance estimations and hydropower forecasting. These improvements will also benefit the operational HARMONIE domains that cover the Svalbard archipelago, the Alps and the Scandinavian mountain glaciers. Future uses of HCLIM for these regions, where accurately characterizing glacial terrain will be crucial for climate and glaciological applications, are also expected to benefit from this improvement. Here, we report the first results with a new glacier surface scheme in the HARMONIE model, validated with observations from the PROMICE network of automatic weather stations in Greenland. The scheme upgrades the existing surface energy balance over glaciers by including a new albedo parameterization for bare glacier ice and appropriate coefficients for calculating the turbulent fluxes. In addition the snow scheme from the SURFEX land surface module has been upgraded to allow the retention and refreezing of meltwater in the snowpack. These changes allow us to estimate surface mass balance over glaciers at a range of model resolutions that can take full

  17. The GLIMS Glacier Database

    NASA Astrophysics Data System (ADS)

    Raup, B. H.; Khalsa, S. S.; Armstrong, R.

    2007-12-01

    The Global Land Ice Measurements from Space (GLIMS) project has built a geospatial and temporal database of glacier data, composed of glacier outlines and various scalar attributes. These data are being derived primarily from satellite imagery, such as from ASTER and Landsat. Each "snapshot" of a glacier is from a specific time, and the database is designed to store multiple snapshots representative of different times. We have implemented two web-based interfaces to the database; one enables exploration of the data via interactive maps (web map server), while the other allows searches based on text-field constraints. The web map server is an Open Geospatial Consortium (OGC) compliant Web Map Server (WMS) and Web Feature Server (WFS). This means that other web sites can display glacier layers from our site over the Internet, or retrieve glacier features in vector format. All components of the system are implemented using Open Source software: Linux, PostgreSQL, PostGIS (geospatial extensions to the database), MapServer (WMS and WFS), and several supporting components such as Proj.4 (a geographic projection library) and PHP. These tools are robust and provide a flexible and powerful framework for web mapping applications. As a service to the GLIMS community, the database contains metadata on all ASTER imagery acquired over glacierized terrain. Reduced-resolution of the images (browse imagery) can be viewed either as a layer in the MapServer application, or overlaid on the virtual globe within Google Earth. The interactive map application allows the user to constrain by time what data appear on the map. For example, ASTER or glacier outlines from 2002 only, or from Autumn in any year, can be displayed. The system allows users to download their selected glacier data in a choice of formats. The results of a query based on spatial selection (using a mouse) or text-field constraints can be downloaded in any of these formats: ESRI shapefiles, KML (Google Earth), Map

  18. Glaciers of Greenland

    USGS Publications Warehouse

    Williams, Richard S.; Ferrigno, Jane G.

    1995-01-01

    Landsat imagery, combined with aerial photography, sketch maps, and diagrams, is used as the basis for a description of the geography, climatology, and glaciology, including mass balance, variation, and hazards, of the Greenland ice sheet and local ice caps and glaciers. The Greenland ice sheet, with an estimated area of 1,736,095+/-100 km2 and volume of 2,600,000 km3, is the second largest glacier on the planet and the largest relict of the Ice Age in the Northern Hemisphere. Greenland also has 48,599+/-100 km2 of local ice caps and other types of glaciers in coastal areas and islands beyond the margin of the ice sheet.

  19. Karakoram glacier surge dynamics

    NASA Astrophysics Data System (ADS)

    Quincey, D. J.; Braun, M.; Glasser, N. F.; Bishop, M. P.; Hewitt, K.; Luckman, A.

    2011-09-01

    We examine the surges of five glaciers in the Pakistan Karakoram using satellite remote sensing to investigate the dynamic nature of surges in this region and how they may be affected by climate. Surface velocity maps derived by feature-tracking quantify the surge development spatially in relation to the terminus position, and temporally with reference to seasonal weather. We find that the season of surge initiation varies, that each surge develops gradually over several years, and that maximum velocities are recorded within the lowermost 10 km of the glacier. Measured peak surge velocities are between one and two orders of magnitude greater than during quiescence. We also note that two of the glaciers are of a type not previously reported to surge. The evidence points towards recent Karakoram surges being controlled by thermal rather than hydrological conditions, coinciding with high-altitude warming from long-term precipitation and accumulation patterns.

  20. Greenland Glacier Albedo Variability

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The program for Arctic Regional Climate Assessment (PARCA) is a NASA-funded project with the prime goal of addressing the mass balance of the Greenland ice sheet. Since the formal initiation of the program in 1995, there has been a significant improvement in the estimates of the mass balance of the ice sheet. Results from this program reveal that the high-elevation regions of the ice sheet are approximately in balance, but the margins are thinning. Laser surveys reveal significant thinning along 70 percent of the ice sheet periphery below 2000 m elevations, and in at least one outlet glacier, Kangerdlugssuaq in southeast Greenland, thinning has been as much as 10 m/yr. This study examines the albedo variability in four outlet glaciers to help separate out the relative contributions of surface melting versus ice dynamics to the recent mass balance changes. Analysis of AVHRR Polar Pathfinder albedo shows that at the Petermann and Jakobshavn glaciers, there has been a negative trend in albedo at the glacier terminus from 1981 to 2000, whereas the Stor+strommen and Kangerdlugssuaq glaciers show slightly positive trends in albedo. These findings are consistent with recent observations of melt extent from passive microwave data which show more melt on the western side of Greenland and slightly less on the eastern side. Significance of albedo trends will depend on where and when the albedo changes occur. Since the majority of surface melt occurs in the shallow sloping western margin of the ice sheet where the shortwave radiation dominates the energy balance in summer (e.g. Jakobshavn region) this region will be more sensitive to changes in albedo than in regions where this is not the case. Near the Jakobshavn glacier, even larger changes in albedo have been observed, with decreases as much as 20 percent per decade.

  1. Exploring the links between transient water inputs and glacier velocity in a small temperate glacier in southeastern Alaska

    NASA Astrophysics Data System (ADS)

    Heavner, M.; Habermann, M.; Hood, E. W.; Fatland, D. R.

    2009-12-01

    Glaciers along the Gulf of Alaska are thinning and retreating rapidly. An important control on the rate at which ice is being lost is basal motion because higher glacier velocities increase the rate at which ice is delivered to ablation zones. Recent research has focused on understanding the effects of sub-glacial water storage on glacier basal motion. In this study, we examined two seasons of the effect of hydrologic controls (from large rainfall events as well as a glacier lake outburst floods) on the velocity of the Lemon Creek Glacier in southeastern Alaska. Lemon Creek Glacier is a moderately sized (~16~km2) temperate glacier at the margin of the Juneau Icefield. An ice-marginal lake forms at the head of the glacier and catastrophically drains once or twice every melt season. We have instrumented the glacier with two meteorological stations: one at the head of the glacier near the ice-marginal lake and another several kilometers below the terminus. These stations measure temperature, relative humidity, precipitation, incoming solar radiation and wind speed and direction. Lake stage in the ice-marginal lake was monitored with a pressure transducer. In addition, Lemon Creek was instrumented with a water quality sonde at the location of a US Geological Survey gaging station approximately 3 km downstream from the glacier terminus. The sonde provides continuous measurements of water temperature, dissolved oxygen, turbidity and conductivity. Finally, multiple Trimble NetRS dual frequency, differential GPS units were deployed on the glacier along the centerline of the glacier. All of the instruments were run continuously from May-September 2008 and May-September 2009 and captured threee outburst floods associated with the ice-marginal lake drainage as well as several large (>3~cm) rainfall events associated with frontal storms off of the Gulf of Alaska in late summer. Taken together, these data allow us to test the hypothesis that water inputs which overwhelm

  2. Climate regime of Asian glaciers revealed by GAMDAM glacier inventory

    NASA Astrophysics Data System (ADS)

    Sakai, A.; Nuimura, T.; Fujita, K.; Takenaka, S.; Nagai, H.; Lamsal, D.

    2015-05-01

    Among meteorological elements, precipitation has a large spatial variability and less observation, particularly in high-mountain Asia, although precipitation in mountains is an important parameter for hydrological circulation. We estimated precipitation contributing to glacier mass at the median elevation of glaciers, which is presumed to be at equilibrium-line altitude (ELA) such that mass balance is zero at that elevation, by tuning adjustment parameters of precipitation. We also made comparisons between the median elevation of glaciers, including the effect of drifting snow and avalanche, and eliminated those local effects. Then, we could obtain the median elevation of glaciers depending only on climate to estimate glacier surface precipitation. The calculated precipitation contributing to glacier mass can elucidate that glaciers in arid high-mountain Asia receive less precipitation, while much precipitation makes a greater contribution to glacier mass in the Hindu Kush, the Himalayas, and the Hengduan Shan due to not only direct precipitation amount but also avalanche nourishment. We classified glaciers in high-mountain Asia into summer-accumulation type and winter-accumulation type using the summer-accumulation ratio and confirmed that summer-accumulation-type glaciers have a higher sensitivity than winter-accumulation-type glaciers.

  3. Climate regime of Asian glaciers revealed by GAMDAM Glacier Inventory

    NASA Astrophysics Data System (ADS)

    Sakai, A.; Nuimura, T.; Fujita, K.; Takenaka, S.; Nagai, H.; Lamsal, D.

    2014-07-01

    Among meteorological elements, precipitation has a large spatial variability and less observation, particularly in High Mountain Asia, although precipitation in mountains is an important parameter for hydrological circulation. We estimated precipitation contributing to glacier mass at median elevation of glaciers, which is presumed to be at equilibrium-line altitude (ELA) so that mass balance is zero at that elevation, by tuning adjustment parameters of precipitation. We also made comparisons between median elevation of glaciers, including the effect of drifting snow and avalanche, and eliminated those local effects. Then, we could obtain median elevation of glaciers depending only on climate to estimate glacier surface precipitation. The calculated precipitation contributing to glacier mass can elucidate that glaciers in the arid High Mountain Asia have very less precipitation, while much precipitation contribute to glacier mass in the Hindu Kush, the Himalayas, and the Hengduan Shan due to not only direct precipitation amount but also avalanche nourishment. We classified glaciers in High Mountain Asia into summer-accumulation type and winter-accumulation type using the summer accumulation ratio, and confirmed that summer-accumulation type glaciers have a higher sensitivity than winter-accumulation type glaciers.

  4. Svalbard surging glacier landsystems

    NASA Astrophysics Data System (ADS)

    Lovell, Harold; Benn, Douglas; Lukas, Sven; Flink, Anne

    2014-05-01

    The percentage of Svalbard glaciers thought to be of surge-type is somewhere between 13-90% according to different sources variously based on statistical analysis and observations of diagnostic glaciological and geomorphological features, e.g. looped moraines. Developing a better understanding of which of these figures, if either, is most realistic is important in the context of glacier dynamics and related contributions of small glaciers and ice caps to sea level change in the immediate future. We present detailed geomorphological assessments of the margins of several known surge-type glaciers in Svalbard in order to update and improve the existing framework by which they are identified, and to provide a foundation for future reassessments of the surge-type glacier population based on distinct landform-sediment assemblages. Three landsystems are proposed: (1) Surges of small valley glaciers produce a prominent ice-cored latero-frontal moraine at their surge maximum and are characterised by an inner zone of ice stagnation terrain (hummocky topography, kettle lakes, debris flows) with no or only very few poorly-defined bedforms (crevasse squeeze ridges, eskers and flutes) and no recessional moraines. Many of these glaciers may have surged in the past but show no signs that they have the capability to do so again in the future. (2) Larger land-terminating glaciers, often with several tributaries, typically produce a push moraine complex which contains evidence for multiple advances, as identified from ridge-meltwater channel relationships. The inner zone often contains a large lagoon, partly dammed by the push moraine complex, and widespread ice stagnation terrain. Crevasse squeeze ridges, eskers and flutes are well-defined but small and limited in number and distribution. (3) Surges of large tidewater glaciers produce distinctive, often multi-generational, landform assemblages both in submarine and lateral terrestrial positions. The well-preserved submarine record

  5. One decade of scientific studies of snow management on Austria's glacier ski resorts

    NASA Astrophysics Data System (ADS)

    Fischer, Andrea; Helfricht, Kay

    2016-04-01

    After the extremely warm summer of 2003, when melt affected Austria's glaciers up to the highest elevations, a scientific study on artificial modification of mass balance was initiated. It examined the effects of glacier covers and water injection, but also various grooming methods and snow accumulations based on monitoring and modelling of snow and energy balance. The results showed that covering the glacier was the most effective and cheapest method, saving about 70% of glacier melt in places. But covers are restricted to a small portion of the area, as they require high maintenance. In recent years, snow production and snow accumulation by wind drift have gained more and more importance, not only modifying glacier mass balance, but also guaranteeing an early season start. Initially about 35 ha of the glacier area (<10% of the ski resort area and less than one per mille of the total glacier area in Austria) were covered and later the area was reduced as snow production possibilities increased. Snow depots are often used as fun parks for snow boarders. Glacier covers are not primarily used for keeping snow for early season start on ski tracks, but to maintain the surface, especially close to cable car infrastructure, at a constant elevation and slope. Despite glacier dynamics, glacier surfaces with snow management show reduced decrease of surface elevation , both on piste and along lift tracks.

  6. A dynamic physical characterization of the receding Mendenhall Glacier lake front terminus Juneau, Alaska

    NASA Astrophysics Data System (ADS)

    Connor, C. L.; Fatland, D. R.; Heavner, M.; Korzen, N.; Galbraith, J.; Sauer, D.; Hood, E. W.

    2009-12-01

    Extrapolation of 2000-2009 GPS results from terminus position surveys of the Mendenhall Glacier near Juneau, Alaska suggests that the lake front glacier terminus will no longer be in contact with proglacial Mendenhall Lake by July 2011. Meteorologic stations located near the glacier terminus at 44m asl, on the glacier surface at 430m (Northstar Camp), and at 1569m near the Mendenhall-Taku Glacier ice divide, provide data from rainfall events and temperature variation which contribute to glacier velocity and ultimately ice mass transfer to the lower glacier. Mendenhall weather data in combination with wind direction, wind velocity, and lake water temperature profiles (0-40m) and bathymetric surveys in 2009 provide detailed information about the physical conditions of the glacier and lake which are also captured visually by hourly and 30 second image records of the glacier terminus. Cameras are located at 500m from the terminus on bedrock and at ~2km from the terminus at the USFS Mendenhall Glacier Visitor Center roof. Ice berg motions and their changing positions in Mendenhall Lake can be used to create a gyre model for lake circulation. Summer 2009 lake water column temperature profiles collected at 15 minute intervals can also be linked with met station data, and USGS discharge data for the Mendenhall River to identify subglacial meltwater discharge events into the lake. We present here a synthetic view of these sensor data to evaluate what can be inferred and what remains mysterious concerning Mendenhall Glacier recession. Webcam photo Mendenhall Glacier Terminus 01-Sept-2009 10:02 am http://seamonster.jun.alaska.edu/webcam/Mendterm

  7. Glacier generated floods

    USGS Publications Warehouse

    Walder, J.S.; Fountain, A.G.; ,

    1997-01-01

    Destructive floods result from drainage of glacier-dammed lakes and sudden release of water stored within glaciers. There is a good basis - both empirical and theoretical - for predicting the magnitude of floods from ice-dammed lakes, although some aspects of flood initiation need to be better understood. In contrast, an understanding of floods resulting from release of internally stored water remains elusive, owing to lack of knowledge of how and where water is stored and to inadequate understanding of the complex physics of the temporally and spatially variable subglacial drainage system.Destructive floods result from drainage of glacier-dammed lakes and sudden release of water stored within glaciers. There is a good basis - both empirical and theoretical - for predicting the magnitude of floods from ice-dammed lakes, although some aspects of flood initiation need to be better understood. In contrast, an understanding of floods resulting from release of internally stored water remains elusive, owing to lack of knowledge of how and where water is stored and to inadequate understanding of the complex physics of the temporally and spatially variable subglacial drainage system.

  8. Characteristics of Glacier Ecosystem and Glaciological Importance of Glacier Microorganisms

    NASA Astrophysics Data System (ADS)

    Kohshima, S.; Yoshimura, Y.; Takeuchi, N.; Segawa, T.; Uetake, J.

    2004-12-01

    Biological activity on glaciers has been believed to be extremely limited. However, we found various biotic communities specialized to the glacier environment in various part of the world, such as Himalaya, Patagonia and Alaska. Some of these glacier hosted biotic communities including various cold-tolerant insects, annelids and copepods that were living in the glacier by feeding on algae and bacteria growing in the snow and ice. Thus, the glaciers are simple and relatively closed ecosystems sustained by the primary production in the snow and ice. Since these microorganisms growing on the glacier surface are stored in the glacial strata every year, ice-core samples contain many layers with these microorganisms. Recently, it was shown that the snow algae in the ice-core are useful for ice core dating and could be new environmental signals for the studies on past_@environment using ice cores. These microorganisms in the ice core will be important especially in the studies of ice core from the glaciers of warmer regions, in which chemical and isotopic contents are often heavily disturbed by melt water percolation. Blooms of algae and bacteria on the glacier can reduce the surface albedo and significantly affect the glacier melting. For example, the surface albedo of some Himalayan glaciers was significantly reduced by a large amount of dark-colored biogenic material (cryoconite) derived from snow algae and bacteria. It increased the melting rates of the surfaces by as much as three-fold. Thus, it was suggested that the microbial activity on the glacier could affect the mass balance and fluctuation of the glaciers.

  9. Snow and Glacier Hydrology

    NASA Astrophysics Data System (ADS)

    Brubaker, Kaye

    The study of snow and ice is rich in both fundamental science and practical applications. Snow and Glacier Hydrology offers something for everyone, from resource practitioners in regions where water supply depends on seasonal snow pack or glaciers, to research scientists seeking to understand the role of the solid phase in the water cycle and climate. The book is aimed at the advanced undergraduate or graduate-level student. A perusal of online documentation for snow hydrology classes suggests that there is currently no single text or reference book on this topic in general use. Instructors rely on chapters from general hydrology texts or operational manuals, collections of journal papers, or their own notes. This variety reflects the fact that snow and ice regions differ in climate, topography, language, water law, hazards, and resource use (hydropower, irrigation, recreation). Given this diversity, producing a universally applicable book is a challenge.

  10. Glaciers of Antarctica

    USGS Publications Warehouse

    Williams, Richard S.; Ferrigno, Jane G.

    1988-01-01

    Of all the world?s continents Antarctica is the coldest, the highest, and the least known. It is one and a half times the size of the United States, and on it lies 91 percent (30,109,800 km3) of the estimated volume of all the ice on Earth. Because so little is known about Antarctic glaciers compared with what is known about glaciers in populated countries, satellite imagery represents a great leap forward in the provision of basic data. From the coast of Antarctica to about 81?south latitude, there are 2,514 Landsat nominal scene centers (the fixed geographic position of the intersection of orbital paths and latitudinal rows). If there were cloud-free images for all these geographic centers, only about 520 Landsat images would be needed to provide complete coverage. Because of cloud cover, however, only about 70 percent of the Landsat imaging area, or 55 percent of the continent, is covered by good quality Landsat images. To date, only about 20 percent of Antarctica has been mapped at scales of 1:250,000 or larger, but these maps do include about half of the coastline. The area of Antarctica that could be planimetrically mapped at a scale of 1:250,000 would be tripled if the available Landsat images were used in image map production. This chapter contains brief descriptions and interpretations of features seen in 62 carefully selected Landsat images or image mosaics. Images were chosen on the basis of quality and interest; for this reason they are far from evenly spaced around the continent. Space limitations allow less than 15 percent of the Landsat imaging area of Antarctica to be shown in the illustrations reproduced in this chapter. Unfortunately, a wealth of glaciological and other features of compelling interest is present in the many hundreds of images that could not be included. To help show some important features beyond the limit of Landsat coverage, and as an aid to the interpretation of certain features seen in the images, 38 oblique aerial photographs

  11. Air temperature, radiation budget and area changes of Quisoquipina glacier in the Cordillera Vilcanota (Peru)

    NASA Astrophysics Data System (ADS)

    Suarez, Wilson; Macedo, Nicolás; Montoya, Nilton; Arias, Sandro; Schauwecker, Simone; Huggel, Christian; Rohrer, Mario; Condom, Thomas

    2015-04-01

    The Peruvian Andes host about 71% of all tropical glaciers. Although several studies have focused on glaciers of the largest glaciered mountain range (Cordillera Blanca), other regions have received little attention to date. In 2011, a new program has been initiated with the aim of monitoring glaciers in the centre and south of Peru. The monitoring program is managed by the Servicio Nacional de Meteorología e Hidrología del Perú (SENAMHI) and it is a joint project together with the Universidad San Antonio Abad de Cusco (UNSAAC) and the Autoridad Nacional del Agua (ANA). In Southern Peru, the Quisoquipina glacier has been selected due to its representativeness for glaciers in the Cordillera Vilcanota considering area, length and orientation. The Cordillera Vilcanota is the second largest mountain range in Peru with a glaciated area of approximately 279 km2 in 2009. Melt water from glaciers in this region is partly used for hydropower in the dry season and for animal breeding during the entire year. Using Landsat 5 images, we could estimate that the area of Quisoquipina glacier has decreased by approximately 11% from 3.66 km2 in 1990 to 3.26 km2 in 2010. This strong decrease is comparable to observations of other tropical glaciers. In 2011, a meteorological station has been installed on the glacier at 5180 m asl., measuring air temperature, wind speed, relative humidity, net short and longwave radiation and atmospheric pressure. Here, we present a first analysis of air temperature and the radiation budget at the Quisoquipina glacier for the first three years of measurements. Additionally, we compare the results from Quisoquipina glacier to results obtained by the Institut de recherche pour le développement (IRD) for Zongo glacier (Bolivia) and Antizana glacier (Ecuador). For both, Quisoquipina and Zongo glacier, net shortwave radiation may be the most important energy source, thus indicating the important role of albedo in the energy balance of the glacier

  12. Listening to Glaciers: Passive hydroacoustics near marine-terminating glaciers

    USGS Publications Warehouse

    Pettit, E.C.; Nystuen, J.A.; O'Neel, Shad

    2012-01-01

    The catastrophic breakup of the Larsen B Ice Shelf in the Weddell Sea in 2002 paints a vivid portrait of the effects of glacier-climate interactions. This event, along with other unexpected episodes of rapid mass loss from marine-terminating glaciers (i.e., tidewater glaciers, outlet glaciers, ice streams, ice shelves) sparked intensified study of the boundaries where marine-terminating glaciers interact with the ocean. These dynamic and dangerous boundaries require creative methods of observation and measurement. Toward this effort, we take advantage of the exceptional sound-propagating properties of seawater to record and interpret sounds generated at these glacial ice-ocean boundaries from distances safe for instrument deployment and operation.

  13. Water, ice, and meteorological measurements at South Cascade Glacier, Washington, 1995 balance year

    USGS Publications Warehouse

    Krimmel, R.M.

    1996-01-01

    Winter snow accumulation and summer snow, firn, and ice melt were measured at South Cascade Glacier, Washington to determine the winter and net balances for the 1995 balance year. The 1995 winter balance, averaged over the glacier, was 2.86 meters, and the net balance was -0.69 meter. The winter balance was approximately 0.5 meter greater than the 1977-94 average winter balance. The net balance was approximately 0.3 meter less negative than the 1977-94 average net balance. Runoff was measured from the glacier and an adjacent non-glacierized basin. Air temperature, precipitation, barometric pressure, solar radiation, and wind speed were measured adjacent to the glacier. This report makes these data available to the glaciological and climatological community.

  14. Modeled and measured glacier change and related glaciological, hydrological, and meteorological conditions at South Cascade Glacier, Washington, balance and water years 2006 and 2007

    USGS Publications Warehouse

    Bidlake, William R.; Josberger, Edward G.; Savoca, Mark E.

    2010-01-01

    terminus retreated at a rate of about 13 meters per year during balance year 2006 and at a rate of about 8 meters per year during balance year 2007. Glacier area near the end of balance years 2006 and 2007 was 1.74 and 1.73 square kilometers, respectively. Runoff from the basin containing the glacier and from an adjacent nonglacierized basin was gaged during all or parts of water years 2006 and 2007. Air temperature, wind speed, precipitation, and incoming solar radiation were measured at selected locations on and near the glacier. Air-temperature over the glacier at a height of 2 meters generally was less than at the same altitude in the air mass away from the glacier. Cooling of the air by the glacier increased systematically with increasing ambient air temperature. Empirically based equations were developed to estimate 2-meter-height air temperature over the glacier at five sites from site altitude and temperature at a non-glacier reference site.

  15. Mass balance model parameter transferability on a tropical glacier

    NASA Astrophysics Data System (ADS)

    Gurgiser, Wolfgang; Mölg, Thomas; Nicholson, Lindsey; Kaser, Georg

    2013-04-01

    The mass balance and melt water production of glaciers is of particular interest in the Peruvian Andes where glacier melt water has markedly increased water supply during the pronounced dry seasons in recent decades. However, the melt water contribution from glaciers is projected to decrease with appreciable negative impacts on the local society within the coming decades. Understanding mass balance processes on tropical glaciers is a prerequisite for modeling present and future glacier runoff. As a first step towards this aim we applied a process-based surface mass balance model in order to calculate observed ablation at two stakes in the ablation zone of Shallap Glacier (4800 m a.s.l., 9°S) in the Cordillera Blanca, Peru. Under the tropical climate, the snow line migrates very frequently across most of the ablation zone all year round causing large temporal and spatial variations of glacier surface conditions and related ablation. Consequently, pronounced differences between the two chosen stakes and the two years were observed. Hourly records of temperature, humidity, wind speed, short wave incoming radiation, and precipitation are available from an automatic weather station (AWS) on the moraine near the glacier for the hydrological years 2006/07 and 2007/08 while stake readings are available at intervals of between 14 to 64 days. To optimize model parameters, we used 1000 model simulations in which the most sensitive model parameters were varied randomly within their physically meaningful ranges. The modeled surface height change was evaluated against the two stake locations in the lower ablation zone (SH11, 4760m) and in the upper ablation zone (SH22, 4816m), respectively. The optimal parameter set for each point achieved good model skill but if we transfer the best parameter combination from one stake site to the other stake site model errors increases significantly. The same happens if we optimize the model parameters for each year individually and transfer

  16. Malaspina Glacier, Alaska

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra satellite covers an area of 55 by 40 kilometers (34 by 25 miles) over the southwest part of the Malaspina Glacier and Icy Bay in Alaska. The composite of infrared and visible bands results in the snow and ice appearing light blue, dense vegetation is yellow-orange and green, and less vegetated, gravelly areas are in orange. According to Dr. Dennis Trabant (U.S. Geological Survey, Fairbanks, Alaska), the Malaspina Glacier is thinning. Its terminal moraine protects it from contact with the open ocean; without the moraine, or if sea level rises sufficiently to reconnect the glacier with the ocean, the glacier would start calving and retreat significantly. ASTER data are being used to help monitor the size and movement of some 15,000 tidal and piedmont glaciers in Alaska. Evidence derived from ASTER and many other satellite and ground-based measurements suggests that only a few dozen Alaskan glaciers are advancing. The overwhelming majority of them are retreating.

    This ASTER image was acquired on June 8, 2001. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next six years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, along-term research and

  17. Chernobyl fallout on Alpine glaciers

    SciTech Connect

    Ambach, W.; Rehwald, W.; Blumthaler, M.; Eisner, H.; Brunner, P.

    1989-01-01

    Measurements of the gross beta activity of snow samples from four Alpine glaciers contaminated by radioactive fallout from the Chernobyl nuclear accident and a gamma-spectrum analysis of selected samples are reported. The results are discussed with respect to possible risks to the population from using meltwater from these glaciers as drinking water.

  18. Patagonia Glacier, Chile

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This ASTER images was acquired on May 2, 2000 over the North Patagonia Ice Sheet, Chile near latitude 47 degrees south, longitude 73 degrees west. The image covers 36 x 30 km. The false color composite displays vegetation in red. The image dramatically shows a single large glacier, covered with crevasses. A semi-circular terminal moraine indicates that the glacier was once more extensive than at present. ASTER data are being acquired over hundreds of glaciers worldwide to measure their changes over time. Since glaciers are sensitive indicators of warming or cooling, this program can provide global data set critical to understand climate change.

    This image is located at 46.5 degrees south latitude and 73.9 degrees west longitude.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud

  19. Water, Ice, and Meteorological Measurements at South Cascade Glacier, Washington, Balance Years 2004 and 2005

    USGS Publications Warehouse

    Bidlake, William R.; Josberger, Edward G.; Savoca, Mark E.

    2007-01-01

    gaged during all or parts of water years 2004 and 2005. Air temperature, wind speed, precipitation, and incoming solar radiation were measured at selected locations on and near the glacier.

  20. Water, Ice, and Meteorological Measurements at Xiao Dongkemadi Glacier, Central Tibetan Plateau, Balance Years from 2008 to 2011

    NASA Astrophysics Data System (ADS)

    Xiaobo, He; Baisheng, Ye; Yongjian, Ding; Jian, Zhang

    2013-04-01

    The glaciers on Tibetan Plateau play an important role in the catchment hydrology and climatology of this region. However, our knowledge with respect to water circulation in this remote area is scarce. Xiao Dongkemadi Glacier (XDG) is located near Tanggula Pass (the highest point on the Lanzhou-Lhasa road 5231ma.s.l.), central Tibetan Plateau (33°04'N, 92°04'E). Here, glacier mass balance and runoff directly reflects the glacier's response to local climate change, and glacier changes on the Tibetan Plateau strongly influence human welfare since water supplies in this arid/semi-arid region are predominantly from glacier melt. Due to its remote location, the mass balance of XDG has been monitored discontinuously since 1988 by the direct glaciological method. Recently, a more complete and fine-grained glacier monitoring system has been established on the cap of XDG, and is expected to make further contributions to research on the change of the cryospheric and climatic environment in the area. Winter snow accumulation and summer snow and ice ablation were measured at XDG, to estimate glacier mass-balance quantities for balance years from 2008 to 2011. Runoff from the basin containing the glacier and from an adjacent nonglacierized basin was gaged during all or parts of water years from 2008 and 2011. Air temperature, wind speed, precipitation, and incoming solar radiation were measured at selected locations on and near the glacier.

  1. Polythermal Glacier Hydrology: A Review

    NASA Astrophysics Data System (ADS)

    Irvine-Fynn, Tristram D. L.; Hodson, Andrew J.; Moorman, Brian J.; Vatne, Geir; Hubbard, Alun L.

    2011-11-01

    The manner by which meltwater drains through a glacier is critical to ice dynamics, runoff characteristics, and water quality. However, much of the contemporary knowledge relating to glacier hydrology has been based upon, and conditioned by, understanding gleaned from temperate valley glaciers. Globally, a significant proportion of glaciers and ice sheets exhibit nontemperate thermal regimes. The recent, growing concern over the future response of polar glaciers and ice sheets to forecasts of a warming climate and lengthening summer melt season necessitates recognition of the hydrological processes in these nontemperate ice masses. It is therefore timely to present an accessible review of the scientific progress in glacial hydrology where nontemperate conditions are dominant. This review provides an appraisal of the glaciological literature from nontemperate glaciers, examining supraglacial, englacial, and subglacial environments in sequence and their role in hydrological processes within glacierized catchments. In particular, the variability and complexity in glacier thermal regimes are discussed, illustrating how a unified model of drainage architecture is likely to remain elusive due to structural controls on the presence of water. Cold ice near glacier surfaces may reduce meltwater flux into the glacier interior, but observations suggest that the transient thermal layer of near surface ice holds a hydrological role as a depth-limited aquifer. Englacial flowpaths may arise from the deep incision of supraglacial streams or the propagation of hydrofractures, forms which are readily able to handle varied meltwater discharge or act as locations for water storage, and result in spatially discrete delivery of water to the subglacial environment. The influence of such drainage routes on seasonal meltwater release is explored, with reference to summer season upwellings and winter icing formation. Moreover, clear analogies emerge between nontemperate valley glacier and

  2. Water, ice, and meteorological measurements at South Cascade Glacier, Washington, balance year 2002

    USGS Publications Warehouse

    Bidlake, William R.; Josberger, Edward G.; Savoca, Mark E.

    2004-01-01

    Winter snow accumulation and summer snow and ice ablation were measured at South Cascade Glacier, Washington, to estimate glacier mass balance quantities for balance year 2002. The 2002 glacier-average maximum winter snow balance was 4.02 meters, the second largest since 1959. The 2002 glacier summer, net, and annual (water year) balances were -3.47, 0.55, and 0.54 meters, respectively. The area of the glacier near the end of the balance year was 1.92 square kilometers, and the equilibrium-line altitude and the accumulation area ratio were 1,820 meters and 0.84, respectively. During September 20, 2001 to September 13, 2002, the terminus retreated 4 meters, and computed average ice speeds in the ablation area ranged from 7.8 to 20.7 meters per year. Runoff from the subbasin containing the glacier and from an adjacent non-glacierized basin were measured during part of the 2002 water year. Air temperature, precipitation, atmospheric water-vapor pressure, wind speed and incoming solar radiation were measured at selected locations near the glacier.

  3. Extended T-index models for glacier surface melting: a case study from Chorabari Glacier, Central Himalaya, India

    NASA Astrophysics Data System (ADS)

    Karakoti, Indira; Kesarwani, Kapil; Mehta, Manish; Dobhal, D. P.

    2016-10-01

    Two enhanced temperature-index (T-index) models are proposed by incorporating meteorological parameters viz. relative humidity, wind speed and net radiation. The models are an attempt to explore different climatic variables other than temperature affecting glacier surface melting. Weather data were recorded at Chorabari Glacier using an automatic weather station during the summers of 2010 (July 10 to September 10) and 2012 (June 10 to October 25). The modelled surface melt is validated against the measured point surface melting at the snout. Performance of the developed models is evaluated by comparing with basic temperature-index model and is quantified through different efficiency criteria. The results suggest that proposed models yield considerable improvement in surface melt simulation . Consequently, the study reveals that glacier surface melt depends not only on temperature but also on weather parameters viz. relative humidity, wind speed and net radiation play a significant role in glacier surface melting. This approach provides a major improvement on basic temperature-index method and offers an alternative to energy balance model.

  4. Water flow through temperate glaciers

    USGS Publications Warehouse

    Fountain, A.G.; Walder, J.S.

    1998-01-01

    Understanding water movement through a glacier is fundamental to several critical issues in glaciology, including glacier dynamics, glacier-induced floods, and the prediction of runoff from glacierized drainage basins. to this end we have synthesized a conceptual model os water movement through a temperate glacier from the surface to the outlet stream. Processes that regulate the rate and distribution of water input at the glacier surface and that regulate water movement from the surface to the bed play important but commonly neglected roles in glacier hydrology. Where a glacier is covered by a layer of porous, permeable firn (the accumulation zone), the flux of water to the glacier interior varies slowly because the firn temporarily stores water and thereby smooths out variations in the supply rate. In the firn-free ablation zone, in contrast, the flux of water into the glacier depends directly on the rate of surface melt or rainfall and therefore varies greatly in time. Water moves from the surface to the bed through an upward branching arborescent network consisting of both steeply inclined conduits, formed by the enlargement of intergranular veins, and gently inclined conduits, sprqwned by water flow along the bottoms of near-surface fractures (crevasses). Englacial drainage conduits deliver water to the glacier bed at a linited number of points, probably a long distance downglacier of where water enters the glacier. Englacial conduits supplied from the accumulation zone are quasi steady state features that convey the slowly varying water flux delivered via the firn. their size adjusts so that they are usually full of water and flow is pressurized. In contrast, water flow in englacial conduits supplied from the ablation area is pressurized only near times of peak daily flow or during rainstorms; flow is otherwise in an open-channel configuration. The subglacial drainage system typically consists of several elements that are distinct both morpphologically and

  5. Widespread evidences of hoarfrost formation at a rock glacier in the Seckauer Tauern, Austria

    NASA Astrophysics Data System (ADS)

    Kellerer-Pirklbauer, A.; Winkler, G.; Pauritsch, M.

    2012-04-01

    The mechanism of deep reversible air circulation (the so called "chimney effect" or "wind tube") is known to be a process of ground overcooling in the lower and deeper parts of porous sediments and related landforms such as scree slopes or intact and relict rock glaciers. Warm air outflow emerging from relatively small voids within these mostly coarse-grained sediment bodies is sometimes noticeable. However, easier to identify are associated phenomena such as snowmelt windows, snow cover depressions and hoarfrost formations. Generally, these indications for warm air outflow are found at the upper part of scree slopes or the rooting zone of rock glaciers. Here we present widespread field evidences of hoarfrost from the pseudo-relict Schöneben Rock Glacier in the Seckauer Tauern Range, Austria located at E14°40'26'' and N47°22'31''. Herewith, a pseudo-relict rock glacier is defined as an intermediate rock glacier type between a relict and a climatic-inactive rock glacier, hence a relict rock glacier with locally isolated patches of permafrost. The rock glacier covers an area of about 0.11km2, ranges from ca. 1720 to 1905 m a.s.l., and consists predominantly of coarse-grained gneissic sediments with blocks up to a size of several cubic metres at the surface. In particular the lower part and some ridges in the central and upper part are covered by dwarf pines (pinus mugo) mirroring the flow structure of the previously active rock glacier. Isolated permafrost occurs presumably at the rooting zone of the rock glacier as indicated by evidences from a neighbouring rock glacier in a comparable setting. Field observations in November 2011 showed widespread occurrences of hoarfrost crystals growing around the funnel edge indicating the sublimation of vapour from warm funnels. Such hoarfrost sites were found at more than 50 single locations distributed over the entire rock glacier from the tongue to the rooting zone generally. The occurrence of hoarfrost can get classified

  6. Pine Island Glacier, Antarctica

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This ASTER image was acquired on December 12, 2000, and covers an area of 38 x 48 km. Pine Island Glacier has undergone a steady loss of elevation with retreat of the grounding line in recent decades. Now, space imagery has revealed a wide new crack that some scientists think will soon result in a calving event. Glaciologist Robert Bindschadler of NASA's Goddard Space Flight Center predicts this crack will result in the calving of a major iceberg, probably in less than 18 months. Discovery of the crack was possible due to multi-year image archives and high resolution imagery. This image is located at 74.1 degrees south latitude and 105.1 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  7. Beardmore Glacier proposals wanted

    NASA Astrophysics Data System (ADS)

    Proposals for research projects to be conducted in the upper Beardmore Glacier area of Antarctica during the 1985-1986 field season are being accepted by t h e National Science Foundation (NSF) through August 15. Later proposal submissions should be discussed with the appropriate program managers (see below).A temporary camp with helicopter support will be established in the region. Occupation by scientific parties will likely be between mid-November 1985 and mid-January 1986. Transportation in the field will be by UH1-N twin-engine Huey helicopters (with a range of approximately 185 km) and by motor toboggans. Satellite tent camps will be established within the range of the helicopters. The exact position of the main camp will be determined in November. Likely candidates, however, are Buckley Island Quadrangle, in the area of the Walcott Névé or the Bowden Névé, near Coalsack Bluff or Mount Sirius.

  8. Spatio-temporal Variation in Glacier Ice as Habitat for Harbor Seals in an Alaskan Tidewater Glacier Fjord

    NASA Astrophysics Data System (ADS)

    Womble, J. N.; McNabb, R. W.; Gens, R.; Prakash, A.

    2015-12-01

    Some of the largest aggregations of harbor seals (Phoca vitulina richardii) in Alaska occur in tidewater glacier fjords where seals rest upon icebergs that are calved from tidewater glaciers into the marine environment. The distribution, amount, and size of floating ice in fjords are likely important factors influencing the spatial distribution and abundance of harbor seals; however, fine-scale characteristics of ice habitat that are used by seals have not been quantified using automated methods. We quantified the seasonal changes in ice habitat for harbor seals in Johns Hopkins Inlet, a tidewater glacier fjord in Glacier Bay National Park, Alaska, using aerial photography, object-based image analysis, and spatial models. Aerial photographic surveys (n = 53) were conducted of seals and ice during the whelping (June) and molting (August) seasons from 2007-2014. Surveys were flown along a grid of 12 transects and high-resolution digital photos were taken directly under the plane using a vertically aimed camera. Seal abundance and spatial distribution was consistently higher during June (range: 1,672-4,340) than August (range: 1,075-2,582) and corresponded to the spatial distribution and amount of ice. Preliminary analyses from 2007 suggest that the average percent of icebergs (ice ≥ than 1.6m2) and brash ice (ice < 1.6m2) per scene were greater in June (icebergs: 1.8% ± 1.6%; brash ice: 43.8% ± 38.9%) than August (icebergs: 0.2% ± 0.7%; brash ice; 15.8% ± 26.4%). Iceberg angularity (an index of iceberg shape) was also greater in June (1.7 ± 0.9) than August (0.9 ± 0.9). Potential factors that may influence the spatio-temporal variation in ice habitat for harbor seals in tidewater glacier fjords include frontal ablation rates of glaciers, fjord circulation, and local winds. Harbor seals exhibit high seasonal fidelity to tidewater glacier fjords, thus understanding the relationships between glacier dynamics and harbor seal distribution will be critical for

  9. Flow instabilities of Alaskan glaciers

    NASA Astrophysics Data System (ADS)

    Turrin, James Bradley

    Over 300 of the largest glaciers in southern Alaska have been identified as either surge-type or pulse-type, making glaciers with flow instabilities the norm among large glaciers in that region. Consequently, the bulk of mass loss due to climate change will come from these unstable glaciers in the future, yet their response to future climate warming is unknown because their dynamics are still poorly understood. To help broaden our understanding of unstable glacier flow, the decadal-scale ice dynamics of 1 surging and 9 pulsing glaciers are investigated. Bering Glacier had a kinematic wave moving down its ablation zone at 4.4 +/- 2.0 km/yr from 2002 to 2009, which then accelerated to 13.9 +/- 2.0 km/yr as it traversed the piedmont lobe. The wave first appeared in 2001 near the confluence with Bagley Ice Valley and it took 10 years to travel ~64 km. A surge was triggered in 2008 after the wave activated an ice reservoir in the midablation zone, and it climaxed in 2011 while the terminus advanced several km into Vitus Lake. Ruth Glacier pulsed five times between 1973 and 2012, with peak velocities in 1981, 1989, 1997, 2003, and 2010; approximately every 7 years. A typical pulse increased ice velocity 300%, from roughly 40 m/yr to 160 m/yr in the midablation zone, and involved acceleration and deceleration of the ice en masse; no kinematic wave was evident. The pulses are theorized to be due to deformation of a subglacial till causing enhanced basal motion. Eight additional pulsing glaciers are identified based on the spatiotemporal pattern of their velocity fields. These glaciers pulsed where they were either constricted laterally or joined by a tributary, and their surface slopes are 1-2°. These traits are consistent with an overdeepening. This observation leads to a theory of ice motion in overdeepenings that explains the cyclical behavior of pulsing glaciers. It is based on the concept of glaciohydraulic supercooling, and includes sediment transport and erosion

  10. Surface melt dominates Alaska glacier mass balance

    USGS Publications Warehouse

    Larsen Chris F,; Burgess, E; Arendt, A.A.; O'Neel, Shad; Johnson, A.J.; Kienholz, C.

    2015-01-01

    Mountain glaciers comprise a small and widely distributed fraction of the world's terrestrial ice, yet their rapid losses presently drive a large percentage of the cryosphere's contribution to sea level rise. Regional mass balance assessments are challenging over large glacier populations due to remote and rugged geography, variable response of individual glaciers to climate change, and episodic calving losses from tidewater glaciers. In Alaska, we use airborne altimetry from 116 glaciers to estimate a regional mass balance of −75 ± 11 Gt yr−1 (1994–2013). Our glacier sample is spatially well distributed, yet pervasive variability in mass balances obscures geospatial and climatic relationships. However, for the first time, these data allow the partitioning of regional mass balance by glacier type. We find that tidewater glaciers are losing mass at substantially slower rates than other glaciers in Alaska and collectively contribute to only 6% of the regional mass loss.

  11. Ocean forcing drives glacier retreat sometimes

    NASA Astrophysics Data System (ADS)

    Bassis, J. N.; Ultee, E.; Ma, Y.

    2015-12-01

    Observations show that marine-terminating glaciers respond to climate forcing nonlinearly, with periods of slow or negligible glacier advance punctuated by abrupt, rapid retreat. Once glacier retreat has initiated, glaciers can quickly stabilize with a new terminus position. Alternatively, retreat can be sustained for decades (or longer), as is the case for Columbia Glacier, Alaska where retreat initiated ~1984 and continues to this day. Surprisingly, patterns of glacier retreat show ambiguous or even contradictory correlations with atmospheric temperature and glacier surface mass balance. Despite these puzzles, observations increasingly show that intrusion of warm subsurface ocean water into fjords can lead to glacier erosion rates that can account for a substantial portion of the total mass lost from glaciers. Here we use a simplified flowline model to show that even relatively modest submarine melt rates (~100 m/a) near the terminus of grounded glaciers can trigger large increases in iceberg calving leading to rapid glacier retreat. However, the strength of the coupling between submarine melt and calving is a strong function of the geometry of the glacier (bed topography, ice thickness and glacier width). This can lead to irreversible retreat when the terminus is thick and grounded deeply beneath sea level or result in little change when the glacier is relatively thin, grounded in shallow water or pinned in a narrow fjord. Because of the strong dependence on glacier geometry, small perturbations in submarine melting can trigger glaciers in their most advanced—and geometrically precarious—state to undergo sudden retreat followed by much slower re-advance. Although many details remain speculative, our model hints that some glaciers are more sensitive than others to ocean forcing and that some of the nonlinearities of glacier response to climate change may be attributable to variations in difficult-to-detect subsurface water temperatures that need to be better

  12. Modelling Greenland Outlet Glaciers

    NASA Technical Reports Server (NTRS)

    vanderVeen, Cornelis; Abdalati, Waleed (Technical Monitor)

    2001-01-01

    The objective of this project was to develop simple yet realistic models of Greenland outlet glaciers to better understand ongoing changes and to identify possible causes for these changes. Several approaches can be taken to evaluate the interaction between climate forcing and ice dynamics, and the consequent ice-sheet response, which may involve changes in flow style. To evaluate the icesheet response to mass-balance forcing, Van der Veen (Journal of Geophysical Research, in press) makes the assumption that this response can be considered a perturbation on the reference state and may be evaluated separately from how this reference state evolves over time. Mass-balance forcing has an immediate effect on the ice sheet. Initially, the rate of thickness change as compared to the reference state equals the perturbation in snowfall or ablation. If the forcing persists, the ice sheet responds dynamically, adjusting the rate at which ice is evacuated from the interior to the margins, to achieve a new equilibrium. For large ice sheets, this dynamic adjustment may last for thousands of years, with the magnitude of change decreasing steadily over time as a new equilibrium is approached. This response can be described using kinematic wave theory. This theory, modified to pertain to Greenland drainage basins, was used to evaluate possible ice-sheet responses to perturbations in surface mass balance. The reference state is defined based on measurements along the central flowline of Petermann Glacier in north-west Greenland, and perturbations on this state considered. The advantage of this approach is that the particulars of the dynamical flow regime need not be explicitly known but are incorporated through the parameterization of the reference ice flux or longitudinal velocity profile. The results of the kinematic wave model indicate that significant rates of thickness change can occur immediately after the prescribed change in surface mass balance but adjustments in flow

  13. Aletsch Glacier, Switzerland

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Aletsch Glacier, the largest glacier of Europe, covers more than 120 square kilometers (more than 45 square miles)in southern Switzerland. At its eastern extremity lies a glacierlake, Mdrjelensee (2,350 meters/7,711 feet above sea level). To the west rises Aletschhorn (4,195 meters/13,763 feet), which was first climbed in 1859. The Rhone River flows along the southern flank of the mountains.

    This image was acquired on July 23, 2001 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as

  14. From Glaciers to Icebergs

    NASA Astrophysics Data System (ADS)

    Zhang, Wendy

    I will describe works from a collaboration between physics and glaciology that grew out of interactions at the Computations in Science seminar Leo Kadanoff organized at the University of Chicago. The first project considers the interaction between ocean waves and Antarctic ice shelves, large floating portions of ice formed by glacial outflows. Back-of-envelop calculation and seismic sensor data suggest that crevasses may be distributed within an ice shelf to shield it from wave energy. We also examine numerical scenarios in which changes in environmental forcing causes the ice shelf to fail catastrophically. The second project investigates the aftermath of iceberg calving off glacier terminus in Greenland using data recorded via time-lapse camera and terrestrial radar. Our observations indicate that the mélange of icebergs within the fjord experiences widespread jamming during a calving event and therefore is always close to being in a jammed state during periods of terminus quiescence. Joint work with Jason Amundson, Ivo R. Peters, Julian Freed Brown, Nicholas Guttenberg, Justin C Burton, L. Mac Cathles, Ryan Cassotto, Mark Fahnestock, Kristopher Darnell, Martin Truffer, Dorian S. Abbot and Douglas MacAyeal. Kadanoff Session DCMP.

  15. Glacial ice and atmospheric forcing on the Mertz Glacier Polynya over the past 250 years

    NASA Astrophysics Data System (ADS)

    Campagne, P.; Crosta, Xavier; Houssais, M. N.; Swingedouw, D.; Schmidt, S.; Martin, A.; Devred, E.; Capo, S.; Marieu, V.; Closset, I.; Massé, G.

    2015-03-01

    The Mertz Glacier Polynya off George V Land, East Antarctica, is a source of Adélie Land Bottom Water, which contributes up to ~25% of the Antarctic Bottom Water. This major polynya is closely linked to the presence of the Mertz Glacier Tongue that traps pack ice upstream. In 2010, the Mertz Glacier calved a massive iceberg, deeply impacting local sea ice conditions and dense shelf water formation. Here we provide the first detailed 250-year long reconstruction of local sea ice and bottom water conditions. Spectral analysis of the data sets reveals large and abrupt changes in sea surface and bottom water conditions with a ~70-year cyclicity, associated with the Mertz Glacier Tongue calving and regrowth dynamics. Geological data and atmospheric reanalysis, however, suggest that sea ice conditions in the polynya were also very sensitive to changes in surface winds in relation to the recent intensification of the Southern Annular Mode.

  16. Water, ice, and meteorological measurements at South Cascade Glacier, Washington, 1994 balance year

    USGS Publications Warehouse

    Krimmel, R.M.

    1995-01-01

    Winter snow accumulation and summer snow, firn, and ice melt were measured at South Cascade Glacier, Washington to determine the winter and net balances for the 1994 balance year. The 1994 winter balance, averaged over the glacier, was 2.39 meters, and the net balance was -1.60 meters. The winter balance was approximately that of the 1977-94 average winter balance. The net balance was more negative than the 1977-94 average net balance of -1.02 meters. Runoff was measured from the glacier and an adjacent non- glacierized basin. Air temperature, precipitation, barometric pressure, solar radiation, and wind speed were measured nearby. This report makes these data available to the glaciological and climatological community.

  17. Water, ice, and meteorological measurements at South Cascade Glacier, Washington, 2000-01 balance years

    USGS Publications Warehouse

    Krimmel, Robert M.

    2002-01-01

    Winter snow accumulation and summer snow, firn, and ice melt were measured at South Cascade Glacier, Washington, to determine the winter and net balances for the 2000 and 2001 balance years. In 2000, the winter balance, averaged over the glacier, was 3.32 meters, and the net balance was 0.38 meters. The winter balance was the ninth highest since the record began in 1959. The net balance was greater than 33 of the 41 years since 1959. In 2001, the winter balance was 1.90 meters, and net balance was -1.57 meters. The winter balance was lower than all but 4 years since 1959, and the net balance was more negative than all but 5 other years. Runoff was measured from the glacier basin and an adjacent non-glacierized basin. Air temperature, precipitation, humidity, wind speed and solar radiation were measured nearby. Ice displacements were measured for the 1998-2001 period.

  18. Arctic polynya and glacier interactions

    NASA Astrophysics Data System (ADS)

    Edwards, Laura

    2013-04-01

    Major uncertainties surround future estimates of sea level rise attributable to mass loss from the polar ice sheets and ice caps. Understanding changes across the Arctic is vital as major potential contributors to sea level, the Greenland Ice Sheet and the ice caps and glaciers of the Canadian Arctic archipelago, have experienced dramatic changes in recent times. Most ice mass loss is currently focused at a relatively small number of glacier catchments where ice acceleration, thinning and calving occurs at ocean margins. Research suggests that these tidewater glaciers accelerate and iceberg calving rates increase when warming ocean currents increase melt on the underside of floating glacier ice and when adjacent sea ice is removed causing a reduction in 'buttressing' back stress. Thus localised changes in ocean temperatures and in sea ice (extent and thickness) adjacent to major glacial catchments can impact hugely on the dynamics of, and hence mass lost from, terrestrial ice sheets and ice caps. Polynyas are areas of open water within sea ice which remain unfrozen for much of the year. They vary significantly in size (~3 km2 to > ~50,000 km2 in the Arctic), recurrence rates and duration. Despite their relatively small size, polynyas play a vital role in the heat balance of the polar oceans and strongly impact regional oceanography. Where polynyas develop adjacent to tidewater glaciers their influence on ocean circulation and water temperatures may play a major part in controlling subsurface ice melt rates by impacting on the water masses reaching the calving front. Areas of open water also play a significant role in controlling the potential of the atmosphere to carry moisture, as well as allowing heat exchange between the atmosphere and ocean, and so can influence accumulation on (and hence thickness of) glaciers and ice caps. Polynya presence and size also has implications for sea ice extent and therefore potentially the buttressing effect on neighbouring

  19. Erosion by an Alpine glacier

    NASA Astrophysics Data System (ADS)

    Herman, Frédéric; Beyssac, Olivier; Lane, Stuart; Brughelli, Mattia; Leprince, Sebastien; Brun, Fanny

    2015-04-01

    Most mountain ranges on Earth owe their morphology to the action of glaciers and icecaps over the last few million years. Our current understanding of how glaciers have modified mountainous landforms has mainly been driven through landscape evolution models. These have included an array of erosion laws and mainly progressed through the implementation of various levels of sophistication regarding ice dynamics, subglacial hydrology or thermodynamics of water flow. However, the complex nature of the erosion processes involved and the difficulty of directly examining the ice-bedrock interface of contemporary glaciers has precluded the establishment of a prevailing erosion theory. Here we quantify the spatial variations in ice sliding velocity and erosion rate of a fast-flowing Alpine glacier in New Zealand during a 5-month period. By combining high resolution 3D measurements of surface velocity from optical satellite imagery with the quantification of both the production and provenance of sediments by the glacier, we show that erosion rates are proportional to sliding velocity raised to a power of about two. This result is consistent with abrasion theory. Given that the ice sliding velocity is a nonlinear function of ice thickness and ice surface slope, the response of glacial erosion to precipitation changes is highly nonlinear. Finally, our ability to constrain the glacial abrasion law present opportunities to further examine the interaction between glaciation and mountain evolution.

  20. Columbia Glacier, Alaska, 1986-2011

    NASA Video Gallery

    The Columbia Glacier in Alaska is one of many vanishing around the world. Glacier retreat is one of the most direct and understandable effects of climate change. The consequences of the decline in ...

  1. Analysis of time series of glacier speed: Columbia Glacier, Alaska

    USGS Publications Warehouse

    Walters, R.A.; Dunlap, W.W.

    1987-01-01

    During the summer of 1984 and 1985, laser measurements were made of the distance from a reference location to markers on the surface of the lower reach of Columbia Glacier, Alaska. The speed varies from 7 to 15 m/d and has three noteworthy components: 1) a low-frequency perturbation in speed with a time scale of days related to increased precipitation, 2) semidiurnal and diurnal variations related to sea tides, and 3) diurnal variations related to glacier surface melt. -from Authors

  2. Reconstructing deglaciation of Kolahoi glacier, western Himalaya and validation through field observations

    NASA Astrophysics Data System (ADS)

    Tayal, S.

    2011-12-01

    Kolahoi glacier, western Himalaya is located in Jammu and Kashmir, India between N 340 07'-340 12' and E 750 19'-750 23'. The glacier makes the head of Liddar valley and provides origin to west Liddar river, draining into river Jhelum. Kolahoi is characterized by the frontal activities of westerly winds from Dec to March-April and by dry subtropical climate during summer season. The glacier represents a twin glacier system with one branch from two sides of Kolahoi peak-east and west, merging together to form a common ablation zone and a north facing snout. The first recorded visit to Kolahoi Glacier was made by E. F. Neve in 1909. The earliest attempt to establish the quaternary glacial history of Liddar valley can be attributed to Grinlinton (1928) followed by Terra & Patterson (1939). As a result of their work, the quaternary glaciation of Liddar valley has been divided into a main series of four glacial and three interglacial epochs, of which the first two glaciations were more intensive than the later two. A significant result of this history has been that as compared with the interglacial periods the glacial periods were much shorter, in SW Kashmir. Presence of various glacial features of fourth stage, observed in the valley were correlated with the literature, coordinates taken through GPS and built on a GIS platform with overlyering of satellite image time series of recent decades. Decadal history of Kolahoi glacier deglaciation was reconstructed based on the satellite image time series, indirect volume-area scaling methods and field experiments, indicating variable retreat rate contributing to a total recession of 485m in the snout of glacier and an area loss of 15% in previous four decades, since 1965. Annual measurement of mass balance for Kolahoi glacier were conducted through glaciologic method since the first drilling of ablation stakes in 2008, which indicate a range from -2.0 m.w.e. to -3.5 m.w.e. per annum for the glacier. However, field observance

  3. Fast shrinkage of tropical glaciers in Colombia

    NASA Astrophysics Data System (ADS)

    Ceballos, Jorge Luis; Euscátegui, Christian; Ramírez, Jair; Cañon, Marcela; Huggel, Christian; Haeberli, Wilfried; Machguth, Horst

    As a consequence of ongoing atmospheric temperature rise, tropical glaciers belong to the unique and threatened ecosystems on Earth, as defined by the Intergovernmental Panel on Climate Change (Houghton and others, 2001). Worldwide glacier monitoring, especially as part of the Global Climate Observing System (GCOS), includes the systematic collection of data on such perennial surface ice masses. Several peaks in the sierras of Colombia have lost their glacier cover during recent decades. Today, high-altitude glaciers still exist in Sierra Nevada de Santa Marta, in Sierra Nevada del Cocuy and on the volcanoes of Nevados del Ruiz, de Santa Isabel, del Tolima and del Huila. Comparison of reconstructions of maximum glacier area extent during the Little Ice Age with more recent information from aerial photographs and satellite images clearly documents a fast-shrinking tendency and potential disappearance of the remaining glaciers within the next few decades. In the past 50 years, Colombian glaciers have lost 50% or more of their area. Glacier shrinkage has continued to be strong in the last 15 years, with a loss of 10-50% of the glacier area. The relationship between fast glacier retreat and local, regional and global climate change is now being investigated. Preliminary analyses indicate that the temperature rise of roughly 1° C in the last 30 years recorded at high-altitude meteorological stations exerts a primary control on glacier retreat. The investigations on the Colombian glaciers thus corroborate earlier findings concerning the high sensitivity of glaciers in the wet inner tropics to temperature rise. To improve understanding of fast glacier retreat in Colombia, a modern monitoring network has been established according to the multilevel strategy of the Global Terrestrial Network for Glaciers (GTN-G) within GCOS. The observations are also contributions to continued assessments of hazards from the glacier-covered volcanoes and to integrated global change

  4. Erosion by an Alpine glacier.

    PubMed

    Herman, Frédéric; Beyssac, Olivier; Brughelli, Mattia; Lane, Stuart N; Leprince, Sébastien; Adatte, Thierry; Lin, Jiao Y Y; Avouac, Jean-Philippe; Cox, Simon C

    2015-10-01

    Assessing the impact of glaciation on Earth's surface requires understanding glacial erosion processes. Developing erosion theories is challenging because of the complex nature of the erosion processes and the difficulty of examining the ice/bedrock interface of contemporary glaciers. We demonstrate that the glacial erosion rate is proportional to the ice-sliding velocity squared, by quantifying spatial variations in ice-sliding velocity and the erosion rate of a fast-flowing Alpine glacier. The nonlinear behavior implies a high erosion sensitivity to small variations in topographic slope and precipitation. A nonlinear rate law suggests that abrasion may dominate over other erosion processes in fast-flowing glaciers. It may also explain the wide range of observed glacial erosion rates and, in part, the impact of glaciation on mountainous landscapes during the past few million years.

  5. Erosion by an Alpine glacier

    NASA Astrophysics Data System (ADS)

    Herman, Frédéric; Beyssac, Olivier; Brughelli, Mattia; Lane, Stuart N.; Leprince, Sébastien; Adatte, Thierry; Lin, Jiao Y. Y.; Avouac, Jean-Philippe; Cox, Simon C.

    2015-10-01

    Assessing the impact of glaciation on Earth’s surface requires understanding glacial erosion processes. Developing erosion theories is challenging because of the complex nature of the erosion processes and the difficulty of examining the ice/bedrock interface of contemporary glaciers. We demonstrate that the glacial erosion rate is proportional to the ice-sliding velocity squared, by quantifying spatial variations in ice-sliding velocity and the erosion rate of a fast-flowing Alpine glacier. The nonlinear behavior implies a high erosion sensitivity to small variations in topographic slope and precipitation. A nonlinear rate law suggests that abrasion may dominate over other erosion processes in fast-flowing glaciers. It may also explain the wide range of observed glacial erosion rates and, in part, the impact of glaciation on mountainous landscapes during the past few million years.

  6. Flow velocities of Alaskan glaciers.

    PubMed

    Burgess, Evan W; Forster, Richard R; Larsen, Christopher F

    2013-01-01

    Our poor understanding of tidewater glacier dynamics remains the primary source of uncertainty in sea level rise projections. On the ice sheets, mass lost from tidewater calving exceeds the amount lost from surface melting. In Alaska, the magnitude of calving mass loss remains unconstrained, yet immense calving losses have been observed. With 20% of the global new-water sea level rise coming from Alaska, partitioning of mass loss sources in Alaska is needed to improve sea level rise projections. Here we present the first regionally comprehensive map of glacier flow velocities in Central Alaska. These data reveal that the majority of the regional downstream flux is constrained to only a few coastal glaciers. We find regional calving losses are 17.1 Gt a(-1), which is equivalent to 36% of the total annual mass change throughout Central Alaska.

  7. Climatic controls of western U.S. glaciers at the last glacial maximum

    USGS Publications Warehouse

    Hostetler, S.W.; Clark, P.U.

    1997-01-01

    We use a nested atmospheric modeling strategy to simulate precipitation and temperature of the western United States 18,000 years ago (18 ka). The high resolution of the nested model allows us to isolate the regional structure of summer temperature and winter precipitation that is crucial to determination of the net mass balance of late-Pleistocene mountain glaciers in this region of diverse topography and climate. Modeling results suggest that climatic controls of these glaciers varied significantly over the western U.S. Glaciers in the northern Rocky Mountains existed under relatively cold July temperatures and low winter accumulation, reflecting anticyclonic, easterly wind flow off the Laurentide Ice Sheet. In contrast, glaciers that existed under relatively warmer and wetter conditions are located along the Pacific coast south of Oregon, where enhanced westerlies delivered higher precipitation than at present. Between these two groupings lie glaciers that were controlled by a mix of cold and wet conditions attributed to the convergence of cold air from the ice sheet and moisture derived from the westerlies. Sensitivity tests suggest that, for our simulated 18 ka climate, many of the glaciers exhibit a variable response to climate but were generally more sensitive to changes in temperature than to changes in precipitation, particularly those glaciers in central Idaho and the Yellowstone Plateau. Our results support arguments that temperature depression generally played a larger role in lowering equilibrium line altitudes in the western U.S. during the last glacial maximum than did increased precipitation, although the magnitude of temperature depression required for steady-state mass balance varied from 8-18??C. Only the Sierra Nevada glaciers required a substantial increase in precipitation to achieve steady-state mass balance, while glaciers in the Cascade Range existed with decreased precipitation.

  8. Rock glaciers of the Karakoram Himalaya and surrounding mountains, Inner Asia

    NASA Astrophysics Data System (ADS)

    Hewitt, Kenneth

    2013-04-01

    The transHimalayan upper Indus Basin contains thousands of rock glaciers. An exceptional diversity of forms and sizes exist, hitherto largely unresearched. They are in a well-defined elevation band across the mountains, usually less than 1400 m vertically, although total relief exceeds 7000 m. The zone varies from north to south, west to east, and with slope orientation. Interfluve elevations are primary constraints. Rock glaciers are absent below the lowest and the highest interfluves. They are uncommon in the highest Mustagh Karakoram, Nanga Parbat, and Hindu Kush where glacier ice blankets the elevations where they could develop. The heaviest concentrations occur in sub-ranges of intermediate elevation. A full spectrum of generative conditions is found; related to periglacial, talus, glacial, avalanche, wind-blown snow, and rock avalanche processes. Forms vary between north and south slopes; arid, rainshadowed and more snowy, humid valleys. Rock glacier complexes, where two or more join to create extensive lobes, may have tributaries with different source conditions. The larger examples are several kilometres in length,usually glacier-derived, evidently affected by Holocene glacial history, trans-glacial processes, and paraglacial instabilities. In lesser ranges, many smaller rock glaciers are associated with glacier-free cirques, glacially sculpted valley walls, and floors with abundant glacial deposits. In general, they are transitional in genesis, process, and spatially relative to glacierization, to the vertical cascade of moisture and debris, and climate change in the vertical. Their landscape roles include extensive fragmentation of drainage systems. Countless inactive rock glaciers occur, typically continuing below active ones.

  9. Climatic controls of Western U.S. Glaciers at the last glacial maximum

    NASA Astrophysics Data System (ADS)

    Hostetler, Steven W.; Clark, Peter U.

    We use a nested atmospheric modeling strategy to simulate precipitation and temperature of the western United States 18,000 years ago (18 ka). The high resolution of the nested model allows us to isolate the regional structure of summer temperature and winter precipitation that is crucial to determination of the net mass balance of late-Pleistocene mountain glaciers in this region of diverse topography and climate. Modeling results suggest that climatic controls of these glaciers varied significantly over the western U.S. Glaciers in the northern Rocky Mountains existed under relatively cold July temperatures and low winter accumulation, reflecting anticyclonic, easterly wind flow off the Laurentide Ice Sheet. In contrast, glaciers that existed under relatively warmer and wetter conditions are located along the Pacific coast south of Oregon, where enhanced westerlies delivered higher precipitation than at present. Between these two groupings lie glaciers that were controlled by a mix of cold and wet conditions attributed to the convergence of cold air from the ice sheet and moisture derived from the westerlies. Sensitivity tests suggest that, for our simulated 18 ka climate, many of the glaciers exhibit a variable response to climate but were generally more sensitive to changes in temperature than to changes in precipitation, particularly those glaciers in central Idaho and the Yellowstone Plateau. Our results support arguments that temperature depression generally played a larger role in lowering equilibrium line altitudes in the western U.S. during the last glacial maximum than did increased precipitation, although the magnitude of temperature depression required for steady-state mass balance varied from 8-18°C. Only the Sierra Nevada glaciers required a substantial increase in precipitation to achieve steady-state mass balance, while glaciers in the Cascade Range existed with decreased precipitation.

  10. Revealing basin and regional scale snow accumulation magnitude and variability on glaciers throughout Alaska

    NASA Astrophysics Data System (ADS)

    McGrath, D.; Oneel, S.; Sass, L. C., III; Gusmeroli, A.; Arendt, A. A.; Wolken, G. J.; Kienholz, C.; McNeil, C.

    2014-12-01

    Mass loss from Alaskan glaciers (-50 ± 17 Gt/a, 2003-2009) constitutes one of the largest contributions to global sea level rise outside of the Greenland and Antarctic ice sheets. The largest process-related uncertainties in this calculation arise from the difficulty in accurately measuring accumulation on glaciers and from the large variability of accumulation over a range of spatio-temporal scales. Further, the physical processes governing snow distribution in complex terrain elude model parameterization. Using ground-penetrating radar, constrained with probe and pit observations, we quantify the magnitude and variability of snow accumulation at six prominent glaciers throughout Alaska at the end of 2013 winter. We find that total SWE magnitude and variability are strongly controlled by the large-scale climate system (i.e. distance from the coastal moisture source along prevailing storm track). On average, total SWE decreases by 0.33 m per 100 km from the coast, while the SWE elevation gradient decreases by 0.06 m / 100 m per 100 km from the coast. SWE variability over small spatial scales (<200 m) is similar at most sites, although two glaciers exhibit notably low and high variability, likely related to their respective climatic provenance. On individual glaciers, strong elevation gradients, increasing from 0.07 m SWE / 100 m at the interior Gulkana Glacier to 0.30 m SWE / 100 m at the coastal Scott Glacier, exert the primary control on accumulation. Results from multi-variable linear regression models (based on topographic variables) find wind exposure/shelter is the most frequent secondary control on accumulation variability. Finally, we find strong agreement (<10% difference) between the radar derived and stake derived total SWE estimates at two glaciers in the USGS Benchmark Glacier Program.

  11. Get Close to Glaciers with Satellite Imagery.

    ERIC Educational Resources Information Center

    Hall, Dorothy K.

    1986-01-01

    Discusses the use of remote sensing from satellites to monitor glaciers. Discusses efforts to use remote sensing satellites of the Landsat series for examining the global distribution, mass, balance, movements, and dynamics of the world's glaciers. Includes several Landsat images of various glaciers. (TW)

  12. Quantifying Spatially-Variable Ablation of Bering Glacier Lobes Using Low-Cost Automated Samplers and Remote Sensing Imagery

    NASA Astrophysics Data System (ADS)

    Shuchman, R.; Josberger, E.; Erickson, T. A.; Hatt, C.; Liversedge, L.; Roussi, C.; Payne, J. F.

    2006-12-01

    The Bering Glacier is the largest and longest glacier in continental North America, with an area of approximately 5,175 km2 and a length of 190 km. It is also the largest surging glacier in America, having surged at least five times during the twentieth century. Bering Glacier alone covers more than 6% of the glacier covered area of Alaska and may contain 15-20% of Alaska's total glacier ice. The entire glacier lies within 100 km of the Gulf of Alaska. The last great surge of the Bering Glacier occurred in 1993-95. An interdisciplinary research team has been actively monitoring the Bering Glacier since 2000, in order to understand the post-surge dynamics in respect to its effect on the Bering Glacier system hydrology. A comprehensive sampling of the lakes, rivers, runoff, and glacier volumetric change is being conducted to understand how changes in the glacier affect the hydrological environment which in turn determines the individual habitat of the flora and fauna that defines the ecology of the region. The monitoring program consists of a combination of highly-detailed local measurements with coarser resolution measurements over large spatial extents. Detailed measurements were collected using an inexpensive, field-deployable data measurement and logging system was designed and fabricated in 2004. The Glacier Ablation Sensor System (GASS) collects environmental information on glacier melting (temperature, barometric pressure, light level, wind speed) and movement (GPS coordinates, depth to glacier surface). The system uses solar cells with a battery to provide the required power, and is capable of storing an entire summer season's worth of hourly data. A set of GASS units (5-8) were deployed during the summers of 2004, 2005, and 2006 on the Bering and Stellar lobes of the Bering Glacier. To complement the local measurements, optical remote sensing imagery has been collected to monitor changes in the glacial terminus and to quantify the spatial variability of

  13. Assessing streamflow sensitivity to variations in glacier mass balance

    USGS Publications Warehouse

    O'Neel, Shad; Hood, Eran; Arendt, Anthony; Sass, Louis

    2014-01-01

    The purpose of this paper is to evaluate relationships among seasonal and annual glacier mass balances, glacier runoff and streamflow in two glacierized basins in different climate settings. We use long-term glacier mass balance and streamflow datasets from the United States Geological Survey (USGS) Alaska Benchmark Glacier Program to compare and contrast glacier-streamflow interactions in a maritime climate (Wolverine Glacier) with those in a continental climate (Gulkana Glacier). Our overall goal is to improve our understanding of how glacier mass balance processes impact streamflow, ultimately improving our conceptual understanding of the future evolution of glacier runoff in continental and maritime climates.

  14. The Effects of Changing Climate on Glaciers in the Central Alaska Range, Alaska, USA: A Case Study on the Kahiltna Glacier

    NASA Astrophysics Data System (ADS)

    Young, J. C.; Arendt, A. A.

    2010-12-01

    This study will develop a set of modeling tools to provide estimates of melt evolution for the Kahiltna Glacier and glaciers of the Central Alaska Range (CAKR), over a number of future climate change scenarios. To parameterize the model, field measurements of mass balance and meteorological variables are being collected on the Kahiltna Glacier. These measurements include winter accumulation surveys along both a centerline transect and several lateral profiles of the main glacier branch, and summer ablation measurements at ten centerline index locations spaced evenly over a range of elevations. Snow density measurements are also being recorded at three elevations. Temperature and relative humidity is being sampled at five of the index locations, and a full meteorological station (measuring temperature, humidity, wind speed and direction, snow accumulation, ice ablation, and solar radiation) will be positioned on the lower ablation area. Here we present preliminary results from the 2010 melt season, comparing data collected on the Kahiltna Glacier to measurements from nearby sites within the CAKR. Data from a single index site monitored by the National Park Service (NPS) is compared to the accumulation and ablation measurements taken at the ten sites visited during 2010 as part of this study, to show the NPS index site’s representativeness at different elevations. Accumulation at these locations is also compared to a nearby snow telemetry (SNOTEL) site to determine whether there is a systematic offset between station data and conditions on the glacier. Lapse rates are calculated from temperature readings at five different elevations, for comparison with data from a meteorological station located in an adjacent glacier basin. From these analyses we provide a preliminary assessment of the extent to which our in situ measurements on the Kahiltna Glacier are representative of regional trends. The project will leverage 20 years of NPS mass balance data for the Kahiltna

  15. Geodetic Glacier Mass Balance of Norway

    NASA Astrophysics Data System (ADS)

    Andreassen, L. M.; Elvehøy, H.; Kjøllmoen, B.

    2014-12-01

    Glaciers in mainland Norway cover 2692 km2and span a large range from south to north. Glacier surface mass balance is monitored by the direct (also called glaciological, traditional or conventional) method and indirectly assessed by the geodetic (or cartographic) method. The current glacier monitoring programme includes direct surface mass-balance investigations on 14 glaciers. Since measurements started at Storbreen in 1949, mass balance has been measured on a total of 43 glaciers. The accuracy of the direct measurements depends on both the accuracy of the point observations and inter- and extrapolation of point values to spatially distributed values. Long series of measurements can be inhomogeneous because of changes in personnel, methods, and glacier topography. Reanalysing glacier mass balance series is recommended as standard procedure for every mass balance monitoring programme with increasing importance for long time series. Repeated, detailed glacier mapping by aerial photography and photogrammetric methods, and recently by laser scanning (LIDAR), have been performed to calculate geodetic mass balance. The geodetic results are used as an independent check of the direct method as well as to monitor volume, area and mass changes of glaciers that lack direct measurements. Since 2007, LIDAR campaigns have been conducted on a 1/3 of the glacier area in Norway including all current mass balance glaciers. The objectives of the surveys are to produce high quality digital elevation models (DEMs) and orthophotos to document the present state of the glaciers and assess glacier changes since previous surveys. Furthermore, the DEMs and orthophotos provide an accurate baseline for future repeated mapping and glacier change detection. Here we present geodetic mass balance results for Norway over the last 50 years and compare the results with the direct in-situ measurements where available. We also show examples of how glacier mass balance data are being reanalyzed

  16. Survey of glaciers in the northern Rocky Mountains of Montana and Wyoming; Size response to climatic fluctuations 1950-1996

    SciTech Connect

    Chatelain, E.E.

    1997-09-01

    An aerial survey of Northern Rocky Mountain glaciers in Montana and Wyoming was conducted in late summer of 1996. The Flathead, Swan, Mission, and Beartooth Mountains of Montana were covered, as well as the Teton and Wind River Ranges of Wyoming. Present extent of glaciers in this study were compared to limits on recent USGS 15 and 7.5 topographic maps, and also from selected personal photos. Large cirque and hanging glaciers of the Flathead and Wind River Ranges did not display significant decrease in size or change in terminus position. Cirque glaciers in the Swan, Mission, Beartooth and Teton Ranges were markedly smaller in size; with separation of the ice body, growth of the terminus lake, or cover of the ice terminus with rockfalls. A study of annual snowfall, snowdepths, precipitation, and mean temperatures for selected stations in the Northern Rocky Mountains indicates no extreme variations in temperature or precipitation between 1950-1996, but several years of low snowfall and warmer temperatures in the 1980`s appear to have been sufficient to diminish many of the smaller cirque glaciers, many to the point of extinction. The disappearance of small cirque glaciers may indicate a greater sensitivity to overall climatic warming than the more dramatic fluctuations of larger glaciers in the same region.

  17. Organic Carbon Dynamics in Glacier Systems

    NASA Astrophysics Data System (ADS)

    Barker, J.; Sharp, M.; Klassen, J.; Foght, J.; Turner, R.

    2004-12-01

    The biogeochemical cycling of organic carbon (OC) has important implications for aquatic system ecology because the abundance and molecular characteristics of OC influence contaminant transport and bioavailability, and determine its suitability as a substrate for microbial metabolism. There have been few studies of OC cycling in glacier systems, and questions remain regarding the abundance, provenance, and biogeochemical transformations of OC in these environments. To address these questions, the abundance and molecular characteristics of OC is investigated in three glacier systems. These systems are characterized by different thermal and hydrological regimes and have different potential OC sources. John Evans Glacier is a polythermal glacier in arctic Canada. Outre Glacier is a temperate glacier in the Coast Mountains of British Columbia, Canada. Victoria Upper Glacier is a cold-based glacier in the McMurdo Dry Valleys of Antarctica. To provide an indication of the extent to which glacier system OC dynamics are microbially mediated, microbial culturing and identification is performed and organic acid abundance and speciation is determined. Where possible, samples of supraglacial runoff, glacier ice and basal ice and subglacial meltwater were collected. The dissolved organic carbon (DOC) concentration in each sample was measured by combustion/non-dispersive infrared gas analysis. Emission and synchronous fluorescence spectroscopy were used to characterize the molecular properties of the DOC from each environment. When possible, microbial culturing and identification was performed and organic acid identification and quantification was measured by ion chromatography. DOC exists in detectable quantities (0.06-46.6 ppm) in all of the glacier systems that were investigated. The molecular characteristics of DOC vary between glaciers, between environments at the same glacier, and over time within a single environment. Viable microbes are recoverable in significant (ca

  18. Glacier recession in Iceland and Austria

    NASA Technical Reports Server (NTRS)

    Hall, Dorothy K.; Williams, Richard S., Jr.; Bayr, Klaus J.

    1992-01-01

    It has been possible to measure glacier recession on the basis of Landsat data, in conjunction with comparisons of the magnitude of recession of a glacier margin with in situ measurements at fixed points along the same margin. Attention is presently given to the cases of Vatnajokull ice cap, in Iceland, and the Pasterze Glacier, in Austria, on the basis of satellite data from 1973-1987 and 1984-1990, respectively. Indications of a trend toward negative mass balance are noted. Nevertheless, while most of the world's small glaciers have been receding, some are advancing either due to local climate or the tidewater glacier cycle.

  19. Glacier fluctuations during the past 2000 years

    NASA Astrophysics Data System (ADS)

    Solomina, Olga N.; Bradley, Raymond S.; Jomelli, Vincent; Geirsdottir, Aslaug; Kaufman, Darrell S.; Koch, Johannes; McKay, Nicholas P.; Masiokas, Mariano; Miller, Gifford; Nesje, Atle; Nicolussi, Kurt; Owen, Lewis A.; Putnam, Aaron E.; Wanner, Heinz; Wiles, Gregory; Yang, Bao

    2016-10-01

    A global compilation of glacier advances and retreats for the past two millennia grouped by 17 regions (excluding Antarctica) highlights the nature of glacier fluctuations during the late Holocene. The dataset includes 275 time series of glacier fluctuations based on historical, tree ring, lake sediment, radiocarbon and terrestrial cosmogenic nuclide data. The most detailed and reliable series for individual glaciers and regional compilations are compared with summer temperature and, when available, winter precipitation reconstructions, the most important parameters for glacier mass balance. In many cases major glacier advances correlate with multi-decadal periods of decreased summer temperature. In a few cases, such as in Arctic Alaska and western Canada, some glacier advances occurred during relatively warm wet times. The timing and scale of glacier fluctuations over the past two millennia varies greatly from region to region. However, the number of glacier advances shows a clear pattern for the high, mid and low latitudes and, hence, points to common forcing factors acting at the global scale. Globally, during the first millennium CE glaciers were smaller than between the advances in 13th to early 20th centuries CE. The precise extent of glacier retreat in the first millennium is not well defined; however, the most conservative estimates indicate that during the 1st and 2nd centuries in some regions glaciers were smaller than at the end of 20th/early 21st centuries. Other periods of glacier retreat are identified regionally during the 5th and 8th centuries in the European Alps, in the 3rd-6th and 9th centuries in Norway, during the 10th-13th centuries in southern Alaska, and in the 18th century in Spitsbergen. However, no single period of common global glacier retreat of centennial duration, except for the past century, has yet been identified. In contrast, the view that the Little Ice Age was a period of global glacier expansion beginning in the 13th century

  20. Glacier recession in Iceland and Austria

    SciTech Connect

    Hall, D.K.; Williams, R.S. Jr.; Bayr, K.J. USGS, Reston, VA Keene State College, NH )

    1992-03-01

    It has been possible to measure glacier recession on the basis of Landsat data, in conjunction with comparisons of the magnitude of recession of a glacier margin with in situ measurements at fixed points along the same margin. Attention is presently given to the cases of Vatnajokull ice cap, in Iceland, and the Pasterze Glacier, in Austria, on the basis of satellite data from 1973-1987 and 1984-1990, respectively. Indications of a trend toward negative mass balance are noted. Nevertheless, while most of the world's small glaciers have been receding, some are advancing either due to local climate or the tidewater glacier cycle. 21 refs.

  1. Spatially heterogeneous wastage of Himalayan glaciers.

    PubMed

    Fujita, Koji; Nuimura, Takayuki

    2011-08-23

    We describe volumetric changes in three benchmark glaciers in the Nepal Himalayas on which observations have been made since the 1970s. Compared with the global mean of glacier mass balance, the Himalayan glaciers showed rapid wastage in the 1970s-1990s, but similar wastage in the last decade. In the last decade, a glacier in an arid climate showed negative but suppressed mass balance compared with the period 1970s-1990s, whereas two glaciers in a humid climate showed accelerated wastage. A mass balance model with downscaled gridded datasets depicts the fate of the observed glaciers. We also show a spatially heterogeneous distribution of glacier wastage in the Asian highlands, even under the present-day climate warming.

  2. The contribution of glacier melt to streamflow

    SciTech Connect

    Schaner, Neil; Voisin, Nathalie; Nijssen, Bart; Lettenmaier, D. P.

    2012-09-13

    Ongoing and projected future changes in glacier extent and water storage globally have lead to concerns about the implications for water supplies. However, the current magnitude of glacier contributions to river runoff is not well known, nor is the population at risk to future glacier changes. We estimate an upper bound on glacier melt contribution to seasonal streamflow by computing the energy balance of glaciers globally. Melt water quantities are computed as a fraction of total streamflow simulated using a hydrology model and the melt fraction is tracked down the stream network. In general, our estimates of the glacier melt contribution to streamflow are lower than previously published values. Nonetheless, we find that globally an estimated 225 (36) million people live in river basins where maximum seasonal glacier melt contributes at least 10% (25%) of streamflow, mostly in the High Asia region.

  3. Microbial Habitat on Kilimanjaro's Glaciers

    NASA Astrophysics Data System (ADS)

    Ponce, A.; Beaty, S. M.; Lee, C.; Lee, C.; Noell, A. C.; Stam, C. N.; Connon, S. A.

    2011-03-01

    Kilimanjaro glaciers captured a history of microbial diversity and abundance of supraglacial habitats. We show that a majority of bacterial clones, as determined by bacterial 16S rRNA gene sequencing, are most closely related to those isolated from cold-water environments.

  4. Mountain Glaciers and Ice Caps

    USGS Publications Warehouse

    Ananichheva, Maria; Arendt, Anthony; Hagen, Jon-Ove; Hock, Regine; Josberger, Edward G.; Moore, R. Dan; Pfeffer, William Tad; Wolken, Gabriel J.

    2011-01-01

    Projections of future rates of mass loss from mountain glaciers and ice caps in the Arctic focus primarily on projections of changes in the surface mass balance. Current models are not yet capable of making realistic forecasts of changes in losses by calving. Surface mass balance models are forced with downscaled output from climate models driven by forcing scenarios that make assumptions about the future rate of growth of atmospheric greenhouse gas concentrations. Thus, mass loss projections vary considerably, depending on the forcing scenario used and the climate model from which climate projections are derived. A new study in which a surface mass balance model is driven by output from ten general circulation models (GCMs) forced by the IPCC (Intergovernmental Panel on Climate Change) A1B emissions scenario yields estimates of total mass loss of between 51 and 136 mm sea-level equivalent (SLE) (or 13% to 36% of current glacier volume) by 2100. This implies that there will still be substantial glacier mass in the Arctic in 2100 and that Arctic mountain glaciers and ice caps will continue to influence global sea-level change well into the 22nd century.

  5. Glacier discharge and climate variations

    NASA Astrophysics Data System (ADS)

    Dominguez, M. Carmen; Rodriguez-Puebla, Concepcion; Encinas, Ascension H.; Visus, Isabel; Eraso, Adolfo

    2010-05-01

    Different studies account for the warming in the polar regions that consequently would affect Glacier Discharge (GD). Since changes in GD may cause large changes in sensible and latent heat fluxes, we ask about the relationships between GD and climate anomalies, which have not been quantified yet. In this study we apply different statistical methods such as correlation, Singular Spectral Analysis and Wavelet to compare the behaviour of GD data in two Experimental Pilot Catchments (CPE), one (CPE-KG-62°S) in the Antarctica and the other (CPE-KVIA-64°N) in the Arctic regions. Both CPE's are measuring sub- and endo-glacier drainage for recording of glacier melt water run-off. The CPE-KG-62°S is providing hourly GD time series since January 2002 in Collins glacier of the Maxwell Bay in King George Island (62°S, 58°W). The second one, CPE-KVIA-64°N, is providing hourly GD time series since September 2003 in the Kviarjökull glacier of the Vatnajökull ice cap in Iceland (64°N, 16°W). The soundings for these measurements are pressure sensors installed in the river of the selected catchments for the ice cap (CPE-KG-62°S) and in the river of the glacier for (CPE-KVIA-64°N). In each CPE, the calibration function between level and discharge has been adjusted, getting a very high correlation coefficient (0.99 for the first one and 0.95 for the second one), which let us devise a precise discharge law for the glacier. We obtained relationships between GD with atmospheric variables such as radiation, temperature, relative humidity, atmospheric pressure and precipitation. We also found a negative response of GD to El Niño teleconnection index. The results are of great interest due to the GD impact on the climate system and in particular for sea level rise.

  6. Recent changes detected on two glaciers at the northern part of James Ross Island, Antarctica

    NASA Astrophysics Data System (ADS)

    Nývlt, Daniel; Kopačková, Veronika; Láska, Kamil; Engel, Zbyněk.

    2010-05-01

    Antarctic Peninsula is one of the regions, which have been exposed to the most rapid warming of the Earth since 1950. Consequences of climate changes are clearly documented by recent disintegration of ice shelves on both sides of the Antarctic Peninsula as well as by the retreat of land-based glaciers. James Ross Island, located close to the northernmost tip of the Antarctic Peninsula, represents an excellent place to study changes in the glacier mass-balance and their sensitivity to a regional warming trend. Two different types of glaciers of the Ulu Peninsula, the Whisky Glacier and the Davies Dome have been studied. Multi-temporal remote sensing data (aerial photographs, Landsat MSS, TM and ETM+ and Aster satellite optical and thermal multispectral data) and field survey allowed detecting changes in extent (2-D) as well as calculating glacier mass-balance changes (3-D) for these two glaciers from 1977 to 2009. The Whisky Glacier is a well-delimited valley glacier located mostly below the local Equilibrium line altitude (ELA). The glacier with high-flow velocities is fed by an intensive snow accumulation caused by prevailing southwestern winds. The Whisky Glacier covers an area of 2.3 km2 and its altitude varies from 215 to 475 m a.s.l. The Davies Dome is a flat-bottom dome glacier. Significant parts of its surface are located above the ELA and limited flow velocities are characteristic for the most parts of its body. However, the Davies Dome has a single 500-700 m wide southwestern outlet flowing towards the Whisky Bay. The Davies Dome extends an area of 6.7 km2 and its altitude ranges from 0 to 514 m a.s.l. Both glaciers experienced massive extension of their ice tongues towards the Brandy Bay during the mid Holocene. Lateral moraines located in front of the both glaciers heading down to the left coast of the Brandy Bay document this event. According to the remote sensing data and field investigations both glaciers have retreated since 1977. Between 2006 and

  7. The current disequilibrium of North Cascade glaciers

    NASA Astrophysics Data System (ADS)

    Pelto, Mauri S.

    2006-03-01

    Three lines of evidence indicate that North Cascade (Washington, USA) glaciers are currently in a state of disequilibrium. First, annual balance measured on nine glaciers yields a mean cumulative balance for the 1984-2004 period of -8.58 m water equivalent (w.e.), a net loss of ice thickness exceeding 9.5 m. This is a significant loss for glaciers that average 30-50 m in thickness, representing 18-32% of their entire volume.Second, longitudinal profiles completed in 1984 and 2002 on 12 North Cascade glaciers confirm this volume change indicating a loss of -5.7 to -6.3 m in thickness (5.0-5.6 m w.e.) between 1984 and 2002, agreeing well with the measured cumulative balance of -5.52 m w.e. for the same period. The change in thickness on several glaciers has been equally substantial in the accumulation zone and the ablation zone, indicating that there is no point to which the glacier can retreat to achieve equilibrium. Substantial thinning along the entire length of a glacier is the key indicator that a glacier is in disequilibrium.Third, North Cascade glacier retreat is rapid and ubiquitous. All 47 glaciers monitored are currently undergoing significant retreat or, in the case of four, have disappeared. Two of the glaciers where mass balance observations were begun, Spider Glacier and Lewis Glacier, have disappeared. The retreat since 1984 of eight Mount Baker glaciers that were all advancing in 1975 has averaged 297 m. These observations indicate broad regional continuity in glacial response to climate.

  8. Mass balance, meteorology, area altitude distribution, glacier-surface altitude, ice motion, terminus position, and runoff at Gulkana Glacier, Alaska, 1996 balance year

    USGS Publications Warehouse

    March, Rod S.

    2003-01-01

    The 1996 measured winter snow, maximum winter snow, net, and annual balances in the Gulkana Glacier Basin were evaluated on the basis of meteorological, hydrological, and glaciological data. Averaged over the glacier, the measured winter snow balance was 0.87 meter on April 18, 1996, 1.1 standard deviation below the long-term average; the maximum winter snow balance, 1.06 meters, was reached on May 28, 1996; and the net balance (from August 30, 1995, to August 24, 1996) was -0.53 meter, 0.53 standard deviation below the long-term average. The annual balance (October 1, 1995, to September 30, 1996) was -0.37 meter. Area-averaged balances were reported using both the 1967 and 1993 area altitude distributions (the numbers previously given in this abstract use the 1993 area altitude distribution). Net balance was about 25 percent less negative using the 1993 area altitude distribution than the 1967 distribution. Annual average air temperature was 0.9 degree Celsius warmer than that recorded with the analog sensor used since 1966. Total precipitation catch for the year was 0.78 meter, 0.8 standard deviations below normal. The annual average wind speed was 3.5 meters per second in the first year of measuring wind speed. Annual runoff averaged 1.50 meters over the basin, 1.0 standard deviation below the long-term average. Glacier-surface altitude and ice-motion changes measured at three index sites document seasonal ice-speed and glacier-thickness changes. Both showed a continuation of a slowing and thinning trend present in the 1990s. The glacier terminus and lower ablation area were defined for 1996 with a handheld Global Positioning System survey of 126 locations spread out over about 4 kilometers on the lower glacier margin. From 1949 to 1996, the terminus retreated about 1,650 meters for an average retreat rate of 35 meters per year.

  9. Columbia Glacier in 1984: disintegration underway

    SciTech Connect

    Meier, M.F.; Rasmussen, L.A.; Miller, D.S.

    1985-01-01

    Columbia Glacier is a large, iceberg-calving glacier near Valdez, Alaska. The terminus of this glacier was relatively stable from the time of the first scientific studies in 1899 until 1978. During this period the glacier terminated partly on Heather Island and partly on a submerged moraine shoal. In December, 1978, the glacier terminus retreated from Heather Island, and retreat has accelerated each year since then, except during a period of anomalously low calving in 1980. Although the glacier has not terminated on Heather Island since 1978, a portion of the terminus remained on the crest of the moraine shoal until the fall of 1983. By December 8, 1983, that feature had receded more than 300 m from the crest of the shoal, and by December 14, 1984, had disappeared completely, leaving most of the terminus more than 2000 meters behind the crest of the shoal. Recession of the glacier from the shoal has placed the terminus in deeper water, although the glacier does not float. The active calving face of the glacier now terminates in seawater that is about 300 meters deep at the glacier centerline. Rapid calving appears to be associated with buoyancy effects due to deep water at the terminus and subglacial runoff. 12 refs., 10 figs.

  10. Using Metaphorical Models for Describing Glaciers

    NASA Astrophysics Data System (ADS)

    Felzmann, Dirk

    2014-11-01

    To date, there has only been little conceptual change research regarding conceptions about glaciers. This study used the theoretical background of embodied cognition to reconstruct different metaphorical concepts with respect to the structure of a glacier. Applying the Model of Educational Reconstruction, the conceptions of students and scientists regarding glaciers were analysed. Students' conceptions were the result of teaching experiments whereby students received instruction about glaciers and ice ages and were then interviewed about their understandings. Scientists' conceptions were based on analyses of textbooks. Accordingly, four conceptual metaphors regarding the concept of a glacier were reconstructed: a glacier is a body of ice; a glacier is a container; a glacier is a reflexive body and a glacier is a flow. Students and scientists differ with respect to in which context they apply each conceptual metaphor. It was observed, however, that students vacillate among the various conceptual metaphors as they solve tasks. While the subject context of the task activates a specific conceptual metaphor, within the discussion about the solution, the students were able to adapt their conception by changing the conceptual metaphor. Educational strategies for teaching students about glaciers require specific language to activate the appropriate conceptual metaphors and explicit reflection regarding the various conceptual metaphors.

  11. Generation of the relationship between glacier area and volume for a tropical glacier in Bolivian Andes

    NASA Astrophysics Data System (ADS)

    Liu, T.; Kinouchi, T.; Hasegawa, A.; Tsuda, M.; Iwami, Y.; Asaoka, Y.; Mendoza, J.

    2015-12-01

    In Andes, retreat of tropical glaciers is rapid, thus water resources currently available from glacierized catchments would be changed in its volume and temporal variations due to climate change and glacier shrinkage. The relationship between glacier area and volume is difficult to define however which is important to monitor glaciers especially those are remote or inaccessible. Water resources in La Paz and El Alto in Bolivia, strongly depend on the runoff from glacierized headwater catchments in the Cordillera Real, Andes, which is therefore selected as our study region.To predict annual glacier mass balances, PWRI-Distributed Hydrological Model (PWRI-DHM) was applied to simulate runoff from the partially glacierized catchments in high mountains (i.e. Condoriri-Huayna West headwater catchment located in the Cordillera Real, Bolivian Andes). PWRI-DHM is based on tank model concept in a distributed and 4-tank configuration including surface, unsaturated, aquifer, and river course tanks. The model was calibrated and validated with observed meteorological and hydrological data from 2011 to 2014 by considering different phases of precipitation, various runoff components from glacierized and non-glacierized areas, and the retarding effect by glacial lakes and wetlands. The model is then applied with MRI-AGCM outputs from 1987 to 2003 considering the shrinkage of glacier outlines since 1980s derived from Landsat data. Annual glacier mass balance in each 100m-grid was reproduced, with which the glacier area-volume relationship was generated with reasonable initial volume setting. Out study established a method to define the relationship between glacier area and volume by remote sensing information and glacier mass balances simulated by distributed hydrological model. Our results demonstrated that the changing trend of local glacier had a consistency the previous observed glacier area-volume relationship in the Cordillera Real.

  12. Future glacier runoff at the global scale

    NASA Astrophysics Data System (ADS)

    Huss, Matthias; Hock, Regine

    2016-04-01

    Water resources in mountain areas worldwide importantly depend on the runoff contribution by glaciers. Glacial water storage acts as an equilibrating element in the global hydrological cycle on various temporal scales. With ongoing and future glacier retreat a growing concern regarding water supply security in glacier-fed basins arises. However, glacier runoff projections at the regional or global scale are still rare and better models are urgently needed for planning and adaptation measures to cope with a changing seasonal distribution of water yields. Moreover, it is still an open debate in which region "peak water" - the maximum contribution of melting glaciers to runoff - has already been reached, i.e. whether increasing or declining annual runoff volumes must be expected. Here, we present results of a novel global glacier model for calculating the 21st century response of surface mass balance, three-dimensional glacier geometry and monthly water discharge for each individual glacier around the globe. The current surface geometry and thickness distribution for each of the world's roughly 200'000 glaciers is extracted from the Randolph Glacier Inventory and terrain models. Our simulations are driven with 14 Global Circulation Models from the CMIP5 project using the RCP4.5, RCP8.5 and RCP2.6 scenarios. We focus on the timing of peak water from glacierized catchments in all climatic regions of the earth and the corresponding importance of changes in the runoff regime on hydrological stress. The maximum rate of water release from glacial storage is subject to a high spatio-temporal variability depending on glacier characteristics and the transient response to climatic change. Furthermore, we discuss the significance of projected variations in glacier runoff in relation to the hydrology of the world's large-scale drainage basins and population distribution, and highlight 'hot spot' regions where the wastage of current ice volume is particularly relevant.

  13. Inventory and Spatial distribution of rock glaciers in the Eastern Pyrenees: paleoenvironmental implications

    NASA Astrophysics Data System (ADS)

    Salvador-Franch, Ferran; Pérez-Sánchez, Jordi; Salvà-Catarineu, Montserrat; Gómez-Ortiz, Antonio

    2016-04-01

    . With this purpose, we have identified a total of 149 headwaters, located above 2200 m and with concave morphology (50.3% N slope, 49.7% S slope). In 74% of these units, glacier cirques developed, though only 64% of them housed rock glaciers. No rock glaciers are found outside the formerly glaciated area (cirque, slope or valley bottom). Therefore, 26% of the high headwaters that were not glaciated and 34% of those that were glaciated but did not develop rock glaciers. The analysis of the morphotopographic characteristics of the high headwaters that were not glaciated during the Last Glaciation shows that the unfavourable aspect, exposure to prevailing winds, insufficient catchment area and steep catchment slopes explained the absence of glacier ice accumulation. However, it is not so obvious to interpret the absence of rock glaciers in a significant number of glacial cirques, which will require further analysis.

  14. Supraglacial lakes on Himalayan debris-covered glacier (Invited)

    NASA Astrophysics Data System (ADS)

    Sakai, A.; Fujita, K.

    2013-12-01

    Debris-covered glaciers are common in many of the world's mountain ranges, including in the Himalayas. Himalayan debris-covered glacier also contain abundant glacial lakes, including both proglacial and supraglacial types. We have revealed that heat absorption through supraglacial lakes was about 7 times greater than that averaged over the whole debris-covered zone. The heat budget analysis elucidated that at least half of the heat absorbed through the water surface was released with water outflow from the lakes, indicating that the warm water enlarge englacial conduits and produce internal ablation. We observed some portions at debris-covered area has caved at the end of melting season, and ice cliff has exposed at the side of depression. Those depression has suggested that roof of expanded water channels has collapsed, leading to the formation of ice cliffs and new lakes, which would accelerate the ablation of debris-covered glaciers. Almost glacial lakes on the debris-covered glacier are partially surrounded by ice cliffs. We observed that relatively small lakes had non-calving, whereas, calving has occurred at supraglacial lakes with fetch larger than 80 m, and those lakes expand rapidly. In the Himalayas, thick sediments at the lake bottom insulates glacier ice and lake water, then the lake water tends to have higher temperature (2-4 degrees C). Therefore, thermal undercutting at ice cliff is important for calving processes in the glacial lake expansion. We estimated and subaqueous ice melt rates during the melt and freeze seasons under simple geomorphologic conditions. In particular, we focused on valley wind-driven water currents in various fetches during the melt season. Our results demonstrate that the subaqueous ice melt rate exceeds the ice-cliff melt rate above the water surface when the fetch is larger than 20 m with the water temperature of 2-4 degrees C. Calculations suggest that onset of calving due to thermal undercutting is controlled by water

  15. 5. GLACIER POINT ROAD VIEW AT SENTINEL DOME PARKING AREA. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. GLACIER POINT ROAD VIEW AT SENTINEL DOME PARKING AREA. LOOKING E. GIS: N-37 42 43.8 / W-119 35 12.1 - Glacier Point Road, Between Chinquapin Flat & Glacier Point, Yosemite Village, Mariposa County, CA

  16. 1. PARKING LOT AT GLACIER POINT. HALF DOME AT CENTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. PARKING LOT AT GLACIER POINT. HALF DOME AT CENTER REAR. LOOKING NE. GIS: N-36 43 45.8 / W-119 34 14.1 - Glacier Point Road, Between Chinquapin Flat & Glacier Point, Yosemite Village, Mariposa County, CA

  17. Antarctica: Measuring glacier velocity from satellite images

    USGS Publications Warehouse

    Lucchitta, B.K.; Ferguson, H.M.

    1986-01-01

    Many Landsat images of Antarctica show distinctive flow and crevasse features in the floating part of ice streams and outlet glaciers immediately below their grounding zones. Some of the features, which move with the glacier or ice stream, remain visible over many years and thus allow time-lapse measurements of ice velocities. Measurements taken from Landsat images of features on Byrd Glacier agree well with detailed ground and aerial observations. The satellite-image technique thus offers a rapid and cost-effective method of obtaining average velocities, to a first order of accuracy, of many ice streams and outlet glaciers near their termini.

  18. Antarctica: measuring glacier velocity from satellite images

    SciTech Connect

    Lucchitta, B.K.; Ferguson, H.M.

    1986-11-28

    Many Landsat images of Antarctica show distinctive flow and crevasse features in the floating part of ice streams and outlet glaciers immediately below their grounding zones. Some of the features, which move with the glacier or ice stream, remain visible over many years and thus allow time-lapse measurements of ice velocities. Measurements taken from Landsat images of features on Byrd Glacier agree well with detailed ground and aerial observations. The satellite-image technique thus offers a rapid and cost-effective method of obtaining average velocities, to a first order of accuracy, of many ice streams and outlet glaciers near their termini.

  19. Internationally coordinated glacier monitoring: strategy and datasets

    NASA Astrophysics Data System (ADS)

    Hoelzle, Martin; Armstrong, Richard; Fetterer, Florence; Gärtner-Roer, Isabelle; Haeberli, Wilfried; Kääb, Andreas; Kargel, Jeff; Nussbaumer, Samuel; Paul, Frank; Raup, Bruce; Zemp, Michael

    2014-05-01

    Internationally coordinated monitoring of long-term glacier changes provide key indicator data about global climate change and began in the year 1894 as an internationally coordinated effort to establish standardized observations. Today, world-wide monitoring of glaciers and ice caps is embedded within the Global Climate Observing System (GCOS) in support of the United Nations Framework Convention on Climate Change (UNFCCC) as an important Essential Climate Variable (ECV). The Global Terrestrial Network for Glaciers (GTN-G) was established in 1999 with the task of coordinating measurements and to ensure the continuous development and adaptation of the international strategies to the long-term needs of users in science and policy. The basic monitoring principles must be relevant, feasible, comprehensive and understandable to a wider scientific community as well as to policy makers and the general public. Data access has to be free and unrestricted, the quality of the standardized and calibrated data must be high and a combination of detailed process studies at selected field sites with global coverage by satellite remote sensing is envisaged. Recently a GTN-G Steering Committee was established to guide and advise the operational bodies responsible for the international glacier monitoring, which are the World Glacier Monitoring Service (WGMS), the US National Snow and Ice Data Center (NSIDC), and the Global Land Ice Measurements from Space (GLIMS) initiative. Several online databases containing a wealth of diverse data types having different levels of detail and global coverage provide fast access to continuously updated information on glacier fluctuation and inventory data. For world-wide inventories, data are now available through (a) the World Glacier Inventory containing tabular information of about 130,000 glaciers covering an area of around 240,000 km2, (b) the GLIMS-database containing digital outlines of around 118,000 glaciers with different time stamps and

  20. The climatic mass balance of Svalbard glaciers: a 10-year simulation with a coupled atmosphere-glacier mass balance model

    NASA Astrophysics Data System (ADS)

    Aas, Kjetil S.; Dunse, Thorben; Collier, Emily; Schuler, Thomas V.; Berntsen, Terje K.; Kohler, Jack; Luks, Bartłomiej

    2016-05-01

    In this study we simulate the climatic mass balance of Svalbard glaciers with a coupled atmosphere-glacier model with 3 km grid spacing, from September 2003 to September 2013. We find a mean specific net mass balance of -257 mm w.e. yr-1, corresponding to a mean annual mass loss of about 8.7 Gt, with large interannual variability. Our results are compared with a comprehensive set of mass balance, meteorological, and satellite measurements. Model temperature biases of 0.19 and -1.9 °C are found at two glacier automatic weather station sites. Simulated climatic mass balance is mostly within about 100 mm w.e. yr-1 of stake measurements, and simulated winter accumulation at the Austfonna ice cap shows mean absolute errors of 47 and 67 mm w.e. yr-1 when compared to radar-derived values for the selected years 2004 and 2006. Comparison of modeled surface height changes from 2003 to 2008, and satellite altimetry reveals good agreement in both mean values and regional differences. The largest deviations from observations are found for winter accumulation at Hansbreen (up to around 1000 mm w.e. yr-1), a site where sub-grid topography and wind redistribution of snow are important factors. Comparison with simulations using 9 km grid spacing reveal considerable differences on regional and local scales. In addition, 3 km grid spacing allows for a much more detailed comparison with observations than what is possible with 9 km grid spacing. Further decreasing the grid spacing to 1 km appears to be less significant, although in general precipitation amounts increase with resolution. Altogether, the model compares well with observations and offers possibilities for studying glacier climatic mass balance on Svalbard both historically as well as based on climate projections.

  1. Integration of glacier databases within the Global Terrestrial Network for Glaciers (GTN-G)

    NASA Astrophysics Data System (ADS)

    Zemp, M.; Raup, B. H.; Armstrong, R.; Ballagh, L.; Gärtner-Roer, I.; Haeberli, W.; Hoelzle, M.; Kääb, A.; Kargel, J.; Paul, F.

    2009-04-01

    Changes in glaciers and ice caps provide some of the clearest evidence of climate change and have impacts on global sea level fluctuations, regional hydrological cycles and local natural hazard situations. Internationally coordinated collection and distribution of standardized information about glaciers and ice caps was initiated in 1894 and is today coordinated within the Global Terrestrial Network for Glaciers (GTN-G). A recently established GTN-G Steering Committee coordinates, supports and advices the operational bodies responsible for the international glacier monitoring, which are the World Glacier Monitoring Service (WGMS), the US National Snow and Ice Data Center (NSIDC) and the Global Land Ice Measurements from Space (GLIMS) initiative. In this presentation, we provide an overview of (i) the integration of the various operational databases, (ii) the development of a one-stop web-interface to these databases, and (iii) the available datasets. By joint efforts consistency and interoperability of the different glacier databases is elaborated. Thereby, the lack of a complete worldwide, detailed glacier inventory as well as different historical developments and methodological contexts of the datasets are major challenges for linking individual glaciers throughout the databases. A map-based web-interface, implemented based on OpenLayer 2.0 and Web Map/Feature Services, is elaborated to spatially link the available data and to provide data users a fast overview of all available data. With this new online service, GTN-G provides fast access to information on glacier inventory data from 100,000 glaciers mainly based on aerial photographs and from 80,000 glaciers mainly based on satellite images, length change series from 1,800 glaciers, mass balance series from 230 glaciers, special events (e.g., hazards, surges, calving instabilities) from 130 glaciers, as well as 10,000 photographs from some 470 glaciers.

  2. Ice thickness, ablation, and other glaciological measurements on upper Fremont Glacier, Wyoming

    USGS Publications Warehouse

    Naftz, D.L.; Smith, M.E.

    1993-01-01

    Glaciological investigations of the Upper Fremont Glacier in the Wind River Range of Wyoming were conducted during 1990-1991. The glaciological data will provide baseline information for monitoring future changes to the glacier and support ongoing research utilizing glacial-ice-core composition to reconstruct paleoenvironmental records. Ice thickness, determined by radio-echo sounding, ranged from 60 to 172 m in the upper half of the glacier. Radio-echo sounding of ice thickness at one point was confirmed by drilling 159.7 m to bedrock. Annual ablation (including snow, firn, and ice) measured for the 1990-1991 period averaged about 0.93 m/a. Surface ice velocity and direction were monitored from July 1990 to August 1991. Ice velocity decreased in a downslope direction. The largest measured velocity was about 3.1 m/a and the smallest was 0.8 m/a. -from Authors

  3. Brief communication: Getting Greenland's glaciers right - a new data set of all official Greenlandic glacier names

    NASA Astrophysics Data System (ADS)

    Bjørk, A. A.; Kruse, L. M.; Michaelsen, P. B.

    2015-12-01

    Place names in Greenland can be difficult to get right, as they are a mix of Greenlandic, Danish, and other foreign languages. In addition, orthographies have changed over time. With this new data set, we give the researcher working with Greenlandic glaciers the proper tool to find the correct name for glaciers and ice caps in Greenland and to locate glaciers described in the historic literature with the old Greenlandic orthography. The data set contains information on the names of 733 glaciers, 285 originating from the Greenland Ice Sheet (GrIS) and 448 from local glaciers and ice caps (LGICs).

  4. Advances in Modelling of Valley Glaciers

    NASA Astrophysics Data System (ADS)

    Adhikari, Surendra

    For glaciological conditions typical of valley glaciers, the central idea of this research lies in understanding the effects of high-order mechanics and parameterizing these for simpler dynamical and statistical methods in glaciology. As an effective tool for this, I formulate a new brand of dynamical models that describes distinct physical processes of deformational flow. Through numerical simulations of idealized glacier domains, I calculate empirical correction factors to capture the effects of longitudinal stress gradients and lateral drag for simplified dynamical models in the plane-strain regime. To get some insights into real glacier dynamics, I simulate Haig Glacier in the Canadian Rocky Mountains. As geometric effects overshadow dynamical effects in glacier retreat scenarios, it appears that high-order physics are not very important for Haig Glacier, particularly for evaluating its fate. Indeed, high-order and reduced models all predict that Haig Glacier ceases to exist by about AD2080 under ongoing climate warming. This finding regarding the minimal role of high-order physics may not be broadly valid, as it is not true in advance scenarios at Haig Glacier and it may not be representative of other glaciological settings. Through a 'bulk' parameterization of high-order physics, geometric and climatic settings, sliding conditions, and transient effects, I also provide new insights into the volume-area relation, a widely used statistical method for estimating glacier volume. I find a steady-state power-law exponent of 1:46, which declines systematically to 1:38 after 100 years of sustained retreat, in good accord with the observations. I recommend more accurate scaling relations through characterization of individual glacier morphology and degree of climatic disequilibrium. This motivates a revision of global glacier volume estimates, of some urgency in sea level rise assessments.

  5. Tracking glaciers with the Alaska seismic network

    NASA Astrophysics Data System (ADS)

    West, M. E.

    2015-12-01

    More than 40 years ago it was known that calving glaciers in Alaska created unmistakable seismic signals that could be recorded tens and hundreds of kilometers away. Their long monochromatic signals invited studies that foreshadowed the more recent surge in glacier seismology. Beyond a handful of targeted studies, these signals have remained a seismic novelty. No systematic attempt has been made to catalog and track glacier seismicity across the years. Recent advances in understanding glacier sources, combined with the climate significance of tidewater glaciers, have renewed calls for comprehensive tracking of glacier seismicity in coastal Alaska. The Alaska Earthquake Center has included glacier events in its production earthquake catalog for decades. Until recently, these were best thought of as bycatch—accidental finds in the process of tracking earthquakes. Processing improvements a decade ago, combined with network improvements in the past five years, have turned this into a rich data stream capturing hundreds of events per year across 600 km of the coastal mountain range. Though the source of these signals is generally found to be iceberg calving, there are vast differences in behavior between different glacier termini. Some glaciers have strong peaks in activity during the spring, while others peak in the late summer or fall. These patterns are consistent over years pointing to fundamental differences in calving behavior. In several cases, changes in seismic activity correspond to specific process changes observed through other means at particular glacier. These observations demonstrate that the current network is providing a faithful record of the dynamic behavior of several glaciers in coastal Alaska. With this as a starting point, we examine what is possible (and not possible) going forward with dedicated detection schemes.

  6. Glaciers. Attribution of global glacier mass loss to anthropogenic and natural causes.

    PubMed

    Marzeion, Ben; Cogley, J Graham; Richter, Kristin; Parkes, David

    2014-08-22

    The ongoing global glacier retreat is affecting human societies by causing sea-level rise, changing seasonal water availability, and increasing geohazards. Melting glaciers are an icon of anthropogenic climate change. However, glacier response times are typically decades or longer, which implies that the present-day glacier retreat is a mixed response to past and current natural climate variability and current anthropogenic forcing. Here we show that only 25 ± 35% of the global glacier mass loss during the period from 1851 to 2010 is attributable to anthropogenic causes. Nevertheless, the anthropogenic signal is detectable with high confidence in glacier mass balance observations during 1991 to 2010, and the anthropogenic fraction of global glacier mass loss during that period has increased to 69 ± 24%.

  7. Climatic Forcing of Glacier Surface Mass Balance Changes Along North-Central Peru: A Modeling Perspective

    NASA Astrophysics Data System (ADS)

    Mark, B. G.; Fernandez, A.

    2015-12-01

    Most tropical glaciers are Peru, where they are key water sources for communities in mountain environments and beyond. Thus, their sustained shrinkage portrays these glaciers as archetype of global warming impacts on the local scale. However, there is still no deep understanding on the mechanism connecting temperature and these glaciers. Among others, the effect of temperature on the glacier surface mass balance (GSMB) can be expressed within accumulation regimes and hence in surface albedo, or in ablation dynamics through incoming longwave energy (LE). Here, we report a study combining statistical analyses of reanalysis data (~30km grid-cell), regional climate modeling and glacier mass balance simulations at high resolution (2km) to analyze long-term (30 years) and seasonal GSMB along north-central Peru. Our goal is to mechanistically understand climate change impact on these glaciers. Results suggest temperature as the main factor controlling GSMB changes through the lapse rate (LR). Correlations of GSMB with LR, humidity and zonal wind point to vertical homogenization of temperature, causing LE to increase, despite this flux always remaining negative. This "less negative" LE multiplies the impact of the seasonal fluctuation in albedo, thereby enhancing total ablation. As this mechanism only needs a relative increase in temperature, it may even occur in subfreezing conditions. Model output also indicates that turbulent fluxes are small, largely cancelling out. This suggests that the impact of LE is more likely to occur compared to either turbulent fluxes changes or shifts in the proportion of sublimation versus melt, which we find to be regionally stable. These findings imply that glaciers in north-central Peru are sensitive to subtle changes in temperature. We discuss the implications for process-based understanding and how this non-linear and somewhat hidden effect of temperature reduces the skill of temperature index models to simulate GSMB in the Tropics.

  8. Holocene glacier activity on Kerguelen Island: preliminary results from a novel proglacial lake sediment record

    NASA Astrophysics Data System (ADS)

    Støren, Eivind; Bakke, Jostein; Arnaud, Fabien; Poulenard, Jérôme; Fanget, Bernard; Malet, Emmanuel; Sabatier, Pierre

    2016-04-01

    The Polar-regions are changing rapidly as greenhouse warming is continuing with huge impact on e.g. sea ice extent and snow cover. This change triggers teleconnections to low latitude areas challenging societies and human activity. We have, however, very little quantitative information of past climate in the Polar-regions that can be used to evaluate the potential responses and the response patterns to forcing changes and changes in boundary conditions. Whatever anthropogenic changes may occur in the future, they will be superimposed on, and interact with, natural climate variations due to all the forcing we are aware of. This means we need to better document past climate/environmental variability of the Polar-regions. Especially in the Southern Ocean there are few time series recording past climate due to few suitable land areas and the few Sub-Antarctic Islands is remote and has cumbersome logistics. Continuous terrestrial records from this region are therefore urgently needed for constraining future scenarios from earth system models. Glaciers and ice caps are still ubiquitous in the Polar-regions, although they are rapidly shrinking due to the on-going warming. The continuous sedimentary records produced by glaciers, which are stored in downstream lakes, represent supreme archives of past variability wherefrom quantitative information of key climate system components can be extracted. Kerguelen Island is located within the Antarctic Circumpolar Current and the Southern Westerly wind belt and contains several glaciers and smaller ice caps. Terrestrial archives recording past history of the glaciers at Kerguelen thus have a unique potential to record past changes in oceanic and atmospheric circulation patterns from southern mid-latitudes. Here we present preliminary results from the first distal glacier-fed lake that is sampled from Kerguelen Island. A 2.8 m long sediment core was obtained from Lac Guynemer (121masl.) located at the Peninsule Loranchet at the

  9. Microbial biodiversity in glacier-fed streams

    PubMed Central

    Wilhelm, Linda; Singer, Gabriel A; Fasching, Christina; Battin, Tom J; Besemer, Katharina

    2013-01-01

    While glaciers become increasingly recognised as a habitat for diverse and active microbial communities, effects of their climate change-induced retreat on the microbial ecology of glacier-fed streams remain elusive. Understanding the effect of climate change on microorganisms in these ecosystems is crucial given that microbial biofilms control numerous stream ecosystem processes with potential implications for downstream biodiversity and biogeochemistry. Here, using a space-for-time substitution approach across 26 Alpine glaciers, we show how microbial community composition and diversity, based on 454-pyrosequencing of the 16S rRNA gene, in biofilms of glacier-fed streams may change as glaciers recede. Variations in streamwater geochemistry correlated with biofilm community composition, even at the phylum level. The most dominant phyla detected in glacial habitats were Proteobacteria, Bacteroidetes, Actinobacteria and Cyanobacteria/chloroplasts. Microorganisms from ice had the lowest α diversity and contributed marginally to biofilm and streamwater community composition. Rather, streamwater apparently collected microorganisms from various glacial and non-glacial sources forming the upstream metacommunity, thereby achieving the highest α diversity. Biofilms in the glacier-fed streams had intermediate α diversity and species sorting by local environmental conditions likely shaped their community composition. α diversity of streamwater and biofilm communities decreased with elevation, possibly reflecting less diverse sources of microorganisms upstream in the catchment. In contrast, β diversity of biofilms decreased with increasing streamwater temperature, suggesting that glacier retreat may contribute to the homogenisation of microbial communities among glacier-fed streams. PMID:23486246

  10. Microbial biodiversity in glacier-fed streams.

    PubMed

    Wilhelm, Linda; Singer, Gabriel A; Fasching, Christina; Battin, Tom J; Besemer, Katharina

    2013-08-01

    While glaciers become increasingly recognised as a habitat for diverse and active microbial communities, effects of their climate change-induced retreat on the microbial ecology of glacier-fed streams remain elusive. Understanding the effect of climate change on microorganisms in these ecosystems is crucial given that microbial biofilms control numerous stream ecosystem processes with potential implications for downstream biodiversity and biogeochemistry. Here, using a space-for-time substitution approach across 26 Alpine glaciers, we show how microbial community composition and diversity, based on 454-pyrosequencing of the 16S rRNA gene, in biofilms of glacier-fed streams may change as glaciers recede. Variations in streamwater geochemistry correlated with biofilm community composition, even at the phylum level. The most dominant phyla detected in glacial habitats were Proteobacteria, Bacteroidetes, Actinobacteria and Cyanobacteria/chloroplasts. Microorganisms from ice had the lowest α diversity and contributed marginally to biofilm and streamwater community composition. Rather, streamwater apparently collected microorganisms from various glacial and non-glacial sources forming the upstream metacommunity, thereby achieving the highest α diversity. Biofilms in the glacier-fed streams had intermediate α diversity and species sorting by local environmental conditions likely shaped their community composition. α diversity of streamwater and biofilm communities decreased with elevation, possibly reflecting less diverse sources of microorganisms upstream in the catchment. In contrast, β diversity of biofilms decreased with increasing streamwater temperature, suggesting that glacier retreat may contribute to the homogenisation of microbial communities among glacier-fed streams.

  11. Using Metaphorical Models for Describing Glaciers

    ERIC Educational Resources Information Center

    Felzmann, Dirk

    2014-01-01

    To date, there has only been little conceptual change research regarding conceptions about glaciers. This study used the theoretical background of embodied cognition to reconstruct different metaphorical concepts with respect to the structure of a glacier. Applying the Model of Educational Reconstruction, the conceptions of students and scientists…

  12. Debris-covered Himalayan glaciers under a changing climate: observations and modelling of Khumbu Glacier, Nepal

    NASA Astrophysics Data System (ADS)

    Rowan, Ann; Quincey, Duncan; Egholm, David; Gibson, Morgan; Irvine-Fynn, Tristram; Porter, Philip; Glasser, Neil

    2016-04-01

    Many mountain glaciers are characterised in their lower reaches by thick layers of rock debris that insulate the glacier surface from solar radiation and atmospheric warming. Supraglacial debris modifies the response of these glaciers to climate change compared to glaciers with clean-ice surfaces. However, existing modelling approaches to predicting variations in the extent and mass balance of debris-covered glaciers have relied on numerical models that represent the processes governing glaciers with clean-ice surfaces, and yield conflicting results. Moreover, few data exist describing the mass balance of debris-covered glaciers and many observations are only made over short periods of time, but these data are needed to constrain and validate numerical modelling experiments. To investigate the impact of supraglacial debris on the response of a glacier to climate change, we developed a numerical model that couples the flow of ice and debris to include important feedbacks between mass balance, ice flow and debris accumulation. We applied this model to a large debris-covered Himalayan glacier - Khumbu Glacier in the Everest region of Nepal. Our results demonstrate that supraglacial debris prolongs the response of the glacier to warming air temperatures and causes lowering of the glacier surface in situ, concealing the magnitude of mass loss when compared with estimates based on glacierised area. Since the Little Ice Age, the volume of Khumbu Glacier has reduced by 34%, while glacier area has reduced by only 6%. We predict a further decrease in glacier volume of 8-10% by AD2100 accompanied by dynamic and physical detachment of the debris-covered tongue from the active glacier within the next 150 years. For five months during the 2014 summer monsoon, we measured temperature profiles through supraglacial debris and proglacial discharge on Khumbu Glacier. We found that temperatures at the ice surface beneath 0.4-0.7 m of debris were sufficient to promote considerable

  13. Glacier-derived August runoff in northwest Montana

    USGS Publications Warehouse

    Clark, Adam; Harper, Joel T.; Fagre, Daniel B.

    2015-01-01

    The second largest concentration of glaciers in the U.S. Rocky Mountains is located in Glacier National Park (GNP), Montana. The total glacier-covered area in this region decreased by ∼35% over the past 50 years, which has raised substantial concern about the loss of the water derived from glaciers during the summer. We used an innovative weather station design to collect in situ measurements on five remote glaciers, which are used to parameterize a regional glacier melt model. This model offered a first-order estimate of the summer meltwater production by glaciers. We find, during the normally dry month of August, glaciers in the region produce approximately 25 × 106 m3 of potential runoff. We then estimated the glacier runoff component in five gaged streams sourced from GNP basins containing glaciers. Glacier-melt contributions range from 5% in a basin only 0.12% glacierized to >90% in a basin 28.5% glacierized. Glacier loss would likely lead to lower discharges and warmer temperatures in streams draining basins >20% glacier-covered. Lower flows could even be expected in streams draining basins as little as 1.4% glacierized if glaciers were to disappear.

  14. Glaciers in 21st Century Himalayan Geopolitics

    NASA Astrophysics Data System (ADS)

    Kargel, J. S.; Wessels, R.; Kieffer, H. H.

    2002-05-01

    Glaciers are ablating rapidly the world over. Nowhere are the rates of retreat and downwasting greater than in the Hindu Kush-Himalaya (HKH) region. It is estimated that over the next century, 40,000 square kilometers of present glacier area in the HKH region will become ice free. Most of this area is in major valleys and the lowest glaciated mountain passes. The existence and characteristics of glaciers have security impacts, and rapidly changing HKH glaciers have broad strategic implications: (1) Glaciers supply much of the fresh water and hydroelectric power in South and Central Asia, and so glaciers are valuable resources. (2) Shared economic interests in water, hydroelectricity, flood hazards, and habitat preservation are a force for common cause and reasoned international relations. (3) Glaciers and their high mountains generally pose a natural barrier tending to isolate people. Historically, they have hindered trade and intercultural exchanges and have protected against aggression. This has further promoted an independent spirit of the region's many ethnic groups. (4) Although glaciers are generally incompatible with human development and habitation, many of the HKH region's glaciers and their mountains have become sanctuaries and transit routes for militants. Siachen Glacier in Kashmir has for 17 years been "the world's highest battlefield," with tens of thousands of troops deployed on both sides of the India/Pakistan line of control. In 1999, that conflict threatened to trigger all-out warfare, and perhaps nuclear warfare. Other recent terrorist and military action has taken place on glaciers in Kyrgyzstan and Tajikistan. As terrorists are forced from easily controlled territories, many may tend to migrate toward the highest ground, where definitive encounters may take place in severe alpine glacial environments. This should be a major concern in Nepali security planning, where an Army offensive is attempting to reign in an increasingly robust and brutal

  15. Recent fluctuations of the Argentinian glaciers

    NASA Astrophysics Data System (ADS)

    Leiva, Juan Carlos

    1999-10-01

    Some of the results obtained in the glaciological research carried out since 1979 at the Argentinian Andes are shown in this paper. The research covers a wide latitudinal gap extending from the Agua Negra glacier in the province of San Juan to the Frı´as glacier situated at Mount Tronador. Agua Negra and Piloto glaciers show a very similar behavior of almost continuous retreat since 1965 while at the Plomo region a small advance period, starting in 1982, is observed in five of the 10 glaciers studied. Finally, the Frı´as glacier fluctuations record shows a very strong recession since 1850 only interrupted by the 1976 advance that continued in 1977.

  16. ICESat laser altimetry over small mountain glaciers

    NASA Astrophysics Data System (ADS)

    Treichler, Désirée; Kääb, Andreas

    2016-09-01

    Using sparsely glaciated southern Norway as a case study, we assess the potential and limitations of ICESat laser altimetry for analysing regional glacier elevation change in rough mountain terrain. Differences between ICESat GLAS elevations and reference elevation data are plotted over time to derive a glacier surface elevation trend for the ICESat acquisition period 2003-2008. We find spatially varying biases between ICESat and three tested digital elevation models (DEMs): the Norwegian national DEM, SRTM DEM, and a high-resolution lidar DEM. For regional glacier elevation change, the spatial inconsistency of reference DEMs - a result of spatio-temporal merging - has the potential to significantly affect or dilute trends. Elevation uncertainties of all three tested DEMs exceed ICESat elevation uncertainty by an order of magnitude, and are thus limiting the accuracy of the method, rather than ICESat uncertainty. ICESat matches glacier size distribution of the study area well and measures small ice patches not commonly monitored in situ. The sample is large enough for spatial and thematic subsetting. Vertical offsets to ICESat elevations vary for different glaciers in southern Norway due to spatially inconsistent reference DEM age. We introduce a per-glacier correction that removes these spatially varying offsets, and considerably increases trend significance. Only after application of this correction do individual campaigns fit observed in situ glacier mass balance. Our correction also has the potential to improve glacier trend significance for other causes of spatially varying vertical offsets, for instance due to radar penetration into ice and snow for the SRTM DEM or as a consequence of mosaicking and merging that is common for national or global DEMs. After correction of reference elevation bias, we find that ICESat provides a robust and realistic estimate of a moderately negative glacier mass balance of around -0.36 ± 0.07 m ice per year. This regional

  17. Black soot and the survival of Tibetan glaciers

    PubMed Central

    Xu, Baiqing; Cao, Junji; Hansen, James; Yao, Tandong; Joswia, Daniel R.; Wang, Ninglian; Wu, Guangjian; Wang, Mo; Zhao, Huabiao; Yang, Wei; Liu, Xianqin; He, Jianqiao

    2009-01-01

    We find evidence that black soot aerosols deposited on Tibetan glaciers have been a significant contributing factor to observed rapid glacier retreat. Reduced black soot emissions, in addition to reduced greenhouse gases, may be required to avoid demise of Himalayan glaciers and retain the benefits of glaciers for seasonal fresh water supplies. PMID:19996173

  18. Quantifying global warming from the retreat of glaciers

    SciTech Connect

    Oerlemans, J. )

    1994-04-08

    Records of glacier fluctuations compiled by the World Glacier Monitoring Service can be used to derive an independent estimate of global warming during the last 100 years. Records of different glaciers are made comparable by a two-step scaling procedure; one allowing for differences in glacier geometry, the other for differences in climate sensitivity. The retreat of glaciers during the last 100 years appears to be coherent over the globe. On the basis of modeling of the climate sensitivity of glaciers, the observed glacier retreat can be explained by a linear warming trend of 0.66 kelvin per century.

  19. Geomicrobiology of a Supraglacial Stream on the Cotton Glacier, Victoria Land, Antarctica.

    NASA Astrophysics Data System (ADS)

    Foreman, C. M.; Morris, C. E.; Cory, R. M.

    2006-12-01

    The Cotton Glacier lies in the Transantarctic Mountains north of Cape Roberts and has a limited catchment area in the Clare and St. Johns ranges, but receives a large amount of sedimentary deposits from surrounding areas. The bedrock geology of the area is dominated by basement granite and Ferrar dolerite sills, with minor amounts of amphibolite and schist sandwiched between granite bodies. A unique fluvial system forms on the Cotton Glacier as a result of its location in the Transantarctic Mountains. The prevailing winds converge and deposit debris on the Cotton Glacier, warming up the surface and increasing meltwater production. During the austral summer of 2004-2005 we sampled a braided stream that flowed from mid glacier into a series of crevasses downstream. While low in dissolved organic carbon (44-47 μM C) and nutrients the supraglacial stream on the Cotton Glacier is capable of sustaining life, with bacterial cell abundances from 2.7 - 8.2 x 104 cells ml-1, and bacterial production ranging from 58.84 - 293.18 ng C d-1. Isolates recovered from the Cotton Glacier produced a rainbow of pigment colors and were similar to those recovered from other icy systems (Cytophaga- Flavobateria-Bacteroides and β-Proteobacteria lineages), suggesting that the occurrence of these related phylotoyes from diverse environs is due to similar survival strategies allowing them to remain active at sub- zero temperatures and survive multiple freeze-thaw events. Two isolates from the Cotton Glacier have been shown to possess ice nucleating activity. These bacteria can catalyze ice formation at -3.5°C and colder temperatures and likely possess Type I ice nuclei proteins. The fluorescence and absorbance spectra of the filtered Cotton Glacier water were analyzed to characterize the dissolved organic matter (DOM). The absorbance spectra of the Cotton Glacier sample exhibited a peak around 270 nm, which disappeared over time in the dark at 4°C. Analysis of excitation-emission matrices

  20. Glaciers in Patagonia: Controversy and prospects

    NASA Astrophysics Data System (ADS)

    Kargel, J. S.; Alho, P.; Buytaert, W.; Célleri, R.; Cogley, J. G.; Dussaillant, A.; Guido, Z.; Haeberli, W.; Harrison, S.; Leonard, G.; Maxwell, A.; Meier, C.; Poveda, G.; Reid, B.; Reynolds, J.; Rodríguez, C. A. Portocarrero; Romero, H.; Schneider, J.

    2012-05-01

    Lately, glaciers have been subjects of unceasing controversy. Current debate about planned hydroelectric facilities—a US7- to 10-billion megaproject—in a pristine glacierized area of Patagonia, Chile [Romero Toledo et al., 2009; Vince, 2010], has raised anew the matter of how glaciologists and global change experts can contribute their knowledge to civic debates on important issues. There has been greater respect for science in this controversy than in some previous debates over projects that pertain to glaciers, although valid economic motivations again could trump science and drive a solution to the energy supply problem before the associated safety and environmental problems are understood. The connection between glaciers and climate change—both anthropogenic and natural—is fundamental to glaciology and to glaciers' practical importance for water and hydropower resources, agriculture, tourism, mining, natural hazards, ecosystem conservation, and sea level [Buytaert et al., 2010; Glasser et al., 2011]. The conflict between conservation and development can be sharper in glacierized regions than almost anywhere else. Glaciers occur in spectacular natural landscapes, but they also supply prodigious exploitable meltwater.

  1. Glacier Monitoring: Opportunities, Accomplishments, and Limitations.

    NASA Astrophysics Data System (ADS)

    Meier, M. F.; Dyurgerov, M. B.

    2001-12-01

    Glaciers and ice caps, exclusive of the two major ice sheets, have been monitored for more than a century. Initially sparked by interest in the effect of glaciers on the landscape and their sensitive response to changes of climate, glacier study is now additionally motivated because of impacts on cold-regions ecology and hydrology as well as global sea-level rise. Glacier observations in many areas provide the only real data on climate change in the mountains. A substantial number of mass balance programs were initiated during the 1960s that improved our understanding of spatial and temporal changes in climate, and provided a basis for projecting future changes to glaciers and sea level. These results show a general increase in both snow accumulation and ice melting during the last 40 years (but with net wastage predominating), and a marked increase in the sensitivity of ice wastage to air temperature since the late 1980s. The World Data Center system provided unrestricted exchange of data among glaciologists during the `cold war.' The World Glacier Monitoring Service together with the National Snow and Ice Data Center and several individuals now provide ready access to glacier data. Remaining problems include inadequate access to digital data, a size bias to small glaciers, some traditional methodologies which limit the usefulness of the results, slow incorporation of new technologies, complexity of incorporating glacier dynamics in mass balance analysis, and insufficient attention by some investigators to reporting observational error. Perhaps the most difficult problems are the extension of limited data to the synthesis of broad regional or global conclusions, and a general dwindling of support for monitoring activities.

  2. Central Himalayan Glaciers and Climate Change- Pinder Glacier- A preliminary study

    NASA Astrophysics Data System (ADS)

    Pillai, J.; Patel, L. K.

    2011-12-01

    Glaciers in the Indian Himalayan Region (IHR) are the prime lifeline of Indian Subcontinent. There are about nine thousand glaciers of different size in this region. It is located within the latitudes 270N to 360N and longitude 720E to 960E. The second largest glacier, outside the polar and sub polar regions, Siachen glacier of length 74 km, is located in IHR. Many rivers in this continent originated from these glaciers. Study on the fluctuations especially of the snow cover and related parameters are important for the proper management of these rivers. Annual balance, fluctuations of glaciers, hydrological behaviour and the assessment of the winter snow pack are also critical for the proper flow and control of Himalayan Rivers. There are many hydroelectric and irrigation facilities in these snow fed rivers. Glacial melt is important as far as the river flow is concerned. Researchers had observed that the glacial mass balance has been found to show an inverse relationship with the monsoon. Glacial hydrometry and glacial melt are important aspects as far the studies of glaciers in this region. Himalayan glaciers are also important for ecosystem stability. In this perspective attempts had been made to examine the various environmental parameters of Pindari glacier and the upper reaches of the Pindari river. Pindari glacier is located in the Central Himalayan region. It is of length 8 Km. A few records available with Geological Survey of India for a period of hundred years reveals that Pindari glacial have an annual retreat of 8-10 M. Pindrai glacier had retreated about 425 M with in a period of fifty seven years. Pindari river originates from the buffer zone of Nanda Devi Biosphere Reserve (NDBR) and is located in the lower regime of Pindari glacier. It is one of the prominent tributaries of Alaknanda. Tributaries of Pindari river are from Maktoli glacier, Kafani glacier and Sunderdhunga glacier. The changes in the Pindiari catchment area had been examined from the

  3. Classification of debris-covered glaciers and rock glaciers in the Andes of central Chile

    NASA Astrophysics Data System (ADS)

    Janke, Jason R.; Bellisario, Antonio C.; Ferrando, Francisco A.

    2015-07-01

    In the Dry Andes of Chile (17 to 35° S), debris-covered glaciers and rock glaciers are differentiated from true glaciers based on the percentage of surface debris cover, thickness of surface debris, and ice content. Internal ice is preserved by an insulating cover of thick debris, which acts as a storage reservoir to release water during the summer and early fall. These landforms are more numerous than glaciers in the central Andes; however, the existing legislation only recognizes uncovered or semicovered glaciers as a water resource. Glaciers, debris-covered glaciers, and rock glaciers are being altered or removed by mining operations to extract valuable minerals from the mountains. In addition, agricultural expansion and population growth in this region have placed additional demands on water resources. In a warmer climate, as glaciers recede and seasonal water availability becomes condensed over the course of a snowmelt season, rock glaciers and debris-covered glaciers contribute a larger component of base flow to rivers and streams. As a result, identifying and locating these features to implement sustainable regional planning for water resources is important. The objective of this study is to develop a classification system to identify debris-covered glaciers and rock glaciers based on the interpretation of satellite imagery and aerial photographs. The classification system is linked to field observations and measurements of ice content. Debris-covered glaciers have three subclasses: surface coverage of semi (class 1) and fully covered (class 2) glaciers differentiates the first two forms, whereas debris thickness is critical for class 3 when glaciers become buried with more than 3 m of surface debris. Based on field observations, the amount of ice decreases from more than 85%, to 65-85%, to 45-65% for semi, fully, and buried debris-covered glaciers, respectively. Rock glaciers are characterized by three stages. Class 4 rock glaciers have pronounced

  4. A graph-based approach to glacier flowline extraction: An application to glaciers in Switzerland

    NASA Astrophysics Data System (ADS)

    Le Moine, Nicolas; Gsell, Pierre-Stéphane

    2015-12-01

    In this paper we propose a new, graph-based approach to glacier segmentation and flowline extraction. The method, which requires a set of glacier contours and a Digital Elevation Model (DEM), consists in finding an optimum branching that connects a set of vertices belonging to the topological skeleton of each glacier. First, the challenges associated with glacier flowline extraction are presented. Then, the three main steps of the method are described: the skeleton extraction and pruning algorithm, the definition and computation of a travel cost between all pairs of skeleton vertices, and the identification of the directed minimum spanning tree in the resulting directed graph. The method, which is mainly designed for valley glaciers, is applied to glaciers in Switzerland.

  5. Combining a Distributed Melt Model and Meteorological Data of Shackleton Glacier, Canadian Rockies

    NASA Astrophysics Data System (ADS)

    Mueller, M.; Jiskoot, H.

    2010-12-01

    Runoff from the Canadian Rocky Mountains into the Upper Columbia and Kootenay basins is strongly dominated by winter snow accumulation and spring melt, and it has been suggested that future reductions in snowpack will create increased competition for water between spring and early fall (Hamlet & Lettenmaier, 1999). Although the glacierised area is substantial for affecting summer flows in these basins, there are no measurements or quantified estimates of glacier runoff contribution. In an effort to provide an estimate of glacier runoff for the region, we measured ablation over 5 years, set up weather stations and temperature sensors in Summers 2009 and 2010 and developed a melt model for Shackleton Glacier (42.5 km2), the largest outlet of the Clemenceau Icefield Group (271 km2), which is the major local ice mass feeding into the Upper Columbia basin. Two HOBO weather stations (WS) were installed on the glacier for two weeks in Summer 2010, one near the left lateral moraine on very dirty ice, and one mid-glacier on relatively clean ice. Instrumentation included pyranometers (solar radiation and albedo), and temperature, wind speed and direction, relative humidity and barometric pressure sensors. A weather station off ice provided additional temperature and precipitation data. Other data included daily ablation stake measurements, surface roughness measurements, temperature data from Tidbit loggers on and off ice, and daily manual weather observations. Yearly ablation stake measurements and summer weather observations have been made by our team since 2005. A BC River Forecast Centre automatic snow pillow station provides additional temperature and precipitation data. Using these meteorological and ablation data for parameterisation and optimisation, a distributed GIS melt model was constructed from a simple energy balance model. The model is driven by hourly direct and diffuse radiation and DEM hillshading, an albedo parameterisation based on four ice/snow zones

  6. Himalayan glaciers: understanding contrasting patterns of glacier behavior using multi-temporal satellite imagery

    NASA Astrophysics Data System (ADS)

    Racoviteanu, A.

    2014-12-01

    High rates of glacier retreat for the last decades are often reported, and believed to be induced by 20th century climate changes. However, regional glacier fluctuations are complex, and depend on a combination of climate and local topography. Furthermore, in ares such as the Hindu-Kush Himalaya, there are concerns about warming, decreasing monsoon precipitation and their impact on local glacier regimes. Currently, the challenge is in understanding the magnitude of feedbacks between large-scale climate forcing and small-scale glacier behavior. Spatio-temporal patterns of glacier distribution are still llimited in some areas of the high Hindu-Kush Himalaya, but multi-temporal satellite imagery has helped fill spatial and temporal gaps in regional glacier parameters in the last decade. Here I present a synopsis of the behavior of glaciers across the Himalaya, following a west to east gradient. In particular, I focus on spatial patterns of glacier parameters in the eastern Himalaya, which I investigate at multi-spatial scales using remote sensing data from declassified Corona, ASTER, Landsat ETM+, Quickbird and Worldview2 sensors. I also present the use of high-resolution imagery, including texture and thermal analysis for mapping glacier features at small scale, which are particularly useful in understanding surface trends of debris-covered glaciers, which are prevalent in the Himalaya. I compare and contrast spatial patterns of glacier area and élévation changes in the monsoon-influenced eastern Himalaya (the Everest region in the Nepal Himalaya and Sikkim in the Indian Himalaya) with other observations from the dry western Indian Himalaya (Ladakh and Lahul-Spiti), both field measurements and remote sensing-based. In the eastern Himalaya, results point to glacier area change of -0.24 % ± 0.08% per year from the 1960's to the 2006's, with a higher rate of retreat in the last decade (-0.43% /yr). Debris-covered glacier tongues show thinning trends of -30.8 m± 39 m

  7. A Revised Glacier Inventory of Bhaga Basin Himachal Pradesh, India : Current Status and Recent Glacier Variations

    NASA Astrophysics Data System (ADS)

    Birajdar, F.; Venkataraman, G.; Bahuguna, I.; Samant, H.

    2014-11-01

    Himalayan glaciers show large uncertainty regarding their present and future state due to their sensitive reaction towards change in climatic condition. Himalayan glaciers are unique as they are located in tropical, high altitude regions, predominantly valley type and many are covered with debris. The great northern plains of India sustain on the perennial melt of glaciers meeting the water requirements of agriculture, industries, domestic sector even in the months of summer when large tracts of the country go dry. Therefore, it is important to monitor and assess the state of snow and glaciers and to know the sustainability of glaciers in view of changing global scenarios of climate and water security of the nation. Any information pertaining to Himalayan glaciers is normally difficult to be obtained by conventional means due to its harsh weather and rugged terrains. Due to the ecological diversity and geographical vividness, major part of the Indian Himalaya is largely un-investigated. Considering the fact that Himalayan glaciers are situated in a harsh environment, conventional techniques of their study is challenging and difficult both in terms of logistics and finances whereas the satellite remote sensing offers a potential mode for monitoring glaciers in long term. In order to gain an updated overview of the present state of the glacier cover and its changes since the previous inventories, an attempt has been made to generate a new remotesensing- derived glacier inventory on 1:50,000 scale for Bhaga basin (N32°28'19.7'' - N33°0'9.9'' ; E76°56'16.3'' - E77°25'23.7'' ) Western Himalaya covering an area of 1695.63 km2. having 231 glaciers and occupying glacierized area of 385.17 ±3.71 km2. ranging from 0.03 km2. to 29.28 km2. Glacier inventory has been carried out using high resolution IRS P6 LISS III data of 2011, ASTER DEM and other ancillary data. Specific measurements of mapped glacier features are the inputs for generating the glacier inventory data

  8. Glacier Retreat in the Southern Peruvian Andes: Climate Change, Environmental Impacts, Human Perception and Social Response

    NASA Astrophysics Data System (ADS)

    Orlove, B.

    2007-12-01

    This paper presents results from recent environmental and anthropological research near glacierized areas in the department of Cusco, Peru, home to the well-known Quelccaya Ice Cap and to the peak of Ausangate (6384 m). Glaciers in the region are in negative mass balance, losing volume and area, with upslope movement of the glacier fronts. Somewhat paradoxically, flows in many streams close to the glaciers are reduced, particularly in the dry season, due to a shift in the seasonal distribution of melting, to increased evaporation and to increased percolation into newly-exposed sands and gravels. Associated with this reduction in flow is a desiccation of some anthropogenic and natural wetlands, reducing the availability of dry season forage to wild (vicuna) and domesticated (alpaca, llama) ruminants. Interviews and ethnographic observations with local populations of Quechua-speaking herders at elevations of 4500-5200 meters provide detailed comments on these changes. They have an extensive vocabulary of terms for glacial features associated with retreat. They link this treat with environmental factors (higher temperatures, greater winds that deposit dust on lower portions of glaciers) and with religious factors (divine punishment for human wrong-doing, failure of humans to respect mountain spirits). They describe a variety of economic and extra-economic impacts of this retreat on different spatial, social and temporal scales. Though they face other issues as well (threats of pollution from new mining projects, inadequacy of government services), glacier retreat is their principal concern. Many herders express extreme distress over this unprecedented threat to their livelihoods and communities, though a few propose responses - out-migration, the formation of an association of neighboring communities, development of irrigation works - that could serve as adaptations.

  9. Malaspina Glacier, Alaska, Perspective with Landsat Overlay

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Malaspina Glacier in southeastern Alaska is considered the classic example of a piedmont glacier. Piedmont glaciers occur where valley glaciers exit a mountain range onto broad lowlands, are no longer laterally confined, and spread to become wide lobes. Malaspina Glacier is actually a compound glacier, formed by the merger of several valley glaciers, the most prominent of which seen here are Agassiz Glacier (left) and Seward Glacier (right). In total, Malaspina Glacier is up to 65 kilometers (40 miles) wide and extends up to 45 kilometers (28 miles) from the mountain front nearly to the sea.

    This perspective view was created from a Landsat satellite image and an elevation model generated by the Shuttle Radar Topography Mission (SRTM). Landsat views both visible and infrared light, which have been combined here into a color composite that generally shows glacial ice in light blue, snow in white, vegetation in green, bare rock in grays and tans, and the ocean (foreground) in dark blue. The back (northern) edge of the data set forms a false horizon that meets a false sky.

    Glaciers erode rocks, carry them down slope, and deposit them at the edge of the melting ice, typically in elongated piles called moraines. The moraine patterns at Malaspina Glacier are quite spectacular in that they have huge contortions that result from the glacier crinkling as it gets pushed from behind by the faster-moving valley glaciers.

    Glaciers are sensitive indicators of climatic change. They can grow and thicken with increasing snowfall and/or decreased melting. Conversely, they can retreat and thin if snowfall decreases and/or atmospheric temperatures rise and cause increased melting. Landsat imaging has been an excellent tool for mapping the changing geographic extent of glaciers since 1972. The elevation measurements taken by SRTM in February 2000 now provide a near-global baseline against which future non-polar region glacial thinning or thickening can be assessed.

  10. The geochemical record in rock glaciers

    USGS Publications Warehouse

    Steig, E.J.; Fitzpatrick, J.J.; Potter, N.; Clark, D.H.

    1998-01-01

    A 9.5 m ice core was extracted from beneath the surficial debris cover of a rock glacier at Galena Creek, northwestern Wyoming. The core contains clean, bubble-rich ice with silty debris layers spaced at roughly 20 cm intervals. The debris layers are similar in appearance to those in typical alpine glaciers, reflecting concentration of debris by melting at the surface during the summer ablation season. Profiles of stable isotope concentrations and electrical conductivity measurements provide independent evidence for melting in association with debris layers. These observations are consistent with a glacial origin for the ice, substantiating the glacigenic model for rock glacier formation. The deuterium excess profile in the ice indicates that the total depth of meltwater infiltration is less than the thickness of one annual layer, suggesting that isotope values and other geochemical signatures are preserved at annual resolution. This finding demonstrates the potential for obtaining useful paleoclimate information from rock glacier ice.

  11. Complex Greenland outlet glacier flow captured.

    PubMed

    Aschwanden, Andy; Fahnestock, Mark A; Truffer, Martin

    2016-01-01

    The Greenland Ice Sheet is losing mass at an accelerating rate due to increased surface melt and flow acceleration in outlet glaciers. Quantifying future dynamic contributions to sea level requires accurate portrayal of outlet glaciers in ice sheet simulations, but to date poor knowledge of subglacial topography and limited model resolution have prevented reproduction of complex spatial patterns of outlet flow. Here we combine a high-resolution ice-sheet model coupled to uniformly applied models of subglacial hydrology and basal sliding, and a new subglacial topography data set to simulate the flow of the Greenland Ice Sheet. Flow patterns of many outlet glaciers are well captured, illustrating fundamental commonalities in outlet glacier flow and highlighting the importance of efforts to map subglacial topography. Success in reproducing present day flow patterns shows the potential for prognostic modelling of ice sheets without the need for spatially varying parameters with uncertain time evolution. PMID:26830316

  12. Complex Greenland outlet glacier flow captured

    PubMed Central

    Aschwanden, Andy; Fahnestock, Mark A.; Truffer, Martin

    2016-01-01

    The Greenland Ice Sheet is losing mass at an accelerating rate due to increased surface melt and flow acceleration in outlet glaciers. Quantifying future dynamic contributions to sea level requires accurate portrayal of outlet glaciers in ice sheet simulations, but to date poor knowledge of subglacial topography and limited model resolution have prevented reproduction of complex spatial patterns of outlet flow. Here we combine a high-resolution ice-sheet model coupled to uniformly applied models of subglacial hydrology and basal sliding, and a new subglacial topography data set to simulate the flow of the Greenland Ice Sheet. Flow patterns of many outlet glaciers are well captured, illustrating fundamental commonalities in outlet glacier flow and highlighting the importance of efforts to map subglacial topography. Success in reproducing present day flow patterns shows the potential for prognostic modelling of ice sheets without the need for spatially varying parameters with uncertain time evolution. PMID:26830316

  13. Stabilizing feedbacks in glacier-bed erosion.

    PubMed

    Alley, R B; Lawson, D E; Larson, G J; Evenson, E B; Baker, G S

    2003-08-14

    Glaciers often erode, transport and deposit sediment much more rapidly than nonglacial environments, with implications for the evolution of glaciated mountain belts and their associated sedimentary basins. But modelling such glacial processes is difficult, partly because stabilizing feedbacks similar to those operating in rivers have not been identified for glacial landscapes. Here we combine new and existing data of glacier morphology and the processes governing glacier evolution from diverse settings to reveal such stabilizing feedbacks. We find that the long profiles of beds of highly erosive glaciers tend towards steady-state angles opposed to and slightly more than 50 per cent steeper than the overlying ice-air surface slopes, and that additional subglacial deepening must be enabled by non-glacial processes. Climatic or glaciological perturbations of the ice-air surface slope can have large transient effects on glaciofluvial sediment flux and apparent glacial erosion rate.

  14. Employing terrestrial photogrammetry to determine surface roughness on a debris covered glacier

    NASA Astrophysics Data System (ADS)

    Steiner, J. F.; Miles, E. S.; Brun, F.; Detert, M.

    2015-12-01

    Aerodynamic surface roughness is an essential parameter in energy balance studies on glaciers. While actual measurements on bare ice glaciers are rare, a number of literature values exist for different types of ice and snow covers. There are only very few constant values suggested in the literature for debris covered glaciers and actual measurements are even scarcer. This is a significant shortcoming as the debris surface is often very heterogeneous, which results in variable turbulent fluxes. These fluxes, which use surface roughness as an input parameter, are also employed to derive debris thickness from surface temperature. The increased use of aerial and terrestrial photogrammetry on glaciers provides an opportunity to better account for this present shortcoming. On a number of locations of Lirung Glacier in the Nepalese Himalayas we produced high resolution DEMs from terrestrial photogrammetry, from 1 x 1 m plots to a wider basin spanning more than 100 m. These images were then downsampled to different resolutions, ranging from one millimeter to a few centimeters. Employing different equations from the literature we determine surface roughness at different scales. This way we can discuss (1) the variability of results between different commonly used approaches, (2) the variability of surface roughness in space and (3) the impact of image resolution. From a tower with wind and temperature sensors at different heights we additionally infer surface roughness locally. We can then compare these values as well as see the effect of different wind speeds on the derivation of the value. Employing a software originally developed to determine grain size distributions in river beds from optical imagery, we additionally determine rock shapes and size as well as provide an estimate for the grain size distribution of the debris cover. This could provide an initial step to a better estimation of the porous space of the debris cover, which is essential to determine energy flux

  15. The fleeting glaciers of the Arctic

    NASA Astrophysics Data System (ADS)

    Bakke, Jostein; Røthe, Torgeir; van der Bilt, Willem; Paasche, Øyvind

    2015-04-01

    Glaciers and snow are the very symbol of the Arctic, covering large parts of its terrestrial surface throughout the year. The cool temperatures that have allowed for the widespread coverage of glaciers are now trending towards a warmer climate, and with this gradual shift we observe a non-linear response in the cryosphere of which glaciers are a key component. This change is manifested in retreating fronts and an overall thinning. Because the typology of Arctic glaciers is rich and varied, the response pattern to the on-going warming is not unison. Instead we observe large spatial variations due to the critical balance between summer temperature and winter precipitation, but also other factors such as aspect, altitude, geographical location, debris cover and so forth. Even so, minor variations is superimposed on a larger trends which suggests that in a not so distant future, glaciers will probably be less abundant than what has been common for the last 100 years. In the context of the last 10 000 years it is evident that arctic glaciers have changed significantly and they have even been smaller than they are today, which was the case 9000 to 5000 years ago. On Svalbard, three glacier lake sediment records foretell of large past variations, indicating a more articulated sensitivity to climate change than what is commonly perceived for the Arctic cryosphere. Based on the lake sediment studies we will discuss Arctic glaciers sensitivity to decadal to millenium scale climate fluctuations and discuss possible forcing mechanims behind suitable for explaining what we see.

  16. Regional Observations of Alaska Glacier Dynamics

    NASA Astrophysics Data System (ADS)

    Burgess, E. W.; Forster, R. R.; Hall, D. K.

    2010-12-01

    Alaska glaciers contribute more to sea level rise than any other glacierized mountain region in the world. Alaska is loosing ~84 Gt of ice annually, which accounts for ~0.23 mm/yr of SLR (Luthcke et al., 2008). Complex glacier flow dynamics, frequently related to tidewater environments, is the primary cause of such rapid mass loss (Larsen et al., 2007). Indirect observations indicate these complex flow dynamics occur on many glaciers throughout Alaska, but no comprehensive velocity measurements exist. We are working to measure glacier surface velocities throughout Alaska using synthetic aperture radar (SAR) offset tracking. This work focuses on the Seward/Malaspina, Bering, Columbia, Kaskawulsh, and Hubbard Glaciers and uses a MODIS land surface temperature "melt-day" product (Hall et al., 2006, 2008) to identify potential links between velocity variability and summertime temperature fluctuations. Hall, D., R. Williams Jr., K. Casey, N. DiGirolamo, and Z. Wan (2006), Satellite-derived, melt-season surface temperature of the Greenland Ice Sheet (2000-2005) and its relationship to mass balance, Geophysical Research Letters, 33(11). Hall, D., J. Box, K. Casey, S. Hook, C. Shuman, and K. Steffen (2008), Comparison of satellite-derived and in-situ observations of ice and snow surface temperatures over Greenland, Remote Sensing of Environment, 112(10), 3739-3749. Larsen, C. F., R. J. Motyka, A. A. Arendt, K. A. Echelmeyer, and P. E. Geissler (2007), Glacier changes in southeast Alaska and northwest British Columbia and contribution to sea level rise, J. Geophys. Res. Luthcke, S., A. Arendt, D. Rowlands, J. McCarthy, and C. Larsen (2008), Recent glacier mass changes in the Gulf of Alaska region from GRACE mascon solutions, Journal of Glaciology, 54(188), 767-777.

  17. Integrated glacier and snow hydrological modelling in the Urumqi No.1 Glacier catchment

    NASA Astrophysics Data System (ADS)

    Gao, Hongkai; Hrachowitz, Markus; Savenije, Hubert

    2015-04-01

    The glacier and snow melt water from mountainous area is an essential water resource in Northwest China, where the climate is arid. Therefore a hydrologic model including glacier and snow melt simulation is in an urgent need for water resources management and prediction under climate change in this region. In this study, the Urumqi No.1 Glacier catchment in Northwest China, with 51% area covered by glacier, was selected as the study site. An integrated daily hydrological model was developed to systematically simulate the hydrograph, runoff separation (glacier and non-glacier runoff), the glacier mass balance (GMB), the equilibrium line altitude (ELA), and the snow water equivalent (SWE). Only precipitation, temperature and sunshine hour data is required as forcing input. A combination method, which applies degree-day approach during dry periods and empirical energy balance formulation during wet seasons, was implemented to simulate snow and glacier melt. Detailed snow melt processes were included in the model, including the water holding capacity of snow pack, the liquid water refreezing process in snow pack, and the change of albedo with time. A traditional rainfall-runoff model (Xinanjiang) was applied to simulate the rainfall(snowmelt)-runoff process in non-glacierized area. Additionally, the influence of elevation on temperature and precipitation distribution, and the impact of different aspect on snow and glacier melting were considered. The model was validated, not only by long-term observed daily runoff data, but also by measured snow (SWE) and glacier data (GMB, ELA) of over 50 years. Furthermore, the calibrated model can be upscaled into a larger catchment, which further supports our proposed model and optimized parameter sets.

  18. Where glaciers meet water: Subaqueous melt and its relevance to glaciers in various settings

    NASA Astrophysics Data System (ADS)

    Truffer, Martin; Motyka, Roman J.

    2016-03-01

    Glacier change is ubiquitous, but the fastest and largest magnitude changes occur in glaciers that terminate in water. This includes the most rapidly retreating glaciers, and also several advancing ones, often in similar regional climate settings. Furthermore, water-terminating glaciers show a large range in morphology, particularly when ice flow into ocean water is compared to that into freshwater lakes. All water-terminating glaciers share the ability to lose significant volume of ice at the front, either through mechanical calving or direct melt from the water in contact. Here we present a review of the subaqueous melt process. We discuss the relevant physics and show how different physical settings can lead to different glacial responses. We find that subaqueous melt can be an important trigger for glacier change. It can explain many of the morphological differences, such as the existence or absence of floating tongues. Subaqueous melting is influenced by glacial runoff, which is largely a function of atmospheric conditions. This shows a tight connection between atmosphere, oceans and lakes, and glaciers. Subaqueous melt rates, even if shown to be large, should always be discussed in the context of ice supply to the glacier front to assess its overall relevance. We find that melt is often relevant to explain seasonal evolution, can be instrumental in shifting a glacier into a different dynamical regime, and often forms a large part of a glacier's mass loss. On the other hand, in some cases, melt is a small component of mass loss and does not significantly affect glacier response.

  19. Identifying climatic drivers of glacier mass balance variability of Lewis glacier, Mt. Kenya

    NASA Astrophysics Data System (ADS)

    Nicholson, Lindsey; Prinz, Rainer; Kaser, Georg

    2013-04-01

    Lewis Glacier (Kenya, 0°09' S; 37°18' E) has a 20 year historical annual mass balance record, spanning 1979-1996 and 2010-2012. This offers an opportunity to investigate the glacier-climate interactions at ~4800m a.s.l. in the equatorial zone, which in turn allows investigation of the possible tropical mid-tropospheric conditions that must have prevailed in order to permit formerly larger glacier extents on the mountain. Here we use field data of glacier annual mass balance, seasonal glacier surface height changes and monthly precipitation records to test the impact of potential drivers on the glacier variability. We examine relationships between these glaciological data and ERA-interim atmospheric fields, satellite measurements of outgoing long wave radiation and sea surface temperatures. In all years except the mass balance year of 1989 Lewis glacier experiences a negative mass balance. Strongly negative annual mass balances occur only if one or both of the wet seasons fail to bring snowfall to the summit and both annual mass balance and rainy season surface change is well correlated with measured precipitation and enhanced convection within the equatorial rain belt in East Africa and the western Indian Ocean. Seasonal glacier surface height change is correlated with air temperature throughout the whole tropical African zone during the dry months of January and February, but the only positive mass balance year experienced seasonal cold temperature anomalies over equatorial Africa in all seasons. No single season emerges as the dominant driver of the inter-annual mass balance variability, and the climate sensitivity of the glacier surface change differs between seasons. However Lewis Glacier mass balance over the study period can be explained by moisture variability as the primary driver and temperature variability as an additional driver of glacier mass change.

  20. The slow advance of a calving glacier: Hubbard Glacier, Alaska, U.S.A

    USGS Publications Warehouse

    Trabant, D.C.; Krimmel, R.M.; Echelmeyer, K.A.; Zirnheld, S.L.; Elsberg, D.H.

    2003-01-01

    Hubbard Glacier is the largest tidewater glacier in North America. In contrast to most glaciers in Alaska and northwestern Canada, Hubbard Glacier thickened and advanced during the 20th century. This atypical behavior is an important example of how insensitive to climate a glacier can become during parts of the calving glacier cycle. As this glacier continues to advance, it will close the seaward entrance to 50 km long Russell Fjord and create a glacier-dammed, brackish-water lake. This paper describes measured changes in ice thickness, ice speed, terminus advance and fjord bathymetry of Hubbard Glacier, as determined from airborne laser altimetry, aerial photogrammetry, satellite imagery and bathymetric measurements. The data show that the lower regions of the glacier have thickened by as much as 83 m in the last 41 years, while the entire glacier increased in volume by 14.1 km3. Ice speeds are generally decreasing near the calving face from a high of 16.5 m d-1 in 1948 to 11.5 m d-1 in 2001. The calving terminus advanced at an average rate of about 16 m a-1 between 1895 and 1948 and accelerated to 32 m a-1 since 1948. However, since 1986, the advance of the part of the terminus in Disenchantment Bay has slowed to 28 m a-1. Bathymetric data from the lee slope of the submarine terminal moraine show that between 1978 and 1999 the moraine advanced at an average rate of 32 m a-1, which is the same as that of the calving face.

  1. Comparative metagenome analysis of an Alaskan glacier.

    PubMed

    Choudhari, Sulbha; Lohia, Ruchi; Grigoriev, Andrey

    2014-04-01

    The temperature in the Arctic region has been increasing in the recent past accompanied by melting of its glaciers. We took a snapshot of the current microbial inhabitation of an Alaskan glacier (which can be considered as one of the simplest possible ecosystems) by using metagenomic sequencing of 16S rRNA recovered from ice/snow samples. Somewhat contrary to our expectations and earlier estimates, a rich and diverse microbial population of more than 2,500 species was revealed including several species of Archaea that has been identified for the first time in the glaciers of the Northern hemisphere. The most prominent bacterial groups found were Proteobacteria, Bacteroidetes, and Firmicutes. Firmicutes were not reported in large numbers in a previously studied Alpine glacier but were dominant in an Antarctic subglacial lake. Representatives of Cyanobacteria, Actinobacteria and Planctomycetes were among the most numerous, likely reflecting the dependence of the ecosystem on the energy obtained through photosynthesis and close links with the microbial community of the soil. Principal component analysis (PCA) of nucleotide word frequency revealed distinct sequence clusters for different taxonomic groups in the Alaskan glacier community and separate clusters for the glacial communities from other regions of the world. Comparative analysis of the community composition and bacterial diversity present in the Byron glacier in Alaska with other environments showed larger overlap with an Arctic soil than with a high Arctic lake, indicating patterns of community exchange and suggesting that these bacteria may play an important role in soil development during glacial retreat.

  2. Glacier mass budget measurements by hydrologic means

    USGS Publications Warehouse

    Tangborn, Wendell V.

    1966-01-01

    Ice storage changes for the South Cascade Glacier drainage basin were determined for the 1957–1964 period using basin runoff and precipitation measurements. Measurements indicate that evaporation and condensation are negligible compared with the large runoff and precipitation values. Runoff, measured by a stream discharge station, averaged 4.04 m/yr; precipitation, determined by snow accumulation measurements at a central point on the glacier and by storage gages, averaged 3.82 m/yr, resulting in a basin net loss of about 0.22 m/yr. During the same period, South Cascade Glacier net budgets were determined by ablation stakes, snow density-depth profiles, and maps. The average glacier net budget for the period was −0.61sol;yr of water. This amount is equivalent to −0.26 m of water when averaged over the drainage basin (43% glacier-covered), which is in fair agreement with the net storage change measured by hydrologic methods. Agreement between the two methods for individual years is slightly less perfect. (Key words: Glaciers; water balance.)

  3. Rheology of rock glaciers: a preliminary assessment

    SciTech Connect

    Giardino, J.R.; Vitek, J.D.; Hoskins, E.R.

    1985-01-01

    Movement of rock debris under the influence of gravity, i.e., mass movement, generates a range of phenomena from soil creep, through solifluction,debris flows and rock glaciers to rock falls. Whereas the resultant forms of these phenomena are different, common elements in the mechanics of movement are utilized in the basic interpretation of the processes of formation. Measurements of morphologic variables provide data for deductive analyses of processes that operate too slowly to observe or for processes that generated relict phenomena. External and internal characteristics or rock glacier morphometry and measured rates of motion serve as the basis for the development of a rheological model to explain phenomena classified as rock glaciers. A rock glacier in the Sangre de Cristo Mountains of Southern Colorado, which exhibits a large number of ridges and furrows and lichen bare fronts of lobes, suggests present day movement. A strain-net established on the surface provides evidence of movement characteristics. These data plus morphologic and fabric data suggest two rheological models to explain the flow of this rock glacier. Model one is based upon perfect plastic flow and model two is based upon stratified fluid movement with viscosity changing with depth. These models permit a better understanding of the movement mechanics and demonstrate that catastrophic events and slow creep contribute to the morphologic characteristics of this rock glacier.

  4. Integrated firn elevation change model for glaciers and ice caps

    NASA Astrophysics Data System (ADS)

    Saß, Björn; Sauter, Tobias; Braun, Matthias

    2016-04-01

    We present the development of a firn compaction model in order to improve the volume to mass conversion of geodetic glacier mass balance measurements. The model is applied on the Arctic ice cap Vestfonna. Vestfonna is located on the island Nordaustlandet in the north east of Svalbard. Vestfonna covers about 2400 km² and has a dome like shape with well-defined outlet glaciers. Elevation and volume changes measured by e.g. satellite techniques are becoming more and more popular. They are carried out over observation periods of variable length and often covering different meteorological and snow hydrological regimes. The elevation change measurements compose of various components including dynamic adjustments, firn compaction and mass loss by downwasting. Currently, geodetic glacier mass balances are frequently converted from elevation change measurements using a constant conversion factor of 850 kg m-³ or the density of ice (917 kg m-³) for entire glacier basins. However, the natural conditions are rarely that static. Other studies used constant densities for the ablation (900 kg m-³) and accumulation (600 kg m-³) areas, whereby density variations with varying meteorological and climate conditions are not considered. Hence, each approach bears additional uncertainties from the volume to mass conversion that are strongly affected by the type and timing of the repeat measurements. We link and adapt existing models of surface energy balance, accumulation and snow and firn processes in order to improve the volume to mass conversion by considering the firn compaction component. Energy exchange at the surface is computed by a surface energy balance approach and driven by meteorological variables like incoming short-wave radiation, air temperature, relative humidity, air pressure, wind speed, all-phase precipitation, and cloud cover fraction. Snow and firn processes are addressed by a coupled subsurface model, implemented with a non-equidistant layer discretisation. On

  5. Modeling debris-covered glaciers: response to steady debris deposition

    NASA Astrophysics Data System (ADS)

    Anderson, Leif S.; Anderson, Robert S.

    2016-05-01

    Debris-covered glaciers are common in rapidly eroding alpine landscapes. When thicker than a few centimeters, surface debris suppresses melt rates. If continuous debris cover is present, ablation rates can be significantly reduced leading to increases in glacier length. In order to quantify feedbacks in the debris-glacier-climate system, we developed a 2-D long-valley numerical glacier model that includes englacial and supraglacial debris advection. We ran 120 simulations on a linear bed profile in which a hypothetical steady state debris-free glacier responds to a step increase of surface debris deposition. Simulated glaciers advance to steady states in which ice accumulation equals ice ablation, and debris input equals debris loss from the glacier terminus. Our model and parameter selections can produce 2-fold increases in glacier length. Debris flux onto the glacier and the relationship between debris thickness and melt rate strongly control glacier length. Debris deposited near the equilibrium-line altitude, where ice discharge is high, results in the greatest glacier extension when other debris-related variables are held constant. Debris deposited near the equilibrium-line altitude re-emerges high in the ablation zone and therefore impacts melt rate over a greater fraction of the glacier surface. Continuous debris cover reduces ice discharge gradients, ice thickness gradients, and velocity gradients relative to initial debris-free glaciers. Debris-forced glacier extension decreases the ratio of accumulation zone to total glacier area (AAR). Our simulations reproduce the "general trends" between debris cover, AARs, and glacier surface velocity patterns from modern debris-covered glaciers. We provide a quantitative, theoretical foundation to interpret the effect of debris cover on the moraine record, and to assess the effects of climate change on debris-covered glaciers.

  6. Velocities of Thwaites Glacier and smaller glaciers along the Marie Byrd Land coast, West Antarctica

    USGS Publications Warehouse

    Rosanova, C.E.; Lucchitta, B.K.; Ferrigno, J.G.

    1998-01-01

    Average velocities for time intervals ranging from <1 to 15 years were measured by tracking ice-surface patterns on sequential Landsat and European Remote-sensing Satellite synthetic aperture radar images. Velocities of Thwaites Glacier range from 2.2 km a-1 above the grounding line to 3.4 km a-1 at the limit of measurements on Thwaites Glacier ice tongue. The glacier increases in velocity by about 1 km a-1 where it crosses the grounding line. Over the period 1984-93, Thwaites Glacier ice tongue accelerated by about 0.6 km a-1. Velocities of the floating part of several minor glaciers and some ice shelves are also determined: Land Glacier, 1.7-1.9 km a-1; DeVicq Glacier, 0.7-1.1 km a-1; Dotson Ice Shelf, 0.2-0.5 km a-1; Getz Ice Shelf, 0.2-0.8 km a-1; and Sulzberger Ice Shelf, 0.01-0.02 km a-1. The high velocities along the Marie Byrd Land coast are consistent with the high precipitation rates over West Antarctica and, for some of the glaciers, the lack of buttressing ice shelves.

  7. Glacier Changes in the Russian High Arctic.

    NASA Astrophysics Data System (ADS)

    Pritchard, M. E.; Willis, M. J.; Melkonian, A. K.; Golos, E. M.; Stewart, A.; Ornelas, G.; Ramage, J. M.

    2014-12-01

    We provide new surveys of ice speeds and surface elevation changes for ~40,000 km2 of glaciers and ice caps at the Novaya Zemlya (NovZ) and Severnaya Zemlya (SevZ) Archipelagoes in the Russian High Arctic. The contribution to sea level rise from this ice is expected to increase as the region continues to warm at above average rates. We derive ice speeds using pixel-tracking on radar and optical imagery, with additional information from InSAR. Ice speeds have generally increased at outlet glaciers compared to those measured using interferometry from the mid-1990s'. The most pronounced acceleration is at Inostrantseva Glacier, one of the northernmost glaciers draining into the Barents Sea on NovZ. Thinning rates over the last few decades are derived by regressing stacked elevations from multiple Digital Elevations Models (DEMs) sourced from ASTER and Worldview stereo-imagery and cartographically derived DEMs. DEMs are calibrated and co-registered using ICESat returns over bedrock. On NovZ thinning of between 60 and 100 meters since the 1950s' is common. Similar rates between the late 1980s' and the present are seen at SevZ. We examine in detail the response of the outlet glaciers of the Karpinsky and Russanov Ice Caps on SevZ to the rapid collapse of the Matusevich Ice Shelf in the late summer of 2012. We do not see a dynamic thinning response at the largest feeder glaciers. This may be due to the slow response of the cold polar glaciers to changing boundary conditions, or the glaciers may be grounded well above sea level. Speed increases in the interior are difficult to assess with optical imagery as there are few trackable features. We therefore use pixel tracking on Terra SARX acquisitions before and after the collapse of the ice shelf to compute rates of flow inland, at slow moving ice. Interior ice flow has not accelerated in response to the collapse of the ice shelf but interior rates at the Karpinsky Ice Cap have increased by about 50% on the largest outlet

  8. What Influences Climate and Glacier Change in the Southwestern China?

    NASA Technical Reports Server (NTRS)

    Yasunari, Teppei J.

    2012-01-01

    The subject of climate change in the areas of the Tibetan Plateau (TP) and the Himalayas has taken on increasing importance because of available water resources from their mountain glaciers. Many of these glaciers over the region have been retreating, while some are advancing and stable. Other studies report that some glaciers in the Himalayas show acceleration on their shrinkage. However, the causes of the glacier meltings are still difficult to grasp because of the complexity of climatic change and its influence on glacier issues. However, it is vital that we pursue further study to enable the future prediction on glacier changes.

  9. Evaluating the performance of a glacier erosion model applied to Peyto Glacier, Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Vogt, R.; Mlynowski, T. J.; Menounos, B.

    2013-12-01

    Glaciers are effective agents of erosion for many mountainous regions, but primary rates of erosion are difficult to quantify due to unknown conditions at the glacier bed. We develop a numerical model of subglacial erosion and passively couple it to a vertically integrated ice flow model (UBC regional glaciation model). The model accounts for seasonal changes in water pressure at the glacier bed which affect rates of abrasion and quarrying. We apply our erosion model to Peyto Glacier, and compare estimates of glacier erosion to the mass of fine sediment contained in a lake immediately down valley from the glacier. A series of experiments with our model and ones based on subglacial sliding rates are run to explore model sensitivity to bedrock hardness, seasonal hydrology, changes in mass balance, and longer-term dimensional changes of the glacier. Our experiments show that, as expected, erosion rates are most sensitive to bedrock hardness and changes in glacier mass balance. Silt and clay contained in Peyto Lake primarily originate from the glacier, and represent sediments derived from abrasion and comminution of material produced by quarrying. Average specific sediment yield during the period AD1917-1970 from the lake is 467×190 Mg km-2yr-1 and reaches a maximum of 928 Mg km-2yr-1 in AD1941. Converting to a specific sediment yield, modelled average abrasion and quarrying rates during the comparative period are 142×44 Mg km-2yr-1 and 1167×213 Mg km-2yr-1 respectively. Modelled quarrying accounts for approximately 85-95% of the erosion occurring beneath the glacier. The basal sliding model estimates combined abrasion and quarrying. During the comparative period, estimated yields average 427×136 Mg km-2yr-1, lower than the combined abrasion and quarrying models. Both models predict maximum sediment yield when Peyto Glacier reached its maximum extent. The simplistic erosion model shows higher sensitivity to climate, as seen by accentuated sediment yield peaks

  10. Ancient carbon from a melting glacier gives high 14C age in living pioneer invertebrates

    PubMed Central

    Hågvar, Sigmund; Ohlson, Mikael

    2013-01-01

    Glaciers are retreating and predatory invertebrates rapidly colonize deglaciated, barren ground. The paradox of establishing predators before plants and herbivores has been explained by wind-driven input of invertebrate prey. Here we present an alternative explanation and a novel glacier foreland food web by showing that pioneer predators eat locally produced midges containing 21,000 years old ancient carbon released by the melting glacier. Ancient carbon was assimilated by aquatic midge larvae, and terrestrial adults achieved a radiocarbon age of 1040 years. Terrestrial spiders, harvestmen and beetles feeding on adult midges had radiocarbon ages of 340–1100 years. Water beetles assumed to eat midge larvae reached radiocarbon ages of 1100–1200 years. Because both aquatic and terrestrial pioneer communities use ancient carbon, the term “primary succession” is questionable in glacier forelands. If our “old” invertebrates had been collected as subfossils and radiocarbon dated, their age would have been overestimated by up to 1100 years. PMID:24084623

  11. Microbial primary production on an Arctic glacier is insignificant in comparison with allochthonous organic carbon input.

    PubMed

    Stibal, Marek; Tranter, Martyn; Benning, Liane G; Rehák, Josef

    2008-08-01

    Cryoconite holes are unique freshwater environments on glacier surfaces, formed when solar-heated dark debris melts down into the ice. Active photoautotrophic microorganisms are abundant within the holes and fix inorganic carbon due to the availability of liquid water and solar radiation. Cryoconite holes are potentially important sources of organic carbon to the glacial ecosystem, but the relative magnitudes of autochthonous microbial primary production and wind-borne allochthonous organic matter brought are unknown. Here, we compare an estimate of annual microbial primary production in 2006 on Werenskioldbreen, a Svalbard glacier, with the organic carbon content of cryoconite debris. There is a great disparity between annual primary production (4.3 mug C g(-1) year(-1)) and the high content of organic carbon within the debris (1.7-4.5%, equivalent to 8500-22 000 mug C g(-1) debris). Long-term accumulation of autochthonous organic matter is considered unlikely due to ablation dynamics and the surface hydrology of the glacier. Rather, it is more likely that the majority of the organic matter on Werenskioldbreen is allochthonous. Hence, although glacier surfaces can be a significant source of organic carbon for glacial environments on Svalbard, they may be reservoirs rather than oases of high productivity. PMID:18430008

  12. Investigating connections between local-remote atmospheric variability and Greenland outlet glacier behavior

    NASA Astrophysics Data System (ADS)

    Sobolowski, Stefan; Chen, Linling; Miles, Victoria

    2016-04-01

    /climate dynamics in glacier behavior. Our study suggests a strong relationship between large-scale tropospheric circulation patterns, such as the so-called Greenland Blocking Index (GBI), and glacier front position. This relationship is seen in the wintertime (summertime) circulation influence on spring (fall) front position. Dynamically, a physical pathway is illustrated via canonical correlation analyses and composites of low-mid level winds, which show strong southerly advection into the region when the GBI is positive. There are also potential links between local and remote diabatic heating in the atmospheric column, SSTs, sea-ice concentration and front position. Whether there are physical pathways connecting remote surface processes, such as heating along western Greenland is not yet clear. Causality is always difficult to infer in reanalysis-based studies but physical intuition and theory provide multiple lines of evidence, which suggest a substantial influence of large-scale atmospheric dynamics at the margins of the GrIS. Improving our understanding of these physical connections will be crucial, as we know the outlet glaciers will respond under rapidly changing climate conditions.

  13. Analysis of meteorological data and the surface energy balance of Keqicar Glacier, Tien Shan, China

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Liu, S.; Fujita, K.; Han, H.; Li, J.

    2009-04-01

    weather station on the glacier measured an average temperature of 2.6 °C (at 2m height above surface). The lapse rate of air temperature is close to the standard free atmospheric lapse rate (0.6 °C per 100m), which shows the cold effect of glacier is not significant. The local mountain-valley winds is significant, the speed of which is 2.3 m s-1 (at 2m height). Glacier is dominated by the convectional precipitation, 75% of which occurs in day time. The ablation stakes indicate a specific mass balance of -2.5 m w.e. between 1 July and 13 September. The specific mass balance calculated from the surface energy balance, -2.6 m w.e., is in close correspondence to this. The thermal processes on the debris layer are quite different from those on bare ice or snow. The main physical characteristics of the debris layer are the thermal conductivity and albedo that control heat conduction to the ice-debris interface. Net radiation is the main melt energy whether the debris layer is taken into consideration or not, which is lager between July and the middle of August, and then decreases. This is coincides with the glacier ablation. On the debris-covered area, the sensible- and latent-heat fluxes contribute 19.6% of the melt energy, higher than that on the debris-free ice (4.1%). Hence, due to the existing debris layer, the ablation shows a significant spatial distribution.

  14. Climate sensitivity of Tibetan Plateau glaciers - past and future implications

    NASA Astrophysics Data System (ADS)

    Heyman, Jakob; Hubbard, Alun; Stroeven, Arjen P.; Harbor, Jonathan M.

    2013-04-01

    The Tibetan Plateau is one of the most extensively glaciated, non-Polar regions of the world, and its mountain glaciers are the primary source of melt water for several of the largest Asian rivers. During glacial cycles, Tibetan Plateau glaciers advanced and retreated multiple times, but remained restricted to the highest mountain areas as valley glaciers and ice caps. Because glacier extent is dominantly controlled by climate, the past extent of Tibetan glaciers provide information on regional climate. Here we present a study analyzing the past maximum extents of glaciers on the Tibetan Plateau with the output of a 3D glacier model, in an effort to quantify Tibetan Plateau climate. We have mapped present-day glaciers and glacial landforms deposited by formerly more extensive glaciers in eight mountain regions across the Tibetan Plateau, allowing us to define present-day and past maximum glacier outlines. Using a high-resolution (250 m) higher-order glacier model calibrated against present-day glacier extents, we have quantified the climate perturbations required to expand present-day glaciers to their past maximum extents. We find that a modest cooling of at most 6°C for a few thousand years is enough to attain past maximum extents, even with 25-75% precipitation reduction. This evidence for limited cooling indicates that the temperature of the Tibetan Plateau remained relatively stable over Quaternary glacial cycles. Given the significant sensitivity to temperature change, the expectation is perhaps that a future warmer climate might result in intense glacier reduction. We have tested this hypothesis and modeled the future glacier development for the three mountain regions with the largest present-day glacier cover using a projected warming of 2.8 to 6.2°C within 100 years (envelope limits from IPCC). These scenarios result in dramatic glacier reductions, including 24-100% ice volume loss after 100 years and 77-100% ice volume loss after 300 years.

  15. Stationary monitoring of glacier response to climate change in China

    NASA Astrophysics Data System (ADS)

    Ren, Jiawen; Li, Zhongqin; Qin, Xiang; He, Yuanqing; He, Xiaobo; Li, Huilin

    2016-04-01

    At present, there are about 48571 glaciers with a total area of about 51.8×103 km2 and a volume of about 5.6×103 km3 in China. They are distributed widely in the high mountains in and surrounding the Tibetan Plateau and other high mountains such as Tianshan, Altay and Pamir. In view of differences in climatic conditions and glacier types, stationary monitoring of the glacier variations has been ongoing in different regions in order to investigate the glacier response to climate change. The monitoring results show that all the monitoring glaciers have been in retreat during the past decades and especially since 1990's the retreat rate has an accelerating trend. The accumulative mass balance is much negative and has a large annual variability for the monsoonal maritime glaciers in comparison with the continental and sub-continental glaciers. Under climate warming background, the acceleration of glacier melting is mainly attributed to rise in air temperature, ice temperature augment and albedo reduction of glacier surface. Particularly, the albedo reduction has a positive feedback effect on the glacier melting. Based on long term observation of glacier variations and physical properties, a simple dynamics model is coupled with mass balance modeling to make a projection of a typical glacier change in future. The primary modeling results suggest that the glacier will continue in shrinkage until vanishing within 50-90 years.

  16. Rock glaciers and the sediment dynamics in arid mountain belts

    NASA Astrophysics Data System (ADS)

    Blöthe, Jan Henrik; Höser, Thorsten; Rosenwinkel, Swenja; Korup, Oliver

    2016-04-01

    Rock glaciers are common periglacial features in highest elevations of semiarid to arid mountain ranges. Rock glaciers predominate in realms where precipitation values fall below thresholds that allow for ice glacier formation, then even outranging ice glaciers in size and number. The influence of ice glaciers on high-mountain's sediment dynamics is manifold: ice-glacier-driven erosion produces large amounts of clastic material; ice glaciers act as a conveyor belt for sediments, delivering material from their source regions to their terminus; ice glaciers entering trunk valleys form efficient dams that interrupt sediment delivery. While these mechanisms have been addressed in numerous earlier studies, the role of rock glaciers for the sediment dynamics of arid mountain belts remains elusive. We address this shortcoming by analysing a rock glacier inventory that we compiled for the Himalaya-Karakoram ranges and the Tien Shan ranges in Central Asia. Our inventory comprises more than 1000 specimen, a large number of which form dams of large trunk rivers and minor tributaries, disconnecting the sediment fluxes from upstream. In certain regions that are nearly devoid of ice-glaciers, like the Gamugah surface of NW Pakistan, rock glaciers of >10^4-m length occupy valley bottoms entirely, constituting the only mode of transport for sediments produced in headwaters. In conclusion, we call for a better understanding of the role that rock glaciers take in the sediment dynamics of arid mountain belts.

  17. Measured Climate Induced Volume Changes of Three Glaciers and Current Glacier-Climate Response Prediction

    NASA Astrophysics Data System (ADS)

    Trabant, D. C.; March, R. S.; Cox, L. H.; Josberger, E. G.

    2003-12-01

    Small but hydrologically significant shifts in climate have affected the rates of glacier volume change at the three U.S. Geological Survey Benchmark glaciers. Rate changes are detected as inflections in the cumulative conventional and reference-surface mass-balances of Wolverine and Gulkana Glaciers in Alaska and South Cascade Glacier in Washington. The cumulative mass balances are robust and have recently been corroborated by geodetic determinations of glacier volume change. Furthermore, the four-decade length of record is unique for the western hemisphere. Balance trends at South Cascade Glacier in Washington are generally in the opposite sense compared with Wolverine Glacier in Alaska; NCEP correlation of winter balance with local winter temperatures is positive at 0.59 for Wolverine and -0.64 for South Cascade Glacier. At Wolverine Glacier, the negative trend of cumulative mass balances, since measurements began in 1965, was replaced by a growth trend \\(positive mass balances\\) during the late 1970s and 1980s. The positive mass-balance trend was driven by increased precipitation during the 1976/77 to 1989 period. At Gulkana Glacier, the cumulative mass-balance trend has been negative throughout its measurement history, but with rate-change inflection points that coincide with the interdecadal climate-regime shifts in the North Pacific indices. At South Cascade Glacier, the mass-loss trend, observed since measurements began in 1953, was replaced by a positive trend between 1970 and 1976 then became strongly and continuously negative until 1997 when the rate of loss generally decreased. Since 1989, the trends of the glaciers in Alaska have also been strongly negative. These loss rates are the highest rates in the entire record. The strongly negative trends during the 1990s agree with climate studies that suggest that the period since the 1989 regime shift has been unusual. Volume response time and reference surface balance are the current suggested methods for

  18. Annual and seasonal mass balances of Chhota Shigri Glacier (benchmark glacier, Western Himalaya), India

    NASA Astrophysics Data System (ADS)

    Mandal, Arindan; Ramanathan, Alagappan; Farooq Azam, Mohd; Wagnon, Patrick; Vincent, Christian; Linda, Anurag; Sharma, Parmanand; Angchuk, Thupstan; Bahadur Singh, Virendra; Pottakkal, Jose George; Kumar, Naveen; Soheb, Mohd

    2015-04-01

    Several studies on Himalayan glaciers have been recently initiated as they are of particular interest in terms of future water supply, regional climate change and sea-level rise. In 2002, a long-term monitoring program was initiated on Chhota Shigri Glacier (15.7 square km, 9 km long, 6263-4050 m a.s.l.) located in Lahaul and Spiti Valley, Himachal Pradesh, India. This glacier lies in the monsoon-arid transition zone (western Himalaya) and is a representative glacier in Lahaul and Spiti Valley. While annual mass balances have been measured continuously since 2002 using the glaciological method, seasonal scale observations began in 2009. The annual and seasonal mass balances were then analyzed along with meteorological conditions in order to understand the role of winter and summer balances on annual glacier-wide mass balance of Chhota Shigri glacier. During the period 2002-2013, the glacier experienced a negative glacier-wide mass balance of -0.59±0.40 m w.e. a-1 with a cumulative glaciological mass balance of -6.45 m w.e. Annual glacier-wide mass balances were negative except for four years (2004/05, 2008/09, 2009/10 and 2010/11) where it was generally close to balanced conditions. Equilibrium line altitude (ELA) for steady state condition is calculated as 4950 m a.s.l. corresponding to an accumulation area ratio (AAR) of 62% using annual glacier-wide mass balance, ELA and AAR data between 2002 and 2013. The winter glacier-wide mass balance between 2009 and 2013 ranges from a maximum value of 1.38 m w.e. in 2009/10 to a minimum value of 0.89 in 2012/13 year whereas the summer glacier-wide mass balance varies from the highest value of -0.95 m w.e. in 2010/11 to the lowest value of -1.72 m w.e. in 2011/12 year. The mean vertical mass balance gradient between 2002 and 2013 was 0.66 m w.e. (100 m)-1 quite similar to Alps, Nepalese Himalayas etc. Over debris covered area, the gradients are highly variable with a negative mean value of -2.15 m w.e. (100 m)-1 over 2002

  19. Rapid Thinning of a Lake Calving Glacier: Yakutat Glacier, Southeast Alaska

    NASA Astrophysics Data System (ADS)

    Truessel, B.; Motyka, R. J.; Larsen, C. F.; Truffer, M.

    2010-12-01

    Calving glaciers around the world have recently undergone a rapid retreat and are important contributors to global sea level rise. Due to their greatly increased mass loss, tidewater glaciers in particular have long received much attention, whereas lake calving glaciers have just been identified as significant contributors. In southeast Alaska, numerous glaciers have experienced rapid retreat and significant thinning during the last several decades. To better understand the causes for these rapid changes we have focused on Yakutat Glacier, a lake calving glacier in southeast Alaska. Yakutat Glacier is part of the Yakutat Ice field and drains into Harlequin Lake, which has depths of over 300 m at the calving face. The ice field covers an area of 668 sq km and lies in a maritime area off the coast of the Gulf of Alaska. The average precipitation in the nearby town of Yakutat is over 3800 mm per year. However, the ice field divide is essentially at or below the current equilibrium line altitude (ELA) of 800 - 900 m for this region, thereby ensuring the glacier will continue to thin, provided the current trend of regional warming does not reverse. The ongoing thinning continues to lower the glaciers average elevation, increasing its average ablation, even under constant climate. This forms a positive feedback loop that is known as the Bovardsson effect. In addition, radio echo sounding shows much of the glacier base near or below sea level, indicating that lake calving will remain playing a role in the retreat. We obtained a 40 m-grid digital elevation model (DEM) derived from September 3, 2007 SPOT imagery and obtained under the IPY SPIRIT program. We used August 26, 2007 laser altimetry profiles to check the accuracy of the DEM and found a mean difference of 2 m (DEM greater) with a standard deviation of 2.3 m. We differenced this DEM from a DEM from the February 2000 Shuttle Radar Topography Mission to determine the extent of the volume change and thinning. During

  20. Distinct patterns of seasonal Greenland glacier velocity

    PubMed Central

    Moon, Twila; Joughin, Ian; Smith, Ben; van den Broeke, Michiel R; van de Berg, Willem Jan; Noël, Brice; Usher, Mika

    2014-01-01

    Predicting Greenland Ice Sheet mass loss due to ice dynamics requires a complete understanding of spatiotemporal velocity fluctuations and related control mechanisms. We present a 5 year record of seasonal velocity measurements for 55 marine-terminating glaciers distributed around the ice sheet margin, along with ice-front position and runoff data sets for each glacier. Among glaciers with substantial speed variations, we find three distinct seasonal velocity patterns. One pattern indicates relatively high glacier sensitivity to ice-front position. The other two patterns are more prevalent and appear to be meltwater controlled. These patterns reveal differences in which some subglacial systems likely transition seasonally from inefficient, distributed hydrologic networks to efficient, channelized drainage, while others do not. The difference may be determined by meltwater availability, which in some regions may be influenced by perennial firn aquifers. Our results highlight the need to understand subglacial meltwater availability on an ice sheet-wide scale to predict future dynamic changes. Key Points First multi-region seasonal velocity measurements show regional differences Seasonal velocity fluctuations on most glaciers appear meltwater controlled Seasonal development of efficient subglacial drainage geographically divided PMID:25821275

  1. ICESat Observations of Southern Alaska Glaciers

    NASA Technical Reports Server (NTRS)

    Sauber, Jeanne; Molnia, Bruce F.; Mitchell, Darius

    2003-01-01

    In late February and March, 2003, the Ice, Cloud, and land Elevation Satellite (ICESat) measured ice and land elevations along profiles across southern Alaska. During this initial data acquisition stage ICESat observations were made on 8-day repeat tracks to enable calibration and validation of the ICESat data products. Each profile consists of a series of single point values derived from centroid elevations of an $\\approx$70 m diameter laser footprint. The points are s4pakated by $\\approx$172 m along track. Data siets of 8-day observations (an ascending and descending ground track) crossed the Bering and Malaspina Glacier. Following its 1993--1995 surge; the Bering Glacier has undergone major terminus retreat as well as ike thinning in the abtation zone. During the later part of the 20th century, parts of the Malaspina thinned by about 1 m/yr. The multiple observation profiles across the Bering and Malaspina piedmont lobes obtained in February/March are being geolocated on Landsat images and the elevation profiles will be used for a number o scientific objectives. Based on our simulations of ICESat performance over the varied ice surface of the Jakobshavn Glacier of GReenland, 2003, we expect to measure annual, and possibly seasonal, ice elevation changes on the large Alaskan glaciers. Using elevation data obtained from a second laser, we plan to estimate ice elevation changes on the Bering Glacier between March and October 2003.

  2. Exploration of Uncertainty in Glacier Modelling

    NASA Technical Reports Server (NTRS)

    Thompson, David E.

    1999-01-01

    There are procedures and methods for verification of coding algebra and for validations of models and calculations that are in use in the aerospace computational fluid dynamics (CFD) community. These methods would be efficacious if used by the glacier dynamics modelling community. This paper is a presentation of some of those methods, and how they might be applied to uncertainty management supporting code verification and model validation for glacier dynamics. The similarities and differences between their use in CFD analysis and the proposed application of these methods to glacier modelling are discussed. After establishing sources of uncertainty and methods for code verification, the paper looks at a representative sampling of verification and validation efforts that are underway in the glacier modelling community, and establishes a context for these within overall solution quality assessment. Finally, an information architecture and interactive interface is introduced and advocated. This Integrated Cryospheric Exploration (ICE) Environment is proposed for exploring and managing sources of uncertainty in glacier modelling codes and methods, and for supporting scientific numerical exploration and verification. The details and functionality of this Environment are described based on modifications of a system already developed for CFD modelling and analysis.

  3. Improving Mass Balance Modeling of Benchmark Glaciers

    NASA Astrophysics Data System (ADS)

    van Beusekom, A. E.; March, R. S.; O'Neel, S.

    2009-12-01

    The USGS monitors long-term glacier mass balance at three benchmark glaciers in different climate regimes. The coastal and continental glaciers are represented by Wolverine and Gulkana Glaciers in Alaska, respectively. Field measurements began in 1966 and continue. We have reanalyzed the published balance time series with more modern methods and recomputed reference surface and conventional balances. Addition of the most recent data shows a continuing trend of mass loss. We compare the updated balances to the previously accepted balances and discuss differences. Not all balance quantities can be determined from the field measurements. For surface processes, we model missing information with an improved degree-day model. Degree-day models predict ablation from the sum of daily mean temperatures and an empirical degree-day factor. We modernize the traditional degree-day model as well as derive new degree-day factors in an effort to closer match the balance time series and thus better predict the future state of the benchmark glaciers. For subsurface processes, we model the refreezing of meltwater for internal accumulation. We examine the sensitivity of the balance time series to the subsurface process of internal accumulation, with the goal of determining the best way to include internal accumulation into balance estimates.

  4. Mathematical challenges in glacier modeling (Invited)

    NASA Astrophysics Data System (ADS)

    jouvet, G.

    2013-12-01

    Many of Earth's glaciers are currently shrinking and it is expected that this trend will continue as global warming progresses. To virtually reproduce the evolution of glaciers and finally to predict their future, one needs to couple models of different disciplines and scales. Indeed, the slow motion of ice is described by fluid mechanics equations while the daily snow precipitations and melting are described by hydrological and climatic models. Less visible, applied mathematics are essential to run such a coupling at two different levels: by solving numerically the underlying equations and by seeking parameters using optimisation methods. This talk aims to make visible the role of mathematics in this area. I will first present a short educational film I have made for the "Mathematics of Planet Earth 2013", which is an introduction to the topic. To go further, solving the mechanical model of ice poses several mathematical challenges due to the complexity of the equations and geometries of glaciers. Then, I will describe some strategies to deal with such difficulties and design robust simulation tools. Finally, I will present some simulations of the largest glacier of the European Alps, the Aletsch glacier. As a less unexpected application, I will show how these results allowed us to make a major advance in a police investigation started in 1926.

  5. Calibration of a distributed ablation model for Zhadang Glacier, Tibetan Plateau,using a time lapse camera system

    NASA Astrophysics Data System (ADS)

    Schneider, C.; Huintjes, E.; Bhattacharya, A.; Sauter, T.; Yang, W.; Bolch, T.; Pieczonka, T.; Maussion, F.; Kang, S.; Buchroithner, M.; Scherer, D.; Yao, T.

    2011-12-01

    A 1-dimensional energy balance model for calculation of snow melt including sub-surface refreezing has been applied in a simplified version for distributed ablation modeling on Zhadang Glacier, Nyainqentanglha Range, Tibetan Plateau. The model includes a distributed computation of short-wave radiation on a digital elevation model. Reduction of short-wave radiation due to cloud cover has been accounted for by comparing calculated radiation against measurements at an automatic weather station (AWS) on the glacier. Air temperature was distributed using the lapse rate as derived from AWS measurements in different altitudes along the Zhadang Valley. Specific humidity and wind speed were assumed to be spatially invariant. Also, ice temperature in spring at 10 m depth was assumed to be equal all over the glacier. In the same way, accumulation as measured at the AWS using an ultra-sonic ranging system was assumed to be the same for the whole glacier surface. Snow accumulation was corrected using daily imagery obtained from an automatic time lapse camera system installed outside the glacier. The same time series of pictures allows for detailed spatial and temporal observation of the transient snow line. Gaps in AWS data are filled by downscaling of the output of WRF numerical atmospheric model output to the AWS location on the glacier. The runs of the ablation model are initialized using spatially distributed snow depth measured at a series of ablation stakes on the glacier. From the model results the location of the transient snow line can be precisely located. The findings are compared to the transient snow line as derived from the picture series. Besides the possibility of post-calibrating the spatially distributed ablation model, the results of this approach also allow for identifying further relevant spatial processes that are not yet considered.

  6. The differing biogeochemical and microbial signatures of glaciers and rock glaciers

    USGS Publications Warehouse

    Fegel, Timothy S.; Baron, Jill S.; Fountain, Andrew G.; Johnson, Gunnar F.; Hall, Edward K.

    2016-01-01

    Glaciers and rock glaciers supply water and bioavailable nutrients to headwater mountain lakes and streams across all regions of the American West. Here we present a comparative study of the metal, nutrient, and microbial characteristics of glacial and rock glacial influence on headwater ecosystems in three mountain ranges of the contiguous U.S.: The Cascade Mountains, Rocky Mountains, and Sierra Nevada. Several meltwater characteristics (water temperature, conductivity, pH, heavy metals, nutrients, complexity of dissolved organic matter (DOM), and bacterial richness and diversity) differed significantly between glacier and rock glacier meltwaters, while other characteristics (Ca2+, Fe3+, SiO2 concentrations, reactive nitrogen, and microbial processing of DOM) showed distinct trends between mountain ranges regardless of meltwater source. Some characteristics were affected both by glacier type and mountain range (e.g. temperature, ammonium (NH4+) and nitrate (NO3- ) concentrations, bacterial diversity). Due to the ubiquity of rock glaciers and the accelerating loss of the low latitude glaciers our results point to the important and changing influence that these frozen features place on headwater ecosystems.

  7. The differing biogeochemical and microbial signatures of glaciers and rock glaciers

    NASA Astrophysics Data System (ADS)

    Fegel, Timothy S.; Baron, Jill S.; Fountain, Andrew G.; Johnson, Gunnar F.; Hall, Ed K.

    2016-03-01

    Glaciers and rock glaciers supply water and bioavailable nutrients to headwater mountain lakes and streams across all regions of the American West. Here we present a comparative study of the metal, nutrient, and microbial characteristics of glacial and rock glacial influence on headwater ecosystems in three mountain ranges of the contiguous U.S.: the Cascade Mountains, Rocky Mountains, and Sierra Nevada. Several meltwater characteristics (water temperature, conductivity, pH, metals, nutrients, complexity of dissolved organic matter (DOM), and bacterial richness and diversity) differed significantly between glacier and rock glacier meltwaters, while other characteristics (Ca2+, Fe3+, SiO2 concentrations, reactive nitrogen, and microbial processing of DOM) showed distinct trends between mountain ranges regardless of meltwater source. Some characteristics were affected both by glacier type and mountain range (e.g., temperature, ammonium (NH4+) and nitrate (NO3-) concentrations, and bacterial diversity). Due to the ubiquity of rock glaciers and the accelerating loss of the low-latitude glaciers, our results point to the important and changing influence that these frozen features place on headwater ecosystems.

  8. Modeled climate-induced glacier change in Glacier National Park, 1850-2100

    USGS Publications Warehouse

    Hall, M.H.P.; Fagre, D.B.

    2003-01-01

    The glaciers in the Blackfoot-Jackson Glacier Basin of Glacier National Park, Montana, decreased in area from 21.6 square kilometers (km2) in 1850 to 7.4 km2 in 1979. Over this same period global temperatures increased by 0.45??C (?? 0. 15??C). We analyzed the climatic causes and ecological consequences of glacier retreat by creating spatially explicit models of the creation and ablation of glaciers and of the response of vegetation to climate change. We determined the melt rate and spatial distribution of glaciers under two possible future climate scenarios, one based on carbon dioxide-induced global warming and the other on a linear temperature extrapolation. Under the former scenario, all glaciers in the basin will disappear by the year 2030, despite predicted increases in precipitation; under the latter, melting is slower. Using a second model, we analyzed vegetation responses to variations in soil moisture and increasing temperature in a complex alpine landscape and predicted where plant communities are likely to be located as conditions change.

  9. Comparison of energy balance on Gangotri and Chhota Shigri Glaciers

    NASA Astrophysics Data System (ADS)

    Rastogi, G.; Ajai

    2014-11-01

    Surface energy balance of a glacier governs the physical processes taking place at the surface-atmosphere interface and connects ice ablation/accumulation to climate variability. To understand the response of Himalayan glaciers to climatic variability, a study was taken to formulate energy balance equation on two of the Indian Himalayan glaciers, one each from Indus and Ganga basins, which have different climatic and physiographic conditions. Study was carried out over Gangotri glacier (Ganga basin) and Chhota Shigri(CS) glacier from Chandra sub-basin (Indus basin). Gangotri glacier is one of the largest glaciers in the central Himalaya located in Uttarkashi District, Uttarakhand, India. Chhota Shigri glacier of Chandra sub-basin lies in Lahaul and Spiti valley of Himachal Pradesh. Energy balance components have been computed using inputs derived from satellite data, AWS (Automatic Weather Station) data and field measurements. Different components of energy balance computed are net radiation (includes net shortwave and net longwave radiation), sensible heat flux and latent heat flux. In this study comparison has been made for each of the above energy balance components as well as total energy for the above glaciers for the months of November and December, 2011. It is observed that net radiation in Gangotri glacier is higher by approximately 43 % in comparison to Chhota Shigri glacier; Sensible heat flux is lesser by 77 %; Latent heat flux is higher by 66 % in the month of November 2011. Comparison in the month of December shows that net radiation in Gangotri glacier is higher by approximately 22 % from Chhota Shigri glacier; Sensible heat flux is lesser by 90 %; Latent heat flux is higher by 3 %.Total energy received at the glacier surface and contributes for melting is estimated to be around 32 % higher in Gangotri than Chhota Shigri glacier in November, 2011 and 1.25 % higher in December, 2011. The overall results contribute towards higher melting rate in

  10. Earthshots: Satellite images of environmental change – Petermann Glacier, Greenland

    USGS Publications Warehouse

    Adamson, Thomas

    2016-01-01

    This calving is normal, but it’s worth watching Petermann and other Greenland glaciers closely. Petermann is one of the major marine-terminating glaciers of Greenland. Ice loss from the Greenland Ice Sheet has increased recently. An article in Nature concluded that climate change may cause Petermann and other Greenland glaciers to contribute to sea level rise. Landsat helps glaciologists keep a close eye on this remote but significant glacier.

  11. Columbia Glacier, Alaska: changes in velocity 1977-1986

    USGS Publications Warehouse

    Krimmel, R.M.; Vaughn, B.H.

    1987-01-01

    The Columbia Glacier, a grounded, iceberg-calving tidewater glacier near Valdez, Alaska, began to retreat about 1977. Drastic retreat occurred in 1984, and by early 1986, retreat amounted to 2km. The glacier has thinned more than 100m since 1974 at a point 4km behind the 1974 terminus position. Between 1977 and 1985 the lower glacier ice velocity increased from 3-8m/d to 10-15m/d. -from Authors

  12. Determining the maximum contribution of glacier ice to streamflow

    NASA Astrophysics Data System (ADS)

    Schaner, N. A.; Voisin, N.; Lettenmaier, D. P.

    2010-12-01

    The importance of mountain glaciers as reservoirs of water is well known. With the receding of many mountain glaciers over recent decades, concerns have been voiced about the implications for water supply systems. Previous efforts to estimate the contribution of glacier melt to streamflow have used a variety of approaches, many of which are either for very small areas or include the contribution of seasonal snowmelt in addition to glacier melt. Over larger areas, the extent of glaciers remains somewhat uncertain - the primary source is satellite observations, but estimates of glacier extent can be confounded both by the possible presence of seasonal snow cover, and glacier debris cover. We attempt a slightly different approach, and apply a simple energy balance model globally at one-quarter degree spatial and monthly temporal resolutions to provide a basis for estimating an upper bound on the contribution of glacier melt to seasonal runoff. We assume that at the time of maximum glacier melt contribution, all available energy is converted to glacier melt. Melt water quantities are then compared to monthly total runoff simulated using the Variable Infiltration Capacity (VIC) macroscale hydrology model on grid cell basis. Melt water runoff and total runoff are routed downstream to track the signature of glacier melt. Drainage basins meeting a threshold ratio of glacier melt to total runoff are used to estimate populations at risk of lowered water resources. In general, our estimates of the population at risk are lower than other, published values. When applied to USGS Benchmark glaciers, we generally underestimate glacier melt as compared to drainage basin discharge records, but we overestimate the loss of mass for the same Benchmark glaciers. Despite uncertainties in the specific quantity of melt water, our model serves to highlight areas dependent on glacier water resources at a time of climatic uncertainty.

  13. The influence of air temperature inversions on snowmelt and glacier mass-balance simulations, Ammassalik island, SE Greenland

    SciTech Connect

    Mernild, Sebastian Haugard; Liston, Glen

    2009-01-01

    In many applications, a realistic description of air temperature inversions is essential for accurate snow and glacier ice melt, and glacier mass-balance simulations. A physically based snow-evolution modeling system (SnowModel) was used to simulate eight years (1998/99 to 2005/06) of snow accumulation and snow and glacier ice ablation from numerous small coastal marginal glaciers on the SW-part of Ammassalik Island in SE Greenland. These glaciers are regularly influenced by inversions and sea breezes associated with the adjacent relatively low temperature and frequently ice-choked fjords and ocean. To account for the influence of these inversions on the spatiotemporal variation of air temperature and snow and glacier melt rates, temperature inversion routines were added to MircoMet, the meteorological distribution sub-model used in SnowModel. The inversions were observed and modeled to occur during 84% of the simulation period. Modeled inversions were defined not to occur during days with strong winds and high precipitation rates due to the potential of inversion break-up. Field observations showed inversions to extend from sea level to approximately 300 m a.s.l., and this inversion level was prescribed in the model simulations. Simulations with and without the inversion routines were compared. The inversion model produced air temperature distributions with warmer lower elevation areas and cooler higher elevation areas than without inversion routines due to the use of cold sea-breeze base temperature data from underneath the inversion. This yielded an up to 2 weeks earlier snowmelt in the lower areas and up to 1 to 3 weeks later snowmelt in the higher elevation areas of the simulation domain. Averaged mean annual modeled surface mass-balance for all glaciers (mainly located above the inversion layer) was -720 {+-} 620 mm w.eq. y{sup -1} for inversion simulations, and -880 {+-} 620 mm w.eq. y{sup -1} without the inversion routines, a difference of 160 mm w.eq. y

  14. Malaspina Glacier, Alaska, Anaglyph with Landsat Overlay

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This anaglyph view of Malaspina Glacier in southeastern Alaska was created from a Landsat satellite image and an elevation model generated by the Shuttle Radar Topography Mission (SRTM). Malaspina Glacier is considered the classic example of a piedmont glacier. Piedmont glaciers occur where valley glaciers exit a mountain range onto broad lowlands, are no longer laterally confined, and spread to become wide lobes. Malaspina Glacier is actually a compound glacier, formed by the merger of several valley glaciers, the most prominent of which seen here are Agassiz Glacier (left) and Seward Glacier (right). In total, Malaspina Glacier is up to 65 kilometers (40 miles) wide and extends up to 45 kilometers (28 miles) from the mountain front nearly to the sea.

    Glaciers erode rocks, carry them down slope, and deposit them at the edge of the melting ice, typically in elongated piles called moraines. The moraine patterns at Malaspina Glacier are quite spectacular in that they have huge contortions that result from the glacier crinkling as it gets pushed from behind by the faster-moving valley glaciers.

    Numerous other features of the glaciers and the adjacent terrain are clearly seen when viewing this image at full resolution. The series of tonal arcs on Agassiz Glacier's extension onto the piedmont are called 'ogives.' These arcs are believed to be seasonal features created by deformation of the glacier as it passes over bedrock irregularities at differing speeds through the year. Assuming one light-and-dark ogive pair per year, the rate of motion of the glacial ice can be estimated (in this case, about 200 meters per year where the ogives are most prominent). Just to the west, moraine deposits abut the eroded bedrock terrain, forming a natural dam that has created a lake. Near the northwest corner of the scene, a recent landslide has deposited rock debris atop a small glacier. Sinkholes are common in many areas of the moraine deposits. The sinkholes form when

  15. Snow and glacier mapping with polarimetric SAR

    NASA Technical Reports Server (NTRS)

    Shi, Jiancheng; Dozier, Jeff; Rott, Helmut; Davis, Robert E.

    1991-01-01

    The objective of this study was to examine the capability of mapping snow and glaciers in alpine regions using synthetic aperture radar (SAR) imagery when topographic information is not available. The topographic effects on the received power for a resolution cell can be explained by the change in illumination area and incidence angle in a slant-rante representation of SAR imagery. The specific polarization signatures and phase difference between HH and VV components are relatively independent of the illuminated are, and the incidence angle has only a small effect on these parameters. They provide a suitable measurement data set for snow and glacier mapping in a high-relief area. The results show that the C-band images of the enhancement factor, the phase difference between HH and VV scattering components, and the normalized cross product of VV scattering elements provide the capability to discriminate among snow with different wetnesses, glaciers, and rocky regions.

  16. More Data and Better Tools for the GLIMS Glacier Database

    NASA Astrophysics Data System (ADS)

    Raup, B. H.; Armstrong, R. L.; Cogley, J. G.; Hock, R.

    2015-12-01

    Earth's glaciers are changing rapidly in response to a changing climate, and this has implications for people in numerous ways, such as increased hazards from glacial lake outburst floods, changes to water resources, and increasing sea level. To understand these changes, it is vitally important to monitor glaciers through time, measuring their areal extent, changes in volume, flow velocities, snow lines, elevation distribution, and changes to associated water bodies. The glacier database of the Global Land Ice Measurements from Space (GLIMS) initiative is the only multi-temporal glacier database capable of tracking all these glacier measurements and providing them to the scientific community and broader public.This contribution presents recent results in 1) expansion of the GLIMS Glacier Database in geographic coverage by drawing on the Randolph Glacier Inventory (RGI) and other new data sets; 2) new tools for visualizing and downloading GLIMS data in a choice of formats and data models; 3) a new data model for handling multiple glacier records through time while avoiding double-counting of glacier number or area; and 4) a new system of collaboration between all members of the glacier mapping community to streamline the process of meeting various community needs. The result of this work promises to be an improved glacier data repository that will be useful for tracking changes in water resources, hazards, and mass budgets of the world's glaciers.

  17. Contrasting responses of Central Asian rock glaciers to global warming.

    PubMed

    Sorg, Annina; Kääb, Andreas; Roesch, Andrea; Bigler, Christof; Stoffel, Markus

    2015-02-06

    While the responses of Tien Shan glaciers--and glaciers elsewhere--to climatic changes are becoming increasingly well understood, this is less the case for permafrost in general and for rock glaciers in particular. We use a novel approach to describe the climate sensitivity of rock glaciers and to reconstruct periods of high and low rock glacier activity in the Tien Shan since 1895. Using more than 1500 growth anomalies from 280 trees growing on rock glacier bodies, repeat aerial photography from Soviet archives and high-resolution satellite imagery, we present here the world's longest record of rock glacier movements. We also demonstrate that the rock glaciers exhibit synchronous periods of activity at decadal timescales. Despite the complex energy-balance processes on rock glaciers, periods of enhanced activity coincide with warm summers, and the annual mass balance of Tuyuksu glacier fluctuates asynchronously with rock glacier activity. At multi-decadal timescales, however, the investigated rock glaciers exhibit site-specific trends reflecting different stages of inactivation, seemingly in response to the strong increase in air temperature since the 1970s.

  18. Contrasting responses of Central Asian rock glaciers to global warming

    PubMed Central

    Sorg, Annina; Kääb, Andreas; Roesch, Andrea; Bigler, Christof; Stoffel, Markus

    2015-01-01

    While the responses of Tien Shan glaciers – and glaciers elsewhere – to climatic changes are becoming increasingly well understood, this is less the case for permafrost in general and for rock glaciers in particular. We use a novel approach to describe the climate sensitivity of rock glaciers and to reconstruct periods of high and low rock glacier activity in the Tien Shan since 1895. Using more than 1500 growth anomalies from 280 trees growing on rock glacier bodies, repeat aerial photography from Soviet archives and high-resolution satellite imagery, we present here the world's longest record of rock glacier movements. We also demonstrate that the rock glaciers exhibit synchronous periods of activity at decadal timescales. Despite the complex energy-balance processes on rock glaciers, periods of enhanced activity coincide with warm summers, and the annual mass balance of Tuyuksu glacier fluctuates asynchronously with rock glacier activity. At multi-decadal timescales, however, the investigated rock glaciers exhibit site-specific trends reflecting different stages of inactivation, seemingly in response to the strong increase in air temperature since the 1970s. PMID:25657095

  19. 36 CFR 7.3 - Glacier National Park.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Glacier National Park. 7.3... REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.3 Glacier National Park. (a) Fishing. (1) Fishing... food, drink, or lodging for sale may be operated on any privately owned lands within Glacier...

  20. ASTER Imaging and Analysis of Glacier Hazards

    NASA Astrophysics Data System (ADS)

    Kargel, Jeffrey; Furfaro, Roberto; Kaser, Georg; Leonard, Gregory; Fink, Wolfgang; Huggel, Christian; Kääb, Andreas; Raup, Bruce; Reynolds, John; Wolfe, David; Zapata, Marco

    Most scientific attention to glaciers, including ASTER and other satellite-derived applications in glacier science, pertains to their roles in the following seven functions: (1) as signposts of climate change (Kaser et al. 1990; Williams and Ferrigno 1999, 2002; Williams et al. 2008; Kargel et al. 2005; Oerlemans 2005), (2) as natural reservoirs of fresh water (Yamada and Motoyama 1988; Yang and Hu 1992; Shiyin et al. 2003; Juen et al. 2007), (3) as contributors to sea-level change (Arendt et al. 2002), (4) as sources of hydropower (Reynolds 1993); much work also relates to the basic science of glaciology, especially (5) the physical phenomeno­logy of glacier flow processes and glacier change (DeAngelis and Skvarca 2003; Berthier et al. 2007; Rivera et al. 2007), (6) glacial geomorphology (Bishop et al. 1999, 2003), and (7) the technology required to acquire and analyze satellite images of glaciers (Bishop et al. 1999, 2000, 2003, 2004; Quincey et al. 2005, 2007; Raup et al. 2000, 2006ab; Khalsa et al. 2004; Paul et al. 2004a, b). These seven functions define the important areas of glaciological science and technology, yet a more pressing issue in parts of the world is the direct danger to people and infrastructure posed by some glaciers (Trask 2005; Morales 1969; Lliboutry et al. 1977; Evans and Clague 1988; Xu and Feng 1989; Reynolds 1993, 1998, 1999; Yamada and Sharma 1993; Hastenrath and Ames 1995; Mool 1995; Ames 1998; Chikita et al. 1999; Williams and Ferrigno 1999; Richardson and Reynolds 2000a, b; Zapata 2002; Huggel et al. 2002, 2004; Xiangsong 1992; Kääb et al. 2003, 2005, 2005c; Salzmann et al. 2004; Noetzli et al. 2006).

  1. Ocean and glaciers interactions in Svalbard area

    NASA Astrophysics Data System (ADS)

    Walczowski, Waldemar; Błaszczyk, Małgorzata; Wawrzyniak, Tomasz; Beszczyńska-Möller, Agnieszka

    2016-04-01

    Arctic fjords are a link between land and ocean. The inshore boundary of the fjords system is usually dominated by the tidewater glaciers and seasonal freshwater input while its offshore boundary is strongly influenced by oceanic waters. Improved understanding of the fjords-ocean exchange and processes within Arctic fjords is of a highest importance because their response to atmospheric, oceanic and glacial variability provides a key to understand the past and to forecast the future of the high latitude glaciers and Arctic climate. Rapidly changed Arctic climate requires multidisciplinary and complex investigations of the basic climate components and interactions between them. The aim of the Polish-Norwegian project 'Arctic climate system study of ocean, sea ice and glaciers interactions in Svalbard area' (AWAKE-2) is to understand the interactions between the ocean, atmosphere and cryosphere. The main oceanic heat source in Svalbard region is the West Spitsbergen Current consisting of multi-branch, northward flow of warm, Atlantic origin water (AW). During its transit through the Nordic Seas, AW releases a large amount of heat to the atmosphere. When entering the Western Svalbard fjords, AW modifies hydrographic conditions, reduces winter ice cover and directly influences tidewater glaciers. An impact of the AW variability on atmosphere and sea ice is clearly visible with strong correlations between AW properties and air temperature or sea ice coverage. For tidewater glaciers these effects can be recognized, but correlations are weaker due to different processes that influence the intensity of glaciers melting and calving. The dedicated, multidisciplinary approach was adopted to achieve the AWAKE-2 project's aims by carrying out the coordinated meteorological, oceanographic, glaciological and geophysical observations in the Hornsund fjord, the adjacent shelf and ocean.

  2. Controls on microalgal community structures in cryoconite holes upon high-Arctic glaciers, Svalbard

    NASA Astrophysics Data System (ADS)

    Vonnahme, T. R.; Devetter, M.; Žárský, J. D.; Šabacká, M.; Elster, J.

    2016-02-01

    Glaciers are known to harbor surprisingly complex ecosystems. On their surface, distinct cylindrical holes filled with meltwater and sediments are considered hot spots for microbial life. The present paper addresses possible biological interactions within the community of prokaryotic cyanobacteria and eukaryotic microalgae (microalgae) and relations to their potential grazers, such as tardigrades and rotifers, additional to their environmental controls. Svalbard glaciers with substantial allochthonous input of material from local sources reveal high microalgal densities. Small valley glaciers with high sediment coverages and high impact of birds show high biomasses and support a high biological diversity. Invertebrate grazer densities do not show any significant negative correlation with microalgal abundances but rather a positive correlation with eukaryotic microalgae. Shared environmental preferences and a positive effect of grazing are the proposed mechanisms to explain these correlations. Most microalgae found in this study form colonies (< 10 cells, or > 25 µm), which may protect them against invertebrate grazing. This finding rather indicates grazing as a positive control on eukaryotic microalgae by nutrient recycling. Density differences between the eukaryotic microalgae and prokaryotic cyanobacteria and their high distinction in redundancy (RDA) and principal component (PCA) analyses indicate that these two groups are in strong contrast. Eukaryotic microalgae occurred mainly in unstable cryoconite holes with high sediment loads, high N : P ratios, and a high impact of nutrient input by bird guano, as a proxy for nutrients. In these environments autochthonous nitrogen fixation appears to be negligible. Selective wind transport of Oscillatoriales via soil and dust particles is proposed to explain their dominance in cryoconites further away from the glacier margins. We propose that, for the studied glaciers, nutrient levels related to recycling of limiting

  3. Controls on microalgal community structures in cryoconite holes upon high Arctic glaciers, Svalbard

    NASA Astrophysics Data System (ADS)

    Vonnahme, T. R.; Devetter, M.; Žárský, J. D.; Šabacká, M.; Elster, J.

    2015-07-01

    Glaciers are known to harbor surprisingly complex ecosystems. On their surface, distinct cylindrical holes filled with meltwater and sediments are considered as hot spots for microbial life. The present paper addresses possible biological interactions within the community of prokaryotic cyanobacteria and eukaryotic microalgae (microalgae) and relations to their potential grazers, additional to their environmental controls. Svalbard glaciers with substantial allochthonous input of material from local sources reveal high microalgal densities. Small valley glaciers with high sediment coverages and high impact of birds show high biomasses and support a high biological diversity. Invertebrate grazer densities do not show any significant negative correlation with microalgal abundances, but a positive correlation with eukaryotic microalgae. Most microalgae found in this study form large colonies (< 10 cells, or > 25 μm), which may protect them against invertebrate grazing. This finding rather indicates grazing as a positive control on eukaryotic microalgae by nutrient recycling. Density differences between the eukaryotic microalgae and prokaryotic cyanobacteria and their high distinction in RDA and PCA analyses indicate that these two groups are in strong contrast. Eukaryotic microalgae occurred mainly in unstable cryoconite holes with high sediment loads, high N : P ratios, and a high impact of bird guano, as a proxy for nutrients. In these environments autochthonous nitrogen fixation appears to be negligible. Selective wind transport of Oscillatoriales via soil and dust particles is proposed to explain their dominance in cryoconites further away from the glacier margins. We propose that, for the studied glaciers, nutrient levels related to recycling of limiting nutrients is the main factor driving variation in the community structure of microalgae and grazers.

  4. Columbia Glacier in 1986; 800 meters retreat

    USGS Publications Warehouse

    Krimmel, R.M.

    1987-01-01

    Columbia Glacier, in Prince William Sound, Alaska, continued its rapid retreat in 1986, with a retreat of 800 m. Average velocity of the lower portion of the glacier, 10 September 1986 to 26 January 1987, was three km/yr, or about one-half of the velocity during similar periods for the previous three years. This reduced velocity is a new development in the progression of the retreat, and if the calving rate follows the pattern of previous years, will result in continued retreat. (Author 's abstract)

  5. Glacier fluctuations in the Kenai Fjords, Alaska, U.S.A.: An evaluation of controls on Iceberg-calving glaciers

    SciTech Connect

    Wiles, G.C.; Calkin, P.E.; Post, A.

    1995-08-01

    The histories of four iceberg-calving outlet-glacier systems in the Kenai Fjords National Park underscore the importance of fiord depth, sediment supply, and fiord geometry on glacier stability. These parameters, in turn, limit the reliability of calving glacier chronologies as records of climatic change. Tree-ring analysis together with radiocarbon dating show that the Northwestern and McCarty glaciers, with large drainage basins, were advancing in concert with nearby land-terminating glaciers about A.D. 600. After an interval of retreat and possible nonclimatically induced extension during the Medieval Warm Period, these ice margins advanced again through the Little Ice Age and then retreated synchronously with the surrounding land-terminating glaciers about A.D. 1900. In contrast, Holgate and Aialik glaciers, with deeper fiords and smaller basins, retreated about 300 yr earlier. Reconstructions of Little Ice Age glaciers suggest that equilibrium-line altitudes of Northwestern and McCarty glaciers were, respectively, 270 and 500 m lower than now. Furthermore, the reconstructions show that these two glaciers were climatically sensitive when at their terminal moranies. However, with ice margins at their present recessional positions and accumulation area ratios between 0.8 and 0.9, only McCarty Glacier shows evidence of advance. Aialik and Holgate glaciers were climatically insensitive during the Little Ice Age maxima and remain insensitive to climate. 40 refs., 7 figs., 2 tabs.

  6. Surface characteristics and evolution of debris covered glaciers

    NASA Astrophysics Data System (ADS)

    Mölg, Nico; Vieli, Andreas; Bolch, Tobias; Bauder, Andreas; Bhattacharya, Atanu

    2016-04-01

    Global climate change has led to increasing glacier retreat in most parts of the world. However, many heavily debris-covered glaciers have shown much smaller recession rates than their clean-ice neighbours. This can be attributed to the insulation effect of the supraglacial debris. Remote-sensing based investigations revealed that recent mass balances of debris-covered glaciers are equally negative. This fact is partly due to enhanced melting at supra-glacial lakes and ice cliffs but can also be caused by reduced mass flux. In this context, insufficient process understanding constitutes a major challenge for large scale glacier change assessment and modelling. In this project, we aim at better understanding the evolution of glaciers in connection with changes in supra-glacial debris coverage. It is performed on Zmutt Glacier in Matter valley in Switzerland and on Gangotri Glacier in Garwhal Himalaya in India. Changes in glacier length, area, debris coverage, and surface elevation were compiled based on topographic maps, oblique photos, aerial and satellite orthoimages, digital terrain models (DTMs), and glacier monitoring data for a 50 (Gangotri) and 120 (Zmutt) year period, respectively. The subsequent analysis revealed that Zmutt Glacier has been in a slow but almost continuous retreating state since the end of the 19th century and showed a clear reduction in glacier area and volume. Similarly, Gangotri Glacier has retreated and, to a smaller degree, lost volume. However, the change in glacier length and area is clearly smaller than for other nearby, less debris-covered or debris-free glaciers. This fact is attributed to the larger debris-covered area that has steadily increased. Further in the project, this data will serve as an important input and validation for the envisaged 3D flow modelling and, hence, will contribute to the understanding of the development of glaciers and debris-covered ice in a period of fast climatic changes.

  7. Impact of sublimation losses in the mass balance of glaciers in semi-arid mountain regions

    NASA Astrophysics Data System (ADS)

    Ayala, Alvaro; Pellicciotti, Francesca; Burlando, Paolo; MacDonell, Shelley; McPhee, James

    2016-04-01

    Glaciers in semiarid mountain regions may lose an important part of their winter snow accumulation through sublimation processes that are enhanced by the high-elevation, intense radiation and dry atmosphere of these environments. As glaciers in these regions secure freshwater resources to lower valleys during summer and drought periods, it is important to advance in a detailed quantification of their sublimation losses. However, logistical concerns and complex meteorological features make the measuring and modelling of glacier mass balances a difficult task. In this study, we estimated the spring-summer mass balances of Tapado and Juncal Norte glaciers in the semiarid Andes of north-central Chile by running a distributed energy balance model that accounts for melt, refreezing and sublimation from the surface and blowing snow. Meteorological input data were available from on-glacier Automatic Weather Stations (AWS) that were installed during the ablation season of years 2005-06, 2008-09, 2013-14 and 2014-15. Snow pits, ablation stakes and a time-lapse camera that provided surface albedo were also available. Distributed air temperature and wind speed were dynamically downscaled from NASA MERRA reanalysis using the software WINDSIM and validated against the data from the AWSs. The rest of the meteorological variables were distributed using statistical relations with air temperature derived from the AWSs data. Initial snow conditions were estimated using satellite images and distributed manual snow depth measurements. Preliminary results show that total ablation diminishes with elevation and that, during the early ablation season (October-November), melt is the main ablation component below 4500 m with sublimation dominating the ablation above this elevation. Above 4500 m an important fraction of meltwater refreezes during night. As the ablation season advances (December-February), melt extends to higher elevations, refreezing plays a smaller role and sublimation is

  8. Malaspina Glacier, Alaska as seen from STS-66 Atlantis

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Malaspina Glacier can be seen in this north-northeastern photograph taken in November, 1994. The glacier, located in the south shore of Alaska is a classic example of a piedmont glacier lying along the foot of a mountain range. The principal source of ice for the glacier is provided by the Seward Ice Field to the north (top portion of the view) which flows through three narrow outlets onto the coastal plain. The glacier moves in surges that rush earlier-formed moraines outward into the expanding concentric patterns along the flanks of the ice mass.

  9. Sensitivity of glaciers and small ice caps to greenhouse warming

    SciTech Connect

    Oerlemans, J.; Fortuin, J.P.F. )

    1992-10-02

    Recent field programs on glaciers have supplied information that makes simulation of glacier mass balance with meteorological models meaningful. An estimate of world-wide glacier sensitivity based on a modeling study of 12 selected glaciers situated in widely differing climatic regimes shows that for a uniform 1 K warming the area-weighted glacier mass balance will decrease by 0.40 meter per year. This corresponds to a sea-level rise of 0.58 millimeter per year, a value significantly less than earlier estimates.

  10. Contrasting response of South Greenland glaciers to recent climatic change

    SciTech Connect

    Warren, C.R.; Glasser, N.F. )

    1992-05-01

    A unique geographical configuration of glaciers exists in the Narsarsuaq district of South Greenland. Two large outlet glaciers divide into seven distributaries, such that each glacier system has land-terminating, tidewater-calving, and fresh-water-calving termini. Despite a similar climatic regime, these seven glaciers have exhibited strongly contrasting terminal behavior in historical time, as shown by historical records, aerial photographs, and fieldwork in 1989. The behavior of the calving glaciers cannot be accounted for with reference solely to climatic parameters. The combination of iceberg calving dynamics and topographic control has partially decoupled them from climatic forcing such that their oscillations relate more closely to glaciodynamic than glacioclimatic factors.

  11. Monitoring and Modelling Glacier Melt and Runoff on Juncal Norte Glacier, Aconcagua River Basin, Central Chile

    NASA Astrophysics Data System (ADS)

    Pellicciotti, F.; Helbing, J. F.; Araos, J.; Favier, V.; Rivera, A.; Corripio, J.; Sicart, J. M.

    2006-12-01

    Results from a recent glacio-meteorological experiment on the Juncal Norte glacier, in central Chile, are presented. Melt water is a crucial resource in the Central Andes, as it provides drinking water, water for agriculture and for industrial uses. There is also increasing competition for water use and allocation, as water demands from mining and industry are rising. Assessing water availability in this region and its relation with climatic variations is therefore crucial. The Dry Central Andes are characterised by a climatic setting different from that of the Alps and the subtropical Andes of Bolivia and Peru. Summers are very dry and stable, with precipitation close to zero and low relative humidity. Solar radiation is very intense, and plays a key role in the energy balance of snow covers and glaciers. The main aim of this study is to investigate the glacier-climate interaction in this area, with particular attention devoted to advanced modelling techniques for the spatial redistribution of meteorological variables, in order to gain an accurate picture of the ablation processes typical of these latitudes. During the ablation season 2005/2006, an extensive field campaign was conducted on the Juncal Norte glacier, aimed at monitoring the melt and runoff generation processes on this remote glacier in the dry Andes. Melt rates, runoff at the snout, meteorological variables over and near the glacier, GPS data and glacier topography were recorded over the entire ablation season. Using this extensive and accurate data set, the spatial and temporal variability of the meteorological variables that drive the melt process on the glacier is investigated, together with the process of runoff generation. An energy balance model is used to simulate melt across the glacier, and special attention is devoted to the modelling of the solar radiation energy flux. The components of the energy balance are compared with those of Alpine basins. The validity of parameterisations of the

  12. Malaspina Glacier: a modern analog to the Laurentide Glacier in New England

    SciTech Connect

    Gustavson, T.C.; Boothroyd, J.C.

    1985-01-01

    The land-based temperate Malaspina Glacier is a partial analog to the late Wisconsinan Laurentide Ice Sheet that occupied New England and adjacent areas. The Malaspina occupies a bedrock basin similar to basins occupied by the margin of the Laurentide Ice Sheet. Ice lobes of the Malaspina are similar in size to end moraine lobes in southern New England and Long Island,New York. Estimated ice temperature, ablation rates, surface slopes and meltwater discharge per unit of surface area for the Laurentide Ice Sheet are similar to those for the Malaspina Glacier. In a simple hydrologic-fluvial model for the Malaspina Glacier meltwater moves towards the glacier bed and down-glacier along intercrystalline pathways, crevasses and moulins, and a series of tunnels. Regolith and bedrock at the glacier floor, which are eroded and transported by subglacial and englacial streams, are the sources of essentially all fluvio-lacustrine sediment on the Malaspina Foreland. Supraglacial eskers containing coarse gravels occur as much as 100 m above the glacier bed and are evidence that bedload can be lifted hydraulically. Subordinant amounts of sediment are contributed to outwash by small surface streams draining the ice margin. By analogy a similar hydrologic-fluvial system existed along the southeastern margin of the Laurentide Ice Sheet. Subglacial regolith and bedrock eroded from beneath the Laurentide Ice Sheet by meltwater was also the source of most glaciofluvial and glaciolacustrine deposits in southern New England, not sediment carried to the surface of the ice sheet along shear planes and washed off the glacier by meltwater.

  13. Long-term linkages between glaciers, permafrost and hydrology at two glacierized watersheds in Alaska

    NASA Astrophysics Data System (ADS)

    Gaedeke, A.; Liljedahl, A. K.; Gatesman, T.; Campbell, S. W.; Hock, R.; Oneel, S.

    2015-12-01

    Climate warming is expected to have considerable impact on the regional water balance of high latitude Arctic and sub-Arctic glacerized watersheds. In this study we combine field observations and the physically based Water Balance Simulation Model WaSiM to refine our understanding of the linkages between glaciers, permafrost and hydrology at two nearby basins with contrasting precipitation regimes: Jarvis Cr. watershed (630 km2) on the north (rain-shadow) side of Eastern Alaska Range and the south facing Phelan Cr. (32 km2), which include the US Geological Survey benchmark site Gulkana Glacier. Both are characterized by a semi-arid climate and are sub-watersheds of the Tanana River basin (12,000 km2). Our research questions include: How has glacier water storage and release varied in the past and how are they expected to change in the future? And what are the subsequent effects on lowland runoff and regional groundwater recharge? Our analyses show i) an increase in air temperature and summer warmth index (the sum of all mean monthly air temperature above 0 °C) in recent decades and ii) a continued negative glacier mass balance. Our findings suggest that, on the larger spatial scale (Tanana River basin), the reduced glacier coverage and increased glacier wastage has, in combination with limited changes in precipitation, lead to (i) increased mean annual and (ii) late winter (March) runoff. We postulate that this is due to increased groundwater recharge, which has been fueled by the 20% reduction in glacier coverage of the Tanana River basin. Here we aim to assess the combined effect of climate change, glacier shrinkage and thawing permafrost on the regional sub-arctic mountain- to lowland hydrologic system, which may transition into a regime with less surface and more subsurface water availability.

  14. Exploiting SENTINEL-1 Amplitude Data for Glacier Surface Velocity Field Measurements: Feasibility Demonstration on Baltoro Glacier

    NASA Astrophysics Data System (ADS)

    Nascetti, A.; Nocchi, F.; Camplani, A.; Di Rico, C.; Crespi, M.

    2016-06-01

    The leading idea of this work is to continuously retrieve glaciers surface velocity through SAR imagery, in particular using the amplitude data from the new ESA satellite sensor Sentinel-1 imagery. These imagery key aspects are the free access policy, the very short revisit time (down to 6 days with the launch of the Sentinel-1B satellite) and the high amplitude resolution (up to 5 m). In order to verify the reliability of the proposed approach, a first experiment has been performed using Sentinel-1 imagery acquired over the Karakoram mountain range (North Pakistan) and Baltoro and other three glaciers have been investigated. During this study, a stack of 11 images acquired in the period from October 2014 to September 2015 has been used in order to investigate the potentialities of the Sentinel-1 SAR sensor to retrieve the glacier surface velocity every month. The aim of this test was to measure the glacier surface velocity between each subsequent pair, in order to produce a time series of the surface velocity fields along the investigated period. The necessary coregistration procedure between the images has been performed and subsequently the glaciers areas have been sampled using a regular grid with a 250 × 250 meters posting. Finally the surface velocity field has been estimated, for each image pair, using a template matching procedure, and an outlier filtering procedure based on the signal to noise ratio values has been applied, in order to exclude from the analysis unreliable points. The achieved velocity values range from 10 to 25 meters/month and they are coherent to those obtained in previous studies carried out on the same glaciers and the results highlight that it is possible to have a continuous update of the glacier surface velocity field through free Sentinel-1 imagery, that could be very useful to investigate the seasonal effects on the glaciers fluid-dynamics.

  15. Glaciers and Global Climate: Field and Remote-Sensing Studies of the Arctic

    NASA Technical Reports Server (NTRS)

    Hall, D. K.

    1998-01-01

    Glaciers are important indicators of global climate. Glacier recession, as observed from space and in the field, has been occurring for about 100 years. The present extent of glaciers and glaciers in the last Ice Age will be discussed. I will show slides of field work on glaciers and show instruments used to measure ice and snow. I will discuss reasons for studying glaciers and why remote sensing is important for glacier studies.

  16. A complex relationship between calving glaciers and climate

    USGS Publications Warehouse

    Post, A.; O'Neel, S.; Motyka, R.J.; Streveler, G.

    2011-01-01

    Many terrestrial glaciers are sensitive indicators of past and present climate change as atmospheric temperature and snowfall modulate glacier volume. However, climate interpretations based on glacier behavior require careful selection of representative glaciers, as was recently pointed out for surging and debris-covered glaciers, whose behavior often defies regional glacier response to climate [Yde and Paasche, 2010]. Tidewater calving glaciers (TWGs)mountain glaciers whose termini reach the sea and are generally grounded on the seaflooralso fall into the category of non-representative glaciers because the regional-scale asynchronous behavior of these glaciers clouds their complex relationship with climate. TWGs span the globe; they can be found both fringing ice sheets and in high-latitude regions of each hemisphere. TWGs are known to exhibit cyclic behavior, characterized by slow advance and rapid, unstable retreat, largely independent of short-term climate forcing. This so-called TWG cycle, first described by Post [1975], provides a solid foundation upon which modern investigations of TWG stability are built. Scientific understanding has developed rapidly as a result of the initial recognition of their asynchronous cyclicity, rendering greater insight into the hierarchy of processes controlling regional behavior. This has improved the descriptions of the strong dynamic feedbacks present during retreat, the role of the ocean in TWG dynamics, and the similarities and differences between TWG and ice sheet outlet glaciers that can often support floating tongues.

  17. Satellite-Based Study of Glaciers Retreat in Northern Pakistan

    NASA Astrophysics Data System (ADS)

    Munir, Siraj

    Glaciers serve as a natural regulator of regional water supplies. About 16933 Km 2 area of glaciers is covered by Pakistan. These glaciers are enormous reservoirs of fresh water and their meltwater is an important resource which feed rivers in Pakistan. Glacier depletion, especially recent melting can affect agriculture, drinking water supplies, hydro-electric power, and ecological habitats. This can also have a more immediate impact on Pakistan's economy that depends mainly on water from glacier melt. Melting of seasonal snowfall and permanent glaciers has resulted not only in reduction of water resources but also caused flash floods in many areas of Pakistan. With the advent of satellite technology, using optical and SAR data the study of glaciers, has become possible. Using temporal data, based on calculation of snow index, band ratios and texture reflectance it has been revealed that the rate of glacier melting has increased as a consequent of global warming. Comparison of Landsat images of Batura glacier for October 1992 and October 2000 has revealed that there is a decrease of about 17 sq km in Batura glaciers. Although accurate changes in glacier extent cannot be assessed without baseline information, these efforts have been made to analyze future changes in glaciated area.

  18. Implications of Glacier Volume Change for Ice-Ocean Interactions

    NASA Astrophysics Data System (ADS)

    Hood, E. W.; O'Neel, S.; Fellman, J.; Bidlack, A.; Arendt, A. A.; Arimitsu, M.; Spencer, R. G.

    2015-12-01

    Changes in climate are forcing complex glaciological responses that can be transmitted to downstream ecosystems via glacier runoff. Along the Gulf of Alaska, rates of glacier mass loss are among the highest measured on Earth. Changes in glacier volume in this region are altering the amount of glacier runoff delivered to the coastal ocean. Moreover, shifts in glacier extent are changing the location of the ice-ocean interface and, in cases where tidewater glaciers become grounded, fundamentally altering circulation in glacierized fjords. The runoff from glacier ecosystems is unique in terms of its physical and chemical properties when compared to runoff from non-glacial ecosystems. For example, the silt and chemical constituents in glacier discharge alter light penetration and the nutrient regime in near-shore marine ecosystems, which, in turn, influence levels of marine primary productivity. Future changes in the magnitude, timing, and location of glacier runoff have important implications for biogeochemical and ecological processes in glacially-dominated fjords and estuaries. This talk will highlight research from glacierized watersheds and fjords to synthesize what is known about the physical, chemical, and biological linkages that characterize icefield-ocean ecosystems along the Gulf of Alaska.

  19. Glacier modeling in support of field observations of mass balance at South Cascade Glacier, Washington, USA

    USGS Publications Warehouse

    Josberger, Edward G.; Bidlake, William R.

    2010-01-01

    The long-term USGS measurement and reporting of mass balance at South Cascade Glacier was assisted in balance years 2006 and 2007 by a new mass balance model. The model incorporates a temperature-index melt computation and accumulation is modeled from glacier air temperature and gaged precipitation at a remote site. Mass balance modeling was used with glaciological measurements to estimate dates and magnitudes of critical mass balance phenomena. In support of the modeling, a detailed analysis was made of the "glacier cooling effect" that reduces summer air temperature near the ice surface as compared to that predicted on the basis of a spatially uniform temperature lapse rate. The analysis was based on several years of data from measurements of near-surface air temperature on the glacier. The 2006 and 2007 winter balances of South Cascade Glacier, computed with this new, model-augmented methodology, were 2.61 and 3.41 mWE, respectively. The 2006 and 2007 summer balances were -4.20 and -3.63 mWE, respectively, and the 2006 and 2007 net balances were -1.59 and -0.22 mWE. PDF version of a presentation on the mass balance of South Cascade Glacier in Washington state. Presented at the American Geophysical Union Fall Meeting 2010.

  20. Effects of volcanism on the glaciers of Mount St. Helens

    USGS Publications Warehouse

    Brugman, Melinda M.; Post, Austin

    1981-01-01

    The cataclysmic eruption of Mount St. Helens May 18, 1980, removed 2.9 km2 (about 0.13 km3) of glacier snow and ice including a large part of Shoestring, Forsyth, Wishbone, Ape, Nelson, and all of Loowit and Leschi Glaciers. Minor eruptions and bulging of the volcano from March 27 to May 17 shattered glaciers which were on the deforming rock and deposited ash on other glaciers. Thick ash layers persisted after the May 18 eruption through the summer on most of the remaining snow and ice, and protected winter snow from melting on Swift and Dryer Glaciers. Melting and recrystalization of snow and ice surviving on Mount St. Helens could cause and lubricate mudflows and generate outburst floods. Study of glaciers that remain on this active volcano may assist in recognizing potential hazards on other volcanoes and lead to new contributions to knowledge of the transient response of glaciers to changes in mass balance or geometry.

  1. SAR investigations of glaciers in northwestern North America

    NASA Technical Reports Server (NTRS)

    Lingle, Craig S.; Harrison, William D.

    1995-01-01

    The objective of this project was to investigate the utility of satellite synthetic aperture radar (SAR) imagery for measurement of geophysical parameters on Alaskan glaciers relevant to their mass balance and dynamics, including: (1) the positions of firn lines (late-summer snow lines); (2) surface velocities on fast-flowing (surging) glaciers, and also on slower steady-flow glaciers; and (3) the positions and changes in the positions of glacier termini. Preliminary studies of topography and glacier surface velocity with SAR interferometry have also been carried out. This project was motivated by the relationships of multi-year to decadal changes in glacier geometry to changing climate, and the probable significant contribution of Alaskan glaciers to rising sea level.

  2. Subglacial till: the deforming glacier bed

    NASA Astrophysics Data System (ADS)

    van der Meer, Jaap J. M.; Menzies, John; Rose, James

    2003-07-01

    "Till is a sediment and is perhaps more variable than any sediment known by a single name." R.F. Flint 1957 Glacial and Pleistocene Geology Tills are commonly classified according to the perceived process of deposition. However, it is increasingly recognised that this classification, which is mainly based on macroscopic field data, has severe limitations. At the same time the concept of the deforming glacier bed has become more realistic as a framework for discussing tills and their properties, and this (tectonic) concept is irreconcilable with the existing (depositional) till classification scheme. Over the last 20 years large thin sections have been used to study tills, which has provided new insights into the textural and structural properties of tills. These results have revolutionised till sedimentology as they show that, in the main, subglacial tills possess deformational characteristics. Depositional properties are rare. Based on this new insight the process of subglacial till formation is discussed in terms of glacier/ice sheet basal velocity, clay, water and carbonate content and the variability of these properties in space and time. The end result of this discussion is: till, the deforming glacier bed. To distinguish subglacial till from depositional sediments the term 'tectomict' is proposed. Within the single framework of subglacial till as the deforming glacier bed, many textural, structural and geomorphological features of till beds can be more clearly and coherently explained and understood.

  3. Stream temperature response to glacier retreat (Invited)

    NASA Astrophysics Data System (ADS)

    Moore, R. D.

    2013-12-01

    Stream temperature is a fundamental aspect of aquatic habitat, and there has been increasing concern in recent years that climatic change and glacier retreat will result in increased water temperatures, with potentially negative influences on cold and cool water species such as salmonids. A statistical model was developed to predict the maximum weekly average stream temperature based on data from 418 sites located throughout British Columbia, Canada. Catchment-scale glacier coverage was a significant predictor in the model, and example calculations indicate that plausible decreases in glacier coverage over the next few decades have the potential to result in warming that would be sufficient to cause shifts in fish species assemblages. However, this space-for-time substitution rests on assumptions that may not be valid, especially in the context of a changing climate, leading to a need to develop and apply physically based models. Reach-scale energy budget analyses indicate that parameterizations of energy fluxes used in current stream temperature models are not appropriate for steep channels with cascading flow. In particular, the sensible and latent heat fluxes are more efficient than in lower-gradient channels, and the albedo is enhanced by aeration. Over longer time scales, development of riparian forest has the potential to mitigate the effect of glacier retreat in alpine areas by shading the stream, but it may take centuries for functional riparian forest to develop at higher elevation sites.

  4. Asia High Mountain Glacier Mass Balance

    NASA Astrophysics Data System (ADS)

    Shum, C. K.; Su, X.; Shang, K.; Cogley, J. G.; Zhang, G.; Howat, I. M.; Braun, A.; Kuo, C. Y.

    2015-12-01

    The Asian High Mountain encompassing the Qinghai-Tibetan Plateau has the largest glaciated regions in the world outside of Greenland and Antarctica. The Tibetan Plateau is the source or headwater of many major river systems, which provide water resources to more than a billion people downstream. The impact of climate change on the Tibetan Plateau physical processes, including mountain glacier wastage, permafrost active layer thickening, the timing and the quantity of the perennial snowpack melt affecting upstream catchments, river runoffs, land-use, have significant effects on downstream water resources. Exact quantification of the Asian High Mountain glacier wastage or its mass balance on how much of the melt water contributes to early 21st century global sea-level rise, remain illusive or the published results are arguably controversial. The recent observed significant increase of freshwater storage within the Tibetan Plateaus remains a limitation to exactly quantify mountain glacier wastage. Here, we provide an updated estimate of Asia high mountain glacier mass balance using satellite geodetic observations during the last decade, accounting for the hydrologic and other processes, and validated against available in situ mass balance data.

  5. A Facies Model for Temperate Continental Glaciers.

    ERIC Educational Resources Information Center

    Ashley, Gail Mowry

    1987-01-01

    Discusses the presence and dynamics of continental glaciers in the domination of the physical processes of erosion and deposition in the mid-latitudes during the Pleistocene period. Describes the use of a sedimentary facies model as a guide to recognizing ancient temperate continental glacial deposits. (TW)

  6. The Bay in Place of a Glacier.

    ERIC Educational Resources Information Center

    Howell, Wayne

    1997-01-01

    The cultural resource specialist at Glacier Bay National Park (Alaska) explains the collaborative efforts of park staff and the Hoonah Tlingit to overcome language and cultural barriers in documenting park place names and clan oral history and traditions. The new park-community relationship, which follows decades of conflict, includes training…

  7. The first glacier inventory for entire Greenland

    NASA Astrophysics Data System (ADS)

    Rastner, P.; Bolch, T.; Mölg, N.; Le Bris, R.; Paul, F.

    2012-04-01

    Detailed glacier data is becoming more and more important in the last decades to solve several research issues. One of the most prominent questions in this regard is the potential contribution of glaciers and icecaps (GIC) to global sea-level rise. Primarily, estimates are uncertain due to the globally still incomplete information about glacier location and size, as well as large uncertainties in future climate scenarios. Recent studies that calculate global sea-level rise from GIC have developed simplified approaches using information from glacier inventories or gridded data sets and a range of different global climate models and emission scenarios. However, for several strongly glacierized regions very rough assumptions about the ice distribution have to be made and an urgent demand for a globally complete glacier inventory is expressed. The GIC on Greenland are one of the regions with lacking information. Within the EU FP7 project ice2sea we mapped the GIC on Greenland using Landsat TM/ETM+ imagery acquired around the year 2000, along with an additional dataset in the North (DCW - Digital Chart of the World). A digital elevation model (DEM) with 90 m resolution (GIMP DEM) was used to derive drainage divides and henceforth topographic parameters for each entity. A major challenge in this regard is the application of a consistent strategy to separate the local GIC from the ice sheet. For this purpose we have defined different levels of connectivity (CL) of the local GIC with the ice sheet: CL0: Not connected. CL1: Connected but separable (either with drainage divides in the accumulation region or in touch only - and thus separable - in the ablation region). CL2: Connected but non-separable (the local GIC contribute to the flow of an ice sheet outlet in the ablation area). Up to now close to 12'000 GIC (only CL0 and CL1) with a total area of about 129'000 km2 have been mapped considering only entities larger than 0.1 km2. The area of the ice sheet itself is

  8. Glaciers along proposed routes extending the Copper River Highway, Alaska

    USGS Publications Warehouse

    Glass, R.L.

    1996-01-01

    Three inland highway routes are being considered by the Alaska Department of Transportation and Public Facilities to connect the community of Cordova in southcentral Alaska to a statewide road system. The routes use part of a Copper River and Northwest Railway alignment along the Copper River through mountainous terrain having numerous glaciers. An advance of any of several glaciers could block and destroy the roadway, whereas retreating glaciers expose large quantities of unconsolidated, unvegetated, and commonly ice-rich sediments. The purpose of this study was to map historical locations of glacier termini near these routes and to describe hazards associated with glaciers and seasonal snow. Historical and recent locations of glacier termini along the proposed Copper River Highway routes were determined by reviewing reports and maps and by interpreting aerial photographs. The termini of Childs, Grinnell, Tasnuna, and Woodworth Glaciers were 1 mile or less from a proposed route in the most recently available aerial photography (1978-91); the termini of Allen, Heney, and Schwan Glaciers were 1.5 miles or less from a proposed route. In general, since 1911, most glaciers have slowly retreated, but many glaciers have had occasional advances. Deserted Glacier and one of its tributary glaciers have surge-type medial moraines, indicating potential rapid advances. The terminus of Deserted Glacier was about 2.1 miles from a proposed route in 1978, but showed no evidence of surging. Snow and rock avalanches and snowdrifts are common along the proposed routes and will periodically obstruct the roadway. Floods from ice-dammed lakes also pose a threat. For example, Van Cleve Lake, adjacent to Miles Glacier, is as large as 4.4 square miles and empties about every 6 years. Floods from drainages of Van Cleve Lake have caused the Copper River to rise on the order of 20 feet at Million Dollar Bridge.

  9. Glacier and hydrology changes in future climate over western Canada

    NASA Astrophysics Data System (ADS)

    Winger, Katja; Sushama, Laxmi; Marshall, Shawn

    2016-04-01

    Glaciers are frozen fresh water reservoirs that respond to changes in temperature and snowfall. Concern is growing about the impact that changes in glaciers may have on water resources in regions such as western Canada that derive a lot of their summer streamflow from glacier melt. Given that RCM projections are an important tool and are increasingly being used in assessing projected changes to water resources, particularly due to its high resolution compared with GCMs, realistic representation of glaciers in RCMs is very important. Currently, glaciers are only represented in an extremely simplified way in the fifth generation Canadian Regional Climate Model (CRCM5). This simple approach of representing glaciers as static glacier masks is appropriate for short-term integrations, where the response of glacier to changing atmospheric conditions might still be small due to glacier response times and therefore the feedback of changing glacier extent on large-scale atmospheric flow conditions might be negligible. A new dynamic glacier scheme has been developed for use within CRCM5, based on volume-area relationships. Simulations have been performed with this glacier model and Land Surface Scheme CLASS for the 2000-2100 period over a domain covering western Canada. These simulations were driven by outputs from a CRCM5 transient climate change simulation driven by CanESM2 at the lateral boundaries, for RCPs 4.5 and 8.5. Preliminary results suggest significant decreases to glacier fractions in future climate. Though the glacier contribution to streamflows is found to dramatically decrease in future climate, the total streamflows did not show any dramatic decreases due to the increase in precipitation for these regions.

  10. Hypsometric control on glacier mass balance sensitivity in Alaska

    NASA Astrophysics Data System (ADS)

    McGrath, D.; Sass, L.; Arendt, A. A.; O'Neel, S.; Kienholz, C.; Larsen, C.; Burgess, E. W.

    2015-12-01

    Mass loss from glaciers in Alaska is dominated by strongly negative surface balances, particularly on small, continental glaciers but can be highly variable from glacier to glacier. Glacier hypsometry can exert significant control on mass balance sensitivity, particularly if the equilibrium line altitude (ELA) is in a broad area of low surface slope. In this study, we explore the spatial variability in glacier response to future climate forcings on the basis of hypsometry. We first derive mass balance sensitivities (30-70 m ELA / 1° C and 40-90 m ELA / 50% decrease in snow accumulation) from the ~50-year USGS Benchmark glaciers mass balance record. We subsequently assess mean climate fields in 2090-2100 derived from the IPCC AR5/CMIP5 RCP 6.0 5-model mean. Over glaciers in Alaska, we find 2-4° C warming and 10-20% increase in precipitation relative to 2006-2015, but a corresponding 0-50% decrease in snow accumulation due to rising temperatures. We assess changes in accumulation area ratios (AAR) to a rising ELA using binned individual glacier hypsometries. For an ELA increase of 150 m, the mean statewide AAR drops by 0.45, representing a 70% reduction in accumulation area on an individual glacier basis. Small, interior glaciers are the primary drivers of this reduction and for nearly 25% of all glaciers, the new ELA exceeds the glacier's maximum elevation, portending eventual loss. The loss of small glaciers, particularly in the drier interior of Alaska will significantly modify streamflow properties (flashy hydrographs, earlier and reduced peak flows, increased interannual variability, warmer temperatures) with poorly understood downstream ecosystem and oceanographic impacts.

  11. Model based historical runoff contribution from an Alpine glacier

    NASA Astrophysics Data System (ADS)

    Zoccatelli, Davide; Bonato, Paola; Carturan, Luca; Dalla Fontana, Giancarlo; De Blasi, Fabrizio; Borga, Marco

    2016-04-01

    The aim of this work is to analyze how climatic variability and glacier retreat impact the water balance of a small (8.5 km2) glaciarised catchment in the Eastern Italia Alps over a 30 year (1983-2013) period. The analysis is carried out by coupling local high quality data and a glacio-hydrological model able to simulate both the glacier and hydrology dynamics. Runoff contribution from glacier ice is related with trends in climatic variables and with glacier retreat. The area analyzed is the headwater of Noce Bianco river basin, lying in the Ortles-Cevedale group and including the La Mare glacier. During the study period the glacier area decreased from 4.7 km2 (50% basin area) to 3.47 km2 (40% basin area). In this area the following observations are available: 30 years of daily meteorological data at high elevation close to the catchment; three DTMs of the glacier, covering the entire period, which enable the calculation of the volume change and geodetic mass balance; direct glaciological mass balance observations over the period 2003-2013; discharge measurement at the catchment outlet over the period 2007-2013. The data availability and the significant shrinking of the glacier during the analyzed period make this catchment ideal for studying the hydrological impacts of glacier retreat. The semi-distributed conceptual model includes a snow and glacier accumulation and ablation module, based on temperature-radiation index and a glacier retreat model. The glacier retreat model allows to use the annual simulated glacier mass balance to update the glacier area (Huss et al., 2010). The model simulations are carried out from 1983 to 2013. We show that the model is able to capture adequately the measured daily discharge, the observed changes in glacier area and their spatial distribution. The contribution of glacier ice meltwater to annual runoff is below 10% in the first decade of simulation. This variable however showed a clear increasing trend, with peaks for single

  12. Snowline observations to remotely derive glacier-wide mass balance on four Kyrgyz glaciers from 2003 to 2015

    NASA Astrophysics Data System (ADS)

    Barandun, Martina; Huss, Matthias; Sold, Leo; Kienholz, Christian; Usubaliev, Ryskul; Bolch, Tobias; Hoelzle, Martin

    2016-04-01

    The monitoring of glacier mass balance in remote regions is challenging but vital for understanding the response of glaciers to climate change. Direct mass balance observations are sparse and discontinuous in the Kyrgyz Tien Shan and Pamir. The under-sampling problem of glacier change assessments limits change predictions and impact projections. In this study, we elaborate on novel approaches to derive sub-seasonal glacier mass balance based on remote snowline monitoring on four Kyrgyz glaciers for a period from 2003 to 2015. The proposed methodology is based on the information content of short-term changes in snowline elevation detected with repeated remote sensing imagery for both the quantities of winter accumulation and summer ablation. By backward modelling the observed snowline position and the glacier geometry are related to the glacier-wide mass balance. Snowline position over the glacier area is detected with a semi-automatic procedure on remote sensing images (Landsat, ASTER) and automatically on terrestrial photographs. We apply the methodology to four glaciers on which direct mass balance measurements have been (re)-initiated recently and use reanalysed and partly reconstructed mass balance series as a first source to validate our approach to remotely determine the seasonal glacier mass budget. In a second step, the derived glacier-wide mass balance is compared to geodetic mass balance calculations for the first decade of the 21st century.

  13. A GRASS GIS module to obtain an estimation of glacier behavior under climate change: A pilot study on Italian glacier

    NASA Astrophysics Data System (ADS)

    Strigaro, Daniele; Moretti, Massimiliano; Mattavelli, Matteo; Frigerio, Ivan; Amicis, Mattia De; Maggi, Valter

    2016-09-01

    The aim of this work is to integrate the Minimal Glacier Model in a Geographic Information System Python module in order to obtain spatial simulations of glacier retreat and to assess the future scenarios with a spatial representation. The Minimal Glacier Models are a simple yet effective way of estimating glacier response to climate fluctuations. This module can be useful for the scientific and glaciological community in order to evaluate glacier behavior, driven by climate forcing. The module, called r.glacio.model, is developed in a GRASS GIS (GRASS Development Team, 2016) environment using Python programming language combined with different libraries as GDAL, OGR, CSV, math, etc. The module is applied and validated on the Rutor glacier, a glacier in the south-western region of the Italian Alps. This glacier is very large in size and features rather regular and lively dynamics. The simulation is calibrated by reconstructing the 3-dimensional dynamics flow line and analyzing the difference between the simulated flow line length variations and the observed glacier fronts coming from ortophotos and DEMs. These simulations are driven by the past mass balance record. Afterwards, the future assessment is estimated by using climatic drivers provided by a set of General Circulation Models participating in the Climate Model Inter-comparison Project 5 effort. The approach devised in r.glacio.model can be applied to most alpine glaciers to obtain a first-order spatial representation of glacier behavior under climate change.

  14. 52 glaciers and one lake: how to reconstruct past regional glacier variability

    NASA Astrophysics Data System (ADS)

    Vasskog, Kristian; Paasche, Øyvind; Nesje, Atle; Boyle, John F.; Birks, H. John B.

    2014-05-01

    Sediment records from distal glacier-fed lakes have been used in numerous reconstructions of past glacier activity, where the basic assumption is that the amount of minerogenic material deposited in the lake is directly proportional to the amount of upstream glacier erosion. However, the minerogenic component of the sediments in a distal glacier-fed lake is commonly derived from several different sources, not only subglacial erosion. Furthermore, glacier reconstructions tend to focus on individual mountain glaciers, which due to local effects might not always reflect regional scale glacier variability. Presently, certain high-resolution analysis techniques allow for fast multi-proxy analyses of sediment cores, which improve the basis for inferring the provenance of lake sediments; however, the only way of actually testing such inferences is to identify the different sediment sources in the adjacent catchment and characterize them using the same proxy measurements as in the lake core. Multi-proxy sedimentary fingerprinting techniques are labor-intensive, however, and proxies such as bulk geochemistry may prove of little use in differentiating between source areas if the bedrock lithology is uniform across the catchment. Here we present a simple method based on environmental magnetism that allow for tracking lake sediments to their sources in catchments where the bedrock lithology is uniform. Unlike ferro- and ferrimagnetic minerals, the magnetic susceptibility of paramagnetic minerals is inversely proportional to temperature. Thus, by measuring the bulk magnetic susceptibility (chi-Bulk) of a sediment sample both at room temperature (293K) and after freezing in liquid nitrogen (77K), the relative contribution from paramagnetic minerals to the total chi-Bulk can be inferred from the ratio of chi-Bulk77K over chi-Bulk293K. Theoretically, a ratio of 3.8 will indicate a purely paramagnetic sample, whereas progressively lower values reflect an increasing contribution

  15. Internationally coordinated glacier monitoring - a timeline since 1894

    NASA Astrophysics Data System (ADS)

    Nussbaumer, Samuel U.; Armstrong, Richard; Fetterer, Florence; Gärtner-Roer, Isabelle; Hoelzle, Martin; Machguth, Horst; Mölg, Nico; Paul, Frank; Raup, Bruce H.; Zemp, Michael

    2016-04-01

    Changes in glaciers and ice caps provide some of the clearest evidence of climate change, with impacts on sea-level variations, regional hydrological cycles, and natural hazard situations. Therefore, glaciers have been recognized as an Essential Climate Variable (ECV). Internationally coordinated collection and distribution of standardized information about the state and change of glaciers and ice caps was initiated in 1894 and is today organized within the Global Terrestrial Network for Glaciers (GTN-G). GTN-G ensures the continuous development and adaptation of the international strategies to the long-term needs of users in science and policy. A GTN-G Steering Committee coordinates, supports and advices the operational bodies responsible for the international glacier monitoring, which are the World Glacier Monitoring Service (WGMS), the US National Snow and Ice Data Center (NSIDC), and the Global Land Ice Measurements from Space (GLIMS) initiative. In this presentation, we trace the development of the internationally coordinated glacier monitoring since its beginning in the 19th century. Today, several online databases containing a wealth of diverse data types with different levels of detail and global coverage provide fast access to continuously updated information on glacier fluctuation and inventory data. All glacier datasets are made freely available through the respective operational bodies within GTN-G, and can be accessed through the GTN-G Global Glacier Browser (http://www.gtn-g.org/data_browser.html). Glacier inventory data (e.g., digital outlines) are available for about 180,000 glaciers (GLIMS database, RGI - Randolph Glacier Inventory, WGI - World Glacier Inventory). Glacier front variations with about 45,000 entries since the 17th century and about 6,200 glaciological and geodetic mass (volume) change observations dating back to the 19th century are available in the Fluctuations of Glaciers (FoG) database. These datasets reveal clear evidence that

  16. A study of discrete glacier motion

    NASA Astrophysics Data System (ADS)

    Zoet, Lucas K.

    Knowledge of process which control glacial dynamics are imperative in quantifying the response of a glacier or ice sheet to external forcing. This dissertation focuses mainly upon the characterization of sliding ice over a bed in an unstable fashion. I investigate unstable sliding through instances where it is observed in passive seismology as well as a focused laboratory study. The laboratory study attempts to isolate specific aspects of the sliding interface, which could lead to unstable sliding. Implications of unstable sliding with regards to erosion are also dealt with. Initially the TAMSEIS array is used to observe a unique set of seismicity originating at the base of David Glacier Antarctica in which ˜ 20,000 events were located over a ˜300 day period as the ice slid over an asperity. Tidal effects at the terminus modulated the interevent spacing and magnitude of events allowing for a basic analysis of healing process between a glacier and its bed. The 300 day period of repeat seismicity is hypothesized to arise from advection of debris rich ice over the asperity. Next the erosion implications of stick slip sliding are investigated. Sudden advancement associated with seismic energy generation is hypothesized to rapidly expand water filled cavities, which form in lee of bedrock highs. The rapid expansion creates a drop in water pressure within the cavity resulting in a pressure gradient leading to rapid fracture of bedrock. During the interseismic period of a stick slipping glacier the static coefficient of friction transfers a larger shear stress to the bed than the dynamic coefficient of friction from stably sliding glacier would. Next laboratory experimentation is conducted using a biaxial shearing apparatus in order to test the hypothesis that debris rich ice can affect the stability regime of a sliding glacier. This is preformed on a suite of ice-debris samples with range entrained debris percentages and temperatures. Both synthetic ice constructed in

  17. Franz Josef and Fox Glaciers, New Zealand: Historic length records

    NASA Astrophysics Data System (ADS)

    Purdie, Heather; Anderson, Brian; Chinn, Trevor; Owens, Ian; Mackintosh, Andrew; Lawson, Wendy

    2014-10-01

    Compilation of modern and historical length change records for Franz Josef and Fox Glaciers demonstrates that these glaciers have lost ~ 3 km in length and at least 3-4 km2 in area since the 1800s, with the greatest overall loss occurring between 1934 and 1983. Within this dramatic and ongoing retreat, both glaciers have experienced periods of re-advance. The record from Franz Josef Glacier is the most detailed, and shows major advances from 1946 to 1951 (340 m), 1965-1967 (400 m), 1983-1999 (1420 m) and 2004-2008 (280 m). At Fox Glacier the record is similar, with advances recorded during 1964-1968 (60 m), 1985-1999 (710 m) and 2004-2008 (290 m). Apart from the latest advance event, the magnitude of advance has been greater at Franz Josef Glacier, suggesting a higher length sensitivity. Analysis of the relationship between glacier length and a reconstructed annual equilibrium line altitude (ELA) record shows that the glaciers react very quickly to ELA variations - with the greatest correlation at 3-4 years' lag. The present (2014) retreat is the fastest retreat in the records of both glaciers. While decadal length fluctuations have been linked to hemispheric ocean-atmosphere variability, the overall reduction in length is a clear sign of twentieth century warming. However, documenting glacier length changes can be challenging; especially when increased surface debris-cover makes identification of the 'true' terminus a convoluted process.

  18. Rock glaciers in the South Shetland Islands, Western Antarctica

    NASA Astrophysics Data System (ADS)

    Serrano, Enrique; López-Martínez, Jerónimo

    2000-10-01

    Rock glaciers are found in the peripheral regions of Antarctica particularly in the Antarctic Peninsula region. Study of these features is relevant for the palaeoenvironmental reconstruction of maritime Antarctica because they are indicators of permafrost and periglacial conditions. This paper reports and analyzes the results of an inventory of rock glaciers and protalus lobes in the South Shetland Islands. Nine rock glaciers and eleven protalus lobes have been identified. All of them are located in recently deglaciated zones between 300 m a.s.l. and sea level and they cover an area of 497×103 m 2. Tongue-shaped rock glaciers are more common than lobate types, being in general of medium and small sizes. They are talus rock glaciers (55%) and debris rock glaciers (45%), according to the genetic classification. The lack of a preferred orientation suggests that there is no significant microclimate control on their distribution. They are related to particular morphodynamic situations. Estimated annual velocities, based on relationships with raised beaches and transported debris volumes, range between 2.4 and 97 cm year -1, within the ranges reported for other rock glaciers. Three groups of rock glaciers can be recognised: (a) those immediate postdating the last major ice recession, (b) rock glaciers younger than 2000 years BP but pre-dating the Little Ice Age (LIA), and (c) rock glaciers formed during the LIA.

  19. Assessing streamflow sensitivity to variations in glacier mass balance

    NASA Astrophysics Data System (ADS)

    Oneel, S.; Hood, E. W.; Arendt, A. A.; Sass, L. C.; March, R. S.

    2013-12-01

    We examine long-term streamflow and mass balance data from two Alaskan glaciers located in climatically distinct basins: Gulkana Glacier, a continental glacier located in the Alaska Range, and Wolverine Glacier, a maritime glacier located in the Kenai Mountains. Both glaciers lost mass, primarily as a result of summer warming, and both basins exhibit increasing streamflow over the 1966-2011 study interval. We estimated total glacier runoff via summer mass balance, and separated the fraction related to annual mass imbalances. In both climates, the fraction of streamflow related to annual mass balance averages less than 20%, substantially smaller than the fraction related to total summer mass loss (>50%), which occurs even in years of glacier growth. The streamflow fraction related to changes in annual mass balance has increased only in the continental environment. In the maritime climate, where deep winter snowpacks and frequent rain events drive consistently high runoff, the magnitude of this streamflow fraction is small and highly variable, precluding detection of any existing trend. Changes in streamflow related to annual balance are often masked by interannual variability of maritime glacier mass balance, such that predicted scenarios of continued glacier recession are more likely to impact the quality and timing of runoff than the total basin water yield.

  20. Glacier Changes in the Bhutanese Himalaya - Present and Future

    NASA Astrophysics Data System (ADS)

    Rupper, S.; Schaefer, J. M.; Burgener, L. K.; Maurer, J.; Smith, R.; Cook, E.; Putnam, A. E.; Krusic, P.; Tsering, K.; Koenig, L.

    2012-12-01

    Glacierized change in the Himalayas affects river-discharge, hydro-energy and agricultural production, and Glacial Lake Outburst Flood potential, but its quantification and extent of impacts remains highly uncertain. Here we present conservative, comprehensive and quantitative predictions for glacier area and meltwater flux changes in Bhutan, monsoonal Himalayas. In particular, we quantify the uncertainties associated with the glacier area and meltwater flux changes due to uncertainty in climate data, a critical problem for much of High Asia. Based on a suite of gridded climate data and a robust glacier melt model, our results show that glacier area and meltwater change projections can vary by an order of magnitude for different climate datasets. The most conservative results indicate that, even if climate were to remain at the present-day mean values (1980-2000), almost 10% of Bhutan's glacierized area would vanish and the meltwater flux would drop by as much as 30%. New mapping of glacierized area from 2000-2010 shows a significant change in glacierized area of 4-6%. Thus the conservative steady-state area changes predicted by the model are already being realized. Under the conservative scenario of an additional 1°C regional warming, glacier retreat is predicted to continue until about 25% of Bhutan's glacierized area will have disappeared and the annual meltwater flux, after an initial spike, would drop by as much as 65%.

  1. Glacier melt-model parameter sensitivity and transferability in the dry subarctic environment of the southwest Yukon

    NASA Astrophysics Data System (ADS)

    MacDougall, A. H.; Flowers, G. E.

    2011-12-01

    Regional hydrology and eustatic sea-level are expected to change as a consequence of climate warming. Accurate projection of these changes requires glacier melt-models with high parameter transferability in space and time. We have assessed the parameter transferability and sensitivity of a suite of glacier melt-models for two glaciers 10 km apart in the dry subarctic environment of the St. Elias Mountains, Yukon, Canada. The melt models range in complexity from a classical temperature-index model to a simplified energy balance model. Two experiments are conducted: (1) the models are tuned to the output of a full energy balance model forced under idealized conditions to assess the sensitivity of model parameters to variations in glacier geometric attributes, surface conditions, and meteorological conditions; (2) the models are tuned to real ablation stake data from our two study glaciers over two melt seasons, and the parameter transferability between the two sites and the two melt seasons is evaluated. The parameters of the temperature-index models demonstrate high sensitivity to glacier aspect, mean surface elevation, albedo, wind speed, mean annual temperature, and temperature lapse rate. The simplified energy balance model is sensitive to snow albedo. The simplified energy balance model more often than not (in seven of twelve tests) produces the highest model transferability. In the remaining five tests the classical temperature-index model produces the highest transferability twice, and a temperature-index model, where the degree-day factor is a function of potential shortwave radiation, produces the highest transferability three times. The full energy balance model when forced with real data inputs produces higher model parameter transferability than the empirical melt models in nine out of twelve tests. These results suggest that caution should be observed when extending the use of melt models beyond the locations where they were developed and tested.

  2. Spring bloom dynamics in a subarctic fjord influenced by tidewater outlet glaciers (Godthåbsfjord, SW Greenland)

    NASA Astrophysics Data System (ADS)

    Meire, Lorenz; Mortensen, John; Rysgaard, Søren; Bendtsen, Jørgen; Boone, Wieter; Meire, Patrick; Meysman, Filip J. R.

    2016-06-01

    In high-latitude fjord ecosystems, the spring bloom accounts for a major part of the annual primary production and thus provides a crucial energy supply to the marine food web. However, the environmental factors that control the timing and intensity of these spring blooms remain uncertain. In 2013, we studied the spring bloom dynamics in Godthåbsfjord, a large fjord system adjacent to the Greenland Ice Sheet. Our surveys revealed that the spring bloom did not initiate in the inner stratified part of the fjord system but only started farther away from tidewater outlet glaciers. A combination of out-fjord winds and coastal inflows drove an upwelling in the inner part of the fjord during spring (April-May), which supplied nutrient-rich water to the surface layer. This surface water was subsequently transported out-fjord, and due to this circulation regime, the biomass accumulation of phytoplankton was displaced away from the glaciers. In late May, the upwelling weakened and the dominant wind direction changed, thus reversing the direction of the surface water transport. Warmer water was now transported toward the inner fjord, and a bloom was observed close to the glacier terminus. Overall, our findings imply that the timing, intensity, and location of the spring blooms in Godthåbsfjord are controlled by a combination of upwelling strength and wind forcing. Together with sea ice cover, the hydrodynamic regime hence plays a crucial role in structuring food web dynamics of the fjord ecosystem.

  3. Modelling glacier change in the Everest region, Nepal Himalaya

    NASA Astrophysics Data System (ADS)

    Shea, J. M.; Immerzeel, W. W.; Wagnon, P.; Vincent, C.; Bajracharya, S.

    2014-10-01

    In this study, we apply a glacier mass balance and ice redistribution model to simulate historical and future glacier change in the Everest region of Nepal. High-resolution temperature and precipitation fields derived from gridded APHRODITE data, and validated against independent station observations from the EVK2CNR network, are used to drive the historical model from 1961 to 2007. The model is calibrated against geodetically derived estimates of net glacier mass change from 1992 to 2008, termini position of four large glaciers at the end of the calibration period, average velocities observed on selected debris-covered glaciers, and total glacierized area. We integrate field-based observations of glacier mass balance and ice thickness with remotely-sensed observations of decadal glacier change to validate the model. Between 1961 and 2007, the mean modelled volume change over the Dudh Kosi basin is -6.4 ± 1.5 km3, a decrease of 15.6% from the original estimated ice volume in 1961. Modelled glacier area change between 1961 and 2007 is -101.0 ± 11.4 km2, a decrease of approximately 20% from the initial extent. Scenarios of future climate change, based on CMIP5 RCP4.5 and RCP8.5 end members, suggest that glaciers in the Everest region will continue to lose mass through the 21st century. Glaciers in the basin are concentrated between 5000 and 6000 m of elevation, and are thus expected to be sensitive to changes in temperature and equilibrium line altitude (ELA). Glacier volume reductions between -35 to -62% are possible by 2050, and sustained temperature increases to 2100 may result in total glacier volume losses of between -73 and -96%.

  4. Controlling mechanisms of Thwaites Glacier, West Antarctica

    NASA Astrophysics Data System (ADS)

    Seroussi, H. L.; Morlighem, M.; Rignot, E. J.; Larour, E. Y.; Mouginot, J.; Khazendar, A.

    2013-12-01

    Ice shelves play a major role in the stability of fast flowing ice streams in Antarctica, by exerting buttressing on inland ice and controlling the discharge of ice into the ocean. However, the mechanisms at work remain poorly understood and interactions between floating and grounded ice need to be better characterized in order to estimate the impact of climate change on the ice sheets. Thwaites glacier, in West Antarctica, features a small and heavily fractured ice shelf that provides limited back stress pressure on inland ice but is pinned on the eastern part on a prominent ridge. Thwaites glacier has maintained a consistently high velocity and negative mass balance for at least 20 years. Recent observations show a widening of its fast flowing area as well as a sustained acceleration since 2006 and a rapid retreat of its grounding line in the center of the glacier. The objective of this work is to characterize the dynamic response of Thwaites glacier to changes in its floating tongue on decadal to centennial time scales. To achieve this objective, we rely on high resolution ice flow modeling and grounding line dynamics using the Ice Sheet System Model (ISSM). We will focus on the complex interplay between the main floating tongue of Thwaites Glacier and its eastern, slow moving ice shelf, which is pinned down by an ice rumple. The speed of the eastern ice shelf is strongly affected by the coupling with the main floating ice tongue, which results in significant fluctuations in speed of the eastern ice shelf the formation of ice shelf cracks at the grounding line during acceleration phases. Our results show that ice rigidity at the junction between the eastern and western part of the shelf controls the dynamic regime of the ice shelf and suggest that Thwaites Glacier is likely to undergo substantial changes in the coming decades. This work was performed at the California Institute of Technology's Jet Propulsion Laboratory and the University of California Irvine

  5. Climatic Teleconnections Recorded By Tropical Mountain Glaciers

    NASA Astrophysics Data System (ADS)

    Thompson, L. G.; Permana, D.; Mosley-Thompson, E.; Davis, M. E.

    2014-12-01

    Information from ice cores from the world's highest mountains in the Tropics demonstrates both local climate variability and a high degree of teleconnectivity across the Pacific basin. Here we examine recently recovered ice core records from glaciers near Puncak Jaya in Papua, Indonesia, which lie on the highest peak between the Himalayas and the South American Andes. These glaciers are located on the western side of the Tropical Pacific warm pool, which is the "center of action" for interannual climate variability dominated by El Niño-Southern Oscillation (ENSO). ENSO either directly or indirectly affects most regions of Earth and their populations. In 2010, two ice cores measuring 32.13 m and 31.25 m were recovered to bedrock from the East Northwall Firn ice field. Both have been analyzed in high resolution (~3 cm sample length, 1156 and 1606 samples, respectively) for stable isotopes, dust, major ions and tritium concentrations. To better understand the controls on the oxygen isotopic (δ18 O) signal for this region, daily rainfall samples were collected between January 2013 and February 2014 at five weather stations over a distance of ~90 km ranging from 9 meters above sea level (masl) on the southern coast up to 3945 masl. The calculated isotopic lapse rate for this region is 0.24 ‰/100m. Papua, Indonesian ice core records are compared to ice core records from Dasuopu Glacier in the central Himalayas and from Quelccaya, Huascarán, Hualcán and Coropuna ice fields in the tropical Andes of Peru on the eastern side of the Pacific Ocean. The composite of the annual isotopic time series from these cores is significantly (R2 =0.53) related to tropical Pacific sea surface temperatures (SSTs), reflecting the strong linkage between tropical Pacific SSTs associated with ENSO and tropospheric temperatures in the low latitudes. New data on the already well-documented concomitant loss of ice on Quelccaya, Kilimanjaro in eastern Africa and the ice fields near Puncak

  6. Glacier melt on the Third Pole

    NASA Astrophysics Data System (ADS)

    Yao, T.

    2015-12-01

    With an average elevation above 4,000 metres, the Third Pole (TP) is a unique region with many high mountains centered on the Tibetan Plateau stretching over 5 million square kilometers. Major environmental changes are taking place on the TP characterized by complex interactions of atmospheric, cryospheric, hydrological, geological and environmental processes. These processes are critical for the well-being of the three billion people inhabiting the plateau and the surrounding regions. Glacier melt is one of the most significant environmental changes observed on the TP. Over the past decade, most of the glaciers on the TP have undergone considerable melt. The Third Pole Environment (TPE) has focused on the causes of the glacier melt by conducting large-scale ground in-situ observation and monitoring, analyzing satellite images and remote sensing data, and applying numerical modeling to environmental research on the TP. The studies of long-term record of water stable isotopes in precipitation and ice core throughout the TP have revealed different features with regions, thus proposing significant influence of atmospheric circulations on spatial precipitation pattern over the TP. Validation of the result by isotope-equipped general circulation models confirms the spatial distribution of different atmospheric circulation dominances on the TP, with northern part dominated by the westerlies, southern part by the summer monsoon, and central part featuring the influences of both circulation systems. Such unique circulation patterns also bear directly on the status of glaciers and lakes over the TP and its surroundings. The studies therefore found the largest glacier melt in the monsoon-dominated southern part, moderate melt in the central part of transition, and the least melt, or even slight advance in the westerlies-dominated northern TP. It is clear that some mountains on the TP are undergoing rapid melt and the consequence of without ice and snow will be very soon. The

  7. A metagenomic snapshot of taxonomic and functional diversity in an alpine glacier cryoconite ecosystem

    NASA Astrophysics Data System (ADS)

    Edwards, Arwyn; Pachebat, Justin A.; Swain, Martin; Hegarty, Matt; Hodson, Andrew J.; Irvine-Fynn, Tristram D. L.; Rassner, Sara M. E.; Sattler, Birgit

    2013-09-01

    Cryoconite is a microbe-mineral aggregate which darkens the ice surface of glaciers. Microbial process and marker gene PCR-dependent measurements reveal active and diverse cryoconite microbial communities on polar glaciers. Here, we provide the first report of a cryoconite metagenome and culture-independent study of alpine cryoconite microbial diversity. We assembled 1.2 Gbp of metagenomic DNA sequenced using an Illumina HiScanSQ from cryoconite holes across the ablation zone of Rotmoosferner in the Austrian Alps. The metagenome revealed a bacterially-dominated community, with Proteobacteria (62% of bacterial-assigned contigs) and Bacteroidetes (14%) considerably more abundant than Cyanobacteria (2.5%). Streptophyte DNA dominated the eukaryotic metagenome. Functional genes linked to N, Fe, S and P cycling illustrated an acquisitive trend and a nitrogen cycle based upon efficient ammonia recycling. A comparison of 32 metagenome datasets revealed a similarity in functional profiles between the cryoconite and metagenomes characterized from other cold microbe-mineral aggregates. Overall, the metagenomic snapshot reveals the cryoconite ecosystem of this alpine glacier as dependent on scavenging carbon and nutrients from allochthonous sources, in particular mosses transported by wind from ice-marginal habitats, consistent with net heterotrophy indicated by productivity measurements. A transition from singular snapshots of cryoconite metagenomes to comparative analyses is advocated.

  8. Glacier Dynamics and Outburst Flood Potential from the Imja and Thulagi Glacier-Lake Systems (Nepal)

    NASA Astrophysics Data System (ADS)

    Kargel, Jeffrey; Leonard, Gregory; Regmi, Dhananjay; Haritashya, Umesh; Chand, Mohan; Pradhan, Suresh; Sapkota, Nawaraj; Byers, Alton; Joshi, Sharad; McKinney, Daene; Mool, Pradeep; Somos-Valenzuela, Marcelo; Huggel, Christian

    2015-04-01

    Thulagi and Imja lakes are, according to ICIMOD, among Nepal's most dangerous glacier lakes, i.e., most likely to cause death and destruction in case of a glacier lake outburst flood (GLOF). Imja Lake and the associated Imja and Lhoste-Shar glaciers have been intensively studied; Thulagi Glacier and its lake are much less studied. Collectively, we have undertaken a series of increasingly thorough bathymetric and land surveys and satellite remote sensing analyses of Imja Lake and its glacier setting. We are analyzing several expeditions' data to build a detailed assessment of the glacier and lake to better establish the dynamical evolution of the system and its future GLOF potential. Our most recent, most complete bathymetric survey of Imja Lake has revealed a much greater volume (75,200,000 cubic meters) and maximum depth (149.8 m) than found before. Our analysis suggests that not all possible Imja GLOF scenarios would result in devastation. Some moraine melt-through or down-cutting mechanisms -- perhaps induced by extreme monsoon precipitation or an earthquake -- could generate outbursts lasting from 10,000-100,000 seconds ("slow GLOFs"), thus limiting peak flows and downstream damage. The potential damage from a slow GLOF from Imja Lake -- even if there is a large total volume -- is lessened by the relatively low peak discharge and because the major villages downstream from Imja Lake are situated just outside of and above a deep, broad outwash and debris-flow channel system. Imja and other glaciers in the area have built a large fan, now deeply trenched, which is able to accommodate the peak discharges of potential slow GLOFs, such that Dingboche and other villages would be spared. However, local geomorphology also bears evidence of "fast GLOFs," such as may be issued by a tsunami, which could be initiated by a large mass movement into Imja Lake and which might override and damage the end moraine in <100 seconds. Dingboche and other villages are vulnerable to

  9. Surge-type glaciers in the Tien Shan (Central Asia)

    NASA Astrophysics Data System (ADS)

    Mukherjee, Kriti; Bolch, Tobias

    2016-04-01

    Surge-type glaciers in High Mountain Asia are mostly observed in Karakoram and Pamir. However, few surge-type glaciers also exist in the Tien Shan, but have not comprehensively studied in detail in the recent literature. We identified surge-type glaciers in the Tien Shan either from available literature or by manual interpretation using available satellite images (such as Corona, Hexagon, Landsat, SPOT, IRS) for the period 1960 to 2014. We identified 39 possible surge-type glaciers, showing typical characteristics like looped moraines. Twenty-two of them rapidly advanced during different periods or a surge was clearly described in the literature. For the remaining possible surge-type glaciers either the advance, in terms of time and length, were not mentioned in detail in the literature, or the glaciers have remained either stable or retreated during the entire period of our study. Most of the surge-type glaciers cluster in the Inner Tien Shan (especially in the Ak-Shiirak rage) and the Central Tien Shan, are in size and are facing North, West or North West. Pronounced surge events were observed for North Inylchek and Samoilowitsch glaciers, both of which are located in the Central Tien Shan. Samoilowitsch Glacier retreated by more than 3 km between 1960 (length ~8.9 km) and 1992 (~5.8 km), advanced by almost 3 km until 2006 and slightly retreated thereafter. The most pronounced advance occurred between 2000 and 2002. DEM differencing (based on SRTM3 data and stereo Hexagon and Cartosat-1 data) revealed a significant thickening in the middle reaches (reservoir area) of the glacier between 1973 and 2000 while the surface significantly lowered in the middle and upper parts of the glacier between 2000 and 2006. Hence, the ice mass was transferred to the lower reaches (receiving area) and caused the advance with a maximum thickening of more than 80 m. The ~30 km long North Inylchek Glacier retreated since 1943 and showed a very rapid advance of ~3.5 km especially in

  10. Recent Activity of Glaciers of Mount Rainier, Washington

    USGS Publications Warehouse

    Sigafoos, Robert S.; Hendricks, E.L.

    1972-01-01

    Knowing the ages of trees growing on recent moraines at Mount Rainier, Wash., permits the moraines to be dated. Moraines which are ridges of boulders, gravel, sand, and dust deposited at the margins of a glacier, mark former limits of a receding glacier. Knowing past glacial activity aids our understanding of past climatic variations. The report documents the ages of moraines deposited by eight glaciers. Aerial photographs and planimetric maps show areas where detailed field studies were made below seven glaciers. Moraines, past ice positions, and sample areas are plotted on the photographs and maps, along with trails, roads, streams, and landforms, to permit critical areas to be identified in the future. Ground photographs are included so that sample sites and easily accessible moraines can be found along trails. Tables present data about trees sampled in areas near the glaciers of Mount Rainier, Wash. The data in the tables show there are modern moraines of different age around the mountain; some valleys contain only one modern moraiine; others contain as many as nine. The evidence indicates a sequence of modern glacial advances terminating at about the following A.D. dates: 1525, 1550, 1625-60, 1715, 1730-65, 1820-60, 1875, and 1910. Nisqually River valley near Nisqually Glacier contains one moraine formed before A.D. 1842; Tahoma Creek valley near South Tahoma Glacier contains three moraines formed before A.D. 1528; 1843, and 1864; South Puyallup River valley near Tahoma Glacier, six moraines A.D. 1544, 1761, 1841, 1851, 1863, 1898; Puyallup Glacier, one moraine, A.D. 1846; Carbon Glacier, four moraines, 1519, 1763, 1847, 1876; Winthrop Glacier, four moraines, 1655, 1716, 1760, amid 1822; Emmons Glacier, nine moraines, 1596, 1613, 1661, 1738, 1825, 1850, 1865, 1870, 1901; and Ohanapecosh Glacier, three moraines, 1741, 1846, and 1878. Abandoned melt-water and flood channels were identified within moraine complexes below three glaciers, and their time of

  11. Glacier and climate change in Pakistan and Afghanistan

    NASA Astrophysics Data System (ADS)

    Shroder, J.; Bishop, M.; Burgett, A.

    2012-04-01

    Climate change predictions and water resource related issuesin Afghanistan and Pakistan have led to the need for detailed assessments and understanding of glacier fluctuations, and the determination of the dominant controlling factors governing glacier sensitivity to climate change. Consequently, we studied glacier fluctuations and the role of topography in an attempt to understand glacier fluctuations.Specifically we used ASTER imagery, Landsat ETM data, and an SRTM digital elevation model, together with Google Earth™ high-resolution imagery to examine terminus fluctuations, ice velocity variations, and local- and meso-scale topographic parameters that are related to irradiance variations, ablation, and glacial geomorphology.Multispectral satellite imagery were utilized to estimate advance and retreat rates, along with glacier profile velocities. Geomorphometric analysis was utilized to generateglacier altitude profiles of hypsometry, slope, curvature, and topographic shielding. Our results reveal that glacier response to climate change is highly variable in Pakistan, as many glaciers are advancing as well as retreating, while others exhibit a stationary terminus. It is important to note that advances in the Karakoram do not appear to be restricted to glaciers at high elevations, suggesting climate forcing. Glaciers in the Hindu Raj and Hindu Kush are retreating, with fewer glaciers advancing, indicating the possibility of a spatial trend from West to East in Pakistan. There is a dramatic diminution of Hindu Kush ice in Afghanistan. In the Karakoram, many new surging glaciers have been identified with flow velocities ranging from 200-1000 m/yr. Non- surging glaciers also exhibit relative high velocities there. Spatial patternsof relief appear to be associated with glacier debris cover, as snow/ice avalanchescontribute debris and ice mass. In addition, patterns of topographic shielding are highly variable, revealing variations in the diffuse-skylight irradiance

  12. Twentieth century thinning of Mendenhall Glacier, Alaska, and its relationship to climate, lake calving, and glacier run-off

    NASA Astrophysics Data System (ADS)

    Motyka, Roman J.; O'Neel, Shad; Connor, Cathy L.; Echelmeyer, Keith A.

    2003-01-01

    Mendenhall Glacier is a dynamic maritime glacier in southeast Alaska that is undergoing substantial recession and thinning. The terminus has retreated 3 km during the 20th century and the lower part of the glacier has thinned 200 m or more since 1909. Glacier-wide volume loss between 1948 and 2000 is estimated at 5.5 km 3. Wastage has been the strongest in the glacier's lower reaches, but the glacier has also thinned at higher elevations. The shrinkage of Mendenhall Glacier appears to be due primarily to surface melting and secondarily to lake calving. The change in the average rate of thinning on the lower glacier, <1 m a -1 between 1948 and 1982 and >2 m a -1 since 1982, agrees qualitatively with observed warming trends in the region. Mean annual temperatures in Juneau decreased slightly from 1947 to 1976; they then began to increase, leading to an overall warming of ˜1.6 °C since 1943. Lake calving losses have periodically been a small but significant fraction of glacier ablation. The portion of the terminus that ends in the lake is becoming increasingly vulnerable to calving because of a deep pro-glacial lake basin. If current climatic trends persist, the glacier will continue to shrink and the terminus will recede onto land at a position about 500 m inland within one to two decades. The glacier and the meltwaters that flow from it are integral components of the Mendenhall Valley hydrologic system. Approximately 13% of the recent average annual discharge of the Mendenhall River is attributable to glacier shrinkage. Glacier melt contributes 50% of the total river discharge in summer.

  13. Differences in dissolved organic matter lability between alpine glaciers and alpine rock glaciers of the American West

    NASA Astrophysics Data System (ADS)

    Hall, E.; Fegel, T. S., II; Baron, J.; Boot, C. M.

    2015-12-01

    While alpine glaciers in montane regions represent the largest flux of dissolved organic matter (DOM) from global ice melt no research has examined the bioavailability of DOM melted out of glacial ice in the western continental United States. Furthermore, rock glaciers are an order of magnitude more abundant than ice glaciers in U.S., yet are not included in budgets for perennial ice carbon stores. Our research aims to understand differences in the bioavailability of carbon from ice glaciers and rock glaciers along the Central Rocky Mountains of Colorado. Identical microbial communities were fed standardized amounts of DOM from four different ice glacier-rock glaciers pairs. Using laboratory incubations, paired with mass spectrometry based metabolomics and 16S gene sequencing; we were able to examine functional definitions of DOM lability in glacial ice. We hypothesized that even though DOM quantities are similar in the outputs of both glacial types in our study area, ice glacial DOM would be more bioavailable than DOM from rock glaciers due to higher proportions of byproducts from microbial metabolism than rock glacier DOM, which has higher amounts of "recalcitrant" plant material. Our results show that DOM from ice glaciers is more labile than DOM from geologically and geographically similar paired rock glaciers. Ice glacier DOM represents an important pool of labile carbon to headwater ecosystems of the Rocky Mountains. Metabolomic analysis shows numerous compounds from varying metabolite pathways, including byproducts of nitrification before and after incubation, meaning that, similar to large maritime glaciers in Alaska and Europe, subglacial environments in the mountain ranges of the United States are hotspots for biological activity and processing of organic carbon.

  14. Modeling Runoff from Partially Glacierized Catchments in the Tropical Andes with Different Glacier Coverage and Land Cover Conditions

    NASA Astrophysics Data System (ADS)

    Kinouchi, T.; Mendoza, J.; Luna, J.; Asaoka, Y.

    2014-12-01

    In Bolivian Andes, retreats of tropical glaciers are rapid, thus water resources currently available from glacierized catchments for drinking, agriculture, industry and hydropower would be changed in its volume and variations due to changing climate. Water resources in La Paz and El Alto, the capital city areas of Bolivia, strongly depend on the runoff from partially glacierized catchments located in the Cordillera Real, which is a combined contribution of surface and subsurface flow from glacierized and non-glacierized areas due to rainfall, snow melt and glacier melt. To predict the long-term availability of water resources for the capital city areas, we developed a semi-distributed conceptual glacio-hydrological model that considers various runoff pathways from partially glacierized high-altitudinal catchments located in the outer tropics. In the model, the retarding effect of lakes and wetlands was considered, based on the observed hydraulic functions and distribution of wetlands. The model was applied to three sub-catchments of the Tuni Lake watershed (98km2), from which the water resources for La Paz and El Alto are supplied. With calibrated parameters, the model reproduced well the observed seasonal variations of daily runoff during recent two years. Simulated results of water balance suggested that for the catchment with a larger glacier cover, more than 40% of the annual total runoff is contributed from glacierized areas due to glacier melt and snowmelt. The contribution from glacierized areas in other two sub-catchments, with relatively smaller areas covered by glacier ice, was calculated to be between 10-15%. We found that the role of wetlands and lakes are essential in retarding and regulating the runoff from partially glacierized high-mountain catchments.

  15. Glaciers and ice caps outside Greenland

    USGS Publications Warehouse

    Sharp, Marin; Wolken, G.; Burgess, D.; Cogley, J.G.; Copland, L.; Thomson, L.; Arendt, A.; Wouters, B.; Kohler, J.; Andreassen, L.M.; O'Neel, Shad; Pelto, M.

    2015-01-01

    Mountain glaciers and ice caps cover an area of over 400 000 km2 in the Arctic, and are a major influence on global sea level (Gardner et al. 2011, 2013; Jacob et al. 2012). They gain mass by snow accumulation and lose mass by meltwater runoff. Where they terminate in water (ocean or lake), they also lose mass by iceberg calving. The climatic mass balance (Bclim, the difference between annual snow accumulation and annual meltwater runoff) is a widely used index of how glaciers respond to climate variability and change. The total mass balance (ΔM) is defined as the difference between annual snow accumulation and annual mass losses (by iceberg calving plus runoff).

  16. Mass loss on Himalayan glacier endangers water resources

    NASA Astrophysics Data System (ADS)

    Kehrwald, Natalie M.; Thompson, Lonnie G.; Tandong, Yao; Mosley-Thompson, Ellen; Schotterer, Ulrich; Alfimov, Vasily; Beer, Jürg; Eikenberg, Jost; Davis, Mary E.

    2008-11-01

    Ice cores drilled from glaciers around the world generally contain horizons with elevated levels of beta radioactivity including 36Cl and 3H associated with atmospheric thermonuclear bomb testing in the 1950s and 1960s. Ice cores collected in 2006 from Naimona'nyi Glacier in the Himalaya (Tibet) lack these distinctive marker horizons suggesting no net accumulation of mass (ice) since at least 1950. Naimona'nyi is the highest glacier (6050 masl) documented to be losing mass annually suggesting the possibility of similar mass loss on other high-elevation glaciers in low and mid-latitudes under a warmer Earth scenario. If climatic conditions dominating the mass balance of Naimona'nyi extend to other glaciers in the region, the implications for water resources could be serious as these glaciers feed the headwaters of the Indus, Ganges, and Brahmaputra Rivers that sustain one of the world's most populous regions.

  17. A macroscopic approach to glacier dynamics

    USGS Publications Warehouse

    Harrison, W.D.; Raymond, C.F.; Echelmeyer, K.A.; Krimmel, R.M.

    2003-01-01

    A simple approach to glacier dynamics is explored in which there is postulated to be a relationship between area and volume with three parameters: the time for area to respond to changes in volume, a thickness scale, and an area characterizing the condition of the initial state. This approach gives a good fit to the measurements of cumulative balance and area on South Cascade Glacier from 1970-97; the area time-scale is roughly 8 years, the thickness scale about 123 m, and the 1970 area roughly 4% larger than required for adjustment with volume. Combining this relationship with a version of mass continuity expressed in terms of area and volume produces a theory of glacier area and volume response to climate in which another time constant, the volume time-scale, appears. Area and volume both respond like a damped spring and mass system. The damping of the South Cascade response is approximately critical, and the volume time-scale is roughly 48 years, six times the area time-scale. The critically damped spring and mass analogy reproduces the time dependence predicted by the more complicated traditional theory of Nye.

  18. Pathways of Petermann Glacier meltwater, Greenland

    NASA Astrophysics Data System (ADS)

    Heuzé, Céline; Wåhlin, Anna; Johnson, Helen; Münchow, Andreas

    2016-04-01

    Radar and satellite observations suggest that the floating ice shelf of Petermann Glacier loses up to 80% of its mass through basal melting, caused by the intrusion of warm Atlantic Water into the fjord and under the ice shelf. The fate of Petermann's glacial meltwater is still largely unknown. It is investigated here, using hydrographic observations collected during a research cruise on board I/B Oden in August 2015. Two methods are used to detect the meltwater from Petermann: a mathematical one that provides the concentration of ice shelf meltwater, and a geometrical one to distinguish the meltwater from Petermann and the meltwater from other ice shelves. The meltwater from Petermann mostly circulates on the north side of the fjord. At the sill, 0.5 mSv of meltwater leave the fjord, mostly on the northeastern side between 100 and 350 m depth, but also in the central channel, albeit with a lesser concentration. Meltwater from Petermann is found in all the casts in Hall Basin, notably north of the sill by Greenland coast. The geometrical method reveals that the casts closest to the Canadian side mostly contain meltwater from other, unidentified glaciers. As Atlantic Water warms up, it is key to monitor Greenland melting glaciers and track their meltwater to properly assess their impact on the ocean circulation and sea level rise.

  19. Dielectric Signatures of Annealing in Glacier Ice

    NASA Astrophysics Data System (ADS)

    Grimm, R. E.; Stillman, D. E.; MacGregor, J. A.

    2015-12-01

    We analyzed the dielectric spectra of 49 firn and ice samples from ice sheets and glaciers to better understand how differing ice formation and evolution affect electrical properties. The dielectric relaxation of ice is well known and its characteristic frequency increases with the concentration of soluble impurities in the ice lattice. We found that meteoric ice and firn generally possess two such relaxations, indicating distinct crystal populations or zonation. Typically, one population is consistent with that of relatively pure ice, and the other is significantly more impure. However, high temperatures (e.g., temperate ice), long residence times (e.g., ancient ice from Mullins Glacier, Antarctica), or anomalously high impurity concentrations favor the development of a single relaxation. These relationships suggest that annealing causes two dielectrically distinct populations to merge into one population. The dielectric response of temperate ice samples indicates increasing purity with increasing depth, suggesting final rejection of impurities from the lattice. Separately, subglacially frozen samples from the Vostok 5G ice core possess a single relaxation whose variable characteristic frequency likely reflects the composition of the source water. Multi-frequency electrical measurements on cores and in the field can track annealing of glacier ice.

  20. GLACIER PEAK WILDERNESS STUDY AREA, WASHINGTON.

    USGS Publications Warehouse

    Church, S.E.; Stotelmeyer, R.B.

    1984-01-01

    Geologic, geochemical, gravity, aeromagnetic, and mine and prospect surveys were conducted to evaluate the mineral-resource potential of the Glacier Peak Wilderness study area and proposed additions in Washington. In the study area, six areas containing several base and precious metals have been identified that have substantiated mineral-resource potential, two of which are in areas recommended for wilderness addition. An additional 10 areas have probable mineral-resource potential. The most important demonstrated resource identified is the porphyry copper-molybdenum deposit at Glacier Peak mine near the center of the wilderness study area, where a deposit totaling 1. 9 billion tons of mineralized rock has been delineated by drilling. A possible geothermal potential exists on the east side of the Glacier Peak volcano, and a possible 24-million-cu-yd cinder resource is identified at the White Chuck Cinder Cone in the wilderness study area, but both are remote and no resources were identified. No other energy resource potential was identified in this study.

  1. Glacier Bay, Alaska, from the Ground, Air, and Space

    NASA Technical Reports Server (NTRS)

    Hall, Dorothy K.

    1997-01-01

    This tape uses a combination of video, three-dimensional computer imaging, and still photographs to provide a descriptive overview of the life-cycle and environmental effects of glaciers. An historical prospective of researchers and the contribution that they have made to the understanding of glaciers and Glacier Bay is presented. The data collected from these scientists have been documented and used by means of scientific visualization in the hope of learning how glacial activity relates to climate changes.

  2. Holocene cirque glacier activity in Rondane, southern Norway

    NASA Astrophysics Data System (ADS)

    Kvisvik, Bjørn Christian; Paasche, Øyvind; Dahl, Svein Olaf

    2015-10-01

    Skriufonnen is a small cirque glacier (0.03 km2) in the continental mountains of Rondane in southern Norway. At present, it is the only glacier in Rondane, and very little is known about Holocene glacier fluctuations in this region. Direct observations of the glacier began in 2002, since which time Skriufonnen has been in a state of strong decline. In order to provide a temporal context, past glacier fluctuations were reconstructed based on a series of short HTH gravity cores (n = 8) and long piston cores (n = 6) retrieved from three downstream lakes of Skriufonnen. The cores were analysed for selected magnetic properties (χbulk, ARM, SIRM, 77 K/293 K), organic content (LOI), and geochemical trace elements. Soil catchment samples (n = 6) were collected along a transect running from the three lakes up to the present glacier terminus. Bulk susceptibility (χbulk) measurements show that the finest fractions systematically return the highest values and that ferromagnetic minerals are depleted with distance to the glacier front. This means that periods dominated by paramagnetic minerals indicate very little or no glacier activity, whereas intervals with more ferromagnetic minerals suggest increased glacier activity. The quantitative core analyses indicate that Skriufonnen existed prior to 10,200 b2k (years before A.D. 2000) and disappeared ~ 10,000 b2k. No glacier activity is recorded from c. 10,000 b2k until the glacier reoccurred at the onset of the local Neoglacial period, c. 4000 b2k. The glacier attained its maximum extent between 3200 and 2400 b2k and during the end of the 'Little Ice Age' (LIA) c. A.D. 1800. Neoglacial fluctuations of Skriufonnen are in line with shifts in local summer temperatures and show a delayed Neoglacial inception compared to western Norway.

  3. Inventory of glaciers in the Sierra Nevada, California

    USGS Publications Warehouse

    Raub, William; Brown, C. Suzanne; Post, Austin

    2006-01-01

    All perennial bodies of ice in the Sierra Nevada are listed and classified. The inventory includes 497 glaciers covering a total area of 50 square kilometers and 788 small ice bodies which do not meet the definition of a glacier, covering a total of 13 square kilometers. The listings include each ice body's drainage basin, location, orientation, altitude, area, and length the glaciers are also classified as to form, source, surface condition, and nature and activity of the terminus.

  4. Response of debris-covered glaciers to climate change

    NASA Astrophysics Data System (ADS)

    Benn, D. I.; Lindsey, N.; Kathryn, H.

    2004-12-01

    The presence of supraglacial debris strongly influences glacier ablation, and the mass balance of debris-covered glaciers differs significantly from that of clean glaciers in similar climatic settings. Predicting the response of debris-covered glaciers to climate change is important for hazard mitigation strategies in many high mountain environments, especially where temporary lakes are likely to form on stagnating glacier tongues. Accurate prediction of glacier evolution requires a robust mass balance function which incorporates the effect of debris cover. We present a new model for calculating ablation beneath supraglacial debris layer from meteorological data, based on coupling the surface energy balance and conductive heat flux through the debris layer. The model performs well in a wide range of climatic settings, and results correlate well with measured melt rates in the European Alps and Svalbard. The ablation model is used to construct theoretical mass balance curves for debris covered glaciers, providing surface boundary conditions for glacier flow models. Modelled mass balance curves display reverse gradients on glacier termini where the effect of thickening debris cover with decreasing altitude outweighs that of higher air temperatures. This explains the widely-noted tendency for debris-covered glaciers to stagnate under warming climates. When the mass balance of the glacier as a whole is negative, increasing ablation with altitude causes the lower tongue to decrease in gradient. As gradients and ice thicknesses decline, the process is reinforced by a positive feedback with velocity, so less ice is delivered to the terminal zone. Low surface gradients encourage the formation of supraglacial ponds which can grow rapidly, significantly increasing mass loss from the glacier and potentially posing flood hazards.

  5. Modelling mass balance and temperature sensitivity on Shallap glacier, Peru

    NASA Astrophysics Data System (ADS)

    Gurgiser, W.; Marzeion, B.; Nicholson, L. I.; Ortner, M.; Kaser, G.

    2013-12-01

    Due to pronounced dry seasons in the tropical Andes of Peru glacier melt water is an important factor for year-round water availability for the local society. Andean glaciers have been shrinking during the last decades but present day's magnitudes of glacier mass balance and sensitivities to changes in atmospheric drivers are not well known. Therefore we have calculated spatial distributed glacier mass and energy balance of Shallap glacier (4700 m - 5700 m, 9°S), Cordillera Blanca, Peru, on hourly time steps for the period Sept. 2006 to Aug. 2008 with records from an AWS close to the glacier as model input. Our model evaluation against measured surface height change in the ablation zone of the glacier yields our model results to be reasonable and within an expectable error range. For the mass balance characteristics we found similar vertical gradients and accumulation area ratios but markedly differences in specific mass balance from year to year. The differences were mainly caused by large differences in annual ablation in the glacier area below 5000m. By comparing the meteorological conditions in both years we found for the year with more negative mass balance that total precipitation was only slightly lower but mean annual temperature was higher, thus the fraction of liquid precipitation and the snow line altitude too. As shortwave net energy turned out to be the key driver of ablation in all seasons the deviations in snow line altitude and surface albedo explain most of the deviations in available melt energy. Hence, mass balance of tropical Shallap glacier was not only sensitive to precipitation but also to temperature which has not been expected for glaciers in the Peruvian Andes before. We furthermore have investigated impacts of increasing temperature due to its multiple effects on glacier mass and energy balance (fraction of liquid precipitation, long wave incoming radiation, sensible and latent heat flux). Presenting these results should allow for better

  6. Glaciers in Southern Andes seen from STS-63 Discovery

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Glaciers in the Andes Mountains jut into two lakes in the Patagoinian lowlands. Lago Viedman appears at center in the top portion of the 70mm frame. Lago Argentina barely appears in the frame at far right. The glaciers descend from the very high and wet mountains of southern Chile (peaks reach 3,600 meters) in a range locally known as Cordillera Darwin. The lakes in the picture were carved out by the glaciers during advances of the ice.

  7. Columbia Glacier stake location, mass balance, glacier surface altitude, and ice radar data, 1978 measurement year

    USGS Publications Warehouse

    Mayo, L.R.; Trabant, D.C.; March, Rod; Haeberli, Wilfried

    1979-01-01

    A 1 year data-collection program on Columbia Glacier, Alaska has produced a data set consisting of near-surface ice kinematics, mass balance, and altitude change at 57 points and 34 ice radar soundings. These data presented in two tables, are part of the basic data required for glacier dynamic analysis, computer models, and predictions of the number and size of icebergs which Columbia Glacier will calve into shipping lanes of eastern Prince William Sound. A metric, sea-level coordinate system was developed for use in surveying throughout the basin. Its use is explained and monument coordinates listed. A series of seven integrated programs for calculators were used in both the field and office to reduce the surveying data. These programs are thoroughly documented and explained in the report. (Kosco-USGS)

  8. Passive microwave (SSM/I) satellite predictions of valley glacier hydrology, Matanuska Glacier, Alaska

    USGS Publications Warehouse

    Kopczynski, S.E.; Ramage, J.; Lawson, D.; Goetz, S.; Evenson, E.; Denner, J.; Larson, G.

    2008-01-01

    We advance an approach to use satellite passive microwave observations to track valley glacier snowmelt and predict timing of spring snowmelt-induced floods at the terminus. Using 37 V GHz brightness temperatures (Tb) from the Special Sensor Microwave hnager (SSM/I), we monitor snowmelt onset when both Tb and the difference between the ascending and descending overpasses exceed fixed thresholds established for Matanuska Glacier. Melt is confirmed by ground-measured air temperature and snow-wetness, while glacier hydrologic responses are monitored by a stream gauge, suspended-sediment sensors and terminus ice velocity measurements. Accumulation area snowmelt timing is correlated (R2 = 0.61) to timing of the annual snowmelt flood peak and can be predicted within ??5 days. Copyright 2008 by the American Geophysical Union.

  9. Reduced melt on debris-covered glaciers: investigations from Changri Nup Glacier, Nepal

    NASA Astrophysics Data System (ADS)

    Vincent, Christian; Wagnon, Patrick; Shea, Joseph M.; Immerzeel, Walter W.; Kraaijenbrink, Philip; Shrestha, Dibas; Soruco, Alvaro; Arnaud, Yves; Brun, Fanny; Berthier, Etienne; Futi Sherpa, Sonam

    2016-08-01

    Approximately 25 % of the glacierized area in the Everest region is covered by debris, yet the surface mass balance of debris-covered portions of these glaciers has not been measured directly. In this study, ground-based measurements of surface elevation and ice depth are combined with terrestrial photogrammetry, unmanned aerial vehicle (UAV) and satellite elevation models to derive the surface mass balance of the debris-covered tongue of Changri Nup Glacier, located in the Everest region. Over the debris-covered tongue, the mean elevation change between 2011 and 2015 is -0.93 m year-1 or -0.84 m water equivalent per year (w.e. a-1). The mean emergence velocity over this region, estimated from the total ice flux through a cross section immediately above the debris-covered zone, is +0.37 m w.e. a-1. The debris-covered portion of the glacier thus has an area-averaged mass balance of -1.21 ± 0.2 m w.e. a-1 between 5240 and 5525 m above sea level (m a.s.l.). Surface mass balances observed on nearby debris-free glaciers suggest that the ablation is strongly reduced (by ca. 1.8 m w.e. a-1) by the debris cover. The insulating effect of the debris cover has a larger effect on total mass loss than the enhanced ice ablation due to supraglacial ponds and exposed ice cliffs. This finding contradicts earlier geodetic studies and should be considered for modelling the future evolution of debris-covered glaciers.

  10. Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland

    PubMed Central

    Selmes, Nick; James, Timothy D.; Edwards, Stuart; Martin, Ian; O'Farrell, Timothy; Aspey, Robin; Rutt, Ian; Nettles, Meredith; Baugé, Tim

    2015-01-01

    Abstract During summer 2013 we installed a network of 19 GPS nodes at the ungrounded margin of Helheim Glacier in southeast Greenland together with three cameras to study iceberg calving mechanisms. The network collected data at rates up to every 7 s and was designed to be robust to loss of nodes as the glacier calved. Data collection covered 55 days, and many nodes survived in locations right at the glacier front to the time of iceberg calving. The observations included a number of significant calving events, and as a consequence the glacier retreated ~1.5 km. The data provide real‐time, high‐frequency observations in unprecedented proximity to the calving front. The glacier calved by a process of buoyancy‐force‐induced crevassing in which the ice downglacier of flexion zones rotates upward because it is out of buoyant equilibrium. Calving then occurs back to the flexion zone. This calving process provides a compelling and complete explanation for the data. Tracking of oblique camera images allows identification and characterisation of the flexion zones and their propagation downglacier. Interpretation of the GPS data and camera data in combination allows us to place constraints on the height of the basal cavity that forms beneath the rotating ice downglacier of the flexion zone before calving. The flexion zones are probably formed by the exploitation of basal crevasses, and theoretical considerations suggest that their propagation is strongly enhanced when the glacier base is deeper than buoyant equilibrium. Thus, this calving mechanism is likely to dominate whenever such geometry occurs and is of increasing importance in Greenland. PMID:27570721

  11. Observations of Dynamic Changes at an Advancing Tidewater Glacier: Hubbard Glacier, Southeast Alaska

    NASA Astrophysics Data System (ADS)

    Elliott, J.; Stearns, L. A.; Pritchard, M. E.; Bartholomaus, T.

    2015-12-01

    Hubbard Glacier, located in southeast Alaska, is the largest non-polar tidewater glacier in the world and one of a small number of glaciers that is steadily advancing. These attributes make it an intriguing target for observations of variations in ice dynamics over time. We use synthetic aperture radar data (ALOS and TerraSAR-X) and high-resolution optical imagery (WorldView and Quickbird) with a pixel tracking technique to map surface velocities from 2008 to the present, lengthening and broadening the time series of ice velocities presented in previous studies. A key result from our analysis is that Hubbard displays peak speeds of up to 12 m/day during the winter months (December - February) and minimum speeds during late summer (August - September). The times of peak and minimum speeds is quite different from those found in previous studies of Hubbard surface velocities derived from Landsat imagery, GPS, and photogrammetric methods. Those studies found peak speeds during late spring (May - June) and minimum speeds in fall (October-November), a pattern observed generally at tidewater glaciers. A second major feature we observe in our time series is the dramatic seasonal variation in surface speeds. The minimum speeds we find along the terminal lobe of the glacier are much lower than those found in previous studies, with values decreasing to near zero. Such a dramatic slow down of a tidewater glacier has not been widely observed. This result, along with the recent pattern of seasonal velocity peaks and minimas, suggests that Hubbard has undergone a change in ice dynamics.

  12. Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland

    PubMed Central

    Selmes, Nick; James, Timothy D.; Edwards, Stuart; Martin, Ian; O'Farrell, Timothy; Aspey, Robin; Rutt, Ian; Nettles, Meredith; Baugé, Tim

    2015-01-01

    Abstract During summer 2013 we installed a network of 19 GPS nodes at the ungrounded margin of Helheim Glacier in southeast Greenland together with three cameras to study iceberg calving mechanisms. The network collected data at rates up to every 7 s and was designed to be robust to loss of nodes as the glacier calved. Data collection covered 55 days, and many nodes survived in locations right at the glacier front to the time of iceberg calving. The observations included a number of significant calving events, and as a consequence the glacier retreated ~1.5 km. The data provide real‐time, high‐frequency observations in unprecedented proximity to the calving front. The glacier calved by a process of buoyancy‐force‐induced crevassing in which the ice downglacier of flexion zones rotates upward because it is out of buoyant equilibrium. Calving then occurs back to the flexion zone. This calving process provides a compelling and complete explanation for the data. Tracking of oblique camera images allows identification and characterisation of the flexion zones and their propagation downglacier. Interpretation of the GPS data and camera data in combination allows us to place constraints on the height of the basal cavity that forms beneath the rotating ice downglacier of the flexion zone before calving. The flexion zones are probably formed by the exploitation of basal crevasses, and theoretical considerations suggest that their propagation is strongly enhanced when the glacier base is deeper than buoyant equilibrium. Thus, this calving mechanism is likely to dominate whenever such geometry occurs and is of increasing importance in Greenland.

  13. Glacier ice-volume modeling and glacier volumes on Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Trabant, Dennis C.; Hawkins, Daniel B.

    1997-01-01

    Assessment of ice volumes and hydrologic hazards on Redoubt Volcano began four months before the 1989-90 eruptions removed 0.29 cubic kilometer of perennial snow and ice from Drift glacier. A volume model was developed for evaluating glacier volumes on Redoubt Volcano. The volume model is based on third-order polynomial simulations of valley cross sections. The third-order polynomial is an interpolation from the valley walls exposed above glacier surfaces and takes advantage of ice-thickness measurements. The fortuitous 1989-90 eruptions removed the ice from a 4.5-kilometer length of Drift glacier, providing a unique opportunity for verification of the volume model. A 2.5-kilometer length was chosen in the denuded glacier valley and the ice volume was measured by digitally comparing two new maps: one derived from the most recent pre-eruption 1979 aerial photographs and the other from post-eruption 1990 aerial photographs. The measured volume in the reference reach was 99 x 106 cubic meters, about 1 percent less than was estimated by the volume model. The volume estimate produced by this volume model was much closer to the measured volume than was the volume estimated by other techniques. The verified volume model was used to evaluate the total volume of perennial snow and glacier ice on Redoubt Volcano, which was estimated to be 4.1?0.8 cubic kilometers. Substantial snow and ice covers on volcanoes exacerbate the hydrologic hazards associated with eruptions. The volume on Redoubt Volcano is about 23 times the volume that was present on Mount St. Helens before its 1980 eruption, which generated lahars and floods.

  14. Ice loss and sea level rise contribution from Alaskan glaciers

    NASA Astrophysics Data System (ADS)

    Berthier, E.; Schiefer, E.; Clarke, G. K.; Menounos, B.; Rémy, F.; Cazenave, A. A.

    2009-12-01

    Over the last 50 years, retreating glaciers and ice caps (GIC) contributed 0.5 mm/yr to SLR, and one third is believed to originate from ice masses bordering the Gulf of Alaska. However, these estimates of ice wastage in Alaska are based on methods that directly measure mass changes from a limited number of glaciers and extrapolate the results to estimate ice loss for the many thousands of others. Here, using a new glacier inventory with elevation changes derived from sequential digital elevation models (DEMs), we found that, between 1962 and 2006, Alaskan glaciers lost 41.9 ± 8.6 km**3/yr water equivalent (w.e.) and contributed 0.12 ± 0.02 mm/yr to SLR. Our ice loss is 34% lower than previous estimates. Reasons for our lower values include the higher spatial resolution of the glacier inventory used in our study and the complex pattern of ice elevation changes at the scale of individual glaciers and mountain ranges which was not resolved in earlier work. Our ice elevation changes reveal that glacier dynamics (surges, phase of the tidewater cycle, etc...) have a profound effect on the wastage of Alaska glaciers. 3D satellite view of Columbia glacier, Chugach Mountains, Alaska. (Copyright CNES 2007, Distribution Spot Image, processing E. Berthier CNRS)

  15. Inventory of Glaciers in the North Cascades, Washington

    USGS Publications Warehouse

    Post, Austin; Richardson, Don; Tangborn, Wendell V.; Rosselot, F.L.

    1971-01-01

    Perennial bodies of ice in the North Cascades having areas of at least 0.1 km2 (square kilometer) are tabulated and classified. The inventory, a contribution to the International Hydrological Decade, includes 756 glaciers, covering 267 km2, about half of the glacier area in the United States south of Alaska. Listings include each glacier's location, drainage basin, area, length, orientation, altitude, and classification as to form, source, surface, nature of terminus, and activity. These glaciers contribute annually about 800 million cubic meters of water to streamflow in the State of Washington.

  16. Little Ice Age glaciers in the Mediterranean mountains

    NASA Astrophysics Data System (ADS)

    Hughes, Philip

    2014-05-01

    Only a few small glaciers survive today in the Mountains of the Mediterranean. Notable examples are found in the Pyrenees, Maritime Alps, Italian Apennines, the Dinaric and Albanian Alps and the mountains of Turkey. Many glaciers disappeared during the 20th Century. Glaciers were much larger and more numerous during the Little Ice Age (Hughes, 2014). Small glaciers even existed as far south as the High Atlas of Morocco and the Sierra Nevada of southern Spain. In more northerly areas, such as the western Balkans, glaciers and permanent snow patches occupied hundreds of cirques on relatively low-lying mountains. In the High Atlas and the Sierra Nevada no glaciers exist today, whilst in the Balkans only a few modern glaciers have been reported. A similar situation is apparent throughout the mountains of the Mediterranean region. New evidence for glacier change since the Little Ice Age will be published soon in Hughes (2014) and this paper reviews the extent, timing and climatic significance of Little Ice Age glaciation in the Mediterranean region. Reference: Hughes, P.D. (2014) Little Ice Age glaciers in the Mediterranean mountains. In: Carozza, J.-M., Devillers, B., Morhange, C. (eds) Little Ice Age in the Mediterranean, Méditerranée, volume 123.

  17. Effect of fjord geometry on tidewater glacier stability

    NASA Astrophysics Data System (ADS)

    Åkesson, Henning; Nisancioglu, Kerim H.; Nick, Faezeh M.

    2016-04-01

    Many marine-terminating glaciers have thinned, accelerated and retreated during the last two decades, broadly consistent with warmer atmospheric and oceanic conditions. However, these patterns involve considerable spatial and temporal variability, with diverse glacier behavior within the same regions. Similarly, reconstructions of marine-terminating glaciers indicate highly asynchronous retreat histories. While it is well known that retrograde slopes can cause marine ice sheet instabilities, the effect of lateral drag and fjord width has received less attention. Here, we test the hypothesis that marine outlet glacier stability is largely controlled by fjord width, and to a less extent by regional climate forcing. We employ a dynamic flowline model on idealized glacier geometries (representative of different outlet glaciers) to investigate geometric controls on decadal and longer times scales. The model accounts for driving and resistive stresses of glacier flow as well as along-flow stress transfer. It has a physical treatment of iceberg calving and a time-adaptive grid allowing for continuous tracking of grounding-line migration. We apply changes in atmospheric and oceanic forcing and show how wide and narrow fjord sections foster glacier (in)stabilities. We also evaluate the effect of including a surface mass balance - elevation feedback in such a setting. Finally, the relevance of these results to past and future marine-terminating glacier stability is discussed.

  18. Spatial-temporal variation of glacier over koshi basin, Himalaya

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Yang, X.; Yao, T.

    2011-12-01

    Glacial change is a sensitive indicator of climate change and glacier meltwaters are vital water resource for more than 1/6 people in South and Central Asia. Due to the large extent and difficult accessibility of high mountainous terrain, there are few ground-based glacial observations. In the last decade, multi-temporal satellite imagery and older aerial photography have been used extensively to quantify glacier parameters such as glacier area, length, elevation, hypsography, and ice volume in mountainous areas throughout the world. In this study, a glacier inventory for Koshi Basin was generated for the year 1976, 1992, 2000 and 2009 using automated interpretation with remote sensing, GIS techniques and manual adjustments based on topographic maps, Landsat TM/ETM+, and SRTM DEM data. The area change of about ~3,407km2 was identified. During the past two decades, the average retreat rate of these glaciers was ~5.8% while the retreat rate from 2000 to 2009 was ~14.23%. Moreover, heavily debris-covered glaciers exist in this region. Some of them even extend several kilometers upstream from their terminus such as Kong Bu Re Bu Sang glacier. From 1992 to 2000, the decrease in total glacier area is ~30km2 while the debris coverage increased ~20km2. These increases generally occur near the boundary between clean ice and debris-covered glacier, while the glacial fronts are remarkably stable. In order to identify the effect of debris-covered glaciers, the variations of glacier area, length and elevation were calculated with and without debris-covered glaciers, respectively. Results show although the terminuses of glacial front were stagnant, the increase in debris-covered glacier contributes to the clean ice's length decrease and elevation increase, and thereby affects glacier's response to climate change. So we suggest that in the area where debris-covered glaciers are common, the clean ice and debris-covered area should be separated and the debris-covered part should

  19. Short term dynamics of the debris-covered Miage Glacier

    NASA Astrophysics Data System (ADS)

    Fyffe, Catriona; Brock, Ben; Kirkbride, Martin; Mair, Doug; Smiraglia, Claudio; Diolaiuti, Guglielmina

    2016-04-01

    Due to the often inaccessible nature of debris-covered glaciers, studies of their dynamics tend to be restricted to those using remotely sensed data. This paper presents data on the short-term glacier dynamics of the debris-covered Miage Glacier, Western Italian Alps. The glacier velocity was calculated from repeat occupation of up to 22 points using a differential GPS system over two melt seasons. Meteorological, hydrological and water chemistry data were collected over the same time periods, and the nature of the hydrological system was studied using dye tracing, to allow the short term variations in glacier dynamics to be understood in terms of the likely glacial drainage system and its evolution. The highest glacier velocities and the greatest velocity variability was found near to where a cluster of moulins enter the glacier, close to the limit of continuous debris cover. The melt from the clean and dirty ice occasionally led to inputs overcoming the channelized system (both in spring and mid-summer), leading to increased velocities. On the debris-covered lower glacier however velocities were lower and less variable, and significant speed-up was confined to a period when subglacial water was thought to have been transferred subglacially from higher upglacier. The subdued sub-debris melt signal is thought to be the cause of the reduced velocity variability, in spite of the hydrological system beneath this part of the glacier remaining inefficient.

  20. Global Terrestrial Network for Glaciers: Databases and Web interfaces

    NASA Astrophysics Data System (ADS)

    Raup, B.; Armstrong, R.; Fetterer, F.; Gartner-Roer, I.; Haeberli, W.; Hoelzle, M.; Khalsa, S. J. S.; Nussbaumer, S.; Weaver, R.; Zemp, M.

    2012-04-01

    The Global Terrestrial Network for Glaciers (GTN-G) is an umbrella organization with links to the Global Climate Observing System (GCOS), Global Terrestrial Observing System (GTOS), and UNESCO (all organizations under the United Nations), for the curation of several glacier-related databases. It is composed of the World Glacier Monitoring Service (WGMS), the U.S. National Snow and Ice Data Center (NSIDC), and the Global Land Ice Measurements from Space (GLIMS) initiative. The glacier databases include the World Glacier Inventory (WGI), the GLIMS Glacier Database, the Glacier Photograph Collection at NSIDC, and the Fluctuations of Glaciers (FoG) and Mass Balance databases at WGMS. We are working toward increased interoperability between these related databases. For example, the Web interface to the GLIMS Glacier Database has also included queryable layers for the WGI and FoG databases since 2008. To improve this further, we have produced a new GTN-G web portal (http://www.gtn-g.org/), which includes a glacier metadata browsing application. This web application allows the browsing of the metadata behind the main GTN-G databases, as well as querying the metadata in order to get to the source, no matter which database holds the data in question. A new glacier inventory, called the Randolph Glacier Inventory 1.0, has recently been compiled. This compilation, which includes glacier outlines that do not have the attributes or IDs or links to other data like the GLIMS data do, was motivated by the tight deadline schedule of the sea level chapter of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). Now served from the GLIMS website (http://glims.org/), it is designed to serve that narrowly focused research goal in the near term, and in the longer term will be incorporated into the multi-temporal glacier database of GLIMS. For the required merging of large sets of glacier outlines and association of proper IDs that tie together outlines

  1. Colonization of maritime glacier ice by bdelloid Rotifera.

    PubMed

    Shain, Daniel H; Halldórsdóttir, Katrín; Pálsson, Finnur; Aðalgeirsdóttir, Guðfinna; Gunnarsson, Andri; Jónsson, Þorsteinn; Lang, Shirley A; Pálsson, Hlynur Skagfjörð; Steinþórssson, Sveinbjörn; Arnason, Einar

    2016-05-01

    Very few animal taxa are known to reside permanently in glacier ice/snow. Here we report the widespread colonization of Icelandic glaciers and ice fields by species of bdelloid Rotifera. Specimens were collected within the accumulation zones of Langjökull and Vatnajökull ice caps, among the largest European ice masses. Rotifers reached densities up to ∼100 individuals per liter-equivalent of glacier ice/snow, and were freeze-tolerant. Phylogenetic analyses indicate that glacier rotifers are polyphyletic, with independent ancestries occurring within the Pleistocene. Collectively, these data identify a previously undescribed environmental niche for bdelloid rotifers and suggest their presence in comparable habitats worldwide.

  2. How important are glaciers for Indus water resources?

    NASA Astrophysics Data System (ADS)

    Sorteberg, A.

    2013-12-01

    How important are glaciers for Indus water resources? Looking into the literature reveals a wide range of estimates to this question. They partly diverge because of different definitions of a 'water resource' and partly due to the different estimates of the contribution from the glaciers. Defining the Indus water resources as precipitation (rain and snowfall) minus the loss of water due to evapotranspiration and sublimation for non-glaciated regions and the total runoff from the glaciated regions (sum of seasonal snowmelt on top of the glacier, percolating rainfall and loss of glacier ice), we have attempted to estimate the fraction of the total water resource that is coming from the glaciated regions and the fraction due to loss of glacier ice alone (which is the part that may be lost if a glacier disappears). Here we present estimates of water resources from non-glaciated regions using a wide range of estimates from observationally based, reanalysis and land data assimilation systems. Our results indicate large differences between the different estimates even for the annual values averaged over the whole basin. The implication of this finding is that the large uncertainties in the water resources of the non-glaciated regions will prevent us from making narrow estimates of the importance of the glaciers. For estimating the contribution from the glaciers we use an energy balance model with snow metamorphosis forced with 3 hourly reanalysis data (including perturbed precipitation and temperature runs based on the uncertainties in temperature and precipitation found from 10 different datasets). As there is over 10 000 glaciers in Indus it is not possible to model individual glaciers. Instead we model ';representative' glaciers where we get the average elevation of terminus and top, avg. glacier depth etc. from the Extended World Glacier Inventory in a given sub basin (using the FAO HydroSHEDS dataset to divide the Indus basin into subbasins). The mass balance and

  3. Detecting glacier-bed overdeepenings for glaciers in the Western Italian Alps using the GlabTop2 model: the test site of the Rutor Glacier, Aosta Valley

    NASA Astrophysics Data System (ADS)

    Viani, Cristina; Machguth, Horst; Huggel, Christian; Perotti, Luigi; Giardino, Marco

    2016-04-01

    It is expected that the rapid retreat of glaciers, observed in the European Alps and other mountain regions of the world, will continue in the future. One of the most evident and relevant consequences of this phenomenon is the formation of new glacier lakes in recently deglaciated areas. During glacier retreat overdeepened parts of the glacier bed become exposed and, in some cases, filled with water. It is important to understand where these new lakes can appear because of the associated potential risks (i.e. lake outburst and consequent flood) and opportunities (tourism, hydroelectricity, water reservoir, etc.) especially in densely populated areas such as the European Alps. GlabTop2 (Glacier Bed Topography model version 2) allows to model glacier bed topography over large glaciated areas combining digital terrain information and slope-related estimates of glacier thickness. The model requires a minimum set of input data: glaciers outlines and a surface digital elevation model (DEM). In this work we tested the model on the Rutor Glacier (8,1 km2) located in the Aosta Valley. The glacier has a well-known history of a series of glacier lake outburst floods between 1430 AD and 1864 AD due to front fluctuations. After the last advance occurred during the 70s of the previous century, glacier shrinkage has been continuous and new lakes have formed in newly exposed overdeepenings. We applied GlabTop2 to DEMs derived from historical data (topographic maps and aerial photos pair) representing conditions before the proglacial lake formation. The results obtained have been compared with the present situation and existing lakes. Successively we used the model also on present-day DEMs, which are of higher resolution than the historical derived ones, and compared the modeled bed topography with an existing bedrock map obtained by in-situ geophysical investigations (GPR surveys). Preliminary results, obtained with the 1991 surface model, confirm the robustness of GlabTop2 in

  4. Global response of glacier runoff to twenty-first century climate change

    NASA Astrophysics Data System (ADS)

    Bliss, Andrew; Hock, Regine; Radić, Valentina

    2014-04-01

    The hydrology of many important river systems in the world is influenced by the presence of glaciers in their upper reaches. We assess the global-scale response of glacier runoff to climate change, where glacier runoff is defined as all melt and rain water that runs off the glacierized area without refreezing. With an elevation-dependent glacier mass balance model, we project monthly glacier runoff for all mountain glaciers and ice caps outside Antarctica until 2100 using temperature and precipitation scenarios from 14 global climate models. We aggregate results for 18 glacierized regions. Despite continuous glacier net mass loss in all regions, trends in annual glacier runoff differ significantly among regions depending on the balance between increased glacier melt and reduction in glacier storage as glaciers shrink. While most regions show significant negative runoff trends, some regions exhibit steady increases in runoff (Canadian and Russian Arctic), or increases followed by decreases (Svalbard and Iceland). Annual glacier runoff is dominated by melt in most regions, but rain is a major contributor in the monsoon-affected regions of Asia and maritime regions such as New Zealand and Iceland. Annual net glacier mass loss dominates total glacier melt especially in some high-latitude regions, while seasonal melt is dominant in wetter climate regimes. Our results highlight the variety of glacier runoff responses to climate change and the need to include glacier net mass loss in assessments of future hydrological change.

  5. Patterns of Glacier Change in the American West

    NASA Astrophysics Data System (ADS)

    Fountain, A. G.; Basagic, H. J.; Hoffman, M. J.

    2008-12-01

    We examine a century of glacier area change in the American West, exclusive of Alaska, using historic photography, historic maps, and recent aerial photos. Of the approximately 3200 glaciers and permanent snow masses, we track about 400 glaciers across a region that spans from Washington to California and Colorado to Montana. All glaciers have retreated since 1900 with the greatest change in Montana (Lewis Range) and the Sierra Nevada of California, and the least change in Washington including the North Cascades and the Olympic Peninsula. The pattern since 1970s is more complex, with the majority of glaciers having retreated since the 1970s, some vastly more than others. The glaciers that exhibit relatively little retreat are largely restricted to the high stratovolcanoes >3500m in elevation. In these cases we infer elevated snow accumulation at higher elevations compensates for increased ablation (melt) at lower elevations. In addition, many of the most stable glaciers are debris covered in their lower elevations, due to rock fall from the relatively weak volcanic edifice. Small glaciers, <1 km2, show great variability in their behavior, with a few glaciers at equilibrium or slightly advancing, to the majority retreating, with some losing 67% of their area. These differences are more difficult to explain. We infer that local climatic/topographic influences play a dominant role in the magnitude of change while regional climate patterns control the sign of the change. Temporal patterns of glacier change are very similar across broad regions while the magnitude of that change is particular to individual glaciers.

  6. Holocene glacier history from alpine speleothems, Milchbach cave, Switzerland

    NASA Astrophysics Data System (ADS)

    Luetscher, M.; Hoffmann, D. L.; Frisia, S.; Spötl, C.

    2011-02-01

    Mountain glaciers and their sediments are prominent witnesses of climate change, responding sensitively to even small modifications in meteorological parameters. Even in such a classical and thoroughly studied area as the European Alps the record of Holocene glacier mass-balance is only incompletely known. Here we explore a novel and continuous archive of glacier fluctuations in a cave system adjacent to the Upper Grindelwald Glacier in the Swiss Alps. Milchbach cave became partly ice-free only recently and hosts Holocene speleothems. Four coeval stalagmites show consistent petrographic and stable isotopic changes between 9.2 and 2.0 ka which can be tied to abrupt modifications in the cave environment as a result of the closing and opening of multiple cave entrances by the waxing and waning of the nearby glacier. During periods of Holocene glacier advances, columnar calcite fabric is characterized by δ18O values of about -8.0‰ indicative of speleothem growth under quasi-equilibrium conditions, i.e. little affected by kinetic effect related to forced degassing or biological processes. In contrast, fabrics formed during periods of glacier minima are typical of bacterially mediated calcite precipitation within caves overlain by an alpine soil cover. Moreover, δ18O values of the bacterially mediated calcite fabrics are consistent with a ventilated cave system fostering kinetic fractionation. These data suggest that glacier retreats occurred repeatedly before 5.8 ka, and that the amplitudes of glacier retreats became substantially smaller afterwards. Our reconstruction of the Upper Grindelwald Glacier fluctuations agrees well with paleoglaciological studies from other sites in the Alps and provides a higher temporal resolution compared to traditional analyses of peat and wood remains found in glacier forefields.

  7. Iceberg calving at Rapidly Retreating Tidewater Glacier: Columbia Glacier, AK, USA.

    NASA Astrophysics Data System (ADS)

    McNamara, D. E.; O'Neel, S.; Marshall, H.; Pfeffer, T.

    2005-12-01

    An array of eleven seismometers including one broadband instrument was deployed around the lower Columbia Glacier margin during June 2004 for a period one year. This network recorded small local seismic events (icequakes) and four explosions detonated in boreholes on the glacier. Additionally, we documented changes in glacier geometry with a single time lapse camera. For 25 days we made detailed observations of iceberg calving, noting the time of calving events along with the location and size of the event. Ice motion was measured with GPS 7 km upstream from the terminus for 60 days and within 1 km of the terminus for 25 days using optical methods. Waveforms from the broadband sensor are used to characterize seismic signals originating from calving events. Calving events produce seismic signals which have a 1-3 Hz characteristic frequency, and non-impulsive onsets. Submarine events often contain an additional low frequency component that is not present during sub-aerial events. We use motion and photogrammetric measurements to explore the relationship between calving and ice motion and also between calving and near-terminus glacier geometry.

  8. Yeast and yeast-like diversity in the southernmost glacier of Europe (Calderone Glacier, Apennines, Italy).

    PubMed

    Branda, Eva; Turchetti, Benedetta; Diolaiuti, Guglielmina; Pecci, Massimo; Smiraglia, Claudio; Buzzini, Pietro

    2010-06-01

    The present study reports the characterization of psychrophilic yeast and yeast-like diversity in cold habitats (superficial and deep sediments, ice cores and meltwaters) of the Calderone Glacier (Italy), which is the southernmost glacier in Europe. After incubation at 4 and 20 degrees C, sediments contained about 10(2)-10(3) CFU of yeasts g(-1). The number of viable yeast cells in ice and meltwaters was several orders of magnitude lower. The concomitant presence of viable bacteria and filamentous fungi has also been observed. In all, 257 yeast strains were isolated and identified by 26S rRNA gene D1/D2 and internal transcribed spacers (1 and 2) sequencing as belonging to 28 ascomycetous and basidiomycetous species of 11 genera (Candida, Cystofilobasidium, Cryptococcus, Dioszegia, Erythrobasidium, Guehomyces, Mastigobasidium, Mrakia, Mrakiella, Rhodotorula and Sporobolomyces). Among them, the species Cryptococcus gastricus accounted for almost 40% of the total isolates. In addition, 12 strains were identified as belonging to the yeast-like species Aureobasidium pullulans and Exophiala dermatitidis, whereas 15 strains, presumably belonging to new species, yet to be described, were also isolated. Results herein reported indicate that the Calderone Glacier, although currently considered a vanishing ice body due to the ongoing global-warming phenomenon, still harbors viable psychrophilic yeast populations. Differences of yeast and yeast-like diversity between the glacier under study and other worldwide cold habitats are also discussed.

  9. Estimating the risk of glacier cavity collapse during artificial drainage: The case of Tête Rousse Glacier

    NASA Astrophysics Data System (ADS)

    Gagliardini, O.; Gillet-Chaulet, F.; Durand, G.; Vincent, C.; Duval, P.

    2011-05-01

    During the summer of 2010, the presence of a pressurized water-filled subglacial-cavity of at least 50,000 m3 was detected within the Tête Rousse Glacier (French Alps). Artificial drainage was started to avoid an uncontrolled rupture of the ice dam, but was interrupted soon after to evaluate the capacity of the cavity-roof to bear itself. The risk was that the release of pressure within the cavity during the artificial drainage would precipitate the collapse of the cavity roof and potentially flush out the remaining water flooding the valley below. An unprecedented modeling effort was deployed to answer the question of the cavity roof stability. We set up a model of the glacier with its water cavity, solved the three-dimensional full-Stokes problem, predicted the upper surface and cavity surface displacements for various drainage scenarios, and quantified the risk of the cavity failure during artificial drainage. We found that the maximum tensile stress in the cavity roof was below the rupture value, indicating a low risk of collapse. A post drainage survey of the glacier surface displacements has confirmed the accuracy of the model prediction. This practical application demonstrates that ice flow models have reached sufficient maturity to become operational and assist policy-makers when faced with glaciological hazards, thus opening new perspectives in risk management of glacier hazards in high mountain regions.

  10. Evaluating different methods for glacier mass balance interpolation on a tropical glacier

    NASA Astrophysics Data System (ADS)

    Mölg, Nico; Ceballos, Jorge Luis

    2016-04-01

    Glaciers in the inner tropics receive precipitation throughout the year while the annual temperature amplitude is small. Therefore, a seasonal distinction in accumulation and ablation season as for mid-latitude glaciers is hardly applicable. In order to better understand the sub-annual glacier development and its relation to meteorological conditions, a mass balance programme with monthly resolution was established on Conejeras Glacier in the Cordillera Central in Colombia in 2006. After almost ten years of measurements the time series has been reanalysed. The results show a mass balance of around -25 m w.e. during this period and a strong correlation to several warm and cold phases of ENSO. Reanalysis of the monthly mass balance data reveal an often low correlation between ablation/accumulation and elevation. Quality and density of the measurement network allow for the application of several different interpolation methods, recommended ones as well as "outlawed" GIS methods like Kriging. In this study we show the advantages and disadvantages of a number of possibilities and try to rank their usability according to different conditions and purposes. The application of multiple methods can also be of advantage for the estimation of uncertainty ranges.

  11. Mapping the World's glaciers from space: Results from the ESA project GlobGlacier

    NASA Astrophysics Data System (ADS)

    Paul, Frank

    2010-05-01

    The ESA project GlobGlacier aims at making a substantial contribution to current efforts of mapping the World's glaciers from satellite data using (semi-)automated techniques. For this purpose a number of key regions have been identified in close cooperation with the user group of the project and based on a set of criteria (e.g. filling the gaps in current inventories, or their potential contribution to sea-level rise). Apart from glacier outlines and terminus positions, a couple of further data products are created by the project: late summer snowlines (LSSL), topographic information, elevation changes and velocity fields. While most of the products are created from optical sensors like Landsat TM/ETM+ as available from the glovis.usgs.gov website, some of them will also utilize radar sensors and LIDAR data. The inventory data are mainly created for the year 2000 (+/- a few years) to have a good temporal match with the SRTM DEM. In selected regions, multi-temporal data sets will be used for change assessment. The new data sets will be integrated in the existing databases of GLIMS and WGMS. With this contribution we provide an overview of the current status of the project as well as its major achievements. Outlines for several thousand glaciers have already been created in many of the key regions. This includes parts of Alaska (Chigmit Mts., Kenai Peninsula, Chugach Mts.), Arctic Canada (Devon, Bylot, Baffin Island), West Greenland (Disko Island, Nuussuaq, Svartenhuk), Norway (Svartisen, Jostedalsbreen), India (Kashmir) and the European Alps. The products LSSL, topography and elevation changes were also produced for several hundred glaciers and surface velocity fields have been derived for more than 50 glaciers from radar and optical sensors. Topographic information for each glacier is obtained from freely available DEMs (e.g. SRTM, ASTER GDEM) and elevation changes are derived from DEM differencing as well as repeat track altimetry using the GLAS and RA-2

  12. A century of glacier change in the American West

    NASA Astrophysics Data System (ADS)

    Fountain, A. G.

    2007-12-01

    Over the past 100 years glaciers in the American West (exclusive of Alaska) have largely receded. The magnitude of the recession varies across the west, with the greatest loss in Montana and California (>50% area loss) and the least loss on the stratovolcanoes (>35%) of the Pacific Northwest. The variations can be broadly characterized by elevation. Our results suggest that increased mass loss caused by increased summer temperatures affect all glaciers, whereas increasing winter temperatures, that change the phase of precipitation from snow to rain adversely affect those glaciers less than 3000m in elevation. The high glaciers (>3000m) of California and Colorado appear to be immune to variations in snowfall making them sensitive to variations in temperature alone. We infer that these very small, steep glaciers can only hold a given amount of snow beyond which extra snow avalanches or is blown off. Conversely, during winters of little direct snowfall, additional snow may be added through win drift from the surrounding terrain. The relatively little glacier shrinkage on the stratovolcanoes is due to the high altitude of the glacier accumulation zones. An east to west decrease in glacier shrinkage from Montana through Washington is due to enhanced winter precipitation along the west coast that somewhat buffers ice loss due to summer temperatures and winter precipitation phase changes.

  13. Over 400 previously undocumented Svalbard surge-type glaciers identified

    NASA Astrophysics Data System (ADS)

    Farnsworth, Wesley R.; Ingólfsson, Ólafur; Retelle, Michael; Schomacker, Anders

    2016-07-01

    Identifying glaciers that exhibit surge-type behavior is important when using evidence of ice front fluctuations as a proxy for reconstructing past climate oscillations. This study identifies previously undocumented surge-type glaciers in Svalbard, based on the presence of crevasse squeeze ridges in glacier forelands. Crevasse squeeze ridges are landforms suggested to be unique to surging glacier land systems. Estimates vary greatly as to the actual percentage of surge-type glaciers in Svalbard, and consequently their distribution pattern is poorly understood. A detailed survey of recent (2008-2012), high-resolution aerial imagery from TopoSvalbard, provided by the Norwegian Polar Institute, allowed for a survey of all the glacier forelands in Svalbard. Before our study, 277 individual glaciers in Svalbard have been documented to exhibit surge behavior. By using crevasse squeeze ridges as indicators of surge behavior, we have identified 431 additional glaciers that have surged. We suggest that this is a modest value as the unique surge landforms were not visible in approximately one-third of the forelands with documented surge histories. Limits to the crevasse squeeze ridge technique are presented and potential controlling factors for crevasse squeeze ridge formation/preservation are discussed.

  14. Reanalysis of the USGS Alaskan benchmark glacier dataset

    NASA Astrophysics Data System (ADS)

    van Beusekom, A. E.; O'Neel, S.; March, R. S.; Sass, L. C.

    2010-12-01

    Resolving the relationship between glacier surface-forcing (climate) and glacier geometry changes is accomplished through mass-balance estimates which can be made with remote sensing methods or field-based observations. The small scale of Alaskan glaciers has prevented remote sensing methods until recently, and field data are essential for validating new techniques. Field data provide the only long duration record that can be studied with respect to climate. The United States Geological Survey has maintained a 44-year mass-balance program at Alaska’s Gulkana Glacier and Wolverine Glacier. We have reanalyzed the Alaskan benchmark glaciers mass balance time series so that all data are treated similarly and systematically. Both glaciers are undergoing sustained mass loss with an increasing rate in recent years. However, the magnitude of the calculated loss depends on the number and location of the data collection sites. We explore the sensitivity of the glacier-wide balance estimates to the method of integration used on the necessarily point data. The robustness of the balance is strengthened with use of independent photogrammetric measurements.

  15. Sensitivity and Response of Bhutanese Glaciers to Atmospheric Warming

    NASA Technical Reports Server (NTRS)

    Rupper, Summer; Schaefer, Joerg M.; Burgener, Landon K.; Koenig, Lora S.; Tsering, Karma; Cook, Edward

    2013-01-01

    Glacierized change in the Himalayas affects river-discharge, hydro-energy and agricultural production, and Glacial Lake Outburst Flood potential, but its quantification and extent of impacts remains highly uncertain. Here we present conservative, comprehensive and quantitative predictions for glacier area and meltwater flux changes in Bhutan, monsoonal Himalayas. In particular, we quantify the uncertainties associated with the glacier area and meltwater flux changes due to uncertainty in climate data, a critical problem for much of High Asia. Based on a suite of gridded climate data and a robust glacier melt model, our results show that glacier area and meltwater change projections can vary by an order of magnitude for different climate datasets. However, the most conservative results indicate that, even if climate were to remain at the present-day mean values, almost 10% of Bhutan s glacierized area would vanish and the meltwater flux would drop by as much as 30%. Under the conservative scenario of an additional 1 C regional warming, glacier retreat is going to continue until about 25% of Bhutan s glacierized area will have disappeared and the annual meltwater flux, after an initial spike, would drop by as much as 65%. Citation

  16. Exploring tidewater glacier retreat using past and current observations at Columbia Glacier, Alaska. (Invited)

    NASA Astrophysics Data System (ADS)

    O'Neel, S.; Pfeffer, W. T.; Howat, I. M.; Conway, H.; Columbia Glacier Consortium

    2010-12-01

    Since fulfilling Austin Post’s prediction of impending retreat in the late 1970s, Columbia Glacier has repeatedly surprised both casual and careful observers with its ability for rapid change. Over the last three decades, Columbia Glacier has lost approximately 18 km of its original 66 km length, while thinning by approximately 50% at the present terminus. The total ice volume lost to the Gulf of Alaska Estimates upwards of 120 km3 constrain the total ice volume lost to the Gulf of Alaska. Recently, the terminus supported a ~1.5 km long floating tongue for over than a year, contradicting the common assumption that the mechanical properties of temperate ice prohibit flotation over sustained time intervals. The rich history of study offers an opportunity to better understand tidewater glacier retreat, and a valuable analog to the dynamic instability underway at several ice sheet outlet glaciers. Current research aims to improve processing resolution of existing aerial photographic data, while complimenting the 30-year photogrammetric record with a suite of field observations. Recent instrumentation includes: oblique time lapse and still imagery, semi-permanent GPS, airborne radar, mass balance, passive seismology and LiDAR. This presentation will focus on innovative methods developed in recent field seasons, sharing insight each has provided into the retreat process . 1The Columbia Glacier Consortium consists of: Fabian Walter (SIO), Kenichi Matsuoka (NPI), Ben Smith (UW), Ethan Welty (CU-Boulder), Chris Larsen (UAF), Dave Finnegan (CRREL), Dan McNamara (USGS), Yushin Ahn (OSU), Julie Markus (OSU), Adam LeWinter (EIS).

  17. Assessing the potential contribution of blowing snow to the mass balance of glaciers in the Cariboo Mountains of British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Yadghar, A.; Ainslie, B.; Jackson, P. L.; Dery, S. J.

    2009-05-01

    The difference between snow accumulation and ice ablation determines the mass balance of glaciers, with snowfall as the dominant input. However, blowing snow is another important term in glacier mass balance. Blowing snow occurs when loose particles of snow at the surface are entrained by winds exceeding a certain threshold for transport. The role of blowing snow in the surface mass balance of glaciers in the Cariboo Mountains (the northern extension of the Columbia Mountains) of British Columbia, Canada is assessed in this study. The regional atmospheric modeling system (RAMS) model is used to simulate several case studies of blowing snow in the region of interest. The simulations are validated with meteorological data from a mesoscale network (mesonet) of high-elevation automatic weather stations (AWSs) entitled the Cariboo Alpine Mesonet (CAMnet) that has been developed in the region since 2006. The mass divergence (convergence) fields from the RAMS simulations provide an indication of the blowing snow erosion (accumulation) areas. These are then compared with the spatial distribution of glaciers in the Cariboo Mountains. Our results suggest that snow drift may contribute significantly to the mass budget of glaciers in the region.

  18. Examining a Half Century of Northwestern North American Glacier Behavior

    NASA Astrophysics Data System (ADS)

    Molnia, B. F.; Fahey, M. J.; Friesen, B.; Josberger, E. G.

    2015-12-01

    In 1957, as part of the United States' contribution to the International Geophysical Year (IGY), the American Geographical Society (AGS) initiated a multi-institutional mapping project to produce 1:10,000-scale topographic maps of nine northwestern North American glaciers. The project's goal was to prepare precise maps at large scales of selected small glaciers to form a permanent record of the condition of these glaciers so that at a future date they could be resurveyed and compared. Continued surveys would give the history of wastage and accumulation, and more accurate interpretation of the response of these glaciers to meteorological and other factors. The resulting maps and a descriptive summary brochure were published in 1960 by the American Geographical Society. The USGS Global Fiducials Program (GFP) began to systematically image the same nine glaciers approximately half-century after its IGY mapping. The results of the GFP analyses would permit the types of comparisons that were envisioned by the IGY project. Imagery of each of these nine glaciers has been collected from multiple sources, including Next View licensed commercial imagery, vertical and oblique aerial photography, Landsat, and US National Imagery Systems. Exploitation of the imagery has resulted in the production of new 21st century maps that can be compared and contrasted with the vintage AGS map set. Comparison will permit the calculation of a number of parameters which will provide a direct insight into the changes that northwestern North American glaciers have been experiencing during the past half century. Specifically, these comparisons will permit the calculation of changes in glacier length, area, thickness, and volume; computation of rates of glacier advance and/or retreat, rates of glacier thickening and/or thinning, and rates of volume change; production of digital elevation models (DEMs); and generation of velocity fields from crevasse migration. The subsequent re-mapping and

  19. Glacial lakes amplify glacier recession in the central Himalaya

    NASA Astrophysics Data System (ADS)

    King, Owen; Quincey, Duncan; Carrivick, Jonathan; Rowan, Ann

    2016-04-01

    The high altitude and high latitude regions of the world are amongst those which react most intensely to climatic change. Across the Himalaya glacier mass balance is predominantly negative. The spatial and temporal complexity associated with this ice loss across different glacier clusters is poorly documented however, and our understanding of the processes driving change is limited. Here, we look at the spatial variability of glacier hypsometry and glacial mass loss from three catchments in the central Himalaya; the Dudh Koshi basin, Tama Koshi basin and an adjoining section of the Tibetan Plateau. ASTER and SETSM digital elevation models (2014/15), corrected for elevation dependant biases, co-registration errors and along or cross track tilts, are differenced from Shuttle Radar Topographic Mission (SRTM) data (2000) to yield surface lowering estimates. Landsat data and a hypsometric index (HI), a classification scheme used to group glaciers of similar hypsometry, are used to examine the distribution of glacier area with altitude in each catchment. Surface lowering rates of >3 m/yr can be detected on some glaciers, generally around the clean-ice/debris-cover boundary, where dark but thin surface deposits are likely to enhance ablation. More generally, surface lowering rates of around 1 m/yr are more pervasive, except around the terminus areas of most glaciers, emphasising the influence of a thick debris cover on ice melt. Surface lowering is only concentrated at glacier termini where glacial lakes have developed, where surface lowering rates are commonly greater than 2.5 m/yr. The three catchments show contrasting hypsometric distributions, which is likely to impact their future response to climatic changes. Glaciers of the Dudh Koshi basin store large volumes of ice at low elevation (HI > 1.5) in long, debris covered tongues, although their altitudinal range is greatest given the height of mountain peaks in the catchment. In contrast, glaciers of the Tama Koshi

  20. Assessing streamflow sensitivity to variations in glacier mass balance

    USGS Publications Warehouse

    O'Neel, Shad; Hood, Eran; Arendt, Anthony; Sass, Louis

    2014-01-01

    Quantifying the impacts of changing glacier geometries (annual balance) on glacier runoff is essential for predicting future changes in streamflow in glacierized basins. However, determining the role that this component plays in total glacier runoff (Definition 5) requires consistent measurements of seasonal (or shorter period) mass balances, measurements of precipitation at multiple locations within a basin, and streamflow measurements in close proximity to a glacier’s terminus. Practical and logistical challenges associated with assembling such data sets typically preclude such partitioning. As a result, most analyses of the relationship between annual mass balance and streamflow rely on some component of model output to compute glacier runoff (e.g. Huss et al. 2008; Kaser et al. 2010). Ultimately, developing an understanding of how total gl

  1. Ocean forcing of glacier retreat in the western Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Cook, A. J.; Holland, P. R.; Meredith, M. P.; Murray, T.; Luckman, A.; Vaughan, D. G.

    2016-07-01

    In recent decades, hundreds of glaciers draining the Antarctic Peninsula (63° to 70°S) have undergone systematic and progressive change. These changes are widely attributed to rapid increases in regional surface air temperature, but it is now clear that this cannot be the sole driver. Here, we identify a strong correspondence between mid-depth ocean temperatures and glacier-front changes along the ~1000-kilometer western coastline. In the south, glaciers that terminate in warm Circumpolar Deep Water have undergone considerable retreat, whereas those in the far northwest, which terminate in cooler waters, have not. Furthermore, a mid-ocean warming since the 1990s in the south is coincident with widespread acceleration of glacier retreat. We conclude that changes in ocean-induced melting are the primary cause of retreat for glaciers in this region.

  2. Subglacial discharge at tidewater glaciers revealed by seismic tremor

    PubMed Central

    Amundson, Jason M.; Walter, Jacob I.; O'Neel, Shad; West, Michael E.; Larsen, Christopher F.

    2015-01-01

    Abstract Subglacial discharge influences glacier basal motion and erodes and redeposits sediment. At tidewater glacier termini, discharge drives submarine terminus melting, affects fjord circulation, and is a central component of proglacial marine ecosystems. However, our present inability to track subglacial discharge and its variability significantly hinders our understanding of these processes. Here we report observations of hourly to seasonal variations in 1.5–10 Hz seismic tremor that strongly correlate with subglacial discharge but not with basal motion, weather, or discrete icequakes. Our data demonstrate that vigorous discharge occurs from tidewater glaciers during summer, in spite of fast basal motion that could limit the formation of subglacial conduits, and then abates during winter. Furthermore, tremor observations and a melt model demonstrate that drainage efficiency of tidewater glaciers evolves seasonally. Glaciohydraulic tremor provides a means by which to quantify subglacial discharge variations and offers a promising window into otherwise obscured glacierized environments. PMID:27667869

  3. Subglacial discharge at tidewater glaciers revealed by seismic tremor

    NASA Astrophysics Data System (ADS)

    Bartholomaus, Timothy C.; Amundson, Jason M.; Walter, Jacob I.; O'Neel, Shad; West, Michael E.; Larsen, Christopher F.

    2015-08-01

    Subglacial discharge influences glacier basal motion and erodes and redeposits sediment. At tidewater glacier termini, discharge drives submarine terminus melting, affects fjord circulation, and is a central component of proglacial marine ecosystems. However, our present inability to track subglacial discharge and its variability significantly hinders our understanding of these processes. Here we report observations of hourly to seasonal variations in 1.5-10 Hz seismic tremor that strongly correlate with subglacial discharge but not with basal motion, weather, or discrete icequakes. Our data demonstrate that vigorous discharge occurs from tidewater glaciers during summer, in spite of fast basal motion that could limit the formation of subglacial conduits, and then abates during winter. Furthermore, tremor observations and a melt model demonstrate that drainage efficiency of tidewater glaciers evolves seasonally. Glaciohydraulic tremor provides a means by which to quantify subglacial discharge variations and offers a promising window into otherwise obscured glacierized environments.

  4. The physical basis of glacier volume-area scaling

    USGS Publications Warehouse

    Bahr, D.B.; Meier, M.F.; Peckham, S.D.

    1997-01-01

    Ice volumes are known for only a few of the roughly 160,000 glaciers worldwide but are important components of many climate and sea level studies which require water flux estimates. A scaling analysis of the mass and momentum conservation equations shows that glacier volumes can be related by a power law to more easily observed glacier surface areas. The relationship requires four closure choices for the scaling behavior of glacier widths, slopes, side drag and mass balance. Reasonable closures predict a volume-area scaling exponent which is consistent with observations, giving a physical and practical basis for estimating ice volumes. Glacier volume is insensitive to perturbations in the mass balance scaling, but changes in average accumulation area ratios reflect significant changes in the scaling of both mass balance and ice volume. Copyright 1997 by the American Geophysical Union.

  5. Subglacial discharge at tidewater glaciers revealed by seismic tremor

    USGS Publications Warehouse

    Bartholomaus, Timothy C.; Amundson, Jason M.; Walter, Jacob I.; O'Neel, Shad; West, Michael E.; Larsen, Christopher F.

    2015-01-01

    Subglacial discharge influences glacier basal motion and erodes and redeposits sediment. At tidewater glacier termini, discharge drives submarine terminus melting, affects fjord circulation, and is a central component of proglacial marine ecosystems. However, our present inability to track subglacial discharge and its variability significantly hinders our understanding of these processes. Here we report observations of hourly to seasonal variations in 1.5–10 Hz seismic tremor that strongly correlate with subglacial discharge but not with basal motion, weather, or discrete icequakes. Our data demonstrate that vigorous discharge occurs from tidewater glaciers during summer, in spite of fast basal motion that could limit the formation of subglacial conduits, and then abates during winter. Furthermore, tremor observations and a melt model demonstrate that drainage efficiency of tidewater glaciers evolves seasonally. Glaciohydraulic tremor provides a means by which to quantify subglacial discharge variations and offers a promising window into otherwise obscured glacierized environments.

  6. Ocean forcing of glacier retreat in the western Antarctic Peninsula.

    PubMed

    Cook, A J; Holland, P R; Meredith, M P; Murray, T; Luckman, A; Vaughan, D G

    2016-07-15

    In recent decades, hundreds of glaciers draining the Antarctic Peninsula (63° to 70°S) have undergone systematic and progressive change. These changes are widely attributed to rapid increases in regional surface air temperature, but it is now clear that this cannot be the sole driver. Here, we identify a strong correspondence between mid-depth ocean temperatures and glacier-front changes along the ~1000-kilometer western coastline. In the south, glaciers that terminate in warm Circumpolar Deep Water have undergone considerable retreat, whereas those in the far northwest, which terminate in cooler waters, have not. Furthermore, a mid-ocean warming since the 1990s in the south is coincident with widespread acceleration of glacier retreat. We conclude that changes in ocean-induced melting are the primary cause of retreat for glaciers in this region. PMID:27418507

  7. Subglacial discharge at tidewater glaciers revealed by seismic tremor

    PubMed Central

    Amundson, Jason M.; Walter, Jacob I.; O'Neel, Shad; West, Michael E.; Larsen, Christopher F.

    2015-01-01

    Abstract Subglacial discharge influences glacier basal motion and erodes and redeposits sediment. At tidewater glacier termini, discharge drives submarine terminus melting, affects fjord circulation, and is a central component of proglacial marine ecosystems. However, our present inability to track subglacial discharge and its variability significantly hinders our understanding of these processes. Here we report observations of hourly to seasonal variations in 1.5–10 Hz seismic tremor that strongly correlate with subglacial discharge but not with basal motion, weather, or discrete icequakes. Our data demonstrate that vigorous discharge occurs from tidewater glaciers during summer, in spite of fast basal motion that could limit the formation of subglacial conduits, and then abates during winter. Furthermore, tremor observations and a melt model demonstrate that drainage efficiency of tidewater glaciers evolves seasonally. Glaciohydraulic tremor provides a means by which to quantify subglacial discharge variations and offers a promising window into otherwise obscured glacierized environments.

  8. Dust transport from glacierized rivers of southern Alaska to the Gulf of Alaska: Interannual variability in magnitude and sources

    NASA Astrophysics Data System (ADS)

    Crusius, J.; Schroth, A. W.; Campbell, R. W.; Resing, J.; Gasso, S.

    2014-12-01

    Dust from high latitudes is underappreciated and little studied. We recently identified new sites of dust formation, and a new dust generation mechanism, from the southern AK coastline, in Crusius et al, 2011. Dust is generated each autumn from glacierized river valleys as river levels and discharge decrease following summer peak glacier melt. The most prominent such river is the Copper River, the single largest freshwater source to the Gulf of Alaska. Each autumn the exposed river floodplains contain abundant, fine glacial flour and represent a large dust source region, prior to significant snowfall. Strong katabatic winds channeled down mountain river valleys generate dust from the fine glacial flour, which is transported as much as several hundred kilometers into the ocean. This dust is an important source of Fe to the Gulf of Alaska, where phytoplankton growth is limited by available Fe (a micronutrient). Glaciers are rapidly losing mass in this region, so there is an increasing supply of fine glacial flour during the summer melt season, and possibly increased deposition of fine glacial flour in the dust source regions. We initiated continuous, year-round time-series measurements of dust concentration, and its geochemical composition, in August of 2011 on Middleton Island, AK, which lies in the path of the dust plume extending from the Copper River valley. Dust is clearly generated from other glacierized river valleys along the southern coast of AK, as well. We will discuss results from our continuous record spanning three dust seasons, which prominently shows these events each autumn, and displays substantial interannual variability. Dust appears to remain in the boundary layer, but is transported hundreds of kilometers into the ocean, into Fe-limited waters. It is also possible that some of this dust is redeposited on snow or glacier surfaces, enhancing melting. This dust source is not accounted for in typical global dust models.

  9. Worldwide dataset of glacier thickness observations compiled by literature review

    NASA Astrophysics Data System (ADS)

    Naegeli, Kathrin; Gärtner-Roer, Isabelle; Hagg, Wilfried; Huss, Matthias; Machguth, Horst; Zemp, Michael

    2013-04-01

    The volume of glaciers and ice caps is still poorly known, although it is expected to contribute significantly to changes in the hydrological cycle and global sea level rise over the next decades. Studies presenting worldwide estimations are mostly based on modelling and scaling approaches and are usually calibrated with only few measurements. Direct investigations of glacier thickness, a crucial parameter for ice volume calculations, are rather sparse but nevertheless available from all around the globe. This study presents a worldwide compilation of glacier thickness observation data. Literature review revealed mean and/or maximum thickness values from 442 glaciers and ice caps, elevation band information and point measurements for 10 and 14 glaciers, respectively. Resulting in a dataset containing glaciers and ice caps with areas ranging from smaller than 0.1 km2 (e.g. Pizolgletscher, Switzerland) to larger than 10'000 km2 (e.g. Agassiz Ice Cap, Canada), mean ice thicknesses between 4 m (Blaueis, Germany) and 550 m (Aletschgletscher, Switzerland) and 64 values for ice masses with entries from different years. Thickness values are derived from various observation methods and cover a survey period between 1923 and 2011. A major advantage of the database is the included metadata, giving information about specific fields, such as the mean thickness value of Aletschgletscher, which is only valid for the investigation area Konkordiaplatz and not over the entire glacier. The relatively small collection of records in the two more detailed database levels reflects the poor availability of such data. For modelling purposes, where ice thicknesses are implemented to derive ice volumes, this database provides essential information about glacier and ice cap characteristics and enables the comparison between various approaches. However, the dataset offers a great variety of locations, thicknesses and surface areas of glaciers and ice caps and can therefore help to compare

  10. Botanical Evidence of the Modern History of Nisqually Glacier, Washington

    USGS Publications Warehouse

    Sigafoos, Robert S.; Hendricks, E.L.

    1961-01-01

    A knowledge of the areas once occupied by mountain glaciers reveals at least part of the past behavior of these glaciers. From this behavior, inferences of past climate can be drawn. The maximum advance of Nisqually Glacier in the last thousand years was located, and retreat from this point is believed to have started about 1840. The maximum downvalley position of the glacier is marked by either a prominent moraine or by a line of difference between stands of trees of strikingly different size and significantly different age. The thousand-year age of the forest beyond the moraine or line between abutting stands represents the minimum time since the surface was glaciated. This age is based on the age of the oldest trees, plus an estimated interval required for the formation of humus, plus evidence of an ancient fire, plus an interval of deposition of pyroclastics. The estimate of the date when Nisqually Glacier began to retreat from its maximum advance is based upon the ages of the oldest trees plus an interval of 5 years estimated as the time required for the establishment of trees on stable moraines. This interval was derived from a study of the ages of trees growing at locations of known past positions of the glacier. Reconnaissance studies were made on moraines formed by Emmons and Tahoma Glaciers. Preliminary analyses of these data suggest that Emmons Glacier started to recede from its maximum advance in about 1745. Two other upvalley moraines mark positions from which recession started about 1849 and 1896. Ages of trees near Tahoma Glacier indicate that it started to recede from its position of maximum advance in about 1635. About 1835 Tahoma Glacier started to recede again from another moraine formed by a readvance that ter minated near the 1635 position.

  11. Geographic Names of Iceland's Glaciers: Historic and Modern

    USGS Publications Warehouse

    Sigurdsson, Oddur; Williams, Richard S.

    2008-01-01

    Climatic changes and resulting glacier fluctuations alter landscapes. In the past, such changes were noted by local residents who often documented them in historic annals; eventually, glacier variations were recorded on maps and scientific reports. In Iceland, 10 glacier place-names are to be found in Icelandic sagas, and one of Iceland's ice caps, Snaefellsjokull, appeared on maps of Iceland published in the 16th century. In the late 17th century, the first description of eight of Iceland's glaciers was written. Therefore, Iceland distinguishes itself in having a more than 300-year history of observations by Icelanders on its glaciers. A long-term collaboration between Oddur Sigurdsson and Richard S. Williams, Jr., led to the authorship of three books on the glaciers of Iceland. Much effort has been devoted to documenting historical glacier research and related nomenclature and to physical descriptions of Icelandic glaciers by Icelanders and other scientists from as far back as the Saga Age to recent (2008) times. The first book, Icelandic Ice Mountains, was published by the Icelandic Literary Society in 2004 in cooperation with the Icelandic Glaciological Society and the International Glaciological Society. Icelandic Ice Mountains was a glacier treatise written by Sveinn Palsson in 1795 and is the first English translation of this important scientific document. Icelandic Ice Mountains includes a Preface, including a summary of the history and facsimiles of page(s) from the original manuscript, a handwritten copy, and an 1815 manuscript (without maps and drawings) by Sveinn Palsson on the same subject which he wrote for Rev. Ebenezer Henderson; an Editor's Introduction; 82 figures, including facsimiles of Sveinn Palsson's original maps and perspective drawings, maps, and photographs to illustrate the text; a comprehensive Index of Geographic Place-Names and Other Names in the treatise; References, and 415 Endnotes. Professional Paper 1746 (this book) is the second

  12. Models for polythermal ice sheets and glaciers

    NASA Astrophysics Data System (ADS)

    Hewitt, Ian; Schoof, Christian

    2016-04-01

    The dynamics of ice-sheets and glaciers depend sensitively on their thermal structure. Many ice masses are polythermal, containing both cold ice, with temperature below the melting point, and temperate ice, with temperature at the melting point. The temperate ice is really an ice-water mixture, with water produced at grain boundaries by dissipative heating. Although the water content is typically small, it can have an important effect on ice dynamics; water content controls ice viscosity, and internal meltwater percolation affects hydrology. Locations where this may be important are in the enhanced shear layer at the base of fast-flowing outlet glaciers, and in the shear margins of ice streams. In this study, we present a simplified model to describe the temperature and water-content of polythermal ice masses, accounting for the possibility of gravity- and pressure-driven water drainage according to Darcy's law. The model is based on the principle of energy conservation and the theory of viscous compaction. Numerical solutions are described and a number of illustrative test problems presented. The model is compared with existing methods in the literature, including enthalpy gradient methods, to which it reduces under certain conditions. Based on the results of our analysis, we suggest a modified enthalpy method that allows for drainage under gravity but that can be relatively easily implemented in ice-sheet models.

  13. The Physics of Glaciers, 3rd Edition

    NASA Astrophysics Data System (ADS)

    Bahr, David

    At one time or another, who among us has not marveled at the beauty of the snow and ice-covered Alps, or admired the tenacity of polar explorers and the adventurous spirits of climbers on the glacier-clad summits of the high Himalaya? The fascination of distant ice covered expanses has enlisted more than a few recruits into the ranks of glaciologists, but many, if not most, of today's students of glaciology are a slightly less romantic and more mathematical lot, attracted by the quantitative world of physics and the applied sciences of polar climatology, ice mechanics, and snow hydrology.Once a relatively quiet branch of geophysics filled with venturesome climbers capable of reaching the objects of their study, glaciology is now a field that is fueled by a rapid influx of talent, technology, and new ideas due to the increasingly acknowledged relationships between global climate, sea level, and ice sheets. While the understanding of glacier processes has seen significant progress, as a result there is also a sense of being overwhelmed by the voluminous and sometimes speculative theories and field observations associated with an expanding discipline.

  14. Instrument for Analysis of Greenland's Glacier Mills

    NASA Technical Reports Server (NTRS)

    Behar, Alberto E.; Matthews, Jaret B.; Tran, Hung B.; Steffen, Konrad; McGrath, Dan; Phillips, Thomas; Elliot, Andrew; OHern, Sean; Lutz, Colin; Martin, Sujita; Wang, Henry

    2010-01-01

    A new instrument is used to study the inner workings of Greenland s glacier mills by riding the currents inside a glacier s moulin. The West Greenland Moulin Explorer instrument was deployed into a tubular shaft to autonomously record temperature, pressure, 3D acceleration, and location. It is built with a slightly positive buoyancy in order to assist in recovery. The unit is made up of several components. A 3-axis MEMS (microelectromechanical systems) accelerometer with 0.001-g resolution forms the base of the unit. A pressure transducer is added that is capable of withstanding 500 psi (=3.4 MPa), and surviving down to -40 C. An Iridium modem sends out data every 10 minutes. The location is traced by a GPS (Global Positioning System) unit. This GPS unit is also used for recovery after the mission. Power is provided by a high-capacity lithium thionyl chloride D-sized battery. The accelerometer is housed inside a cylindrical, foot-long (=30 cm) polyvinyl chloride (PVC) shell sealed at each end with acrylic. The pressure transducer is attached to one of these lids and a MEMS accelerometer to the other, recording 100 samples per second per axis.

  15. Combined Ice and Water Balances of Maclure Glacier, California, South Cascade Glacier, Washington, and Wolverine and Gulkana Glaciers, Alaska, 1967 Hydrologic Year

    USGS Publications Warehouse

    Tangborn, Wendell V.; Mayo, Lawrence R.; Scully, David R.; Krimmel, Robert M.

    1977-01-01

    Combined ice and water balances were measured in the 1967 hydrologic year (October 1-September 30) on four glaciers in western North America ranging in latitude from 37 deg to 63 deg N. This hydrologic year was characterized by heavier than normal winter precipitation in California and Washington and abnormally dry winter conditions in coastal Alaska. In summer the western conterminous states were abnormally dry and central and southern Alaska experienced very wet conditions. Maclure Glacier (lat 37 deg 45' N., 3,650-m (metres) mean equilibrium line altitude) had an above normal winter balance of 3.46 m and a positive annual balance of 1.05 m (metres of water equivalent). South Cascade Glacier (lat 48 deg 22' N., 1900-m mean equilibrium line altitude) had a winter balance of 3.28 m, slightly above average. Above normal summer ablation resulted in a final annual balance of -0.58 m, slightly more negative than has been the case for the past decade. Wolverine Glacier's (lat 60 deg 24' N., 1,200-m mean equilibrium line altitude) winter balance was 1.17 m, considerably below normal; the annual balance was -2.04 m. Gulkana Glacier (lat 63 deg 15' N., 1,700-m mean equilibrium line altitude) had a winter balance of 1.05 m, approximately normal for this glacier; the final annual balance was -0.30 m.

  16. Scale effects impeding palaeoclimate reconstructions from mountain glaciers

    NASA Astrophysics Data System (ADS)

    Prinz, Rainer; Nicholson, Lindsey; Mölg, Thomas; Kaser, Georg

    2016-04-01

    Lewis Glacier on Mt. Kenya lost more than 80% of its area since its last stadial in the late 19th century (L19). Can we reconstruct climate conditions sustaining Lewis Glacier in its L19 extent? First, we optimized a physical based energy and mass balance model to the modern-day glacier extent with in situ observed climate observations. Second, from this record we constructed synthetic climate scenarios (based on coupled parameter perturbation applying a simple weather generator concept) as input for the mass balance model. These scenarios reflect the observed variability in precipitation and air temperature over recent decades, reproduce the observed mass balance variability for the modern-day glacier extent, and quantify the glacier's sensitivity to climate. Using the mass balance model as optimized for the modern-day glacier on the L19 extent, driven by climate perturbations most favourable to glaciation, results in negative mass balances. This would traditionally be interpreted to mean that even the extremes of the present-day climate are incapable of reproducing the L19 conditions. Alternatively or additionally, the modelling suggests that the L19 Lewis Glacier could be sustained if a favourable climate perturbation is applied in conjunction with a modification of the gradients used to extrapolate the climate observations over the glacier surface from those optimized for the very small modern-day glacier. Such a modification might be justifiable, where the modern-day glacier is so small that it is unlikely to generate significant microclimatological effects that would be expected for the larger L19 extent, when e.g. the glacier filled its cirque reducing long-wave emissions from surrounding terrain drastically. In a general sense this finding indicates that extracting proxy climate conditions from a particular glacier geometry, using a modelling system optimized on a dramatically different geometry, may invalidate the approach, particularly if changes in

  17. Latest Pleistocene and Holocene glacier fluctuations on Mount Baker, Washington

    NASA Astrophysics Data System (ADS)

    Osborn, Gerald; Menounos, Brian; Ryane, Chanone; Riedel, Jon; Clague, John J.; Koch, Johannes; Clark, Douglas; Scott, Kevin; Davis, P. Thompson

    2012-08-01

    Glaciers on stratovolcanoes of the Pacific Northwest of North America offer opportunities for dating late Pleistocene and Holocene glacier advances because tephra and fossil wood are common in lateral moraines and in glacier forefields. We capitalize on this opportunity by examining the Holocene glacial record at Mount Baker, an active stratovolcano in northwest Washington. Earlier workers concluded that glaciers on Mount Baker during the early Holocene were more extensive than during the Little Ice Age and hypothesized that the explanation lay in unusual climatic or hypsometric effects peculiar to large volcanoes. We show that the main argument for an early Holocene glacier advance on Mount Baker, namely the absence of ca 10,000-year-old tephra on part of the south flank of the mountain, is incorrect. Moreover, a lake-sediment core indicates that a small cirque moraine previously thought be of early Holocene age is also likely older than the tephra and consequently of late Pleistocene age. Lateral and end moraines and wood mats ca 2 km downvalley of the present snout of Deming Glacier indicate that an advance during the Younger Dryas interval was little more extensive than the climactic Little Ice Age advance. Tephra and wood between tills in the left lateral moraine of Easton Glacier suggest that ice on Mount Baker was restricted in the early Holocene and that Neoglaciation began ca 6 ka. A series of progressively more extensive Neoglacial advances, dated to about 2.2, 1.6, 0.9, and 0.4 ka, are recorded by stacked tills in the right lateral moraine of Deming Glacier. Intervening retreats were long enough to allow establishment of forests on the moraine. Wood mats in moraines of Coleman and Easton glaciers indicate that Little Ice Age expansion began before 0.7 ka and was followed by retreat and a readvance ca 0.5 ka. Tree-ring and lichen data indicate glaciers on the south side of the mountain reached their maximum extents in the mid-1800s. The similarity between

  18. 36 CFR 13.1132 - What types of commercial fishing are authorized in Glacier Bay?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... fishing are authorized in Glacier Bay? 13.1132 Section 13.1132 Parks, Forests, and Public Property...-Glacier Bay National Park and Preserve Commercial Fishing § 13.1132 What types of commercial fishing are authorized in Glacier Bay? Three types of commercial fishing are authorized in Glacier Bay...

  19. 36 CFR 13.1132 - What types of commercial fishing are authorized in Glacier Bay?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... fishing are authorized in Glacier Bay? 13.1132 Section 13.1132 Parks, Forests, and Public Property...-Glacier Bay National Park and Preserve Commercial Fishing § 13.1132 What types of commercial fishing are authorized in Glacier Bay? Three types of commercial fishing are authorized in Glacier Bay...

  20. 36 CFR 13.1132 - What types of commercial fishing are authorized in Glacier Bay?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... fishing are authorized in Glacier Bay? 13.1132 Section 13.1132 Parks, Forests, and Public Property...-Glacier Bay National Park and Preserve Commercial Fishing § 13.1132 What types of commercial fishing are authorized in Glacier Bay? Three types of commercial fishing are authorized in Glacier Bay...

  1. 36 CFR 13.1132 - What types of commercial fishing are authorized in Glacier Bay?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... fishing are authorized in Glacier Bay? 13.1132 Section 13.1132 Parks, Forests, and Public Property...-Glacier Bay National Park and Preserve Commercial Fishing § 13.1132 What types of commercial fishing are authorized in Glacier Bay? Three types of commercial fishing are authorized in Glacier Bay...

  2. 36 CFR 13.1132 - What types of commercial fishing are authorized in Glacier Bay?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... fishing are authorized in Glacier Bay? 13.1132 Section 13.1132 Parks, Forests, and Public Property...-Glacier Bay National Park and Preserve Commercial Fishing § 13.1132 What types of commercial fishing are authorized in Glacier Bay? Three types of commercial fishing are authorized in Glacier Bay...

  3. Wind Simulation

    2008-12-31

    The Software consists of a spreadsheet written in Microsoft Excel that provides an hourly simulation of a wind energy system, which includes a calculation of wind turbine output as a power-curve fit of wind speed.

  4. High diversity and distinctive community structure of bacteria on glaciers in China revealed by 454 pyrosequencing.

    PubMed

    Liu, Qing; Zhou, Yu-Guang; Xin, Yu-Hua

    2015-12-01

    The bacterial diversity, community structure and preliminary microbial biogeographic pattern were assessed on glacier surfaces, including three northern glaciers (cold glaciers) and three southern glaciers (temperate glaciers) in China that experienced distinct climatic conditions. Pyrosequencing revealed that bacterial diversities were surprisingly high. With respect to operational taxonomic units (OTUs), Proteobacteria was the most dominant phylum on the glacier surfaces, especially Betaproteobacteria. Significant differences of the bacterial communities were observed between northern and southern glacier surfaces. The rare and abundant populations showed similar clustering patterns to the whole community. The analysis of the culturable bacterial compositions from four glaciers supported this conclusion. Redundancy analysis (RDA) and partial Mantel tests indicated that annual mean temperature, as well as geographical distance, was significantly correlated with the bacterial communities on the glaciers. It was inferred that bacterial communities on northern and southern glacier surfaces experienced different climate, water and nutrient patterns, and consequently evolved different lifestyles.

  5. Variations in Alaska tidewater glacier frontal ablation, 1985-2013

    NASA Astrophysics Data System (ADS)

    McNabb, R. W.; Hock, R.; Huss, M.

    2015-01-01

    Our incomplete knowledge of the proportion of mass loss due to frontal ablation (the sum of ice loss through calving and submarine melt) from tidewater glaciers outside of the Greenland and Antarctic ice sheets has been cited as a major hindrance to accurate predictions of global sea level rise. We present a 28 year record (1985-2013) of frontal ablation for 27 Alaska tidewater glaciers (representing 96% of the total tidewater glacier area in the region), calculated from satellite-derived ice velocities and modeled estimates of glacier ice thickness. We account for cross-sectional ice thickness variation, long-term thickness changes, mass lost between an upstream fluxgate and the terminus, and mass change due to changes in terminus position. The total mean rate of frontal ablation for these 27 glaciers over the period 1985-2013 is 15.11 ± 3.63Gta-1. Two glaciers, Hubbard and Columbia, account for approximately 50% of these losses. The regional total ablation has decreased at a rate of 0.14Gta-1 over this time period, likely due to the slowing and thinning of many of the glaciers in the study area. Frontal ablation constitutes only ˜4% of the total annual regional ablation, but roughly 20% of net mass loss. Comparing several commonly used approximations in the calculation of frontal ablation, we find that neglecting cross-sectional thickness variations severely underestimates frontal ablation.

  6. Controls of air temperature variability over an Alpine Glacier

    NASA Astrophysics Data System (ADS)

    Shaw, Thomas; Brock, Ben; Ayala, Álvaro; Rutter, Nick

    2016-04-01

    Near surface air temperature (Ta) is one of the most important controls on energy exchange between a glacier surface and the overlying atmosphere. However, not enough detail is known about the controls on Ta across a glacier due to sparse data availability. Recent work has provided insights into variability of Ta along glacier centre-lines in different parts of the world, yet there is still a limited understanding of off-centreline variability in Ta and how best to estimate it from distant off-glacier locations. We present a new dataset of distributed 2m Ta records for the Tsanteleina Glacier in Northwest Italy from July-September, 2015. Data provide detailed information of lateral (across-glacier) and centre-line variations in Ta, with ~20,000 hourly observations from 17 locations. The suitability of different vertical temperature gradients (VTGs) in estimating air temperature is considered under a range of meteorological conditions and from different forcing locations. A key finding is that local VTGs account for a lot of Ta variability under a broad range of climatic conditions. However, across-glacier variability is found to be significant, particularly for high ambient temperatures and for localised topographic depressions. The relationship of spatial Ta patterns with regional-scale reanalysis data and alternative Ta estimation methodologies are also presented. This work improves the knowledge of local scale Ta variations and their importance to melt modelling.

  7. Surge dynamics in the Nathorstbreen glacier system, Svalbard

    NASA Astrophysics Data System (ADS)

    Sund, M.; Lauknes, T. R.; Eiken, T.

    2014-04-01

    Nathorstbreen glacier system (NGS) recently experienced the largest surge in Svalbard since 1936, and this was examined using spatial and temporal observations from DEM differencing, time series of surface velocities from satellite synthetic aperture radar (SAR) and other sources. The upper basins with maximum accumulation during quiescence corresponded to regions of initial lowering. Initial speed-up exceeded quiescent velocities by a factor of several tens. This suggests that polythermal glacier surges are initiated in the temperate area before mass is displaced downglacier. Subsequent downglacier mass displacement coincided with areas where glacier velocity increased by a factor of 100-200 times (stage 2). After more than 5 years, the joint NGS terminus advanced abruptly into the fjord during winter, increasing velocities even more. The advance was followed by up-glacier propagation of crevasses, indicating the middle and subsequently the upper part of the glaciers reacting to the mass displacement. NGS advanced ~15 km, while another ~3 km length was lost due to calving. Surface lowering of ~50 m was observed in some up-glacier areas, and in 5 years the total glacier area increased by 20%. Maximum measured flow rates were at least 25 m d-1, 2500 times quiescent velocity, while average velocities were about 10 m d-1. The surges of Zawadzkibreen cycle with ca. 70-year periods.

  8. Levoglucosan evidence for biomass burning records over Tibetan glaciers.

    PubMed

    You, Chao; Xu, Chao; Xu, Baiqing; Zhao, Huabiao; Song, Lili

    2016-09-01

    Intense biomass burning (BB) events are widespread in tropical and subtropical Asia. However, the impact of BB aerosols on the Tibetan Plateau (TP), especially on Tibetan glaciers, is poorly understood. In this study, BB signals are revealed using the specific molecular tracer levoglucosan in snow and ice samples from different Tibetan glaciers. Tibetan glaciers mainly act as receptors of BB emissions from surrounding regions. Significant differences in levoglucosan concentrations in glacier samples collected from two slopes on the same mountain range indicate that high mountains can act as natural barriers to block the transport of smoke aerosols to the TP. Levoglucosan concentrations show a decreasing trend from west to east on glaciers impacted by the Indian summer monsoon on the southern edge of the TP, while the opposite pattern was observed on glaciers under the prevailing westerlies along the northern edge. The emission sources, the controlling climate system, as well as deposition and degradation during transport determined the spatial distribution regimes of levoglucosan concentration on Tibetan glaciers. PMID:27262131

  9. Levoglucosan evidence for biomass burning records over Tibetan glaciers.

    PubMed

    You, Chao; Xu, Chao; Xu, Baiqing; Zhao, Huabiao; Song, Lili

    2016-09-01

    Intense biomass burning (BB) events are widespread in tropical and subtropical Asia. However, the impact of BB aerosols on the Tibetan Plateau (TP), especially on Tibetan glaciers, is poorly understood. In this study, BB signals are revealed using the specific molecular tracer levoglucosan in snow and ice samples from different Tibetan glaciers. Tibetan glaciers mainly act as receptors of BB emissions from surrounding regions. Significant differences in levoglucosan concentrations in glacier samples collected from two slopes on the same mountain range indicate that high mountains can act as natural barriers to block the transport of smoke aerosols to the TP. Levoglucosan concentrations show a decreasing trend from west to east on glaciers impacted by the Indian summer monsoon on the southern edge of the TP, while the opposite pattern was observed on glaciers under the prevailing westerlies along the northern edge. The emission sources, the controlling climate system, as well as deposition and degradation during transport determined the spatial distribution regimes of levoglucosan concentration on Tibetan glaciers.

  10. Glacier calving, dynamics, and sea-level rise. Final report

    SciTech Connect

    Meier, M.F.; Pfeffer, W.T.; Amadei, B.

    1998-08-01

    The present-day calving flux from Greenland and Antarctica is poorly known, and this accounts for a significant portion of the uncertainty in the current mass balance of these ice sheets. Similarly, the lack of knowledge about the role of calving in glacier dynamics constitutes a major uncertainty in predicting the response of glaciers and ice sheets to changes in climate and thus sea level. Another fundamental problem has to do with incomplete knowledge of glacier areas and volumes, needed for analyses of sea-level change due to changing climate. The authors proposed to develop an improved ability to predict the future contributions of glaciers to sea level by combining work from four research areas: remote sensing observations of calving activity and iceberg flux, numerical modeling of glacier dynamics, theoretical analysis of the calving process, and numerical techniques for modeling flow with large deformations and fracture. These four areas have never been combined into a single research effort on this subject; in particular, calving dynamics have never before been included explicitly in a model of glacier dynamics. A crucial issue that they proposed to address was the general question of how calving dynamics and glacier flow dynamics interact.

  11. Monitoring of oceanographic properties of Glacier Bay, Alaska 2004

    USGS Publications Warehouse

    2005-01-01

    Glacier Bay is a recently (300 years ago) deglaciated fjord estuarine system that has multiple sills, very deep basins, tidewater glaciers, and many streams. Glacier Bay experiences a large amount of runoff, high sedimentation, and large tidal variations. High freshwater discharge due to snow and ice melt and the presence of the tidewater glaciers makes the bay extremely cold. There are many small- and large-scale mixing and upwelling zones at sills, glacial faces, and streams. The complex topography and strong currents lead to highly variable salinity, temperature, sediment, primary productivity, light penetration, stratification levels, and current patterns within a small area. The oceanographic patterns within Glacier Bay drive a large portion of the spatial and temporal variability of the ecosystem. It has been widely recognized by scientists and resource managers in Glacier Bay that a program to monitor oceanographic patterns is essential for understanding the marine ecosystem and to differentiate between anthropogenic disturbance and natural variation. This year’s sampling marks the 12th continuous year of monitoring the oceanographic conditions at 23 stations along the primary axes within Glacier Bay, AK, making this a very unique and valuable data set in terms of its spatial and temporal coverage.

  12. Biodiversity under threat in glacier-fed river systems

    NASA Astrophysics Data System (ADS)

    Jacobsen, Dean; Milner, Alexander M.; Brown, Lee E.; Dangles, Olivier

    2012-05-01

    Freshwater biodiversity is under threat across the globe, with climate change being a significant contributor. One impact of climate change is the rapid shrinking of glaciers, resulting in a reduction in glacial meltwater contribution to river flow in many glacierized catchments. These changes potentially affect the biodiversity of specialized glacier-fed river communities. Perhaps surprisingly then, although freshwater biodiversity is a major conservation priority, the effects of shrinkage and disappearance of glaciers on river biodiversity have hitherto been poorly quantified. Here we focus on macroinvertebrates (mainly insect larvae) and demonstrate that local (α) and regional (γ) diversity, as well as turnover among reaches (β-diversity), will be consistently reduced by the shrinkage of glaciers. We show that 11-38% of the regional species pools, including endemics, can be expected to be lost following complete disappearance of glaciers in a catchment, and steady shrinkage is likely to reduce taxon turnover in proglacial river systems and local richness at downstream reaches where glacial cover in the catchment is less than 5-30%. Our analysis demonstrates not only the vulnerability of local biodiversity hotspots but also that extinction will probably greatly exceed the few known endemic species in glacier-fed rivers.

  13. Glacier loss and emerging hydrologic vulnerabilities in the Peruvian Andes

    NASA Astrophysics Data System (ADS)

    Mark, B. G.; McKenzie, J. M.; Baraer, M.; Lagos, P.; Lautz, L.; Carey, M.; Bury, J.; Crumley, R.; Wigmore, O.; Somers, L. D.

    2015-12-01

    Accelerating glacier recession in the tropical Andes is transforming downstream hydrology, while increasing demands for water by end-users (even beyond the watershed limits) is complicating the assessment of vulnerability. Future scenarios of hydro-climatic vulnerability require a better understanding of coupled hydrologic and human systems, involving both multiscale process studies and more robust models of glacier-climate interactions. We synthesize research in two proglacial valleys of glacierized mountain ranges in different regions of Peru that are both in proximity to growing water usage from urban sectors, agriculture, hydroelectric generation, and mining. In both the Santa River watershed draining the Cordillera Blanca and the Shullcas River watershed below Hyuatapallana Mountain in Junin, glaciers have receded over 25% since the 1980s. Historical runoff and glacier data, combined with glacier-climate modeling, show a long-term decrease in discharge resulting from a net loss of stored water. We find evidence that this altered hydrology is transforming proglacial wetland ecology and water quality, even while water resource use has intensified. Beyond glaciers, our results show that over 60% of the dry season base flow in each watershed is groundwater sourced from heterogeneous aquifers. Municipal water supply in Huancayo already relies on 18 groundwater wells. Perceptions of water availability and actual water use practices remain relatively divorced from the actual water resources provided from each mountain range. Critical changes in glacier volume and water supply are not perceived or acknowledged consistently amongst different water users, nor reflected in water management decisions. In order to identify, understand, model, and adapt to climate-glacier-water changes, it is vital to integrate the analysis of water availability and groundwater processes (the domain of hydrologists) with that of water use (the focus for social scientists). Attention must be

  14. New glacier inventory of Salzburg 2007/09

    NASA Astrophysics Data System (ADS)

    Stocker-Waldhuber, M.; Wiesenegger, H.; Fischer, A.

    2012-04-01

    Glacier inventories are an important data basis for several investigations such as length-, area- and volume changes in the course of climate change. The new glacier inventory of Salzburg is part of the third Austrian glacier inventory (GI3) and is valid for the years 2007 and 2009 depending on each mountain range. The first inventory (GI1) was compiled in 1969 and the second one (GI2) represents the glacier state from 1998 to 2002. In Salzburg, 150 glaciers are located in the six mountain ranges: Ankogel, Glockner, Granatspitz, Sonnblick (Goldberg), Hochkönig and Venediger. The basis for the new mapping were orthophotos of 2007 and 2009 and the DEM of the southern part of Salzburg. On the basis of former inventories area-, height- and volume changes have been calculated. The biggest loss of glacier area per mountain range was found in the Ankogel range and on Hochkönig because of the disrupted structure of the thin glaciers. Referring to the absolute values, the largest changes took place in the Glockner- and Venediger mountain range with -10.11 km2 and -9.72 km2 during the period between GI1 (1969) and GI3 (2007/2009) respectively. Due to the lack of DEMs (only the southern part was available) volume changes have been calculated for about half of all glaciers in Salzburg. These are located at the Glockner, Granatspitz and Sonnblick mountain range and showed -0.335 km3 on average changes in height of 9.3 m. An extrapolation of these changes to all of the 150 glaciers in Salzburg results in a loss of about 0.7 km3 between GI1 and GI3.

  15. 2011 the first complete glacier inventory for Eastern Greenland

    NASA Astrophysics Data System (ADS)

    Rastner, P.; Bolch, T.; Paul, F.

    2011-12-01

    Meltwater from glaciers and icecaps (GIC) provide a significant contribution to global sea-level rise, but estimates are uncertain due to the globally still incomplete information about glacier location and size, as well as large uncertainties in current Global Climate Models (GCMs). Recent studies that calculate global sea-level rise from GIC have developed simplified approaches using information from glacier inventories or gridded data sets and different GCMs. However, for several strongly glacierized regions very rough assumptions about the ice distribution have to be made and an urgent demand for a globally complete glacier inventory data is expressed. The GIC on Greenland are one of these regions. Within the "EU-funded" project ice2sea we map the Eastern part of Greenland using Landsat ETM imagery acquired around the year 2000 and the ASTER GDEM to derive topographic parameters and drainage divides. Up to now more than 5500 GIC with a total area of about 26.000 square km have been mapped between 62 degrees and 80 degrees N considering only glaciers with an area larger than 0.1 square km that have no direct connection to the ice sheet. The largest valley glaciers are often debris covered, whereas smaller and mountain glaciers are often shaded due to the steep topography. Seasonal snow hiding the real glacier perimeter is a problem in some of the scenes that can only be solved by using scenes with better snow conditions. The artifacts in the GDEM are locally rather severe, but for the GIC considered for this inventory they were manageable. A comparison with the outline of the Greenland ice sheet as used in current models revealed that along the eastern coast a considerable amount of the local GIC is included in the extent of the ice sheet.

  16. On the accuracy of glacier outlines derived from satellite data

    NASA Astrophysics Data System (ADS)

    Paul, F.

    2012-04-01

    The determination of the accuracy of glacier outlines as mapped from satellite data is a mandatory task, in particular when change assessment is performed. However, this is often not correctly done as a direct comparison with a reference data set can give misleading results. Though it is widely accepted that glacier outlines as derived from a higher-resolution data set (e.g. aerial photography) can be used to determine the accuracy of outlines derived from a lower resolution data set (e.g. Landsat TM), this is not generally true and several details have to be considered. At first, changing glacier extents require to compare images acquired in the same year and rapidly changing snow conditions require to use images from the same week or at least with identical snow conditions (i.e. no snow outside of glaciers). Secondly, differences in interpretation result from the higher-spatial resolution itself and the missing shortwave infrared band in high-resolution data. In particular, the determination of the glacier boundary on panchromatic imagery can locally be impossible (when the ice and the surrounding rock have the same reflectance). Thirdly, for natural objects like glaciers the change of the resolution alone results in a change of the area covered by the respective outline. Finally, the required manual correction of debris-covered glacier parts is done differently by different analysts and also by the same analyst when digitized several times. To overcome these challenges and provide an accuracy assessment for a larger data set, we will perform a combined round robin and validation experiment in the framework of the ESA project Glaciers_cci. This will include the manual and automated digitization of glacier outlines on high and low resolution satellite data (e.g. Quickbird / Ikonos vs. Landsat TM / ETM+) in different parts of the world (Alaska, Alps, Himalaya), as well as multiple digitizations of the same set of glaciers (with and without debris cover) by

  17. Small Glacier Area Studies: A New Approach for Turkey

    NASA Technical Reports Server (NTRS)

    Yavasli, Dogukan D.; Tucker, Compton J.

    2012-01-01

    Many regions of Earth have glaciers that have been neglected for study because they are small. We report on a new approach to overcome the problem of studying small glaciers, using Turkey as an example. Prior to our study, no reliable estimates of Turkish glaciers existed because of a lack of systematic mapping, difficulty in using Landsat data collected before 1982, snowpack vs. glacier ice differentiation using existing satellite data and aerial photography, the previous high cost of Landsat images, and a lack of high-resolution imagery of small Turkish glaciers. Since 2008, a large number of < 1 m satellite images have become available at no cost to the research community. In addition, Landsat data are now free of charge from the U.S. Geological Survey, enabling the use of multiple images. We used 174 Landsat and eight high-resolution satellite images to document the areal extent of Turkish glaciers from the 1970s to 2007-2011. Multiple Landsat images, primarily Thematic Mapper (TM) data from 1984 to 2011, enabled us to minimize differentiation problems between snow and glacier ice, a potential source of error. In addition, we used Ikonos, Quickbird, and World View-1 & -2 very high-resolution imagery to evaluate our TM accuracies and determine the area of nine smaller glaciers in Turkey. We also used five Landsat-3 Return Beam Videcon (RBV) 30 m pixel resolution images, all from 1980, for six glaciers. The total area of Turkish glaciers decreased from 23 km2 in the 1970s to 10.1 km2 in 2007-2011. By 2007-2011, six Turkish glaciers disappeared, four were < 0.3 km2, and only three were 1.0 km2 or larger. No trends in precipitation from 1970 to 2006 and cloud cover from 1980 to 2010 were found, while surface temperatures increased, with summer minimum temperatures showing the greatest increase. We conclude that increased surface temperatures during the summer were responsible for the 56% recession of Turkish glaciers from the 1970s to 2006-2011.

  18. Glacier Sensitivity to Climate Change in the Monsoonal Himalaya: Past, Present, and Future

    NASA Astrophysics Data System (ADS)

    Rupper, S.; Maurer, J.; Schaefer, J. M.; Cook, E. R.; Putnam, A. E.; Krusic, P.; Smith, R. G.

    2013-12-01

    Glaciers are particularly sensitive to climate change, making them vulnerable elements of the environment. Of potential concern for societies is the rapid glacier retreat of Himalayan glaciers. However, the temporally short and spatially sparse instrumental records of climate, and arguably shorter and sparser glacier records, make it extremely difficult to quantify glacier sensitivity to climatic change or to place recent glacier changes into a longer, historical context. Here we address many of these issues by quantifying the glacier-climate sensitivity in the Bhutanese Himalaya over the past 800 years using a combination of remote sensing data, paleoclimate data, glacier modeling, and glacial geochronology. Bhutan is chosen for two key reasons. First, Bhutan exemplifies an area where little data on glacier changes are available and where it is logistically difficult to obtain field-based studies, a common problem for many regions of the Himalayas. Thus the methods developed here will be directly applicable to other regions. Second, glaciers in Bhutan, just as neighboring glaciers in India, Nepal, and Southwest China, sit in the bulls-eye of high snow accumulation glaciers. Sensitivity tests using a surface energy- and mass-balance model show that high accumulation regions are extremely temperature-sensitive. Therefore, Bhutan's glaciers form a highly suitable natural laboratory to investigate glacier sensitivity and response to temperature change in the monsoonal Himalaya. In this study, we map Bhutan glacierized area and volume changes over the past forty years, and show significant changes and rapid retreat of these glaciers over this period of time. In addition, we map the former glacier extents for key glacierized regions of Bhutan, and produce a 10Be chronology for glacier fluctuations for one region. Finally, we model the glacierized changes over the past 800 years using Bhutan tree-ring temperature reconstructions as climate input. Our results show that

  19. Analysis of the glacier retreat in the French Alps since the 1960s based on the new glacier inventory

    NASA Astrophysics Data System (ADS)

    Gardent, M.; Rabatel, A.; Dedieu, J. P.; Deline, P.; Schoeneich, P.

    2012-04-01

    One of the most obvious impacts of climate change in high mountain areas is the glacial retreat. Since the French glacier inventory carried out by R. Vivian in the late 1960s within the context of the WGI, there was no updated data from the overall French alpine glaciers. We present here the first results of a new diachronic inventory of the French alpine glaciers based on different sources. Glacier outlines were manually delineated using 1/25,000 topographic maps of the french National Geographical Institute (IGN) from the end of the 1960s, and IGN 50-cm-pixel orthophotographs from 2006 to 2009. For Landsat 5 TM images (30 m resolution) dating from 1985-1986, and Landsat 5 TM and Landsat 7 ETM+ images (30 and 15 m resolutions) dating from 2003, an automatic delineation with the common NDSI method was used to determine glacier limits. Each glacier has been individually checked, with a special care for debris covered and shadowed areas to adjust the delineation, using a 542 spectral bands combination. For compounded glaciers, the same limits were manually adjusted for each period. Data were integrated into a GIS and a database including all the common items (surface area, minimal and maximal elevations, aspect, debris covered area, slope…) was generated. Topographic parameters were extracted from the IGN DEM (resolution of 25 m) for the topographic maps and Landsat images from the mid-80s, and the ASTER GDEM (resolution of 30 m) for the Landsat images of the early 2000s and the orthophotographs. . Current extension of the 593 French alpine glaciers is about 275 km2. It is ~20 % less than in 1985-1986 (end of the last glacial advance period), when glacier extension was 340 km2, and ~26 % less than at the end of the 1960s, when glacier coverage was about 375 km2. Different trends are observed across the French Alps, with a stronger glacial retreat in the southern massifs: for instance, glacier shrinkage in the Ecrins massif is more than three times stronger than in

  20. Polychlorinated Biphenyls in a Temperate Alpine Glacier: 1. Effect of Percolating Meltwater on their Distribution in Glacier Ice.

    PubMed

    Pavlova, Pavlina Aneva; Jenk, Theo Manuel; Schmid, Peter; Bogdal, Christian; Steinlin, Christine; Schwikowski, Margit

    2015-12-15

    In Alpine regions, glaciers act as environmental archives and can accumulate significant amounts of atmospherically derived pollutants. Due to the current climate-warming-induced accelerated melting, these pollutants are being released at correspondingly higher rates. To examine the effect of melting on the redistribution of legacy pollutants in Alpine glaciers, we analyzed polychlorinated biphenyls in an ice core from the temperate Silvretta glacier, located in eastern Switzerland. This glacier is affected by surface melting in summer. As a result, liquid water percolates down and particles are enriched in the current annual surface layer. Dating the ice core was a challenge because meltwater percolation also affects the traditionally used parameters. Instead, we counted annual layers of particulate black carbon in the ice core, adding the years with negative glacier mass balance, that is, years with melting and subsequent loss of the entire annual snow accumulation. The analyzed samples cover the time period 1930-2011. The concentration of indicator PCBs (iPCBs) in the Silvretta ice core follows the emission history, peaking in the 1970s (2.5 ng/L). High PCB values in the 1990s and 1930s are attributed to meltwater-induced relocation within the glacier. The total iPCB load at the Silvretta ice core site is 5 ng/cm(2). A significant amount of the total PCB burden in the Silvretta glacier has been released to the environment. PMID:26632967

  1. Distribution and transportation of mercury from glacier to lake in the Qiangyong Glacier Basin, southern Tibetan Plateau, China.

    PubMed

    Sun, Shiwei; Kang, Shichang; Huang, Jie; Li, Chengding; Guo, Junming; Zhang, Qianggong; Sun, Xuejun; Tripathee, Lekhendra

    2016-06-01

    The Tibetan Plateau is home to the largest aggregate of glaciers outside the Polar Regions and is a source of fresh water to 1.4 billion people. Yet little is known about the transportation and cycling of Hg in high-elevation glacier basins on Tibetan Plateau. In this study, surface snow, glacier melting stream water and lake water samples were collected from the Qiangyong Glacier Basin. The spatiotemporal distribution and transportation of Hg from glacier to lake were investigated. Significant diurnal variations of dissolved Hg (DHg) concentrations were observed in the river water, with low concentrations in the morning (8:00am-14:00pm) and high concentrations in the afternoon (16:00pm-20:00pm). The DHg concentrations were exponentially correlated with runoff, which indicated that runoff was the dominant factor affecting DHg concentrations in the river water. Moreover, significant decreases of Hg were observed during transportation from glacier to lake. DHg adsorption onto particulates followed by the sedimentation of particulate-bound Hg (PHg) could be possible as an important Hg removal mechanism during the transportation process. Significant decreases in Hg concentrations were observed downstream of Xiao Qiangyong Lake, which indicated that the high-elevation lake system could significantly affect the distribution and transportation of Hg in the Qiangyong Glacier Basin. PMID:27266318

  2. Polychlorinated Biphenyls in a Temperate Alpine Glacier: 1. Effect of Percolating Meltwater on their Distribution in Glacier Ice.

    PubMed

    Pavlova, Pavlina Aneva; Jenk, Theo Manuel; Schmid, Peter; Bogdal, Christian; Steinlin, Christine; Schwikowski, Margit

    2015-12-15

    In Alpine regions, glaciers act as environmental archives and can accumulate significant amounts of atmospherically derived pollutants. Due to the current climate-warming-induced accelerated melting, these pollutants are being released at correspondingly higher rates. To examine the effect of melting on the redistribution of legacy pollutants in Alpine glaciers, we analyzed polychlorinated biphenyls in an ice core from the temperate Silvretta glacier, located in eastern Switzerland. This glacier is affected by surface melting in summer. As a result, liquid water percolates down and particles are enriched in the current annual surface layer. Dating the ice core was a challenge because meltwater percolation also affects the traditionally used parameters. Instead, we counted annual layers of particulate black carbon in the ice core, adding the years with negative glacier mass balance, that is, years with melting and subsequent loss of the entire annual snow accumulation. The analyzed samples cover the time period 1930-2011. The concentration of indicator PCBs (iPCBs) in the Silvretta ice core follows the emission history, peaking in the 1970s (2.5 ng/L). High PCB values in the 1990s and 1930s are attributed to meltwater-induced relocation within the glacier. The total iPCB load at the Silvretta ice core site is 5 ng/cm(2). A significant amount of the total PCB burden in the Silvretta glacier has been released to the environment.

  3. Climate downscaling for estimating glacier mass balances in northwestern North America: Validation with a USGS benchmark glacier

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Bhatt, Uma S.; Tangborn, Wendell V.; Lingle, Craig S.

    2007-11-01

    An atmosphere/glacier modeling system is described for estimating the mass balances of glaciers in both current and future climate in order to estimate their probable future contributions to rising sea level. Dynamically downscaled output from a regional atmospheric model, driven by global atmospheric reanalysis, is used to force a precipitation-temperature-area-altitude (PTAA) glacier mass balance model with daily maximum and minimum temperatures and precipitation. The modeling system is verified by hindcasting the mass balances of Gulkana Glacier, a U.S. Geological Survey (USGS) benchmark glacier in the Alaska Range, U.S.A., during a ten-year period from October 1994 to September 2004. The mass balances simulated with the atmosphere/glacier modeling system are comparable to the USGS measurements, and are also in good agreement with the meteorological station observation-forced PTAA simulations. The results suggest this is a promising approach for realistic estimation of the future mass balances of the glaciers of northwestern North America.

  4. Glacier-specific elevation changes in western Alaska

    NASA Astrophysics Data System (ADS)

    Paul, Frank; Le Bris, Raymond

    2013-04-01

    Deriving glacier-specific elevation changes from DEM differencing and digital glacier outlines is rather straight-forward if the required datasets are available. Calculating such changes over large regions and including glaciers selected for mass balance measurements in the field, provides a possibility to determine the representativeness of the changes observed at these glaciers for the entire region. The related comparison of DEM-derived values for these glaciers with the overall mean avoids the rather error-prone conversion of volume to mass changes (e.g. due to unknown densities) and gives unit-less correction factors for upscaling the field measurements to a larger region. However, several issues have to be carefully considered, such as proper co-registration of the two DEMs, date and accuracy of the datasets compared, as well as source data used for DEM creation and potential artefacts (e.g. voids). In this contribution we present an assessment of the representativeness of the two mass balance glaciers Gulkana and Wolverine for the overall changes of nearly 3200 glaciers in western Alaska over a ca. 50-year time period. We use an elevation change dataset from a study by Berthier et al. (2010) that was derived from the USGS DEM of the 1960s (NED) and a more recent DEM derived from SPOT5 data for the SPIRIT project. Additionally, the ASTER GDEM was used as a more recent DEM. Historic glacier outlines were taken from the USGS digital line graph (DLG) dataset, corrected with the digital raster graph (DRG) maps from USGS. Mean glacier specific elevation changes were derived based on drainage divides from a recently created inventory. Land-terminating, lake-calving and tidewater glaciers were marked in the attribute table to determine their changes separately. We also investigated the impact of handling potential DEM artifacts in three different ways and compared elevation changes with altitude. The mean elevation changes of Gulkana and Wolverine glaciers (about -0

  5. UAVs for Glacier Mapping: Lessons Learned

    NASA Astrophysics Data System (ADS)

    McKinnon, T.; McKinnon, K. A.; Anderson, B.

    2014-12-01

    Using two different unmanned aerial vehicles (UAVs) mounted with cameras, we created a digital elevation model (DEM) of the lower 12 km^2 of Tasman Glacier, South Island, New Zealand in March 2014. The project served primarily as a proof-of-concept, and here we discuss the lessons learned, emphasizing the practical, logistical, and flight issues. We tested two different fixed-wing airframes -- a twin-boom tradition and flying wing; two different camera types, both consumer-grade RGB; and various combinations of RC and telemetry radios. We used both commercial and open-source photogrammetry software to create the mosaic and DEM imagery. Some of the most critical UAV-specific issues are: access to a launch/landing site, adequate landing zones, range, airspace contention with manned aircraft, and hardware reliability. While UAVs provide a lower-cost method for photogrammetry access, it also comes with a unique set of challenges.

  6. Analysis of glacier facies using satellite techniques

    USGS Publications Warehouse

    Williams, R.S., Jr.; Hall, D.K.; Benson, C.S.

    1991-01-01

    Landsat-derived reflectance is lowest for exposed ice and increases markedly at the transient snow line. Above the slush zone is a gradual increase in near-infrared reflectance as a result of decreasing grain-size of the snow, which characterizes drier snow. Landsat data are useful in measuring the areal extent of the ice facies, the slush zone within the wet-snow facies, the snow facies (combined wet-snow, percolation and dry-snow facies), and the respective position of the transient snow line and the slush limit. In addition, fresh snowfall and/or airborne contaminants, such as soot and tephra, can limit the utility of Landsat data for delineation of the glacier facies in some cases. -from Authors

  7. Glaciers and ice sheets as a biome.

    PubMed

    Anesio, Alexandre M; Laybourn-Parry, Johanna

    2012-04-01

    The tundra is the coldest biome described in typical geography and biology textbooks. Within the cryosphere, there are large expanses of ice in the Antarctic, Arctic and alpine regions that are not regarded as being part of any biome. During the summer, there is significant melt on the surface of glaciers, ice caps and ice shelves, at which point microbial communities become active and play an important role in the cycling of carbon and other elements within the cryosphere. In this review, we suggest that it is time to recognise the cryosphere as one of the biomes of Earth. The cryospheric biome encompasses extreme environments and is typified by truncated food webs dominated by viruses, bacteria, protozoa and algae with distinct biogeographical structures.

  8. Bathymetry of Patagonia glacier fjords and glacier ice thickness from high-resolution airborne gravity combined with other data

    NASA Astrophysics Data System (ADS)

    An, L.; Rignot, E.; Rivera, A.; Bunetta, M.

    2012-12-01

    The North and South Patagonia Ice fields are the largest ice masses outside Antarctica in the Southern Hemisphere. During the period 1995-2000, these glaciers lost ice at a rate equivalent to a sea level rise of 0.105 ± 0.001 mm/yr. In more recent years, the glaciers have been thinning more quickly than can be explained by warmer air temperatures and decreased precipitation. A possible cause is an increase in flow speed due to enhanced ablation of the submerged glacier fronts. To understand the dynamics of these glaciers and how they change with time, it is critical to have a detailed view of their ice thickness, the depth of the glacier bed below sea or lake level, how far inland these glaciers remain below sea or lake level, and whether bumps or hollows in the bed may slow down or accelerate their retreat. A grid of free-air gravity data over the Patagonia Glaciers was collected in May 2012 and October 2012, funded by the Gordon and Betty Moore Foundation (GBMF) to measure ice thickness and sea floor bathymetry. This survey combines the Sander Geophysics Limited (SGL) AIRGrav system, SGL laser altimetry and Chilean CECS/UCI ANDREA-2 radar. To obtain high-resolution and high-precision gravity data, the helicopter operates at 50 knots (25.7 m/s) with a grid spacing of 400m and collects gravity data at sub mGal level (1 Gal =1 Galileo = 1 cm/s2) near glacier fronts. We use data from the May 2012 survey to derive preliminarily high-resolution, high-precision thickness estimates and bathymetry maps of Jorge Montt Glacier and San Rafael Glacier. Boat bathymetry data is used to optimize the inversion of gravity over water and radar-derived thickness over glacier ice. The bathymetry maps will provide a breakthrough in our knowledge of the ice fields and enable a new era of glacier modeling and understanding that is not possible at present because ice thickness is not known.

  9. Glaciers in a changing global climate: first results of worldwide glacier mass balance measurements 2000/2001

    NASA Astrophysics Data System (ADS)

    Frauenfelder, R.; Hoelzle, M.; Haeberli, W.

    2003-04-01

    Glacier signals from mountain areas are key elements of early detection strategies for dealing with possible man-induced climate change. The IPCC Third Assessment Report indeed defines mountain glaciers as one of the best natural indicators of atmospheric warming with the highest reliability ranking. In the chain of processes linking climate and glacier fluctuations, glacier length variation is the indirect/delayed response, whereas glacier mass change is the direct/undelayed reaction. Internationally coordinated long-term monitoring of glaciers started in 1894. The responsibility to collect and publish standardized data has been assumed since 1986 by the World Glacier Monitoring Service (WGMS). This work is primarily being carried out under the auspices of the International Commission on Snow and Ice (ICSI/IAHS) and the Federation of Astronomical and Geophysical Services (FAGS/ICSU). The WGMS maintains data exchange with the ICSU World Data Center A (WDC-A) for Glaciology in Boulder, Colorado. Corresponding data bases and measurement networks form an essential part of the Global Terrestrial Network for Glaciers (GTN-G: operated by the WGMS) as a pilot project within the Global Terrestrial Observing System (GTOS/GCOS). A network of 60 glacier mass balance observations provides information on presently observed rates of change in glacier mass, corresponding acceleration trends and regional distribution patterns. A preliminary calculation of the mass balance observations in 2000/2001 relating to 23 selected data sets provide a mean specific (annual) net balance of -367 mm w.e., 26 % of the observed balances were positive. The corresponding mean in six mountain ranges was -571 mm w.e. Such values indicate that mass losses in 2000/2001 have been less extreme than in the extraordinary years before but are still strongly negative. Over the past two decades glacier melt appears to continue at a considerable and possibly even an accelerating rate. The observed average

  10. North Cascade Glacier Annual Mass Balance Record Analysis 1984-2013

    NASA Astrophysics Data System (ADS)

    Pelto, M. S.

    2014-12-01

    The North Cascade Glacier Climate Project (NCGCP) was founded in 1983 to monitor 10 glaciers throughout the range and identify their response to climate change. The annual observations include mass balance, terminus behavior, glacier surface area and accumulation area ratio (AAR). Annual mass balance (Ba) measurements have been continued on the 8 original glaciers that still exist. Two glaciers have disappeared: the Lewis Glacier and Spider Glacier. In 1990, Easton Glacier and Sholes Glacier were added to the annual balance program to offset the loss. One other glacier Foss Glacier has declined to the extent that continued measurement will likely not be possible. Here we examine the 30 year long Ba time series from this project. All of the data have been reported to the World Glacier Monitoring Service (WGMS). This comparatively long record from glaciers in one region conducted by the same research program using the same methods offers some useful comparative data. Degree day factors for melt of 4.3 mm w.e.°C-1d-1 for snow and 6.6 mm w.e.°C-1d-1 for ice has been determined from 412 days of ablation observation. The variation in the AAR for equilibrium Ba is small ranging from 60 to 67. The mean annual balance of the glaciers from 1984-2013 is -0.45 ma-1, ranging from -0.31 to -0.57 ma-1 for individual glacier's. The correlation coefficient of Ba is above 0.80 between all glaciers including the USGS benchmark glacier, South Cascade Glacier. This indicates that the response is to regional climate change, not local factors. The mean annual balance of -0.45 ma-1 is close to the WGMS global average for this period -0.50 ma-1. The cumulative loss of 13.5 m w.e. and 15 m of ice thickness represents more than 20% of the volume of the glaciers.

  11. Contribution of small glaciers to global sea level

    USGS Publications Warehouse

    Meier, M.F.

    1984-01-01

    Observed long-term changes in glacier volume and hydrometeorological mass balance models yield data on the transfer of water from glaciers, excluding those in Greenland and Antarctica, to the oceans, The average observed volume change for the period 1900 to 1961 is scaled to a global average by use of the seasonal amplitude of the mass balance. These data are used to calibrate the models to estimate the changing contribution of glaciers to sea level for the period 1884 to 1975. Although the error band is large, these glaciers appear to accountfor a third to half of observed rise in sea level, approximately that fraction not explained by thermal expansion of the ocean.

  12. Accumulation of anthropogenic radionuclides in cryoconites on Alpine glaciers.

    PubMed

    Tieber, A; Lettner, H; Bossew, P; Hubmer, A; Sattler, B; Hofmann, W

    2009-07-01

    Cryoconites are airborne sediments which accumulate on the surface of glaciers. In samples of cryoconites a temperate Austrian glacier high activity concentrations of anthropogenic radionuclides were found, which stem from global and Chernobyl fallouts. Radionuclides identified were (137)Cs, (134)Cs, (238)Pu, (239+240)Pu, (90)Sr, (241)Am, (60)Co, (154)Eu, (207)Bi, and (125)Sb. Given the approximately known isotopic ratios, Cs and Pu can be separated into the contributions of either source of origin. Published (137)Cs/(134)Cs and (239+240)Pu/(238)Pu ratios were used for the discrimination of the Dachstein-glacier cryoconites according to their origin from global or Chernobyl fallout. Two different groups of cryoconites were identified, an older population dominated by nuclear weapons fallout and a younger one with predominant Chernobyl fallout. With those data a simple model was formulated to demonstrate the transition and mixing of these two populations on the glacier surface. PMID:19450909

  13. Modeling East African tropical glaciers during the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Doughty, Alice; Kelly, Meredith; Russell, James; Jackson, Margaret; Anderson, Brian; Nakileza, Robert

    2016-04-01

    The timing and magnitude of tropical glacier fluctuations since the last glacial maximum could elucidate how climatic signals transfer between hemispheres. We focus on ancient glaciers of the East African Rwenzori Mountains, Uganda/D.R. Congo, where efforts to map and date the moraines are on-going. We use a coupled mass balance - ice flow model to infer past climate by simulating glacier extents that match the mapped and dated LGM moraines. A range of possible temperature/precipitation change combinations (e.g. -15% precipitation and -7C temperature change) allow simulated glaciers to fit the LGM moraines dated to 20,140±610 and 23,370±470 years old.

  14. Calving rates at tidewater glaciers vary strongly with ocean temperature

    PubMed Central

    Luckman, Adrian; Benn, Douglas I.; Cottier, Finlo; Bevan, Suzanne; Nilsen, Frank; Inall, Mark

    2015-01-01

    Rates of ice mass loss at the calving margins of tidewater glaciers (frontal ablation rates) are a key uncertainty in sea level rise projections. Measurements are difficult because mass lost is replaced by ice flow at variable rates, and frontal ablation incorporates sub-aerial calving, and submarine melt and calving. Here we derive frontal ablation rates for three dynamically contrasting glaciers in Svalbard from an unusually dense series of satellite images. We combine ocean data, ice-front position and terminus velocity to investigate controls on frontal ablation. We find that frontal ablation is not dependent on ice dynamics, nor reduced by glacier surface freeze-up, but varies strongly with sub-surface water temperature. We conclude that calving proceeds by melt undercutting and ice-front collapse, a process that may dominate frontal ablation where submarine melt can outpace ice flow. Our findings illustrate the potential for deriving simple models of tidewater glacier response to oceanographic forcing. PMID:26450063

  15. The Nisqually Glacier, Mount Rainier, Washington, 1857-1979

    USGS Publications Warehouse

    Heliker, C.C.; Johnson, Aaron H.; Hodge, S.M.

    1984-01-01

    Nisqually Glacier on Mount Ranier, Washington has a long record of terminus position observations and ice-surface altitude measurements along specific profiles, and has been the topic of numerous scientific studies. From the earliest observations in 1857 to the present many individuals and several different organizations have been involved in data collection at Nisqually Glacier. In order to preserve the long-term data, it was assembled and reduced to a standard format for this report. A comprehensive bibliography of scientific publications relating to the glacier is included. Between 1857 and 1979, Nisqually Glacier receded a total of 1,945 meters and advanced a total of 294 meters. Advances occurred from 1963-68 and from 1974-79. Ice-surface altitude changes of as much as 25 meters occurred between 1944 and 1955. (USGS)

  16. 36 CFR 7.3 - Glacier National Park.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-the-Sun Road from West Glacier entrance to Lake McDonald Lodge and from St. Mary entrance to Rising Sun will be permitted. (2) Commercial passenger-carrying motor vehicles operated in the above...

  17. 36 CFR 7.3 - Glacier National Park.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-the-Sun Road from West Glacier entrance to Lake McDonald Lodge and from St. Mary entrance to Rising Sun will be permitted. (2) Commercial passenger-carrying motor vehicles operated in the above...

  18. 36 CFR 7.3 - Glacier National Park.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-the-Sun Road from West Glacier entrance to Lake McDonald Lodge and from St. Mary entrance to Rising Sun will be permitted. (2) Commercial passenger-carrying motor vehicles operated in the above...

  19. Accumulation of anthropogenic radionuclides in cryoconites on Alpine glaciers.

    PubMed

    Tieber, A; Lettner, H; Bossew, P; Hubmer, A; Sattler, B; Hofmann, W

    2009-07-01

    Cryoconites are airborne sediments which accumulate on the surface of glaciers. In samples of cryoconites a temperate Austrian glacier high activity concentrations of anthropogenic radionuclides were found, which stem from global and Chernobyl fallouts. Radionuclides identified were (137)Cs, (134)Cs, (238)Pu, (239+240)Pu, (90)Sr, (241)Am, (60)Co, (154)Eu, (207)Bi, and (125)Sb. Given the approximately known isotopic ratios, Cs and Pu can be separated into the contributions of either source of origin. Published (137)Cs/(134)Cs and (239+240)Pu/(238)Pu ratios were used for the discrimination of the Dachstein-glacier cryoconites according to their origin from global or Chernobyl fallout. Two different groups of cryoconites were identified, an older population dominated by nuclear weapons fallout and a younger one with predominant Chernobyl fallout. With those data a simple model was formulated to demonstrate the transition and mixing of these two populations on the glacier surface.

  20. Undercutting of marine-terminating glaciers in West Greenland

    NASA Astrophysics Data System (ADS)

    Rignot, Eric; Fenty, Ian; Xu, Yun; Cai, Cilan; Kemp, Chris

    2015-07-01

    Marine-terminating glaciers control most of Greenland's ice discharge into the ocean, but little is known about the geometry of their frontal regions. Here we use side-looking, multibeam echo sounding observations to reveal that their frontal ice cliffs are grounded deeper below sea level than previously measured and their ice faces are neither vertical nor smooth but often undercut by the ocean and rough. Deep glacier grounding enables contact with subsurface, warm, salty Atlantic waters (AW) which melts ice at rates of meters per day. We detect cavities undercutting the base of the calving faces at the sites of subglacial water (SGW) discharge predicted by a hydrological model. The observed pattern of undercutting is consistent with numerical simulations of ice melt in which buoyant plumes of SGW transport warm AW to the ice faces. Glacier undercutting likely enhances iceberg calving, impacting ice front stability and, in turn, the glacier mass balance.

  1. Colonization of maritime glacier ice by bdelloid Rotifera.

    PubMed

    Shain, Daniel H; Halldórsdóttir, Katrín; Pálsson, Finnur; Aðalgeirsdóttir, Guðfinna; Gunnarsson, Andri; Jónsson, Þorsteinn; Lang, Shirley A; Pálsson, Hlynur Skagfjörð; Steinþórssson, Sveinbjörn; Arnason, Einar

    2016-05-01

    Very few animal taxa are known to reside permanently in glacier ice/snow. Here we report the widespread colonization of Icelandic glaciers and ice fields by species of bdelloid Rotifera. Specimens were collected within the accumulation zones of Langjökull and Vatnajökull ice caps, among the largest European ice masses. Rotifers reached densities up to ∼100 individuals per liter-equivalent of glacier ice/snow, and were freeze-tolerant. Phylogenetic analyses indicate that glacier rotifers are polyphyletic, with independent ancestries occurring within the Pleistocene. Collectively, these data identify a previously undescribed environmental niche for bdelloid rotifers and suggest their presence in comparable habitats worldwide. PMID:26932187

  2. Fast-flowing outlet glaciers on Svalbard ice caps

    SciTech Connect

    Dowdeswell, J.A. ); Collin, R.L. )

    1990-08-01

    Four well-defined outlet glaciers are present on the 2510 km{sup 2} cap of Vestfonna in Nordaustlandet, Svalbard. Airborne radio echo sounding and aerial-photograph and satellite-image analysis methods are used to analyze the morphology and dynamics of the ice cap and its component outlet glaciers. The heavily crevassed outlets form linear depressions in the ice-cap surface and flow an order of magnitude faster than the ridges of uncrevassed ice between them. Ice flow on the ridges is accounted for by internal deformation alone, whereas rates of outlet glacier flow require basal motion. One outlet has recently switched into and out of a faster mode of flow. Rapid terminal advance, a change from longitudinal compression to tension, and thinning in the upper basin indicate surge behavior. Observed outlet glacier discharge is significantly greater than current inputs of mass of the ice cap, indicating that present rates of flow cannot be sustained under the contemporary climate.

  3. Glacier shrinkage and water resources in the Andes

    NASA Astrophysics Data System (ADS)

    Francou, Bernard; Coudrain, Anne

    For more than a century glaciers around the world have been melting as air temperatures rise due to a combination of natural processes and human activity. The disappearance of these glaciers can have wide-ranging effects, such as the creation of new natural hazards or changes in stream flow that could threaten water suppliesSome of the most dramatic melting has occurred in the Andes mountain range in South America. To highlight the climatic and glacial change in the Andes and to encourage the scientific community to strengthen the glacier observation network that stretches from Colombia to the Patagonian ice fields, the Instituto Nacional de Recursos Naturales (INRENA), Perú, and the Institute of Research and Development (IRD), France, recently organized the second Symposium on Mass Balance of Andean Glaciers in Huaráz,Perú.

  4. Evaluating glacier movement fluctuations using remote sensing: A case study of the Baird, Patterson, LeConte, and Shakes glaciers in central Southeastern Alaska

    NASA Astrophysics Data System (ADS)

    Davidson, Robert Howard

    Global Land Survey (GLS) data encompassing Landsat Multispectral Scanner (MSS), Landsat 5's Thematic Mapper (TM), and Landsat 7's Enhanced Thematic Mapper Plus (ETM+) were used to determine the terminus locations of Baird, Patterson, LeConte, and Shakes Glaciers in Alaska in the time period 1975-2010. The sequences of the terminuses locations were investigated to determine the movement rates of these glaciers with respect to specific physical and environmental conditions. GLS data from 1975, 1990, 2000, 2005, and 2010 in false-color composite images enhancing ice-snow differentiation and Iterative Self-Organizing (ISO) Data Cluster Unsupervised Classifications were used to 1) quantify the movement rates of Baird, Patterson, LeConte, and Shakes Glaciers; 2) analyze the movement rates for glaciers with similar terminal terrain conditions and; 3) analyze the movement rates for glaciers with dissimilar terminal terrain conditions. From the established sequence of terminus locations, movement distances were quantified between the glacier locations. Movement distances were then compared to see if any correlation existed between glaciers with similar or dissimilar terminal terrain conditions. The Global Land Ice Measurement from Space (GLIMS) data was used as a starting point from which glacier movement was measured for Baird, Patterson, and LeConte Glaciers only as the Shakes Glacier is currently not included in the GLIMS database. The National Oceanographic and Atmospheric Administration (NOAA) temperature data collected at the Petersburg, Alaska, meteorological station (from January 1, 1973 to December 31, 2009) were used to help in the understanding of the climatic condition in this area and potential impact on glaciers terminus. Results show that glaciers with similar terminal terrain conditions (Patterson and Shakes Glaciers) and glaciers with dissimilar terminal terrain conditions (Baird, Patterson, and LeConte Glaciers) did not exhibit similar movement rates

  5. Neoglacial fluctuations of Deming Glacier, Mt. Baker, Washington USA.

    NASA Astrophysics Data System (ADS)

    Osborn, G.; Menounos, B.; Scott, K.; Clague, J. J.; Tucker, D.; Riedel, J.; Davis, P.

    2007-12-01

    Deming Glacier flows from the upper west slopes of Mt. Baker, a stratovolcano in the Cascade Range of Washington, USA. The north and south lateral moraines of Deming Glacier are composed of at least four tills separated by layers of detrital wood and sheared stumps in growth position. The stratigraphy records fluctuations of the glacier during the Holocene. The outer ten rings of an in situ stump from the middle wood layer, which is about 40 m below the north lateral moraine crest and 1.2 km downvalley from the present glacier terminus, yielded an age of 1750 ± 50~~ 14C yr BP [1810-1550 cal yr BP]. The stump revealed at least 300 rings and thus records a period of landscape stability and relatively restricted glaciation for several hundred years prior to ca. 1750 14C yr BP . Samples from the lowest wood layer also have been submitted for radiocarbon dating. Outer rings of detrital wood samples collected from two wood mats exposed in the south lateral moraine, 2.3 km downvalley of the glacier terminus, returned radiocarbon ages of 1600 ± 30~~ 14C yr BP [1550- 1410 cal yr BP] and 430 ± 30~~ 14C yr BP [AD 1420-1620]. These data indicate that Deming Glacier advanced over a vegetated moraine sometime after 1810 cal yr BP to a position less extensive that it achieved at the peak of the Little Ice Age. The glacier then receded before it began its final and most extensive Holocene advance after AD 1420. The older advance is correlative with the 'First Millennium AD' advance, recently recognized throughout western North America. The younger advance coincides with an advance of Mt. Baker's Easton Glacier [AD 1430-1630], and advances of many alpine glaciers elsewhere in western North America. Our data suggest that glaciers on Mt. Baker fluctuated in a similar manner to alpine glaciers in the Coast Mountains of British Columbia and in other mountain ranges of northwest North America during Neoglaciation.

  6. Geological Controls on Glacier Surging?: Statistics and Speculation

    NASA Astrophysics Data System (ADS)

    Flowers, G. E.; Crompton, J. W.

    2015-12-01

    Glacier surging represents an end-member behavior in the spectrum of ice dynamics, involving marked acceleration and high flow speeds due to abrupt changes in basal mechanics. Though much effort has been devoted to understanding the role of basal hydrology and thermal regime in fast glacier flow, fewer studies have addressed the potential role of the geologic substrate. One interesting observation is that surge-type glaciers appear almost universally associated with unconsolidated (till) beds, and several large-scale statistical studies have revealed correlations between glacier surging and bedrock properties. We revisit this relationship using field measurements. We selected 20 individual glaciers for sampling in a 40x40 km region of the St. Elias Mountains of Yukon, Canada. Eleven of these glaciers are known to surge and nine are not. The 20 study glaciers are underlain by lithologies that we have broadly classified into two types: metasedimentary only and mixed metasedimentary-granodiorite. We characterized geological and geotechnical properties of the bedrock in each basin, and analyzed the hydrochemistry and mineralogy and grain size distribution (GSD) of the suspended sediments in the proglacial streams. Here we focus on some intriguing results of the GSD analysis. Using statistical techniques, including significance testing and principal component analysis, we find that: (1) lithology determines GSD for non-surge-type glaciers, with metasedimentary basins associated with finer mean grain sizes and mixed-lithology basins with coarser mean grain sizes, but (2) the GSDs associated with surge-type glaciers are intermediate between the distributions described above, and are statistically indistinguishable between metasedimentary and mixed lithology basins. The latter suggests either that surge-type glaciers in our study area occur preferentially in basins where various processes conspire to produce a characteristic GSD, or that the surge cycle itself exerts an

  7. Glacier elevation changes on the Tibetan Plateau derived by ICESat

    NASA Astrophysics Data System (ADS)

    Neckel, N.; Kropacek, J.; Bolch, T.

    2012-04-01

    Glaciers are a sensitive indicator for climate change in high mountain regions where climate stations are rare or non-existent. In addition, glacier changes have a significant impact on the hydrological cycle of the vulnerable region of the Tibetan Plateau. Therefore a continuous monitoring of glaciers is necessary. In-situ measurements are essential but can only be conducted at a very limited number of glaciers in this large and remote region due to enormous logistical efforts and high costs. Remote sensing techniques are suitable to complement these in-situ measurements and address a large area simultaneously. Traditionally, mountain glaciers are monitored in terms of area changes from aerial or satellite image data. However, these changes show, in contrast to volume changes, a delayed signal to climate only. In order to estimate volume changes of glaciers on the Tibetan Plateau data from the Geoscience Laser Altimeter System (GLAS) carried on-board the Ice Cloud and Elevation Satellite (ICESat) was used for extraction of elevation changes for the period 2003 to 2009. GLAS shots over glaciers were selected using the Global Land Ice Measurements from Space (GLIMS) dataset with support of recent cloud free Landsat scenes obtained from USGS. ICESat repeat-tracks are spatially close but do not match exactly. They can be horizontally separated by up to 3000 m. Therefore, an independent reference surface is used for a multi-temporal comparison of GLAS shots. For this purpose we use a Digital Elevation Model (DEM) acquired in February 2000 by the Shuttle Radar Topography Mission (SRTM). Glaciers with an adequate ICESat data coverage (approximately 12% of the glaciers captured in the GLIMS database) were grouped according to the mountain chains in certain compact geographic regions. Mean trends in glacier elevation changes were estimated for these regions for the seven years of ICESat's lifetime. Preliminary results suggest a heterogeneous wastage of glaciers across the

  8. Younger Dryas glaciers in the High Atlas, Morocco

    NASA Astrophysics Data System (ADS)

    Hughes, Philip; Fink, David

    2016-04-01

    Twelve cirque glaciers formed during the Younger Dryas on the mountains of Aksoual (3912 m a.s.l.) and Adrar el Hajj (3129 m a.s.l.) in the Marrakesh High Atlas. Moraines in two separate cirques on these mountains have been dated using 10Be and 36Cl exposure dating. In both cirques the age scatter is relatively small (13.8-10.1 ka) and all ages overlap within error with the Younger Dryas (12.9-11.7 ka). The glaciers were small and covered <2 km2 and formed on north-facing slopes. However, the altitudinal range of the glaciers was very large, with equilibrium line altitudes (ELAs) ranging from 2470 and 3560 m. This large range is attributed to local topoclimatic factors with the lowest glacier (confirmed as Younger Dryas in age by 3 exposure ages) occupying a very steep cirque floor where a combination of steep glacier gradient and a large potential avalanche catchment enabled its low-lying position. This indicates that caution should be taken when using single glacier sites for reconstructing regional palaeoclimate, especially those formed in steep catchments that have strong topoclimatic controls. The average ELA of the twelve Younger Dryas glaciers was c. 3109 m a.s.l. (St Dev = 325 m) and this represents an ELA depression of > 1000 m from the modern theoretical regional ELA. Under precipitation values similar to today this would require a mean annual temperature depression of 9°C. Moreover, the glacier-climate modelling indicates that it is very unlikely that climate was drier than today during the Younger Dryas in the Marrakesh High Atlas.

  9. Eukaryotic microorganisms in cold environments: examples from Pyrenean glaciers.

    PubMed

    García-Descalzo, Laura; García-López, Eva; Postigo, Marina; Baquero, Fernando; Alcazar, Alberto; Cid, Cristina

    2013-01-01

    Little is known about the viability of eukaryotic microorganisms preserved in icy regions. Here we report on the diversity of microbial eukaryotes in ice samples derived from four Pyrenean glaciers. The species composition of eukaryotic communities in these glaciers is unknown mostly because of the presence of a multi-year ice cap, and it is not clear whether they harbor the same populations. The recent deglaciation of these areas is allowing an easy access to glacial layers that correspond to the "Little Ice Age" although some isolated deposits are attributed to previous glacial cycles. In this study, we use molecular 18S rRNA-based approaches to characterize some of the microbial eukaryotic populations associated with Pyrenean glaciers. Firstly, we performed a chemical and microscopical characterization of ice samples. Secondly, molecular analyses revealed interesting protist genetic diversity in glaciers. In order to understand the microbial composition of the ice samples the eukaryotic communities resident in the glacial samples were examined by amplifying community DNA and constructing clone libraries with 18S rRNA primers. After removal of potential chimeric sequences and dereplication of identical sequences, phylogenetic analysis demonstrated that several different protists could be identified. Protist diversity was more phylum rich in Aneto and Monte Perdido glaciers. The dominant taxonomic groups across all samples (>1% of all sequences) were Viridiplantae and Rhizaria. Significant variations in relative abundances of protist phyla between higher and lower glaciers were observed. At the genus level, significant differences were also recorded for the dominant genera Chloromonas, Raphidonema, Heteromita, Koliella, and Bodomorpha. In addition, protist community structure showed significant differences between glaciers. The relative abundances of protist groups at different taxonomic levels correlated with the altitude and area of glaciers and with pH of ice

  10. Elevation change (2000-2004) on the Malaspina Glacier, Alaska

    NASA Technical Reports Server (NTRS)

    Sauber, J.; Molnia, B.; Carabajal, C.; Luthcke, S.; Muskett, R.

    2005-01-01

    The glaciers of the southeastern Alaska coastal region are the largest temperate glacier meltwater source on Earth and may contribute one third of the total glacier meltwater entering the global ocean. Since melt onset and refreeeze timing in this region show a tendency toward earlier onset and longer ablation seasons, accelerated glacier wastage may be occurring. In this study we focus on one of the largest temperate glacier systems on Earth, the Malaspina Glacier. This glacier, with a length of approximately 110 km and an area of approximately square 5,000 km, has the largest piedmont lobe of any temperate glacier. The entire lobe, which lies at elevations below 600 m, is within the ablation zone. We report and interpret ice elevation change between a digital elevation model (DEM) derived from the Shuttle Radar Topography Mission (SRTM C band) observations in Feb. 2000 and ICESat Laser 1-3 observations between Feb. 2003 and Nov. 2004. We use these elevation change results, along with earlier studies, to address the spatial and temporal variability in wastage of the piedmont lobe. Between 2000 and 2004 ice elevation changes of 10-30 meters occurred across the central Malaspina piedmont lobe. From 1972/73 (USGS DEM) to 1999 (SRTM corrected for estimated winter snow accumulation) Malaspina's (Agassiz, Seward Lobe, and Marvine) mean ice thinning was estimated at -47 m with maximum thinning on parts of the lobes to -160 m. The Malaspina's accumulation area is only slightly larger than its ablation area (2,575 km2 vs. 2,433 km2); unfortunately few glaciological observations are available from this source region. Snow accumulation rates have been largely inferred from low-altitude precipitation and temperature data. Comparing sequential ICESat observations in the Malaspina source region, we estimated short-term elevation increases of up to 5 meters during the winter of 2003/04.

  11. Eukaryotic microorganisms in cold environments: examples from Pyrenean glaciers

    PubMed Central

    García-Descalzo, Laura; García-López, Eva; Postigo, Marina; Baquero, Fernando; Alcazar, Alberto; Cid, Cristina

    2013-01-01

    Little is known about the viability of eukaryotic microorganisms preserved in icy regions. Here we report on the diversity of microbial eukaryotes in ice samples derived from four Pyrenean glaciers. The species composition of eukaryotic communities in these glaciers is unknown mostly because of the presence of a multi-year ice cap, and it is not clear whether they harbor the same populations. The recent deglaciation of these areas is allowing an easy access to glacial layers that correspond to the “Little Ice Age” although some isolated deposits are attributed to previous glacial cycles. In this study, we use molecular 18S rRNA-based approaches to characterize some of the microbial eukaryotic populations associated with Pyrenean glaciers. Firstly, we performed a chemical and microscopical characterization of ice samples. Secondly, molecular analyses revealed interesting protist genetic diversity in glaciers. In order to understand the microbial composition of the ice samples the eukaryotic communities resident in the glacial samples were examined by amplifying community DNA and constructing clone libraries with 18S rRNA primers. After removal of potential chimeric sequences and dereplication of identical sequences, phylogenetic analysis demonstrated that several different protists could be identified. Protist diversity was more phylum rich in Aneto and Monte Perdido glaciers. The dominant taxonomic groups across all samples (>1% of all sequences) were Viridiplantae and Rhizaria. Significant variations in relative abundances of protist phyla between higher and lower glaciers were observed. At the genus level, significant differences were also recorded for the dominant genera Chloromonas, Raphidonema, Heteromita, Koliella, and Bodomorpha. In addition, protist community structure showed significant differences between glaciers. The relative abundances of protist groups at different taxonomic levels correlated with the altitude and area of glaciers and with pH of

  12. Eukaryotic microorganisms in cold environments: examples from Pyrenean glaciers.

    PubMed

    García-Descalzo, Laura; García-López, Eva; Postigo, Marina; Baquero, Fernando; Alcazar, Alberto; Cid, Cristina

    2013-01-01

    Little is known about the viability of eukaryotic microorganisms preserved in icy regions. Here we report on the diversity of microbial eukaryotes in ice samples derived from four Pyrenean glaciers. The species composition of eukaryotic communities in these glaciers is unknown mostly because of the presence of a multi-year ice cap, and it is not clear whether they harbor the same populations. The recent deglaciation of these areas is allowing an easy access to glacial layers that correspond to the "Little Ice Age" although some isolated deposits are attributed to previous glacial cycles. In this study, we use molecular 18S rRNA-based approaches to characterize some of the microbial eukaryotic populations associated with Pyrenean glaciers. Firstly, we performed a chemical and microscopical characterization of ice samples. Secondly, molecular analyses revealed interesting protist genetic diversity in glaciers. In order to understand the microbial composition of the ice samples the eukaryotic communities resident in the glacial samples were examined by amplifying community DNA and constructing clone libraries with 18S rRNA primers. After removal of potential chimeric sequences and dereplication of identical sequences, phylogenetic analysis demonstrated that several different protists could be identified. Protist diversity was more phylum rich in Aneto and Monte Perdido glaciers. The dominant taxonomic groups across all samples (>1% of all sequences) were Viridiplantae and Rhizaria. Significant variations in relative abundances of protist phyla between higher and lower glaciers were observed. At the genus level, significant differences were also recorded for the dominant genera Chloromonas, Raphidonema, Heteromita, Koliella, and Bodomorpha. In addition, protist community structure showed significant differences between glaciers. The relative abundances of protist groups at different taxonomic levels correlated with the altitude and area of glaciers and with pH of ice

  13. Spatiotemporal variations in the surface velocities of Antarctic Peninsula glaciers

    NASA Astrophysics Data System (ADS)

    Chen, J.; Ke, C. Q.; Shao, Z. D.

    2014-11-01

    Velocity is an important parameter for the estimation of glacier mass balance, which directly signals the response of glaciers to climate change. Antarctic ice sheet movement and the associated spatiotemporal velocity variations are of great significance to global sea level rise. In this study, we estimate Antarctic Peninsula glacier velocities using the co-registration of optically sensed images and correlation (hereafter referred to as COSI-Corr) based on moderate-resolution imaging spectroradiometer Level 1B data (hereafter referred to as MODIS L1B). The results show that the glaciers of Graham Land and the Larsen Ice Shelf have substantially different velocity features. The Graham Land glaciers primarily flow from the peninsula ridge towards the Weddell Sea and Bellingshausen Sea on the east and west sides, respectively. There are very large velocity variations among the different ice streams, with a minimum of < 20 m a-1 and a maximum of 1500 m a-1 (with an average of 100-150 m a-1). Over the period 2000-2012, the glaciers of Graham Land accelerated in the south but slowed down in the north. In contrast, the Larsen Ice Shelf flows in a relatively uniform direction, mainly towards the northeast into the Weddell Sea. Its average velocity is 750-800 m a-1 and the maximum is > 1500 m a-1. During the period 2000-2012, the Larsen Ice Shelf experienced significant acceleration. The use of COSI-Corr based on MODIS L1B data is suitable for glacier velocity monitoring on the Antarctic Peninsula over long time series and large spatial scales. This method is clearly advantageous for analysing macro-scale spatiotemporal variations in glacier movement.

  14. Mass balance investigation of alpine glaciers through LANDSAT TM data

    NASA Technical Reports Server (NTRS)

    Bayr, Klaus J.

    1989-01-01

    An analysis of LANDSAT Thematic Mapper (TM) data of the Pasterze Glacier and the Kleines Fleisskees in the Austrian Alps was undertaken and compared with meteorological data of nearby weather stations. Alpine or valley glaciers can be used to study regional and worldwide climate changes. Alpine glaciers respond relatively fast to a warming or cooling trend in temperature through an advance or a retreat of the terminus. In addition, the mass balance of the glacier is being affected. Last year two TM scenes of the Pasterze Glacier of Aug. 1984 and Aug. 1986 were used to study the difference in reflectance. This year, in addition to the scenes from last year, one MSS scene of Aug. 1976 and a TM scene from 1988 were examined for both the Pasterze Glacier and the Kleines Fleisskees. During the overpass of the LANDSAT on 6 Aug. 1988 ground truthing on the Pasterze Glacier was undertaken. The results indicate that there was considerable more reflectance in 1976 and 1984 than in 1986 and 1988. The climatological data of the weather stations Sonnblick and Rudolfshuette were examined and compared with the results found through the LANDSAT data. There were relations between the meteorological and LANDSAT data: the average temperature over the last 100 years showed an increase of .4 C, the snowfall was declining during the same time period but the overall precipitation did not reveal any significant change over the same period. With the use of an interactive image analysis computer, the LANDSAT scenes were studied. The terminus of the Pasterze Glacier retreated 348 m and the terminus of the Kleines Fleisskees 121 m since 1965. This approach using LANDSAT MSS and TM digital data in conjunction with meteorological data can be effectively used to monitor regional and worldwide climate changes.

  15. Prolific Sources of Icequakes: The Mulock and Skelton Glaciers, Antarctica

    NASA Astrophysics Data System (ADS)

    Lloyd, A. J.; Wiens, D.; Lough, A. C.; Anandakrishnan, S.; Nyblade, A.; Aster, R. C.; Huerta, A. D.; Winberry, J. P.

    2015-12-01

    The Mulock and Skelton Glaciers are large outlet glaciers that flow through the Transantarctic Mountains and into the Ross Ice Shelf. A regional seismic deployment in the central Transantarctic Mountains (TAM) in 1999-2000 led to the identification of 63 events in the vicinity of Mulock and Skelton Glaciers [Bannister and Kennett, 2002]. A more recent study utilizing seismic data collected as part of the POLENET/A-NET and AGAP projects during 2009 again identified significant seismicity associated with these glaciers and suggested that many of these events were icequakes based on their shallow depths [Lough, 2014]. These two glaciers represent the most seismically active regions in the TAM aside from the well-studied David Glacier region [Danesi et al, 2007; Zoet et al., 2012]. In addition, many of the icequakes from this region have magnitude ML > 2.5, in contrast to most glacial events that are generally of smaller magnitude. Using the waveforms of previously identified icequakes as templates, nearby POLENET/A-NET, AGAP, and GSN seismic stations were scanned using a cross-correlation method to find similar waveforms. We then used a relative location algorithm to determine high-precision locations and depths. The use of regional velocity models derived from recent seismic studies facilitates accurate absolute locations that we interpret in the context of the local geological and glacial features. The icequakes are concentrated in heavily crevassed regions associated with steep bedrock topography, likely icefalls. Future work will focus on determining whether these events are associated with stick-slip events at the bed of the glacier and/or crevasse formation near the surface. In addition the temporal pattern of seismicity will also be examined to search for repeating icequakes, which have been identified at the base of several other glaciers.

  16. Identifying Dynamically Induced Variability in Glacier Mass-Balance Records

    NASA Astrophysics Data System (ADS)

    Christian, J. E.; Siler, N.; Koutnik, M. R.; Roe, G.

    2015-12-01

    Glacier mass-balance (i.e., accumulation vs. ablation) provides a direct indicator of a glacier's relationship with climate. However, mass-balance records contain noise due to internal climate variability (i.e., from stochastic fluctuations in large-scale atmospheric circulation), which can obscure or bias trends in these relatively short timeseries. This presents a challenge in correctly identifying the signature of anthropogenic change. "Dynamical adjustment" is a technique that identifies patterns of variance shared between a climate timeseries of interest (e.g., mass-balance) and independent "predictor" variables associated with large-scale circulation (e.g., Sea Level Pressure, SLP, or Sea Surface Temperature, SST). Extracting the component of variance due to internal variability leaves a residual timeseries for which trends can more confidently be attributed to external forcing. We apply dynamical adjustments based on Partial Least Squares Regression to mass-balance records from South Cascade Glacier in Washington State and Wolverine and Gulkana Glaciers in Alaska, independently analyzing seasonal balance records to assess the dynamical influences on winter accumulation and summer ablation. Seasonally averaged North Pacific SLP and SST fields perform comparably as predictor variables, explaining 50-60% of the variance in winter balance and 30-40% of variance in summer balance for South Cascade and Wolverine Glaciers. Gulkana glacier, located further inland than the other two glaciers, is less closely linked to North Pacific climate variability, with the predictors explaining roughly one-third of variance in its winter and summer balance. We analyze the significance of linear trends in the raw and adjusted mass-balance records, and find that for all three glaciers, a) summer balance shows a statistically significant downward trend that is not substantially altered when dynamically induced variability is removed, and b) winter balance shows no statistically

  17. Distributed modeling of ablation (1996–2011) and climate sensitivity on the glaciers of Taylor Valley, Antarctica

    DOE PAGES

    Hoffman, Matthew J.; Fountain, Andrew G.; Liston, Glen E.

    2016-02-24

    Here, the McMurdo Dry Valleys of Antarctica host the coldest and driest ecosystem on Earth, which is acutely sensitive to the availability of water coming from glacial runoff. We modeled the spatial variability in ablation and assessed climate sensitivity of the glacier ablation zones using 16 years of meteorological and surface mass-balance observations collected in Taylor Valley. Sublimation was the primary form of mass loss over much of the ablation zones, except for near the termini where melt, primarily below the surface, dominated. Microclimates in ~10 m scale topographic basins generated melt rates up to ten times higher than overmore » smooth glacier surfaces. In contrast, the vertical terminal cliffs on the glaciers can have higher or lower melt rates than the horizontal surfaces due to differences in incoming solar radiation. The model systematically underpredicted ablation for the final 5 years studied, possibly due to an increase of windblown sediment. Surface mass-balance sensitivity to temperature was ~–0.02 m w.e. K–1, which is among the smallest magnitudes observed globally. We also identified a high sensitivity to ice albedo, with a decrease of 0.02 having similar effects as a 1 K increase in temperature, and a complex sensitivity to wind speed.« less

  18. Mapping complementarity between solar and hydro power: Sensitivity study to glacier retreat in the Eastern Italian Alps

    NASA Astrophysics Data System (ADS)

    Borga, Marco; Baptiste, François; Zoccatelli, Davide

    2016-04-01

    High penetration of climate related energy sources (such as solar and small hydropower) might be facilitated by using their complementarity in order to increase the balance between energy load and generation. In this study we examine and map the complementarity between solar PV and run-of-the-river energy along the river network of catchments in the Eastern Italian Alps which are significantly affected by glaciers. We analyze energy sources complementarity across different temporal scales using two indicators: the standard deviation of the energy balance and the theoretical storage required for balancing generation and load (François et a., 2016). Temporal scales ranging from hours to years are assessed. By using a glacio-hydrological model able to simulate both the glacier and hydrology dynamics, we analyse the sensitivity of the obtained results with respect to different scenarios of glacier retreat. Reference: François, B., Hingray, B., Raynaud, D., Borga, M., Creutin, J.D., 2016: Increasing climate-related-energy penetration by integrating run-of-the river hydropower to wind/solar mix. Renewable Energy, 87, 686-696.

  19. Tropical glaciers and climate dynamics: Resolving the linkages

    NASA Astrophysics Data System (ADS)

    Mölg, Thomas

    2013-04-01

    Large-scale atmosphere/ocean circulation and mountain glaciers represent two entirely different scales in the climate system. Therefore, statistical linkages between the two mask a cascade of processes that act on different temporal and spatial dimensions. Low-latitude glaciers are particularly well suited for studying such processes, since these glaciers are situated in the "heart" of the global climate system (the tropics). This presentation gives an overview of a decade of research on tropical climate and glaciers on Kilimanjaro (East Africa), which is, to our knowledge, the only case where space/time linkages between high-altitude glaciers and climate dynamics have been investigated systematically throughout the main scales. This includes the complex modification of atmospheric flow when air masses impinge on high mountains, an aspect that has been widely neglected from a cryospheric viewpoint. The case of Kilimanjaro demonstrates (1) the great potential of learning about climate system processes and their connections, (2) advances in our understanding of the importance of moisture for glaciers that lie far above the mean freezing level, and (3) methodological advances in combining atmospheric and cryospheric modelling.

  20. Global distributions of glacier properties: A stochastic scaling paradigm

    NASA Astrophysics Data System (ADS)

    Bahr, David B.

    Many problems in global climate and Earth systems science require knowledge of regional- or global-scale distributions of glacier properties, which includes mass balance, ice velocity, flux, thickness, volume, and surface area, among others. With roughly 160,000 glaciers worlwide, obtaining information on the global probability distributions of most ice properties is expensive and often infeasible. Only surface area distributions are relatively easy to measure, either by direct observation or remote sensing. While other properties are difficult to observe, this work shows that scaling relationships from the continuum dynamics of ice can link the distribution of surface areas to the global and regional distributions of any other continuum property. Some data inventories already exist for constructing reasonable distributions of glacier sizes, and this analysis presents theoretical arguments based on glacier network topologies (similar in concept to river networks) to suggest a power law times an exponential distribution of surface areas (in agreement with the data). Therefore, by using existing data or the theoretical distributions of surface areas, specific distributions for other glacier properties in any region of the world can be constructed. As an example, predictions (up to a scaling constant) are made for the distribution of glacier volumes, characteristic thicknesses, characteristic velocities, and characteristic response times in the Alps.

  1. Deducing high-altitude precipitation from glacier mass balance measurements

    NASA Astrophysics Data System (ADS)

    Giesen, Rianne H.; Immerzeel, Walter W.; Wanders, Niko

    2016-04-01

    The spatial distribution of precipitation in mountainous terrain is generally not well known due to underrepresentation of gauge observations at higher elevations. Precipitation tends to increase with elevation, but since observations are mainly performed in the valleys, the vertical precipitation gradient cannot be deduced from these measurements. Furthermore, the spatial resolution of gridded meteorological data is often too coarse to resolve individual mountain chains. Still, a reliable estimate of high-elevation precipitation is required for many hydrological applications. We present a method to determine the vertical precipitation gradient in mountainous terrain, making use of glacier mass balance observations. These measurements have the advantage that they provide a basin-wide precipitation estimate at high elevations. The precipitation gradient is adjusted until the solid precipitation over the glacier area combined with the calculated melt gives the measured annual glacier mass balance. Results for the glacierized regions in Central Europe and Scandinavia reveal spatially coherent patterns, with predominantly positive precipitation gradients ranging from -4 to +28 % (100 m)‑1. In some regions, precipitation amounts at high elevations are up to four times as large as in the valleys. A comparison of the modelled winter precipitation with observed snow accumulation on glaciers shows a good agreement. Precipitation measured at the few high-altitude meteorological stations is generally lower than our estimate, which may result from precipitation undercatch. Our findings will improve the precipitation forcing for glacier modelling and hydrological studies in mountainous terrain.

  2. First-principles Simulations and the Criticality of Calving Glaciers

    NASA Astrophysics Data System (ADS)

    Vallot, D.; Åström, J. A.; Schäfer, M.; Welty, E.; O'Neel, S.; Bartholomaus, T. C.; Liu, Y.; Riikilä, T.; Zwinger, T.; Timonen, J.; Moore, J.

    2014-12-01

    The algoritm of a first principles calving-simulation computer-code is outlined and demonstrated. The code is particle-based and uses Newtonian dynamics to simulate ice-fracture, motion and calving. The code can simulate real-size glacier but is only able to simualte individual calving events within a few tens of minutes in duration. The code couples to the Elmer/Ice ice flow-simulation code: Elmer is employed to produce various glacier geomteries, which are then tested for stability using the particle code. In this way it is possible to pin-point the location of calving fronts. The particle simulation code and field observations are engaged to investigate the criticality of calving glaciers. The calving mass and inter-event waiting times both have power-law distributions with the same critical exponents as found for Abelian sand-pile models. This indicate that calving glaciers share characteristics with Self-Organized Critical systems (SOC). This would explain why many glacier found in nature may become unstable as a result of even minor changes in their environment. An SOC calving glacier at the critical point will display so large fluctuations in calving rate that it will render the concept 'average calving rate' more or less useless. I.e. 'average calving rate' will depend on measurement time and always have fluctuaions in the range of 100% more or less independent of the averaging time.

  3. Bed Properties of the Taku Glacier from Flowline Modeling Inversion

    NASA Astrophysics Data System (ADS)

    Suhr, I.; Headen, J.; Le Cras, S.; Marshall, H.; O'Neil, J.; Rand-Lewis, L. M.; Riverman, K. L.

    2015-12-01

    The Taku glacier in SE Alaska is the world's deepest and thickest alpine temperate glacier, with the potential for interesting changes in flow dynamics in the coming decades as it erodes fully through the marine sediment package it currently flows over. With limited field data constraining the glacier's current bed elevation and basal slip rate, modeling efforts of present and future glacier dynamics have been limited. Here we present the first 1D Shallow Shelf Approximation finite difference flowline model of the Taku glacier. We run the model with field data collected annually by the Juneau Icefield Research Program, including mass balance derived from shallow ice-penetrating radar and snow pits and bed elevation from active seismics. We vary bed elevation and bed slipperiness parameters in order to fit the modeled glacier surface to the GPS-derived observed surface elevation profile and velocities. In lieu of more extensive seismic surveying on Taku, the best-fitting bed elevation profile product presented here will be useful for future predictive modeling efforts of Taku flow dynamics.

  4. The Wind Energy Potential of Iceland

    NASA Astrophysics Data System (ADS)

    Nawri, Nikolai; Nína Petersen, Guðrún; Bjornsson, Halldór; Hahmann, Andrea N.; Jónasson, Kristján; Bay Hasager, Charlotte; Clausen, Niels-Erik

    2014-05-01

    While Iceland has an abundant wind energy resource, its use for electrical power production has so far been limited. Electricity in Iceland is generated primarily from hydro- and geothermal sources, and adding wind energy has so far not been considered practical or even necessary. However, wind energy is becoming a more viable option, as opportunities for new hydro- or geothermal power installations become limited. In order to obtain an estimate of the wind energy potential of Iceland, a wind atlas has been developed as part of the joint Nordic project 'Improved Forecast of Wind, Waves and Icing' (IceWind). Downscaling simulations performed with the Weather Research and Forecasting (WRF) model were used to determine the large-scale wind energy potential of Iceland. Local wind speed distributions are represented by Weibull statistics. The shape parameter across Iceland varies between 1.2 and 3.6, with the lowest values indicative of near-exponential distributions at sheltered locations, and the highest values indicative of normal distributions at exposed locations in winter. Compared with summer, average power density in winter is increased throughout Iceland by a factor of 2.0 - 5.5. In any season, there are also considerable spatial differences in average wind power density. Relative to the average value within 10 km of the coast, power density across Iceland varies between 50 - 250%, excluding glaciers, or between 300 - 1500 W m-2 at 50 m above ground level in winter. At intermediate elevations of 500 - 1000 m above mean sea level, power density is independent of the distance to the coast. In addition to seasonal and spatial variability, differences in average wind speed and power density also exist for different wind directions. Along the coast in winter, power density of onshore winds is higher by 100 - 700 W m-2 than that of offshore winds. The regions with the highest average wind speeds are impractical for wind farms, due to the distances from road

  5. Estimating Heat Transfer at Glacier Margins using Ground-Based Infrared Imagery

    NASA Astrophysics Data System (ADS)

    Aubry-Wake, C.; Zephir, D.; Baraer, M.; McKenzie, J. M.; Mark, B. G.

    2015-12-01

    Tropical glaciers constitute an important water resource for downstream populations. However, our understanding of their physical processes is limited due to their high elevation and remote location. In order to gain information on the processes driving the ablation of tropical glaciers, we acquired time-lapse (5-10 minute interval) high-resolution (0.64 m2 pixel size) infrared imagery of the Cuchillacocha Glacier in the Cordillera Blanca, Peru, in June 2014. This temperature dataset allows for the investigation of small-scale processes observed on the surface of the glacier and surroundings, such as the longwave transfer from the rock adjacent to the glacier. This process is particularly important for tropical glaciers, where the intense incoming solar radiation results in relatively high temperatures of the rocks adjacent the glacier and enhances longwave radiation emission. This radiative flux, varying between 81 and 120 W m-2 daily, is affected by local shading but shows no significant dependency on elevation. The longwave flux derived from the infrared images is integrated into an energy-balance model of the glacier to compare melt at the glacier margin to that occurring on the surface of the glacier. We can then estimate the melt volume generated by this enhanced longwave radiation at the glacier margins during the dry season. Including the quantification of the longwave flux at the glacier margin results in an improved assessment of glacier energy budget and melt water generation of tropical glaciers.

  6. Seasonal and altitudinal variations in snow algal communities on an Alaskan glacier (Gulkana glacier in the Alaska range)

    NASA Astrophysics Data System (ADS)

    Takeuchi, Nozomu

    2013-09-01

    Snow and ice algae are cold tolerant algae growing on the surface of snow and ice, and they play an important role in the carbon cycles for glaciers and snowfields in the world. Seasonal and altitudinal variations in seven major taxa of algae (green algae and cyanobacteria) were investigated on the Gulkana glacier in Alaska at six different elevations from May to September in 2001. The snow algal communities and their biomasses changed over time and elevation. Snow algae were rarely observed on the glacier in May although air temperature had been above 0 ° C since the middle of the month and surface snow had melted. In June, algae appeared in the lower areas of the glacier, where the ablation ice surface was exposed. In August, the distribution of algae was extended to the upper parts of the glacier as the snow line was elevated. In September, the glacier surface was finally covered with new winter snow, which terminated algal growth in the season. Mean algal biomass of the study sites continuously increased and reached 6.3 × 10 μl m-2 in cell volume or 13 mg carbon m-2 in September. The algal community was dominated by Chlamydomonas nivalis on the snow surface, and by Ancylonema nordenskiöldii and Mesotaenium berggrenii on the ice surface throughout the melting season. Other algae were less abundant and appeared in only a limited area of the glacier. Results in this study suggest that algae on both snow and ice surfaces significantly contribute to the net production of organic carbon on the glacier and substantially affect surface albedo of the snow and ice during the melting season.

  7. Dating buried glacier ice using cosmogenic 3He in surface clasts: Theory and application to Mullins Glacier, Antarctica

    NASA Astrophysics Data System (ADS)

    Mackay, Sean L.; Marchant, David R.

    2016-05-01

    We develop a modeling framework to describe the accumulation of terrestrial cosmogenic 3He in Antarctic debris-covered glaciers. The framework helps quantify the expected range in cosmogenic-nuclide inventories for measured clasts at the surface of supraglacial debris. We first delineate the physical factors that impact clast movement within, and on top of, debris-covered glaciers, including the effects of (1) ice ablation, (2) erosion at the debris surface, and (3) stochastic geomorphic processes that impact clast movement within and on top of supraglacial debris; we then explicitly calculate the impact of each process in altering the total inventory of cosmogenic nuclides in surface clasts. Assuming basic elements of ice-dynamics and debris entrainment are known, the model results provide an estimate for the total accumulation of cosmogenic nuclides, as well as the expected range in nuclide inventories, for any clast at the surface of debris-covered glaciers. Because the values are quantified, the approach can be applied to help evaluate the robustness of existing and future cosmogenic datasets applied to these systems. As a test, we applied our model framework towards Mullins Glacier, a cold-based debris-covered alpine glacier in the Dry Valleys of Antarctica. Our simulated values for cosmogenic-nuclide inventories compare well with those previously measured from fifteen surface cobbles along Mullins Glacier (3He), both in terms of expected ranges and absolute values, and suggest that our model framework adequately incorporates most of the complicating factors that impact cosmogenic datasets for cold-based, debris-covered glaciers. Relating these cosmogenic-nuclide inventories to ice ages, the results show that ice within Mullins Glacier increases non-linearly, ranging from 12 ka to ∼220 ka in areas of active flow, to ≫1.6 Ma in areas of slow-moving-to-stagnant ice.

  8. High-Resolution Monitoring of Glacier Dynamics During Calving Events at Helheim Glacier South-East Greenland

    NASA Astrophysics Data System (ADS)

    Murray, T.; Rutt, I. C.; O'Farrell, T.; Edwards, S.; Selmes, N.; Martin, I.; James, T.; Aspey, R.; Bevan, S. L.; Loskot, P.; Baugé, T.

    2013-12-01

    By bringing together expertise in glaciology, GNSS (Global Navigation Satellite System) technology and processing, and wireless networks we have designed, installed and operated a wireless network of GNSS sensors very close to the margin of the heavily crevassed and fast-flowing Helheim Glacier in south-east Greenland. In 2012, we undertook field trials installing 3 GNSS sensors on the glacier's flowline, and observed the dynamic effects of a major calving event. In 2013, a full 20 node wireless network was installed together with 5 oblique cameras, instrumenting an area ~16 km^2 of the glacier margin. The network will run throughout the summer months. In combination with auxiliary data, such as airborne lidar measurement of surface topography, crevasse spacing and calving rates, oblique photogrammetry, and DEMs and velocity fields from TanDEM-X satellite imagery, the network provides velocity and elevation data of unprecedented resolution in time and space for the key marginal area of the glacier, where recent changes in glacier dynamics appear to have initiated. We present data showing the glacier's dynamic and topographic response to calving events. These data will provide rich opportunities for testing calving models and to improve understanding of the controls on the contribution of these tidewater glaciers to sea-level rise. The network has low energy consumption and a novel base-station topology providing diversity and redundancy: it is also robust to the loss of nodes as the glacier calves. Such a network would also be suitable for data collection in a number of harsh environmental settings such as earthquake, landslide or volcano monitoring.

  9. Sensitivity of very small glaciers in the Swiss Alps to future climate change

    NASA Astrophysics Data System (ADS)

    Huss, Matthias; Fischer, Mauro

    2016-04-01

    Very small glaciers (<0.5km2) currently account for up to 80% of the total number of glaciers in mountain ranges around the globe. Although their total area and volume is small compared to larger glaciers, they are a relevant component of the cryosphere contributing to landscape formation, local hydrology and sea-level rise. Very small glaciers have generally shorter response times than valley glaciers and their mass balance is strongly dependent on snow redistribution processes. Worldwide glacier monitoring has focused on medium-sized to large glaciers leaving us with a relatively limited understanding of the behavior of very small glaciers. With warming climate there is an increasing concern that very small glaciers might be the first to disappear. Already in the next decades this might result in the complete deglaciation of mountain ranges with glacier equilibrium lines close to the highest peaks. Here, we present a comprehensive modeling framework to assess past and future changes of very small glaciers at the mountain-range scale. Among other processes our model accounts for snow redistribution, changes in glacier geometry and the time-varying effect of supraglacial debris. It computes the mass balance distribution, the englacial temperature regime and proglacial runoff. The past evolution of 1'133 glaciers in the Swiss Alps is individually constrained based on geodetic ice volume changes, and the model is validated against an extensive data base of in-situ measurements on very small glaciers. Our results indicate that 52% of all very small glaciers in Switzerland will completely disappear within the next 25 years. However, a few avalanche-fed glaciers at low elevation might be able to survive even substantial atmospheric warming. We find highly variable sensitivities of very small glaciers to air temperature change, gently-sloping, low-elevation, and debris-covered glaciers being most sensitive.

  10. The Glacier Inventory of the Central Andes of Argentina (31°-35°S)

    NASA Astrophysics Data System (ADS)

    Ferri Hidalgo, L.; Zalazar, L.; Castro, M.; Pitte, P.; Masiokas, M. H.; Ruiz, L.; Villalba, R.; Delgado, S.; Gimenez, M.; Gargantini, H.

    2015-12-01

    The National Law for protection of glaciers in Argentina envisages the development of a National Inventory of Glaciers. All glaciers and periglacial landforms which are important as strategic water resource must be properly identified and mapped. Here we present a detailed and complete glacier and rock glacier inventory of the Central Andes of Argentina between 31° and 35°S. This semi-arid region contains some of the highest mountains of South America and concentrates the second most glacierized area in Argentina after the Patagonian Andes. To develop the inventory, we used remotely sensed data and related techniques complemented with field surveys. Clean ice and perennial snowfields were identified applying an automatic extraction method on medium spatial-resolution images. Debris-covered and rock glaciers were manually digitized on higher spatial-resolution images. With minor modifications, the present digital inventory is consistent with GLIMS standards. For each glacier, we derived 38 database fields, adding five specific attributes for rock glaciers, which are not included in the original GLIMS database. In total we identified 8069 glaciers covering an area of 1768 km2. Debris-covered ice and rock glaciers represent 57% of the total inventoried area. In this region, rock glaciers are a common feature in the arid landscape and constitute an important water reserve at regional scale. Many glaciers were characterized by gradual transition from debris-covered glaciers, in the upper part, to rock glaciers, in the lower sector. The remaining 43% includes clean ice glaciers and permanent snowfields. These are mostly mountain and valley-type glaciers with medium-to-small sizes. This detailed inventory constitutes a valuable contribution to the ongoing global efforts (e.g. WGI, RGI and GLIMS) to map the world's glaciers. It is also the base for ongoing glaciological, climatological and hydrological studies in this portion of southern Andes.

  11. Exploring the mobility of cryoconite on High-Arctic glaciers

    NASA Astrophysics Data System (ADS)

    Irvine-Fynn, T. D.; Hodson, A. J.; Bridge, J. W.; Langford, H.; Anesio, A.; Ohlanders, N.; Newton, S.

    2010-12-01

    There has been a growing awareness of the significance of biologically active dust (cryoconite) on the energy balance of, and nutrient cycling at glacier surfaces. Moreover, researchers have estimated the mass of biological material released from glacier ice to downstream environments and ecosystems, including the melt-out of cells from emergent ice in the ablation area. However, the processes, rates and mechanisms of cryoconite mobility and transport have not been fully explored. For many smaller valley glaciers in the High-Arctic, the climate dictates only a thin (~ 1m) layer of ice at the glacier surface is at the melting point during the summer months. This surface ice is commonly characterized by an increased porosity in response to incident energy and hydraulic conditions, and has been termed the “weathering crust”. The presence of cryoconite, with its higher radiation absorption, exacerbates the weathering crust development. Thus, crucially, the transport of cryoconite is not confined to simply a ‘smooth’ ice surface, but rather also includes mobility in the near-surface ice matrix. Here, we present initial results from investigations of cryoconite transport at Midtre Lovénbreen and Longyearbreen, two north-facing valley glaciers in Svalbard (Norway). Using time-lapse imagery, we explore the transport rates of cryoconite on a glacier surface and consider the associations between mobility and meteorological conditions. Results suggest some disparity between micro-, local- and plot-scale observations of cryoconite transport: the differences imply controlling influences of cryoconite volume, ice surface topography and ice structure. While to examine the relative volumes of cryoconite exported from the glacier surface by supraglacial streams we employ flow cytometry, using SYBR-Green-II staining to identify the biological component of the suspended load. Preliminary comparisons between shallow (1m) ice cores and in-stream concentrations suggest

  12. Quantifying the contribution of glacier runoff to streamflow in the upper Columbia River Basin, Canada

    NASA Astrophysics Data System (ADS)

    Jost, G.; Moore, R. D.; Menounos, B.; Wheate, R.

    2012-03-01

    Glacier melt provides important contributions to streamflow in many mountainous regions. Hydrologic model calibration in glacier-fed catchments is difficult because errors in modelling snow accumulation can be offset by compensating errors in glacier melt. This problem is particularly severe in catchments with modest glacier cover, where goodness-of-fit statistics such as the Nash-Sutcliffe model efficiency may not be highly sensitive to the streamflow variance associated with glacier melt. While glacier mass balance measurements can be used to aid model calibration, they are absent for most catchments. We introduce the use of glacier volume change determined from repeated glacier mapping in a guided GLUE (generalized likelihood uncertainty estimation) procedure to calibrate a hydrologic model. This approach is applied to the Mica basin in the Canadian portion of the Columbia River Basin using the HBV-EC hydrologic model. Use of glacier volume change in the calibration procedure effectively reduced parameter uncertainty and helped to ensure that the model was accurately predicting glacier mass balance as well as streamflow. The seasonal and interannual variations in glacier melt contributions were assessed by running the calibrated model with historic glacier cover and also after converting all glacierized areas to alpine land cover in the model setup. Sensitivity of modelled streamflow to historic changes in glacier cover and to projected glacier changes for a climate warming scenario was assessed by comparing simulations using static glacier cover to simulations that accommodated dynamic changes in glacier area. Although glaciers in the Mica basin only cover 5% of the watershed, glacier ice melt contributes up to 25% and 35% of streamflow in August and September, respectively. The mean annual contribution of ice melt to total streamflow varied between 3 and 9% and averaged 6%. Glacier ice melt is particularly important during warm, dry summers following winters

  13. Glacier lake outburst floods - modelling process chains

    NASA Astrophysics Data System (ADS)

    Schaub, Yvonne; Huggel, Christian; Haeberli, Wilfried

    2013-04-01

    New lakes are forming in high-mountain areas all over the world due to glacier recession. Often they will be located below steep, destabilized flanks and are therefore exposed to impacts from rock-/ice-avalanches. Several events worldwide are known, where an outburst flood has been triggered by such an impact. In regions such as in the European Alps or in the Cordillera Blanca in Peru, where valley bottoms are densely populated, these far-travelling, high-magnitude events can result in major disasters. For appropriate integral risk management it is crucial to gain knowledge on how the processes (rock-/ice-avalanches - impact waves in lake - impact on dam - outburst flood) interact and how the hazard potential related to corresponding process chains can be assessed. Research in natural hazards so far has mainly concentrated on describing, understanding, modeling or assessing single hazardous processes. Some of the above mentioned individual processes are quite well understood in their physical behavior and some of the process interfaces have also been investigated in detail. Multi-hazard assessments of the entire process chain, however, have only recently become subjects of investigations. Our study aims at closing this gap and providing suggestions on how to assess the hazard potential of the entire process chain in order to generate hazard maps and support risk assessments. We analyzed different types of models (empirical, analytical, physically based) for each process regarding their suitability for application in hazard assessments of the entire process chain based on literature. Results show that for rock-/ice-avalanches, dam breach and outburst floods, only numerical, physically based models are able to provide the required information, whereas the impact wave can be estimated by means of physically based or empirical assessments. We demonstrate how the findings could be applied with the help of a case study of a recent glacier lake outburst event at Laguna

  14. Interactions of the Greenland Petermann Glacier with the ocean: An initial perspective (Invited)

    NASA Astrophysics Data System (ADS)

    Falkner, K. K.; Johnson, H. L.; Melling, H.; Muenchow, A.; Samelson, R. M.; Friends Of Petermann

    2010-12-01

    be sporadic on a decadal timescale. Multiple factors likely contribute to calving events. These include the geometry of the fjord, absence of sea ice, preconditioning of the glacier by crevassing and melt related cracking and occurrence of strong katabatic or orographically channeled winds. The recent event falls within the realm of previously documented calving rates but the remaining tongue length is the shortest ever directly observed. Gaps in the 134 year record preclude final judgment about whether the recent calving is entirely unprecedented. Rising surface temperature trends and changed sea ice and ocean circulation patterns in the Arctic could render the tongue susceptible to collapse. As this could contribute to accelerated ice mass flux from Greenland, it is important to continue to observe and clarify processes operative in this system.

  15. Distinguishing snow and glacier ice melt in High Asia using MODIS

    NASA Astrophysics Data System (ADS)

    Rittger, Karl; Brodzik, Mary J.; Bair, Edward; Racoviteanu, Adina; Barrett, Andrew; Jodha Khalsa, Siri; Armstrong, Richard; Dozier, Jeff

    2016-04-01

    In High Mountain Asia, snow and glacier ice contribute to streamflow, but the contribution of each of these hydrologic components is not fully understood. We generate daily maps of snow cover and exposed glacier ice derived from MODIS at 500 m resolution as inputs to melt models to estimate daily snow and glacier ice contributions to streamflow. The daily maps of 1) exposed glacier ice (EGI), 2) snow over ice (SOI) and 3) snow over land (SOL) between 2000 and 2014 are generated using fractional snow cover, snow grain size, and annual minimum ice and snow from the MODIS-derived MODSCAG and MODICE products. The method allows a systematic analysis of the annual cycle of snow and glacier ice extents over High Mountain Asia. We compare the time series of these three types of surfaces for nine sub-basins of the Upper Indus Basin (UIB) and characterize the variability over the MODIS record. Results show that the Dras Nala, Astore, and Zanskar sub-basins located in the eastern part of the UIB have the highest annual fraction of SOL driven by mid-winter westerly storms. Sub-basins in the northwestern extent of the UIB with relatively high mean elevations, the Hunza, Shigar, and Shyok show the highest annual fraction of both SOI and EGI (i.e. accumulation and ablation zones of the glacier). The largest sub-basin, Kharmong has the smallest annual fraction of SOL, SOI, and EGI, and a smaller SOI and EGI than the mouth of the river (Tarbela). Using these maps, snow and ice melt contributions are then estimated for the nine Upper Indus sub-basins using two melt models: a calibrated temperature-index (TI) model and an uncalibrated energy balance (EB) model. Near-surface air temperatures for the TI model are downscaled from ERA-Interim upper air temperatures, bias corrected using observed temperatures, and aggregated to 100 m elevation bands. We calibrate the seasonally variable degree-day factors for ice and snow by comparing streamflow to the sum of melt (SOL+SOI+EGI) and

  16. On the influence of debris in glacier melt modelling: a new temperature-index model accounting for the debris thickness feedback

    NASA Astrophysics Data System (ADS)

    Carenzo, Marco; Mabillard, Johan; Pellicciotti, Francesca; Reid, Tim; Brock, Ben; Burlando, Paolo

    2013-04-01

    The increase of rockfalls from the surrounding slopes and of englacial melt-out material has led to an increase of the debris cover extent on Alpine glaciers. In recent years, distributed debris energy-balance models have been developed to account for the melt rate enhancing/reduction due to a thin/thick debris layer, respectively. However, such models require a large amount of input data that are not often available, especially in remote mountain areas such as the Himalaya. Some of the input data such as wind or temperature are also of difficult extrapolation from station measurements. Due to their lower data requirement, empirical models have been used in glacier melt modelling. However, they generally simplify the debris effect by using a single melt-reduction factor which does not account for the influence of debris thickness on melt. In this paper, we present a new temperature-index model accounting for the debris thickness feedback in the computation of melt rates at the debris-ice interface. The empirical parameters (temperature factor, shortwave radiation factor, and lag factor accounting for the energy transfer through the debris layer) are optimized at the point scale for several debris thicknesses against melt rates simulated by a physically-based debris energy balance model. The latter has been validated against ablation stake readings and surface temperature measurements. Each parameter is then related to a plausible set of debris thickness values to provide a general and transferable parameterization. The new model is developed on Miage Glacier, Italy, a debris cover glacier in which the ablation area is mantled in near-continuous layer of rock. Subsequently, its transferability is tested on Haut Glacier d'Arolla, Switzerland, where debris is thinner and its extension has been seen to expand in the last decades. The results show that the performance of the new debris temperature-index model (DETI) in simulating the glacier melt rate at the point scale

  17. Evaluating glacier volume changes since the Little Ice Age maximum and consequences for stream flow by integrating models of glacier flow and hydrology in the Cordillera Blanca, Peru

    NASA Astrophysics Data System (ADS)

    Huh, K. I.; Mark, B. G.; Baraer, M.; Ahn, Y.

    2014-12-01

    Assessing the historical contribution of glacier ice volume loss to stream flow based on reconstructed volume changes through Little Ice Age (LIA) can be directly related to the understanding of glacier-hydrology in the current epoch of rapid glacier ice loss that has disquieting implications for water resources in the Cordillera Blanca of the Peruvian Andes. However, the accurate prediction of the future glacial meltwater availability for the increasing regional Andean society needs more extensive quantitative estimation from long-term glacial meltwater of reconstructed glacial volume. Modeling LIA paleoglaciers using a cellular automata glacier flow model in different catchments of the Cordillera Blanca allows us to reconstruct glacier volume and its change from likely combinations of climatic control variables and time. We compute the rate and magnitude of glacier volume changes for Yanamarey and Queshque glaciers between the LIA and modern defined by 2011 Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model Version 2 (GDEM V2) from the Cordillera Blanca. Also, we employ a recently demonstrated hydrological stream model (Baraer et al., 2012) for integrating the reconstructed glacier volume and its change to calculate glacier contribution to meltwater runoff as a function of glacier loss rate in the Yanamarey and the Queshque catchments, and reconstruct long-term glacier significance to stream flow.

  18. Seismic Monitoring of Ice Generated Events at the Bering Glacier

    NASA Astrophysics Data System (ADS)

    Fitzgerald, K.; Richardson, J.; Pennington, W.

    2008-12-01

    The Bering Glacier, located in southeast Alaska, is the largest glacier in North America with a surface area of approximately 5,175 square kilometers. It extends from its source in the Bagley Icefield to its terminus in tidal Vitus Lake, which drains into the Gulf of Alaska. It is known that the glacier progresses downhill through the mechanisms of plastic crystal deformation and basal sliding. However, the basal processes which take place tens to hundreds of meters below the surface are not well understood, except through the study of sub- glacial landforms and passive seismology. Additionally, the sub-glacial processes enabling the surges, which occur approximately every two decades, are poorly understood. Two summer field campaigns in 2007 and 2008 were designed to investigate this process near the terminus of the glacier. During the summer of 2007, a field experiment at the Bering Glacier was conducted using a sparse array of L-22 short period sensors to monitor ice-related events. The array was in place for slightly over a week in August and consisted of five stations centered about the final turn of the glacier west of the Grindle Hills. Many events were observed, but due to the large distance between stations and the highly attenuating surface ice, few events were large enough to be recorded on sufficient stations to be accurately located and described. During August 2008, six stations were deployed for a similar length of time, but with a closer spacing. With this improved array, events were located and described more accurately, leading to additional conclusions about the surface, interior, and sub-glacial ice processes producing seismic signals. While the glacier was not surging during the experiment, this study may provide information on the non-surging, sub-glacial base level activity. It is generally expected that another surge will take place within a few years, and baseline studies such as this may assist in understanding the nature of surges.

  19. Modeling Ocean-Forced Changes in Smith Glacier

    NASA Astrophysics Data System (ADS)

    Lilien, D.; Joughin, I. R.; Smith, B. E.

    2014-12-01

    Glaciers along the Amundsen Coast are changing rapidly, which has drawn substantial scientific and public attention. Modeling and observation suggest warm-water intrusion and consequent melting as the cause of observed changes, and that unstoppable retreat may have already been triggered in some drainages. While Pine Island and Thwaites Glaciers are losing the most mass and have been the predominant objects study, other systems, particularly Smith, Pope and Kohler Glaciers and the corresponding Dotson and Crosson Shelves, are changing more rapidly relative to their size. Though smaller, these glaciers still have potentially large implications for overall regional dynamics as their beds connect below sea level to surrounding basins. In particular, the long, deep trough of Smith Glacier nearly links to the large eastern tributary of Thwaites, potentially causing rapid changes of Smith to have significant impact on the continuing retreat of Thwaites.We implemented a numerical model in Elmer/Ice, an open-source, full-Stokes, finite-element software package, to investigate the response of the Smith/Pope/Kohler system to different initial conditions. We use various parameterizations of sub-shelf melting with constant magnitude to examine the sensitivity of overall dynamics to melt distribution. Because melt distribution affects lateral buttressing and upstream grounded areas, it is potentially an important control on ice shelf and outlet glacier dynamics. Through comparison to the most recent velocity data, we evaluate the ability of differing melt parameterizations to reproduce the behavior currently seen in Smith/Pope/Kohler glaciers. In addition, we investigate the effect of using different years of velocity data with constant elevation input when initiating model runs. By comparing results over the satellite record to initiation with synchronous observations, we assess the accuracy of the often necessary practice of using differently timestamped datasets.

  20. Velocities of Thwaites and Land glaciers

    NASA Technical Reports Server (NTRS)

    Lucchitta, B. K.; Mullins, Kevin F.; Ferrigno, J. G.

    1993-01-01

    Changes in the area of volume of polar ice sheets are intricately linked to changes in global climate and may severely impact the densely populated coastal regions on Earth. An ice sheet's velocity is a critical parameter, which, together with ice thickness, allows the determination of discharge rates. Using moderate-resolution satellite images such as Landsat, the velocity of floating ice can be measured quickly and relatively inexpensively by tracing crevasse patterns on shelves and ice tongues. Errors in measured velocities are as little as 0.02 km per year, if the following criteria are met: (1) the time interval is longer than 10 years; (2) the velocity is higher than 0.5 km per year; (3) the coregistration points are well dispersed and enclose the area to be measured; and (4) the image pair includes a Landsat 4 or 5 image. The fewer of these conditions that are met, the less accurate the results become; but even for poor conditions, the velocities are generally reliable to near 0.1 km per year. We are in the process of obtaining velocities of all ice shelves and ice tongues along the Bakutis and Ruppert coasts, wherever suitable crevasse patterns exist. So far, we have obtained velocities for the Thwaites and Land glacier tongues.

  1. Geomorphometric Characterization of Debris-covered Glaciers in the Karakoram Himalaya

    NASA Astrophysics Data System (ADS)

    Zhao, P.; Bishop, M. P.

    2015-12-01

    Understanding climate-glacier dynamics in the Himalaya is notoriously difficult, as numerous forcing factors govern glacier mass balance and glacier sensitivity to climate change. There are large uncertainties associated with characterizing and predicting the spatio-temporal dynamics of debris-covered glacier surfaces due to topographic forcing, supraglacial debris sediment fluxes and depth, ablation rates and meltwater production, supraglacial lake development, and ice stress and velocity dynamics. Consequently, it is difficult to characterize glacier sensitivity to climate change and the degree to which glacier topography changes over time. Therefore, we examined the utility of geomorphometric parameters and objects to characterize temporal changes in glacier-surface topography that may be indicative of glacier sensitivity to climate change. Specifically, we utilized STRM and ASTER digital elevation models over the Karakoram Himalaya to evaluate some of the largest glaciers including the Baltoro, Batura, Biafo and Hispar Glaciers. We developed new geomorphometric parameters to characterize the first- and second-order topographic structures for these glaciers, and compared the spatial patterns over multiple years. Our results indicate that glacier-surface topographic patterns are spatially complex compared to the surrounding topography, and that spatial patterns vary significantly over time due to complex climate-glacier dynamics. Various patterns are associated with meltwater and ice flow, downwasting, supraglacial lakes, and the build-up of supraglacial debris. Quantitative characterization of these patterns can be used to map various process-form relationships over time. The presence of unique glacier morphologies and their rates of change may enable a first-order approximation of glacier sensitivity to climate change, as glacier-surface topography integrates feedback mechanisms that account for microclimate, ablation and meltwater production, and sediment

  2. Glacier contribution to streamflow in two headwaters of the Huasco River, Dry Andes of Chile

    NASA Astrophysics Data System (ADS)

    Gascoin, S.; Kinnard, C.; Ponce, R.; Lhermitte, S.; MacDonell, S.; Rabatel, A.

    2011-12-01

    Quantitative assessment of glacier contribution to present-day streamflow is a prerequisite to the anticipation of climate change impact on water resources in the Dry Andes. In this paper we focus on two glaciated headwater catchments of the Huasco Basin (Chile, 29° S). The combination of glacier monitoring data for five glaciers (Toro 1, Toro 2, Esperanza, Guanaco, Estrecho and Ortigas) with five automatic streamflow records at sites with glacier coverage of 0.4 to 11 % allows the estimation of the mean annual glacier contribution to discharge between 2003/2004 and 2007/2008 hydrological years. In addition, direct manual measurements of glacier runoff were conducted in summer at the snouts of four glaciers, which provide the instantaneous contribution of glacier meltwater to stream runoff during summer. The results show that the mean annual glacier contribution to streamflow ranges between 3.3 and 23 %, which is greater than the glaciated fraction of the catchments. We argue that glacier contribution is partly enhanced by the effect of snowdrift from the non-glacier area to the glacier surface. Glacier mass loss is evident over the study period, with a mean of -0.84 m w.e. yr-1 for the period 2003/2004-2007/2008, and also contributes to increase glacier runoff. An El Niño episode in 2002 resulted in high snow accumulation, modifying the hydrological regime and probably reducing the glacier contribution in favor of seasonal snowmelt during the subsequent 2002/2003 hydrological year. At the hourly timescale, summertime glacier contributions are highly variable in space and time, revealing large differences in effective melting rates between glaciers and glacierets (from 1 mm w.e. h-1 to 6 mm w.e. h-1).

  3. Microbial community development on the surface of Hans and Werenskiold Glaciers (Svalbard, Arctic): a comparison.

    PubMed

    Grzesiak, Jakub; Górniak, Dorota; Świątecki, Aleksander; Aleksandrzak-Piekarczyk, Tamara; Szatraj, Katarzyna; Zdanowski, Marek K

    2015-09-01

    Surface ice and cryoconite holes of two types of polythermal Svalbard Glaciers (Hans Glacier--grounded tidewater glacier and Werenskiold Glacier-land-based valley glacier) were investigated in terms of chemical composition, microbial abundance and diversity. Gathered data served to describe supraglacial habitats and to compare microbe-environment interactions on those different type glaciers. Hans Glacier samples displayed elevated nutrient levels (DOC, nitrogen and seston) compared to Werenskiold Glacier. Adjacent tundra formations, bird nesting sites and marine aerosol were candidates for allochtonic enrichment sources. Microbial numbers were comparable on both glaciers, with surface ice containing cells in the range of 10(4) mL(-1) and cryoconite sediment 10(8) g(-1) dry weight. Denaturating gradient gel electrophoresis band-based clustering revealed differences between glaciers in terms of dominant bacterial taxa structure. Microbial community on Werenskiold Glacier benefited from the snow-released substances. On Hans Glacier, this effect was not as pronounced, affecting mainly the photoautotrophs. Over-fertilization of Hans Glacier surface was proposed as the major factor, desensitizing the microbial community to the snow melt event. Nitrogen emerged as a limiting factor in surface ice habitats, especially to Eukaryotic algae. PMID:26104673

  4. Past, present and future glacier variations of southeast Vatnajökull, Iceland

    NASA Astrophysics Data System (ADS)

    Hannesdóttir, H.; Björnsson, H.; Pálsson, F.

    2009-04-01

    Icelandic glaciers are sensitive to climate change and provide important climatic information through variations in mass balance and extent. The small non-surging outlet glaciers in East-Skaftafellssýsla are located in the warmest and wettest area of Iceland. The documentary record of glacier variations and detailed information about glacier geometry is unique for studying the response of glaciers to climate change. Data on the extent, bedrock and surface topography of outlet glaciers of southeast Vatnajökull, along with meteorological data, will be used to study the connection of glacier variations and climate change and tune models. The response of the glaciers to prescribed climate scenarios will be modeled. Runoff changes of glacial rivers will be evaluated in relation to past, current and future changes in glacier geometry. The project is part of a research program at the Earth Science Institute which aims at modeling the response of glaciers in Iceland to climate change. The project involved mapping well-preserved glacial deposits from the Little Ice Age (LIA) maximum, including end and lateral moraines, trimlines and shorelines. It is evident that these glaciers have thinned 100-200 m since the LIA maximum. Historical accounts and personal communication indicate that the outlet glaciers were most extensive in the middle of the 18th century and in the period 1870-1890. Comparison of maps from the 20th century has revealed changes in volume and surface extent of the outlet glaciers.

  5. Sensitivity of very small glaciers in the Swiss Alps to future climate change

    NASA Astrophysics Data System (ADS)

    Huss, Matthias; Fischer, Mauro

    2016-04-01

    Very small glaciers (<0.5 km2) account for more than 80% of the total number of glaciers in mid- to low-latitude mountain ranges. Although their total area and volume is small compared to larger glaciers, they are a relevant component of the cryosphere, contributing to landscape formation, local hydrology and sea-level rise. Worldwide glacier monitoring mostly focuses on medium-sized to large glaciers leaving us with a limited understanding of the response of dwarf glaciers to climate change. In this study, we present a comprehensive modeling framework to assess past and future changes of very small glaciers at the mountain-range scale. Among other processes our model accounts for snow redistribution, changes in glacier geometry and the time-varying effect of supraglacial debris. It computes the mass balance distribution, the englacial temperature regime and proglacial runoff. The evolution of 1,133 individual glaciers in the Swiss Alps is modeled in detail until 2060 based on new distributed data sets. Our results indicate that 52% of all very small glaciers in Switzerland will completely disappear within the next 25 years. However, a few avalanche-fed glaciers at low elevation might be able to survive even substantial atmospheric warming. We find highly variable sensitivities of very small glaciers to air temperature change, with gently-sloping, low-elevation, and debris-covered glaciers being most sensitive.

  6. Microbial community development on the surface of Hans and Werenskiold Glaciers (Svalbard, Arctic): a comparison.

    PubMed

    Grzesiak, Jakub; Górniak, Dorota; Świątecki, Aleksander; Aleksandrzak-Piekarczyk, Tamara; Szatraj, Katarzyna; Zdanowski, Marek K

    2015-09-01

    Surface ice and cryoconite holes of two types of polythermal Svalbard Glaciers (Hans Glacier--grounded tidewater glacier and Werenskiold Glacier-land-based valley glacier) were investigated in terms of chemical composition, microbial abundance and diversity. Gathered data served to describe supraglacial habitats and to compare microbe-environment interactions on those different type glaciers. Hans Glacier samples displayed elevated nutrient levels (DOC, nitrogen and seston) compared to Werenskiold Glacier. Adjacent tundra formations, bird nesting sites and marine aerosol were candidates for allochtonic enrichment sources. Microbial numbers were comparable on both glaciers, with surface ice containing cells in the range of 10(4) mL(-1) and cryoconite sediment 10(8) g(-1) dry weight. Denaturating gradient gel electrophoresis band-based clustering revealed differences between glaciers in terms of dominant bacterial taxa structure. Microbial community on Werenskiold Glacier benefited from the snow-released substances. On Hans Glacier, this effect was not as pronounced, affecting mainly the photoautotrophs. Over-fertilization of Hans Glacier surface was proposed as the major factor, desensitizing the microbial community to the snow melt event. Nitrogen emerged as a limiting factor in surface ice habitats, especially to Eukaryotic algae.

  7. Fifty-Year Record of Glacier Change Reveals Shifting Climate in the Pacific Northwest and Alaska, USA

    USGS Publications Warehouse

    ,

    2009-01-01

    Fifty years of U.S. Geological Survey (USGS) research on glacier change shows recent dramatic shrinkage of glaciers in three climatic regions of the United States. These long periods of record provide clues to the climate shifts that may be driving glacier change. The USGS Benchmark Glacier Program began in 1957 as a result of research efforts during the International Geophysical Year (Meier and others, 1971). Annual data collection occurs at three glaciers that represent three climatic regions in the United States: South Cascade Glacier in the Cascade Mountains of Washington State; Wolverine Glacier on the Kenai Peninsula near Anchorage, Alaska; and Gulkana Glacier in the interior of Alaska (fig. 1).

  8. Glacier Velocities and Elevation Change of the Juneau Icefield, Alaska

    NASA Astrophysics Data System (ADS)

    Melkonian, A. K.; Willis, M. J.; Pritchard, M. E.; Bernstein, S.

    2009-12-01

    Mass-loss from small icefields is the greatest contributor from the cryosphere to sea level rise at present. The Juneau Icefield is a small low-latitude glacier system in southeast Alaska. Remote-sensing data from SAR and optical instruments is examined for inter-annual and seasonal changes in glacier elevation and velocity. We use subpixel offset tracking of satellite SAR and optical images to construct a time-series of average horizontal velocities for the outlet glaciers of the icefield. Optical imagery is available from the ASTER instrument between 2000 and 2009. Eighty ASTER scene-pairs are used to generate pixel-offsets for the region. SAR imagery is available for pixel tracking between 1992-2000, although rapid decorrelation means that only repeat track images separated by 1-2 months are useful. The combined radar and optically derived time-series are compared with sparse GPS measurements made by the Juneau Icefield Research Program (JIRP). JIRP measurements and ASTER-derived velocities at the same points show a velocity of up to 1.1 m/day with differences between the two ranging from 0 to 20 cm/day over coherent areas of the ASTER pixel-offsets. Initial findings over Taku Glacier (the largest outlet glacier in the icefield) indicate that velocities from several ERS tandem-pairs, with short duration repeat passes, taken during the mid-1990s reveal velocities in the middle of Taku glacier of 1 m/day to 1.5 m/day over the faster-moving sections of the glacier. These results are within +/- 25 cm/day of velocities derived from the more recent ASTER scenes, which show a maximum average velocity of around 1.25 m/day. However, Taku Glacier is the only glacier in the icefield still advancing and is therefore not representative of the entire icefield. Data covering other outlet glaciers will be processed to determine overall trends in velocity. Several components of the ASTER processing-chain are tested. Output from two independent pixel-tracking software packages

  9. Climatic controls on the pace of glacier erosion

    NASA Astrophysics Data System (ADS)

    Koppes, Michele; Hallet, Bernard; Rignot, Eric; Mouginot, Jeremie; Wellner, Julia; Love, Katherine

    2016-04-01

    Mountain ranges worldwide have undergone large-scale modification due the erosive action of ice, yet the mechanisms that control the timing of this modification and the rate by which ice erodes remain poorly understood. Available data report a wide range of erosion rates from individual ice masses over varying timescales, suggesting that modern erosion rates exceed orogenic rates by 2-3 orders of magnitude. These modern rates are presumed to be due to dynamic acceleration of the ice masses during deglaciation and retreat. Recent numerical models have focused on replicating the processes that produce the geomorphic signatures of glacial landscapes. Central to these models is a simple quantitative index that relates erosion rate to ice dynamics and to climate. To provide such an index, we examined explicitly the factors controlling modern glacier erosion rates across climatic regimes. Holding tectonic history, bedrock lithology and glacier hypsometries relatively constant across a latitudinal transect from Patagonia to the Antarctic Peninsula, we find that modern, basin-averaged erosion rates vary by three orders of magnitude, from 1->10 mm yr-1 for temperate tidewater glaciers to 0.01-<0.1 mm yr-1 for polar outlet glaciers, largely as a function of temperature and basal thermal regime. Erosion rates also increase non-linearly with both the sliding speed and the ice flux through the ELA, in accord with theory. The general relationship between ice dynamics and erosion suggests that the erosion rate scales non-linearly with basal sliding speed, with an exponent n ≈ 2-2.62. Notably, erosion rates decrease by over two orders of magnitude between temperate and polar glaciers with similar ice discharge rates. The difference in erosion rates between temperate and colder glaciers of similar shape and size is primarily related to the abundance of meltwater accessing the bed. Since all glaciers worldwide have experienced colder than current climatic conditions, the 100-fold

  10. Do rapidly retreating valley glaciers increase catchment sediment export rates?

    NASA Astrophysics Data System (ADS)

    Lane, Stuart; Bakker, Maarten; Gabbud, Chrystelle; Micheletti, Natan; Saugy, Jean-Noël

    2016-04-01

    In the face of rapid climate warming, rapid glacier recession should lead to a marked increase in the spatial extent of paraglacial processes operating in glaciated drainage basins. The paraglacial phase has been well established to be transient but there are very few studies of this transient response and what it means for sediment export. There is good reason to expect that glacier recession could increase basin-scale sediment connectivity as: sediment becomes less dependent on glacier surface transport; proglacial streams are more able to migrate laterally than subglacial streams and so access sediment for transport; and glacier debuttressing may aid the development of gullies that can dissect moraines and so aid hillslope to proglacial zone connectivity. By using records of the flushing of hydroelectric power installations we were able to develop a record of coarse sediment (sand and gravel) export from a basin with a rapidly retreating valley glacier, the Haut Glacier d'Arolla, from 1977 to 2014. Modelling suggested that these data could only be partially controlled by transport capacity implying an important role for sediment supply and potentially for the influence of changing sediment connectivity. Indeed, there was evidence of the effects of glacial debuttressing upon gullying processes and hence a possible increase in the ease of connection of upstream basins to the proglacial area. More recently, it was possible to show possible temperature control on sediment export, which may only have become apparent because of the progressive development of better sediment connectivity. However, whilst rapid glacier recession should result in theory in a progressive increase in connectivity of sediment sources to the basin outlet, the supply to capacity ratio does not increase continually with glacier recession until maximum capacity is reached. We identify two examples of why. First, gullying was also accompanied by the sediment accumulation at the base of moraines

  11. The first complete glacier inventory for the whole of Greenland

    NASA Astrophysics Data System (ADS)

    Rastner, P.; Bolch, T.; Mölg, N.; Machguth, H.; Paul, F.

    2012-07-01

    Glacier inventories provide important baseline information for the determination of water resources, glacier-specific changes in area and volume, climate change impacts, and the past, potential and future contribution of glaciers to sea-level rise. Though heavily glacierized and thus highly relevant for all of the above points, such an inventory of all local glaciers and icecaps (GIC) was not available so far for Greenland. Here we present the details and results of our inventory, that has been compiled from more than 70 Landsat scenes mostly acquired between 1999 and 2002 using semi-automated multispectral mapping techniques. A digital elevation model (DEM) was used to derive drainage divides from watershed analysis and topographic parameters for each glacier entity. We assigned to each entity one of three connectivity levels (CL0, CL1, CL2; i.e. no, weak, and strong connection) with the ice sheet to distinguish the local GIC from the ice sheet and its outlet glaciers and to serve the specific needs of different user communities. All GIC larger 0.05 km2 include ~20 300 entities (of which 900 are marine terminating), covering an area of 129 983 ± 4029 km2, or 89 273 ± 2767 km2 without the CL2 GIC. The latter is about 50% more than according to all previous estimates. Glaciers smaller 0.5 km2 contribute only 1.5% to the total area but more than 50% (11 000) to the total number. In contrast, the 25 largest GIC (>500 km2) contribute 28% to the total area, but only 0.1% to the total number. Most of the ice was located at elevations around 1000 m, except in the eastern sector with elevation arround 1700 m. In addition, a strong dependence of the median elevation to the distance from the ocean was found, but only a weak dependence on aspect. All data will be made available in the Global Land Ice Measurement from Space (GLIMS) glacier database.

  12. Physicochemical impacts of dust particles on alpine glacier meltwater at the Laohugou Glacier basin in western Qilian Mountains, China.

    PubMed

    Dong, Zhiwen; Qin, Dahe; Chen, Jizu; Qin, Xiang; Ren, Jiawen; Cui, Xiaoqing; Du, Zhiheng; Kang, Shichang

    2014-09-15

    This work discusses the temporal variation of various physicochemical species in the meltwater runoff of Laohugou Glacier No. 12 (4260 ma.s.l.) in central Asia, and their correlation with dust particles, based on a two-year field observation in summer 2012 and 2013, mainly focusing on dust concentration and size distribution, meltwater chemistry, particles SEM-EDX analysis in the meltwater, and MODIS atmospheric optical depth fields around the Qilian Mountains in central Asia. We find that, the volume-size distribution of dust particles in the meltwater is mainly composed of three parts, which includes fine aerosol particles (with diameter of 0~3.0 μm, mainly PM 2.5), atmospheric dust (with diameter of 3.0~20 μm), and local dust particles (20~100 μm), respectively. Comparison of dust particles in the snowpack and meltwater runoff indicates that, large part of dust particles in the meltwater may have originated from atmospheric dust deposition to the snow and ice on the glacier, and transported into the meltwater runoff. Moreover, temporal variation of dust and major ions (especially crustal species) is very similar with each other, showing great influence of dust particles to the chemical constituents of the glacier meltwater. SPM and TDS implied significant influences of dust to the physical characteristics of the glacier meltwater. Results showed that, accelerated glacier melting may affect physicochemical characteristics of the meltwater at an alpine basin under global warming. MODIS atmospheric optical depth (AOD) fields derived using the Deep Blue algorithm, showed great influence of regional dust transportation over western Qilian Mountains in springtime. SEM-EDX analysis shows that dust particles in the glacier meltwater contain Si-, Al-, Ca-, K-, and Fe-rich materials, such as quartz, albite, aluminate, and fly ash, similar to that deposited in snowpack. These results showed great and even currently underestimated influences of atmospheric dust

  13. Meteorology (Wind)

    Atmospheric Science Data Center

    2014-09-25

    Wind speed at 50 m (m/s) The average and percent difference minimum and ... are given.   Percent of time for ranges of wind speed at 50 m (percent) Percentage [frequency] of time that wind speed is in each range (0-2, 3-6, 7-10, 11-14, 15-18, 19-25 m/s).   ...

  14. Changing Lake Bathymetry with Deglaciation: The Mendenhall Glacier System

    NASA Astrophysics Data System (ADS)

    Connor, C.; Korzen, N.; Knuth, E.; Sauer, D.; Heavner, M.

    2008-12-01

    Ongoing rapid ice ablation and glacier thinning has continued the buoyancy-driven, large-scale calving events and ice terminus collapse of the Mendenhall Glacier. New bathymetric data collected from Mendenhall Lake between 2004 and 2008 reveal lake shallowing adjacent to the 2008 glacier terminus. Since 2000, the lake has expanded beyond its former 3.4 km2 footprint to 4.02 km2 and enlarged its volume from 0.05 km3 to 0.23 km3 as it elongates to the north, following the receding lakefront terminus and filling its Pleistocene ice-scoured cirque basin. In 2004, the northeastern-most deep in the lake basin reached a maximum depth of ~97 meters below mean lake level. Since that time this deep has shallowed to the north decreasing along the 2008 glacier terminus to depths ranging from 79.85 to 0 m below mean lake level. This new bathymetric data will be used for ongoing mass balance studies as well as for determination of changes in lake sedimentation rates and lake basin morphology since the 1970s when original lake surveys were conducted by the Alaska Dept of Fish and Game personnel. Comparison of lake basin volume with river discharge data will help to better define the seasonal contribution of glacier melt water to Mendenhall River summer discharge, which reached 50 percent during the summer of 1998.

  15. Bacterial succession in a glacier foreland of the High Arctic

    PubMed Central

    Schütte, Ursel M.E.; Abdo, Zaid; Bent, Stephen J.; Williams, Christopher J.; Schneider, G. Maria; Solheim, Bjørn; Forney, Larry J.

    2009-01-01

    Succession is defined as changes in biological communities over time. It has been extensively studied in plant communities, but little is known about bacterial succession, in particular in environments such as High Arctic glacier forelands. Bacteria carry out key processes in the development of soil, biogeochemical cycling, and facilitating plant colonization. In this study we sampled two roughly parallel chronosequences in the foreland of Midre Lovén glacier on Svalbard, Norway and tested whether any of several factors were associated with changes in the structure of bacterial communities, including time after glacier retreat, horizontal variation caused by the distance between chronosequences, and vertical variation at two soil depths. The structures of soil bacterial communities at different locations were compared using terminal restriction fragment length polymorphisms (T-RFLP) of 16S rRNA genes, and the data were analyzed by sequential analysis of log-linear statistical models. While no significant differences in community structure were detected between the two chronosequences, statistically significant differences between sampling locations in the surface and mineral soils could be demonstrated even though glacier forelands are patchy and dynamic environments. These findings suggest bacterial succession occurs in High Arctic glacier forelands but may differ in different soil depths. PMID:19587774

  16. Reconnaissance hydrology of Portage Glacier basin, Alaska--1972

    USGS Publications Warehouse

    Mayo, L.R.; Zenone, Chester; Trabant, Dennis

    1977-01-01

    Early reports of conditions in Portage Pass, Alaska, provide evidence that Portage Glacier was formerly larger and thicker. Past conditions, recent history, current retreat, and possible future changes are summarized from an analysis of reports, photographs of the glacier (1939, 1950, and annually since about 1960), and data on snow and ice balance and bathymetry (1972). Between 1900 and 1972, the glacier terminus retreated 3.4 kilometers, and the lower part of the glacier thinned 200 meters. Climatic change controlled the retreat until about 1930; since then deep water at the terminus has influenced the calving retreat. The calving rate and present terminus position cannot be sustained by current climatic conditions and rate of snow accumulation. Thus the glacier will continue to recede until the terminus stabilizes in shallower water, probably about 1.5 kilometers upvalley from the present terminus and in about year 2020, assuming no change in present climatic conditions and calving rate. Possible small climatic changes could cause a shift in the point at which annual snow accumulation equals annual ablation (500 meters) and a corresponding change in terminus behavior. Potential natural hazards include avalanches, outburst floods from ice-dammed lakes, and unstable icebergs. (Woodard-USGS)

  17. Changing Hydrology in Glacier-fed High Altitude Andean Peatbogs

    NASA Astrophysics Data System (ADS)

    Slayback, D. A.; Yager, K.; Baraer, M.; Mohr, K. I.; Argollo, J.; Wigmore, O.; Meneses, R. I.; Mark, B. G.

    2012-12-01

    Montane peatbogs in the glacierized Andean highlands of Peru and Bolivia provide critical forage for camelids (llama and alpaca) in regionally extensive pastoral agriculture systems. During the long dry season, these wetlands often provide the only available green forage. A key question for the future of these peatbog systems, and the livelihoods they support, is the impact of climate change and glacier recession on their hydrology, and thus forage production. We have already documented substantial regional glacier recession, of, on average, approximately 30% of surface area over the past two decades. As glaciers begin to retreat under climate change, there is initially a period of increased meltwater outflow, culminating in a period of "peak water", and followed by a continual decline in outflows. Based on previous work, we know that some glaciers in the region have already passed peak water conditions, and are now declining. To better understand the impacts of these processes on peatbog hydrology and productivity, we have begun collecting a variety of surface data at several study sites in both Bolivia and Peru. These include precipitation, stream flow, water levels, water chemistry and isotope analyses, and peatbog biodiversity and biomass. These measurements will be used in conjunction with a regional model driven by satellite data to predict likely future impacts. We will present the results from these initial surface measurements, and an overview of satellite datasets to be used in the regional model.

  18. The Status of Glaciers in the Hindu Kush-Himalayas from satellite data

    NASA Astrophysics Data System (ADS)

    Bajracharya, S. R.; Maharjan, S.; Shrestha, F.; Shrestha, B.; Wanqin, G.; Shiyin, L.; Xiaojun, Y.; Khattak, G. A.

    2011-12-01

    In contrary to general glacier retreat in this vast Hindu Kush-Himalayan (HKH) region, some of the glaciers are advancing in the Karakorum (Hewitt, 1985). To understand the climate change impacts on glaciers, it is crucial to update the glacier status. The bigger concern in the HKH region, however, is the lack of long-term information on glaciers at the regional level for any kind of credible baseline or assessment of change. Hence to provide the up to date glacier information the glacier inventory was carried out using a single source satellite images of latest date so far possible. The present mapping of glaciers is the first effort of homogeneous glacier inventory of entire Hindu Kush-Himalayan region, which made the first time reporting of glaciers from Myanmar and first generation of glacier mapping and inventory of Afghanistan and Jammu & Kashmir and Arunachal states of India for ICIMOD. For Nepal, Bhutan, Pakistan, some states of India (Himachal, Uttarakhand and Sikkim) and Ganges basin in China will be the second generation glacier mapping and inventory of ICIMOD. The inventory is based on Landsat 7 ETM+ satellite images from 2005±3 years and SRTM DEM. The methodology of semi-automatic mapping and inventory is developed and implemented in the present study for quick delivery of glacier database. A first attempt is also made to map and deliver the Clean Ice and Debris Cover glaciers data separately. The glacier parameters like Glacier ID (Watershed and GLIMS), Area (Debris Cover and Clean Ice), Elevation, Slope, Aspect, Thickness, Ice reserve and 100m Glacier Area-Altitude bins are generated. The glaciers with sizes larger than 0.02 km2 are mapped. From the entire HKH region about 54,800 glaciers are mapped with about 60,400 km2 glacier area and 6,100 km3 estimated ice reserves. It was found that the average glacier area of the HKH region is 1.10 km2 per glacier (Bajracharya and others 2011).

  19. Area and Elevation Changes of a Debris-Covered Glacier and a Clean-Ice Glacier Between 1952-2013 Using Aerial Images and Structure-from-Motion

    NASA Astrophysics Data System (ADS)

    Lardeux, P.; Glasser, N. F.; Holt, T.; Irvine-Fynn, T. D.; Hubbard, B. P.

    2015-12-01

    Since 1952, the clean-ice Glacier Blanc has retreated twice as fast as the adjacent debris-covered Glacier Noir. Located in the French Alps and separated by only 1 km, both glaciers experience the same climatic conditions, making them ideal to evaluate the impact of debris cover on glacier evolution. We used aerial photographs from 16 acquisitions from 1952 to 2013 to reconstruct and analyze glacier elevation changes using Structure-from-Motion (SfM) techniques. Here, we present the process of developing sub-metric resolution digital elevation models (DEMs) from these aerial photographs. By combining 16 DEMs, we produced a dataset of elevation changes of Glacier Noir and Glacier Blanc, including time-series analysis of lateral and longitudinal profiles, glacier hypsometry and mass balance variation. Our preliminary results indicate that Glacier Noir and Glacier Blanc have both thinned to a similar magnitude, ≤ 20 m, despite a 1 km retreat for Glacier Blanc and only 500 m for Glacier Noir. However, these elevation change reconstructions are hampered by large uncertainties, principally due to the lack of independent camera calibration on the historical imagery. Initial attempts using posteriori correction grids have proven to significantly increase the accuracy of these data. We will present some of the uncertainties and solutions linked to the use of SfM on such a large scale and on such an old dataset. This study demonstrates how SfM can be used to investigate long-term trends in environmental change, allowing glacier monitoring to be up-scaled. It also highlights the need for on-going validation of methods to increase the accuracy and precision of SfM in glaciology. This work is not only advancing our understanding of the role of the debris layer, but will also aid glacial geology more generally with, for example, detailed geomorphological analysis of proglacial terrain and Quaternary sciences with quick and accurate reconstruction of a glacial paleo-environment.

  20. Basal resistance for three of the largest Greenland outlet glaciers

    NASA Astrophysics Data System (ADS)

    Shapero, Daniel R.; Joughin, Ian R.; Poinar, Kristin; Morlighem, Mathieu; Gillet-Chaulet, Fabien

    2016-01-01

    Resistance at the ice-bed interface provides a strong control on the response of ice streams and outlet glaciers to external forcing, yet it is not observable by remote sensing. We used inverse methods constrained by satellite observations to infer the basal resistance to flow underneath three of the Greenland Ice Sheet's largest outlet glaciers. In regions of fast ice flow and high (>250 kPa) driving stresses, ice is often assumed to flow over a strong bed. We found, however, that the beds of these three glaciers provide almost no resistance under the fast-flowing trunk. Instead, resistance to flow is provided by the lateral margins and stronger beds underlying slower-moving ice upstream. Additionally, we found isolated patches of high basal resistivity within the predominantly weak beds. Because these small-scale (<1 ice thickness) features may be artifacts of overfitting our solution to measurement errors, we tested their robustness to different degrees of regularization.

  1. Ice elevations and surface change on the Malaspina Glacier, Alaska

    USGS Publications Warehouse

    Sauber, J.; Molnia, B.; Carabajal, C.; Luthcke, S.; Muskett, R.

    2005-01-01

    Here we use Ice, Cloud and land Elevation Satellite (ICESat)-derived elevations and surface characteristics to investigate the Malaspina Glacier of southern Alaska. Although there is significant elevation variability between ICESat tracks on this glacier, we were able to discern general patterns in surface elevation change by using a regional digital elevation model (DEM) as a reference surface. Specifically, we report elevation differences between ICESat Laser 1-3 observations (February 2003 - November 2004) and a Shuttle Radar Topography Mission (SRTM)-derived DEM from February 2000. Elevation decreases of up to 20-25 m over a 3-4 year time period were observed across the folded loop moraine on the southern portion of the Malaspina Glacier. Copyright 2005 by the American Geophysical Union.

  2. Early Holocene glacier advance, southern Coast Mountains, British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Menounos, Brian; Koch, Johannes; Osborn, Gerald; Clague, John J.; Mazzucchi, David

    2004-07-01

    Terrestrial and lake sediment records from several sites in the southern Coast Mountains, British Columbia, provide evidence for an advance of alpine glaciers during the early Holocene. Silty intervals within organic sediments recovered from two proglacial lakes are bracketed by AMS 14C-dated terrestrial macrofossils and Mazama tephra to 8780-6730 and 7940- 6730 14C yr BP [10,150-7510 and 8990- 7510 cal yr BP]. Radiocarbon ages ranging from 7720 to 7380 14C yr BP [8630- 8020 cal yr BP] were obtained from detrital wood in recently deglaciated forefields of Sphinx and Sentinel glaciers. These data, together with previously published data from proglacial lakes in the Canadian Rockies, imply that glaciers in western Canada advanced during the early Holocene. The advance coincides with the well-documented 8200-yr cold event identified in climate proxy data sets in the North Atlantic region and elsewhere.

  3. Investigating Long-term Behavior of Outlet Glaciers in Greenland

    NASA Technical Reports Server (NTRS)

    Csatho, Beata; vanderVeen, Kees; Schenk, Toni

    2005-01-01

    Repeat surveys by airborne laser altimetry in the 1990s have revealed significant thinning of outlet glaciers draining the interior of the Greenland Ice Sheet, with thinning rates up to several meters per year. To fully appreciate the significance of these recent glacier changes, the magnitude of retreat and surface lowering must be placed within the broader context of the retreat since the Last Glacial Maximum and, more significantly, of the retreat following the temporary glacier advance during the Little Ice Age (LIA). The LIA maximum stand is marked by trimlines, sharp boundaries between recently deglacifated unvegetated rocks, and vegetated surfaces at higher elevations. The objective of this project was to demonstrate the use of remote sensing data to map these trimlines and other glacial geomorphologic features.

  4. Rapid sequestration of rock avalanche deposits within glaciers.

    PubMed

    Dunning, Stuart A; Rosser, Nicholas J; McColl, Samuel T; Reznichenko, Natalya V

    2015-01-01

    Topographic development in mountainous landscapes is a complex interplay between tectonics, climate and denudation. Glaciers erode valleys to generate headwall relief, and hillslope processes control the height and retreat of the peaks. The magnitude-frequency of these landslides and their long-term ability to lower mountains above glaciers is poorly understood; however, small, frequent rockfalls are currently thought to dominate. The preservation of rarer, larger, landslide deposits is exceptionally short-lived, as they are rapidly reworked. The 2013 Mount Haast rock avalanche that failed from the slopes of Aoraki/Mount Cook, New Zealand, onto the glacier accumulation zone below was invisible to conventional remote sensing after just 3 months. Here we use sub-surface data to reveal the now-buried landslide deposit, and suggest that large landslides are the primary hillslope erosion mechanism here. These data show how past large landslides can be identified in accumulation zones, providing an untapped archive of erosive events in mountainous landscapes.

  5. Theoretical Foundations of Remote Sensing for Glacier Assessment and Mapping

    NASA Technical Reports Server (NTRS)

    Bishop, Michael P.; Bush, Andrew B. G.; Furfaro, Roberto; Gillespie, Alan R.; Hall, Dorothy K.; Haritashya, Umesh K.; Shroder, John F., Jr.

    2014-01-01

    The international scientific community is actively engaged in assessing ice sheet and alpine glacier fluctuations at a variety of scales. The availability of stereoscopic, multitemporal, and multispectral satellite imagery from the optical wavelength regions of the electromagnetic spectrum has greatly increased our ability to assess glaciological conditions and map the cryosphere. There are, however, important issues and limitations associated with accurate satellite information extraction and mapping, as well as new opportunities for assessment and mapping that are all rooted in understanding the fundamentals of the radiation transfer cascade. We address the primary radiation transfer components, relate them to glacier dynamics and mapping, and summarize the analytical approaches that permit transformation of spectral variation into thematic and quantitative parameters. We also discuss the integration of satellite-derived information into numerical modeling approaches to facilitate understandings of glacier dynamics and causal mechanisms.

  6. International glacier monitoring and data archiving, from a national perspective

    NASA Astrophysics Data System (ADS)

    Andreassen, Liss M.

    2016-04-01

    The Global Terrestrial Network for Glaciers (GTN-G) is a framework for internationally coordinated monitoring of glaciers and ice caps and run by three operational bodies: the World Glacier Monitoring Service (WGMS), the US National Snow and Ice Data Center (NSIDC), and the Global Land Ice Measurements from Space (GLIMS) initiative. In this talk, I will present recent progresses by GTN-G in efforts to store and provide extensive glaciological data to the community. I will also discuss some of the challenges in monitoring and data archiving, illustrated with examples from my own experiences as a data provider. Finally, I would like to discuss how we as a community could enrich and complete existing databases.

  7. Bibliography of glacier studies by the U.S. Geological Survey

    USGS Publications Warehouse

    Snyder, E.F.

    1996-01-01

    Reports on glaciers written by U.S. Geological Survey members between 1896 and early 1996 are listed. The reports contain information about glacier and had at least one USGS author or was dependent on USGS data or projects. Extensive glacier studies have been done by the USGS in North America, Greenland, Iceland, as well as in Antarctica.

  8. A new glacier model resolving ice dynamics applied to the Alps

    NASA Astrophysics Data System (ADS)

    Maussion, Fabien; Marzeion, Ben

    2016-04-01

    Most regional and global glacier models rely on empirical scaling laws to account for glacier area and volume change with time. These scaling methods are computationally cheap and are statistically robust when applied to many glaciers, but their accuracy considerably lowers at the glacier or catchment scale. The nearest alternative in terms of complexity - glacier flowline modelling - requires significantly more information about the glacier geometry. Here we present a new open source glacier model applicable at regional to global scale implementing i) the determination of glacier centerlines, ii) the inversion of glacier bed topography, and iii) a multi-branch flowline model handling glacier tributaries. Using the HISTALP dataset as climatological input we apply the model in the Alps for 1800 to present and present new estimations of present-day and past glacier volume. The relatively large number of independent data available for validation in this region allow a critical discussion of the added value of our new approach. In particular, we will focus our discussion on two contradictory aspects inherent to any geoscientific model development: while our model clearly opens wide-ranging possibilities to better resolve the glacier processes, this new playground is associated with an increase in complexity, the number of calibration parameters, and…uncertainty?

  9. Space-Based Observations of Eastern Hindu Kush Glaciers between 1992 and 2007, Afghanistan and Pakistan

    NASA Astrophysics Data System (ADS)

    Sarikaya, M. A.; Bishop, M. P.; Shroder, J. F.; Olsenholler, J. A.

    2009-12-01

    Glaciers provide the most important and direct sources of information on climate change. In particular, mountain glaciers promptly respond to minute changes on local and global climate via adjusting their mass balances, and therefore sizes, which can be used as a climate proxy. Himalayan glaciers comprise by area 50% of all glaciers outside of the Polar Regions. However, relatively little is known about glacier fluctuation patterns and glacier sensitivity to climate forcing in that region, precluding the local and global climate interpretations and correlations to other climate proxy data. In this study, we investigated glacier fluctuations in the Hindu Kush mountain range near the end of the Western Himalaya as a part of the international Global Land Ice Measurement from Space (GLIMS) project. Our objective was to estimate average advance/retreat rates of glaciers in that region and to compare our results to previously published records. We used a range of multi-temporal imagery including ASTER (Advanced Spaceborn Thermal Emission and Reflectance Radiometer), Landsat TM (Thematic Mapper) and ETM (Enhanced Thematic Mapper), acquired between 1992 and 2007. Our results indicate that most of the glaciers (more than 95%) had either retreated or showed no change in terminus position during this time period. These findings support the idea that there may be large spatial variations in glacier retreat rates due to topography and climate dynamics, as many glaciers in the Karakoram Himalaya of Pakistan are advancing, whereas glaciers in the Eastern Hindu Kush are retreating.

  10. Evaluating the controls on glacier behaviour on the Kamchatka Peninsula, Russia

    NASA Astrophysics Data System (ADS)

    Lynch, Colleen; Barr, Iestyn, ,, Dr; Mullan, Donal, ,, Dr

    2016-04-01

    Glaciers have been unequivocally linked to changes in global climatic conditions, with an unprecedented and climatically-driven decline in glacier coverage witnessed over recent decades. Despite this relationship, variation in glacier response suggests that other (non-climatic) controls are involved in governing glacier behaviour. This variation presents a challenge when assessing how best to model and predict future glacier behaviour. This study looks at the non-climatic controls on glacial behaviour on the Kamchatka Peninsula, and assesses associated impacts on glacier vulnerability to changes in climate. A detailed multi-annual study was undertaken using Landsat 7 and 8 images to monitor the inter-annual variability of Kamchatka's glaciers, with topographic information obtained from the 30m SRTM DEM. Glaciers were mapped manually, with 676 present in the year 2000, representing an area of 664.79 ± 65.25 km2. Analysis revealed an overall decline in the glacial coverage of ˜30.04 % over the 2000-2014 period. However, there is considerable spatial variability in glacier behaviour across the Peninsula, suggesting corresponding variability in the controls on glacier extent. Here the role of glacier hypsometry, aspect, surface slope and areal extent, basin geometry and distance from the coast are examined to evaluate the role each has played in either enhancing or suppressing glacier vulnerability to the changing climate.

  11. 36 CFR 13.1116 - Do I need a camping permit in Glacier Bay?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Glacier Bay? 13.1116 Section 13.1116 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve General Provisions § 13.1116 Do I need a camping permit in Glacier Bay? From May...

  12. 36 CFR 13.1150 - Is a permit required for a vessel in Glacier Bay?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... vessel in Glacier Bay? 13.1150 Section 13.1150 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve Vessel Permits § 13.1150 Is a permit required for a vessel in Glacier Bay? A permit...

  13. 36 CFR 13.1109 - Off-road vehicle use in Glacier Bay National Preserve.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Glacier Bay National Preserve. 13.1109 Section 13.1109 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve Administrative Provisions § 13.1109 Off-road vehicle use in Glacier Bay...

  14. 36 CFR 13.1312 - Climbing and walking on Exit Glacier.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF... General Provisions § 13.1312 Climbing and walking on Exit Glacier. Except for areas designated by the Superintendent, climbing or walking on, in, or under Exit Glacier is prohibited within 1/2 mile of the...

  15. 36 CFR 13.1150 - Is a permit required for a vessel in Glacier Bay?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... vessel in Glacier Bay? 13.1150 Section 13.1150 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve Vessel Permits § 13.1150 Is a permit required for a vessel in Glacier Bay? A permit...

  16. 36 CFR 13.1150 - Is a permit required for a vessel in Glacier Bay?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... vessel in Glacier Bay? 13.1150 Section 13.1150 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve Vessel Permits § 13.1150 Is a permit required for a vessel in Glacier Bay? A permit...

  17. 36 CFR 13.1150 - Is a permit required for a vessel in Glacier Bay?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... vessel in Glacier Bay? 13.1150 Section 13.1150 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve Vessel Permits § 13.1150 Is a permit required for a vessel in Glacier Bay? A permit...

  18. 36 CFR 13.1116 - Do I need a camping permit in Glacier Bay?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Glacier Bay? 13.1116 Section 13.1116 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve General Provisions § 13.1116 Do I need a camping permit in Glacier Bay? From May...

  19. 36 CFR 13.1312 - Climbing and walking on Exit Glacier.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF... General Provisions § 13.1312 Climbing and walking on Exit Glacier. Except for areas designated by the Superintendent, climbing or walking on, in, or under Exit Glacier is prohibited within 1/2 mile of the...

  20. 36 CFR 13.1312 - Climbing and walking on Exit Glacier.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF... General Provisions § 13.1312 Climbing and walking on Exit Glacier. Except for areas designated by the Superintendent, climbing or walking on, in, or under Exit Glacier is prohibited within 1/2 mile of the...

  1. 36 CFR 13.1109 - Off-road vehicle use in Glacier Bay National Preserve.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Glacier Bay National Preserve. 13.1109 Section 13.1109 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve Administrative Provisions § 13.1109 Off-road vehicle use in Glacier Bay...

  2. 36 CFR 13.1116 - Do I need a camping permit in Glacier Bay?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Glacier Bay? 13.1116 Section 13.1116 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve General Provisions § 13.1116 Do I need a camping permit in Glacier Bay? From May...

  3. 36 CFR 13.1312 - Climbing and walking on Exit Glacier.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF... General Provisions § 13.1312 Climbing and walking on Exit Glacier. Except for areas designated by the Superintendent, climbing or walking on, in, or under Exit Glacier is prohibited within 1/2 mile of the...

  4. 36 CFR 13.1312 - Climbing and walking on Exit Glacier.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF... General Provisions § 13.1312 Climbing and walking on Exit Glacier. Except for areas designated by the Superintendent, climbing or walking on, in, or under Exit Glacier is prohibited within 1/2 mile of the...

  5. 36 CFR 13.1109 - Off-road vehicle use in Glacier Bay National Preserve.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Glacier Bay National Preserve. 13.1109 Section 13.1109 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve Administrative Provisions § 13.1109 Off-road vehicle use in Glacier Bay...

  6. 36 CFR 13.1116 - Do I need a camping permit in Glacier Bay?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Glacier Bay? 13.1116 Section 13.1116 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve General Provisions § 13.1116 Do I need a camping permit in Glacier Bay? From May...

  7. 36 CFR 13.1150 - Is a permit required for a vessel in Glacier Bay?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... vessel in Glacier Bay? 13.1150 Section 13.1150 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve Vessel Permits § 13.1150 Is a permit required for a vessel in Glacier Bay? A permit...

  8. 36 CFR 13.1109 - Off-road vehicle use in Glacier Bay National Preserve.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Glacier Bay National Preserve. 13.1109 Section 13.1109 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve Administrative Provisions § 13.1109 Off-road vehicle use in Glacier Bay...

  9. 36 CFR 13.1116 - Do I need a camping permit in Glacier Bay?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Glacier Bay? 13.1116 Section 13.1116 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Glacier Bay National Park and Preserve General Provisions § 13.1116 Do I need a camping permit in Glacier Bay? From May...

  10. What influences climate and glacier change in southwestern China?

    NASA Astrophysics Data System (ADS)

    Yasunari, Teppei J.

    2011-12-01

    The subject of climate change in the Tibetan Plateau (TP) and Himalayas has taken on increasing importance because of the availability of water resources from their mountain glaciers (Immerzeel et al 2010). Many of the glaciers over these regions have been retreating, while some are advancing and stable (Yao et al 2004, Scherler et al 2011). Other studies report that some glaciers in the Himalayas show acceleration of their shrinkage (e.g., Fujita and Nuimura 2011). However, the causes of glacier melting are still difficult to grasp because of the complexity of climatic change and its influence on glacier issues. Despite this, it is vital that we pursue further study to enable future predictions of glacier changes. The paper entitled 'Climate and glacier change in southwestern China during the past several decades' by Li et al (2011) provided carefully analyzed, quality controlled, long-term data on atmospheric temperature and precipitation during the period 1961-2008. The data were obtained from 111 Chinese stations. The researchers performed systematic analyses of temperature and precipitation over the whole southwestern Chinese domain. They discussed those changes in terms of other meteorological components such as atmospheric circulation patterns, radiation and altitude difference, and then showed how these factors could contribute to climate and glacier changes in the region. Air temperature and precipitation are strongly associated with glacier mass balance because of heat balance and the addition of mass when it snows. Temperature warming trends over many places in southwestern China were unequivocally dominant in all seasons and at higher altitudes. This indicates that the heat contribution to the glaciers has been increasing. On the other hand, precipitation has a wider variability in time and space. It is more difficult to clearly understand the effect of precipitation on the climate and glacier melting characteristics in the whole of southwestern China

  11. Glacier seismology: eavesdropping on the ice-bed interface

    NASA Astrophysics Data System (ADS)

    Walter, F.; Röösli, C.

    2015-12-01

    Glacier sliding plays a central role in ice dynamics. A number of remote sensing and deep drilling initiatives have therefore focused on the ice-bed interface. Although these techniques have provided valuable insights into bed properties, they do not supply theorists with data of sufficient temporal and spatial resolution to rigorously test mathematical sliding laws. As an alternative, passive seismic techniques have gained popularity in glacier monitoring. Analysis of glacier-related seismic sources ('icequakes') has become a useful technique to study inaccessible regions of the cryosphere, including the ice-bed interface. Seismic monitoring networks on the polar ice sheets have shown that ice sliding is not only a smooth process involving viscous deformation and regelation of basal ice layers. Instead, ice streams exhibit sudden slip episodes over their beds and intermittent phases of partial or complete stagnation. Here we discuss new and recently published discoveries of basal seismic sources beneath various glacial bodies. We revisit basal seismicity of hard-bedded Alpine glaciers, which is not the result of pure stick-slip motion. Sudden changes in seismicity suggest that the local configuration of the subglacial drainage system undergoes changes on sub daily time scales. Accordingly, such observations place constraints on basal resistance and sliding of hard-bedded glaciers. In contrast, certain clusters of stick-slip dislocations associated with micro seismicity beneath the Greenland ice sheet undergo diurnal variations in magnitudes and inter event times. This is best explained with a soft till bed, which hosts the shear dislocations and whose strength varies in response to changes in subglacial water pressure. These results suggest that analysis of basal icequakes is well suited for characterizing glacier and ice sheet beds. Future studies should address the relative importance between "smooth" and seismogenic sliding in different glacial environments.

  12. Experiments on the dynamics and sedimentary products of glacier slip

    NASA Astrophysics Data System (ADS)

    Iverson, Neal R.; Zoet, Lucas K.

    2015-09-01

    Experimental work in glacial geomorphology is focused almost entirely on processes in the thin shear zone at the beds of sliding glaciers, where ice at its pressure-melting temperature moves over either rigid rock or deformable till. Experiments with rotary shear devices illuminate constitutive behavior there, central to the dynamics of fast-moving glaciers, and provide a foundation for interpreting the sedimentary record of glacier slip and associated sediment transport. Results from experiments designed to study ice sliding over a rigid wavy bed, shear deformation of till, and plowing of clasts across the surface of a till bed point to a common conclusion: drag at the bed can decrease with increasing slip velocity, thereby concentrating driving stress elsewhere and promoting rapid glacier flow. This rate-weakening behavior at glacier beds is in contrast to the viscous slip resistance assumed in ice-sheet models and most efforts to determine distributions of basal drag from glacier surface velocities. Ring-shear experiments in which various basal tills and more idealized materials are sheared to high strains provide quantitative insight into grain size evolution, mixing at contacts between basal tills, microstructure development, particle-fabric development, and development of anisotropy of magnetic susceptibility. Preferred orientations of principal magnetic susceptibilities provide the most dependable and complete description of till shear patterns. When applied to basal tills of the geologic record, magnetic till fabrics measured along thick till sections and calibrated experimentally indicate that deformation of the bed by two lobes of the Laurentide ice sheet was shallow (< 1 m), patchy, and occurred as till progressively accreted. Rates of sediment transport by bed shear were thus significantly less than estimates based on models that invoke deep, pervasive shear of the bed. The lack of an experimental tradition in glacial geomorphology leaves many research

  13. A Comparison of Seismic Records of Calving Glaciers

    NASA Astrophysics Data System (ADS)

    Walter, Fabian; Amundson, Jason M.; O'Neel, Shad; Clinton, John F.; Luethi, Martin P.; Bassis, Jeremy; Fricker, Helen Amanda

    2010-05-01

    Glacier calving is a key process in the cryosphere's contribution to sea level rise. It is responsible for virtually all of Antarctica's ice mass loss to the ocean and about half of Greenland's negative mass balance. As glacier calving is a highly complicated and variable phenomenon, its physical laws are poorly understood. For this reason "dynamical mass loss" is one of the critical mechanisms that have yet to be incorporated into large-scale ice sheet models that aim to predict future sea level variations. As calving environments are almost always difficult to access, data pertaining to calving processes are usually gathered remotely. Seismometers have recently proven to be a valuable tool for studying calving, even though they may be located far away from the calving front. Pre-existing global and regional seismic networks thus constitute a valuable resource for the study of glacier calving as they allow for automatic detection and monitoring of calving activity. Various sources occurring nearly simultaneously give rise to calving seismicity. Potential source mechanisms include fracturing, hydraulic transients, glacier acceleration, ocean wave action, and icebergs scraping the fjord walls, bottom, or terminus. Fracturing and hydraulic transients emit seismic energy above 1 Hz and are only recorded locally, whereas glacier acceleration, iceberg scraping, and ocean waves may produce waveforms with periods of 100's or 1000's of seconds and can be recorded by far-field seismometers. We present examples of such low-frequency seismicity from Jakobshavn Isbrae, Greenland, and Columbia and Yahtse Glaciers, Alaska. Finally, we discuss the possibility of remotely investigating calving behavior by comparing the seismic signature of individual calving events from different glaciological settings.

  14. Satellite Image Atlas of Glaciers of the World

    USGS Publications Warehouse

    Williams, Richard S.; Ferrigno, Jane G.

    2005-01-01

    In 1978, the USGS began the preparation of the 11-chapter USGS Professional Paper 1386, 'Satellite Image Atlas of Glaciers of the World'. Between 1979 and 1981, optimum satellite images were distributed to a team of 70 scientists, representing 25 nations and 45 institutions, who agreed to author sections of the Professional Paper concerning either a geographic area (chapters B-K) or a glaciological topic (included in Chapter A). The scientists used Landsat 1, 2, and 3 multispectral scanner (MSS) images and Landsat 2 and 3 return beam vidicon (RBV) images to inventory the areal occurrence of glacier ice on our planet within the boundaries of the spacecrafts' coverage (between about 82? north and south latitudes). Some later contributors also used Landsat 4 and 5 MSS and Thematic Mapper, Landsat 7 Enhanced Thematic Mapper-Plus (ETM+), and other satellite images. In addition to analyzing images of a specific geographic area, each author was asked to summarize up-to-date information about the glaciers within each area and compare their present-day areal distribution with reliable historical information (from published maps, reports, and photographs) about their past extent. Because of the limitations of Landsat images for delineating or monitoring small glaciers in some geographic areas (the result of inadequate spatial resolution, lack of suitable seasonal coverage, or absence of coverage), some information on the areal distribution of small glaciers was derived from ancillary sources, including other satellite images. Completion of the atlas will provide an accurate regional inventory of the areal extent of glaciers on our planet during a relatively narrow time interval (1972-1981).

  15. The response of debris-covered glaciers to climate change: A numerical modeling approach

    NASA Astrophysics Data System (ADS)

    Anderson, Leif S.; Anderson, Robert S.

    2016-04-01

    Debris-covered glaciers are common in rapidly-eroding alpine landscapes. When thicker than a few centimeters, surface debris suppresses melt rates. Continuous debris cover can therefore reduce the mass balance gradient in the ablation zone, leading to increases in glacier length. In order to quantify feedbacks in the debris-glacier-climate system, we developed a 2D long-valley numerical glacier model that includes deposition of debris on the glacier surface, and both englacial and supraglacial debris advection. We ran 120 simulations in which a steady state debris-free glacier responds to a step increase of surface debris deposition. Simulated glaciers advance to new steady states in which ice accumulation equals ice ablation, and debris input equals debris loss from the glacier. The debris flux onto the glacier surface, and the details of the relationship between debris thickness and melt rate strongly control glacier length. Debris deposited near the equilibrium-line altitude, where ice discharge is high, results in the greatest glacier extension when other debris-related variables are held constant. Continuous debris cover reduces ice discharge gradients, ice thickness gradients, and velocity gradients relative to debris-free glaciers forced by the same climate. Debris-forced glacier extension decreases the ratio of accumulation zone to total glacier area (AAR). The model reproduces first-order relationships between debris cover, AARs, and glacier surface velocities reported from glaciers in High Asia. We also explore the response of debris-covered glaciers to increases in the equilibrium-line altitude (climate warming). We highlight the conditions required to generate a low surface velocity 'dead' ice terminal reach during a warming climate, and the associated increase of fractional glacier surface debris. We also compare our debris-covered glacier climate response results with data from glaciers in High Asia. Our model provides a quantitative, theoretical

  16. Photographic Snow-cover Monitoring on St Sorlin Glacier, France.

    NASA Astrophysics Data System (ADS)

    Gerbaux, M.; Genthon, C.; Dedieu, J.; Balestrieri, J.

    2004-12-01

    Like most other glaciers in the Alps, the St Sorlin glacier (french Alps, 45.16°N, 6.16°E, 2900 m asl mean elevation and 3km2 of surface area) has been retreating fast in the last 20 years. To understand the meteorological factors responsible for this retreat, and to tentatively predict glaciers evolution in a changing (warming) climate, we use a distributed snow/ice mass and energy balance model derived from the CROCUS snow model (Météo-France). There is no direct meteorological observation on or near St Sorlin glacier yet, and hourly meteorology to force the snow/ice model is obtained from disaggregated meteorological analyses. The model is found to reproduce the St Sorlin mass balance of the last 20 years as obtained from field glaciological measurements and stereophotographic reconstructions. The model is also found to reproduce the interannual variations of the equilibrium line as determined from optical satellite imagery. Because of the albedo feedback involved, it is also important to verify that the summer snow/ice transition on the glacier is correctly simulated. Thus, an automated photographic system was set up facing St Sorlin glacier to monitor the evolution of the snow cover. The system was installed on the 13th of July 2004 and is still in operation at time of abstract writing. Digital photographies are taken every 4 hours, permitting so far at least one non-obstructed (rain, fog) picture per day. The first pictures in the series show an almost fully snow-covered glacier while the latest ones show bare ice up to the highest parts of the glacier. Snow is occasionally deposited during precipitation events but hardly last more than 3 days. Snow line position is deduced from pictures using a DEM with georeferenced points visible on pictures. It should then be compared with the modelled one. The automated photographic system provides not only snow cover to check snow/ice model results at seasonal time-scales, but also qualitative meteorological

  17. High-Resolution Force Balance Analyses of Tidewater Glacier Dynamics

    NASA Astrophysics Data System (ADS)

    Enderlin, E. M.; Hamilton, G. S.; O'Neel, S.

    2015-12-01

    Changes in glacier velocity, thickness, and terminus position have been used to infer the dynamic response of tidewater glaciers to environmental perturbations, yet few analyses have attempted to quantify the associated variations in the glacier force balance. Where repeat high-resolution ice thickness and velocity estimates are available, force balance time series can be constructed to investigate the redistribution of driving and resistive forces associated with changes in terminus position. Comparative force balance analyses may, therefore, help us understand the variable dynamic response observed for glaciers in close proximity to each other. Here we construct force balance time series for Helheim Glacier, SE Greenland, and Columbia Glacier, SE Alaska, to investigate differences in dynamic sensitivity to terminus position change. The analysis relies on in situ and remotely sensed observations of ice thickness, velocity, and terminus position. Ice thickness time series are obtained from stereo satellite image-derived surface elevation and continuity-derived bed elevations that are constrained by airborne radar observations. Surface velocity time series are obtained from interferometric synthetic aperture radar (InSAR) observations. Approximately daily terminus positions are from a combination of satellite images and terrestrial time-lapse photographs. Helheim and Columbia glaciers are two of the best-studied Arctic tidewater glaciers with comprehensive high-resolution observational time series, yet we find that bed elevation uncertainties and poorly-constrained stress-coupling length estimates still hinder the analysis of spatial and temporal force balance variations. Here we use a new observationally-based method to estimate the stress-coupling length which successfully reduces noise in the derived force balance but preserves spatial variations that can be over-smoothed when estimating the stress-coupling length as a scalar function of the ice thickness

  18. Southern Alaska Glaciers: Spatial and Temporal Variations in Ice Volume

    NASA Technical Reports Server (NTRS)

    Sauber, J.; Molnia, B. F.; Lutchke, S.; Rowlands, D.; Harding, D.; Carabajal, C.; Hurtado, J. M.; Spade, G.

    2004-01-01

    Although temperate mountain glaciers comprise less than 1% of the glacier-covered area on Earth, they are important because they appear to be melting rapidly under present climatic conditions and, therefore, make significant contributions to rising sea level. In this study, we use ICESat observations made in the last 1.5 years of southern Alaska glaciers to estimate ice elevation profiles, ice surface slopes and roughness, and bi-annual and/or annual ice elevation changes. We report initial results from the near coastal region between Yakutat Bay and Cape Suckling that includes the Malaspina and Bering Glaciers. We show and interpret ice elevations changes across the lower reaches of the Bagley Ice Valley for the period between October 2003 and May 2004. In addition, we use off-nadir pointing observations to reference tracks over the Bering and Malaspina Glaciers in order to estimate annual ice elevation change. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Shuttle Radar Topography Mission (SRTM) derived DEMs are used to estimate across track regional slopes between ICESat data acquisitions. Although the distribution and quantity of ICESat elevation profiles with multiple, exact repeat data is currently limited in Alaska, individual ICESat data tracks, provide an accurate reference surface for comparison to other elevation data (e.g. ASTER and SRTM X- and C-band derived DEMs). Specifically we report the elevation change over the Malaspina Glacier's piedmont lobe between a DEM derived from SRTM C-band data acquired in Feb. 2000 and ICESat Laser #2b data from Feb.-March 2004. We also report use of ICESat elevation data to enhance ASTER derived absolute DEMs. Mountain glaciers generally have rougher surfaces and steeper regional slopes than the ice sheets for which the ICESat design was optimized. Therefore, rather than averaging ICESat observations over large regions or relying on crossovers, we are working with well-located ICESat

  19. Recent development of glacier complex Adygine and resulting risks

    NASA Astrophysics Data System (ADS)

    Falatkova, Kristyna; Sobr, Miroslav; Engel, Zbynek; Jansky, Bohumir

    2015-04-01

    Recent development of glacier complex Adygine and resulting risks Falátková, K., Šobr, M., Engel, Z., Janský, B. Charles University in Prague, Faculty of Science, Prague, Czech republic Glacier complex Adygine (3,400-4,200 m asl) is situated on the northern flank of the Kyrgyz Range, Tien Shan, Kyrgyzstan. The valley downstream is part of National Park Ala Archa, which is popular with tourists, and is heading towards the country's capital - Bishkek. At the study site there is a glacier which is observed since 1960's. The glacier has been monitored by satellite imagery and in last 10 years by on-site geodetic measurement as well. Due to glacier shrinkage several glacial lakes of different genetic types (moraine-dammed, moraine- and rock-dammed, termokarst) have appeared at the site. Nowadays, the lakes are situated on three levels in front of the glacier's terminus and form a cascade, they are also hydrologically connected. The lakes were subjected to detailed bathymetric measurement and some parts of the dams were surveyed by geophysical methods. Especially the newest lakes in proximity of the terminus has been undergoing dynamic changes and may pose a threat in the near future. The risks arising together with changing climatic conditions and retreat of the glacier are associated with mainly three of the lakes. The largest one with area of 3.2 ha is dammed by a rock step overlaid by a moraine. Geophysical research of the dam revealed buried ice and seepage channels in its western part. It is the capacity of these subsurface channels, which are draining the lake throughout the year that represents a weak point in terms of dam stability. The second lake, a termokarst one, is a similar case but drained solely by subsurface channels. Very steep slopes of the lake basin are covered with loose material which could slide down and block the drainage channels. The lake would then fill all the basin (approx. 50,000 m3) very quickly as it is supplied with water from the

  20. Pathways of warm water to the Northeast Greenland outlet glaciers

    NASA Astrophysics Data System (ADS)

    Schaffer, Janin; Timmermann, Ralph; Kanzow, Torsten; Arndt, Jan Erik; Mayer, Christoph; Schauer, Ursula

    2015-04-01

    The ocean plays an important role in modulating the mass balance of the Greenland Ice Sheet by delivering heat to the marine-terminating outlet glaciers surrounding the Greenland coast. The warming and accumulation of Atlantic Water in the subpolar North Atlantic has been suggested to be a potential driver of the glaciers' retreat over the last decades. The shelf regions thus play a critical role for the transport of Atlantic Water towards the glaciers, but also for the transfer of freshwater towards the deep ocean. A key region for the mass balance of the Greenland Ice Sheet is the Northeast Greenland Ice Stream. This large ice stream drains the second-largest basin of the Greenland Ice Sheet and feeds three outlet glaciers. The largest one is Nioghalvfjerdsfjorden (79°N-Glacier) featuring an 80 km long floating ice tongue. Both the ocean circulation on the continental shelf off Northeast Greenland and the circulation in the cavity below the ice tongue are weakly constrained so far. In order to study the relevant processes of glacier-ocean interaction we combine observations and model work. Here we focus on historic and recent hydrographic observations and on the complex bathymetry in the Northeast Greenland shelf region, which is thought to steer the flux of warm Atlantic water onto the continental shelf and into the sub-ice cavity beneath the 79°N-Glacier. We present a new global topography data set, RTopo-2, which includes the most recent surveys on the Northeast Greenland continental shelf and provides a detailed bathymetry for all around Greenland. In addition, RTopo-2 contains ice and bedrock surface topographies for Greenland and Antarctica. Based on the updated ocean bathymetry and a variety of hydrographic observations we show the water mass distribution on the continental shelf off Northeast Greenland. These maps enable us to discuss possible supply pathways of warm modified Atlantic waters on the continental shelf and thus potential ways of heat

  1. Rapid changes in ice discharge from Greenland outlet glaciers.

    PubMed

    Howat, Ian M; Joughin, Ian; Scambos, Ted A

    2007-03-16

    Using satellite-derived surface elevation and velocity data, we found major short-term variations in recent ice discharge and mass loss at two of Greenland's largest outlet glaciers. Their combined rate of mass loss doubled in less than a year in 2004 and then decreased in 2006 to near the previous rates, likely as a result of fast re-equilibration of calving-front geometry after retreat. Total mass loss is a fraction of concurrent gravity-derived estimates, pointing to an alternative source of loss and the need for high-resolution observations of outlet dynamics and glacier geometry for sea-level rise predictions.

  2. Upper and Lower Bounds on the Stability of Calving Glaciers

    NASA Astrophysics Data System (ADS)

    Ma, Y.; Bassis, J. N.

    2015-12-01

    Iceberg calving is responsible for nearly half of the mass lost from ice sheets to the oceans. However, a lack of a well-parameterized calving model leaves most numerical ice sheet models incomplete. Previous studies have sought to parameterize iceberg calving assuming that calving occurs when a surface crevasse intersects with a basal one. Although a variety of models have successfully reproduced patterns of glacier retreat, they are frequently tuned by adding melt water into surface crevasses until glacier behavior matches observations, which is puzzling because calving also occurs during winter when no melt water is available. Here we examine crevasse propagation using a 2D full-Stokes finite element model along the center flow of an idealized glacier terminating in ocean to see when water-free surface crevasses intersect with water-filled basal crevasses on a lubricated bed. Crevasse propagation is computed using the Nye zero-stress-model, assuming they have a negligible effect on the stress field of the glacier. We find that for a given water depth, simulated glaciers evolve to a state where either basal and surface crevasses intersect or the glacier begins to float. This allows us to map out a stability threshold that predicts for a given water depth if certain ice thicknesses will result in full thickness failure. Assuming seeds for crevasses are present everywhere, this threshold poses an upper limit on ice thickness: as the thickness decreases full thickness penetration is increasingly likely. Comparing our theoretical stability threshold with observational data deduced from Operation IceBridge, we find that most tidewater glaciers have water depth and ice thickness combinations fall in a narrow region above our predicted threshold and below buoyancy. The agreement between observations and our simulations suggests that glaciers evolve until they approach a critical stability threshold where small perturbations can trigger calving events. The stability

  3. Proceedings of the Fourth Glacier Bay Science Symposium

    USGS Publications Warehouse

    Piatt, John F.; Gende, Scott M.

    2007-01-01

    Foreword Glacier Bay was established as a National Monument in 1925, in part to protect its unique character and natural beauty, but also to create a natural laboratory to examine evolution of the glacial landscape. Today, Glacier Bay National Park and Preserve is still a place of profound natural beauty and dynamic landscapes. It also remains a focal point for scientific research and includes continuing observations begun decades ago of glacial processes and terrestrial ecosystems. In recent years, research has focused on glacial-marine interactions and ecosystem processes that occur below the surface of the bay. In October 2004, Glacier Bay National Park convened the fourth in a series of science symposiums to provide an opportunity for researchers, managers, interpreters, educators, students and the general public to share knowledge about Glacier Bay. The Fourth Glacier Bay Science Symposium was held in Juneau, Alaska, rather than at the Park, reflecting a desire to maximize attendance and communication among a growing and diverse number of stakeholders interested in science in the park. More than 400 people attended the symposium. Participants provided 46 oral presentations and 41 posters covering a wide array of disciplines including geology, glaciology, oceanography, wildlife and fisheries biology, terrestrial and marine ecology, socio-cultural research and management issues. A panel discussion focused on the importance of connectivity in Glacier Bay research, and keynote speakers (Gary Davis and Terry Chapin) spoke of long-term monitoring and ecological processes. These proceedings include 56 papers from the symposium. A summary of the Glacier Bay Science Plan-itself a subject of a meeting during the symposium and the result of ongoing discussions between scientists and resource managers-also is provided. We hope these proceedings illustrate the diversity of completed and ongoing scientific studies, conducted within the Park. To this end, we invited all

  4. Holocene glacier activity in the British Columbia Coast Mountains, Canada

    NASA Astrophysics Data System (ADS)

    Mood, Bryan J.; Smith, Dan J.

    2015-11-01

    The Coast Mountains flank the Pacific Ocean in western British Columbia, Canada. Subdivided into the southern Pacific Ranges, central Kitimat Ranges and northern Boundary Ranges, the majority of large glaciers and icefields are located in the Boundary and Pacific ranges. Prior descriptions of the Holocene glacial history of this region indicate the Holocene was characterized by repeated episodes of ice expansion and