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Solgaard AM, Simonsen SB, Grinsted A, Mottram R, Karlsson NB, Hansen K, Kusk A, Sørensen LS. Hagen Bræ: A Surging Glacier in North Greenland-35 Years of Observations. GEOPHYSICAL RESEARCH LETTERS 2020; 47:e2019GL085802. [PMID: 32713980 PMCID: PMC7375144 DOI: 10.1029/2019gl085802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/21/2020] [Accepted: 02/21/2020] [Indexed: 06/11/2023]
Abstract
We use remotely sensed ice velocities in combination with observations of surface elevation and glacier area change to investigate the dynamics of Hagen Bræ, North Greenland in high detail over the last 35 years. From our data, we can establish for the first time that Hagen Bræ is a surge-type glacier with characteristics of both Alaskan- and Svalbard-type surging glaciers. We argue that the observed surge was preconditioned by the glacier geometry and triggered by englacially stored meltwater. At present, the glacier is in a transitional state between active and quiescence phases and is not building up to its pre-surge geometry. We suggest that the glacier is adjusting to the loss of its floating section, general thinning, and changes in fjord conditions that occurred over the study period which are unrelated to the surge behavior. The high temporal resolution of the ice velocity data gives insight to the sub-annual glacier flow.
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Affiliation(s)
- A. M. Solgaard
- The Department of Glaciology and ClimateThe Geological Survey of Denmark and Greenland (GEUS)CopenhagenDenmark
| | - S. B. Simonsen
- National Space InstituteTechnical University of DenmarkLyngbyDenmark
| | - A. Grinsted
- Physics of Ice, Climate, and EarthNiels Bohr Institute, University of CopenhagenCopenhagenDenmark
| | - R. Mottram
- Danish Meteorological Institute (DMI)CopenhagenDenmark
| | - N. B. Karlsson
- The Department of Glaciology and ClimateThe Geological Survey of Denmark and Greenland (GEUS)CopenhagenDenmark
| | - K. Hansen
- The Department of Glaciology and ClimateThe Geological Survey of Denmark and Greenland (GEUS)CopenhagenDenmark
| | - A. Kusk
- National Space InstituteTechnical University of DenmarkLyngbyDenmark
| | - L. S. Sørensen
- National Space InstituteTechnical University of DenmarkLyngbyDenmark
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2
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Mayer C, Schaffer J, Hattermann T, Floricioiu D, Krieger L, Dodd PA, Kanzow T, Licciulli C, Schannwell C. Large ice loss variability at Nioghalvfjerdsfjorden Glacier, Northeast-Greenland. Nat Commun 2018; 9:2768. [PMID: 30018326 PMCID: PMC6050287 DOI: 10.1038/s41467-018-05180-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 06/15/2018] [Indexed: 11/16/2022] Open
Abstract
Nioghalvfjerdsfjorden is a major outlet glacier in Northeast-Greenland. Although earlier studies showed that the floating part near the grounding line thinned by 30% between 1999 and 2014, the temporal ice loss evolution, its relation to external forcing and the implications for the grounded ice sheet remain largely unclear. By combining observations of surface features, ice thickness and bedrock data, we find that the ice shelf mass balance has been out of equilibrium since 2001, with large variations of the thinning rates on annual/multiannual time scales. Changes in ice flux and surface ablation are too small to produce this variability. An increased ocean heat flux is the most plausible cause of the observed thinning. For sustained environmental conditions, the ice shelf will lose large parts of its area within a few decades and ice modeling shows a significant, but locally restricted thinning upstream of the grounding line in response.
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Affiliation(s)
- Christoph Mayer
- Bavarian Academy of Sciences and Humanities, Alfons-Goppel Str. 11, 80539, Munich, Germany.
| | - Janin Schaffer
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Tore Hattermann
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
- Akvaplan-niva AS, Fram Centre, Postbox 6606, 9296, Langnes, Tromsø, Norway
| | - Dana Floricioiu
- Remote Sensing Technology Institute, German Aerospace Centre (DLR), Münchener Straße 20, 82234, Oberpfaffenhofen, Weßling, Germany
| | - Lukas Krieger
- Remote Sensing Technology Institute, German Aerospace Centre (DLR), Münchener Straße 20, 82234, Oberpfaffenhofen, Weßling, Germany
| | - Paul A Dodd
- Norwegian Polar Institute, Fram Centre, Postbox 6606, 9296, Langnes, Tromsø, Norway
| | - Torsten Kanzow
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Carlo Licciulli
- Bavarian Academy of Sciences and Humanities, Alfons-Goppel Str. 11, 80539, Munich, Germany
| | - Clemens Schannwell
- University of Tübingen, Geologie & Geodynamik, Wilhelmstraße 56, 72074, Tübingen, Germany
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Millan R, Rignot E, Mouginot J, Wood M, Bjørk AA, Morlighem M. Vulnerability of Southeast Greenland Glaciers to Warm Atlantic Water From Operation IceBridge and Ocean Melting Greenland Data. GEOPHYSICAL RESEARCH LETTERS 2018; 45:2688-2696. [PMID: 29937604 PMCID: PMC5993238 DOI: 10.1002/2017gl076561] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 02/14/2018] [Accepted: 02/18/2018] [Indexed: 05/02/2023]
Abstract
We employ National Aeronautics and Space Administration (NASA)'s Operation IceBridge high-resolution airborne gravity from 2016, NASA's Ocean Melting Greenland bathymetry from 2015, ice thickness from Operation IceBridge from 2010 to 2015, and BedMachine v3 to analyze 20 major southeast Greenland glaciers. The results reveal glacial fjords several hundreds of meters deeper than previously thought; the full extent of the marine-based portions of the glaciers; deep troughs enabling warm, salty Atlantic Water (AW) to reach the glacier fronts and melt them from below; and few shallow sills that limit the access of AW. The new oceanographic and topographic data help to fully resolve the complex pattern of historical ice front positions from the 1930s to 2017: glaciers exposed to AW and resting on retrograde beds have retreated rapidly, while glaciers perched on shallow sills or standing in colder waters or with major sills in the fjords have remained stable.
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Affiliation(s)
- R. Millan
- Department Earth System ScienceUniversity of California IrvineIrvineCAUSA
| | - E. Rignot
- Department Earth System ScienceUniversity of California IrvineIrvineCAUSA
- Jet Propulsion LaboratoryCaltechPasadenaCAUSA
| | - J. Mouginot
- Department Earth System ScienceUniversity of California IrvineIrvineCAUSA
| | - M. Wood
- Department Earth System ScienceUniversity of California IrvineIrvineCAUSA
| | - A. A. Bjørk
- Centre for GeoGenetics, Natural History Museum of DenmarkUniversity of CopenhagenCopenhagenDenmark
| | - M. Morlighem
- Department Earth System ScienceUniversity of California IrvineIrvineCAUSA
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Veitch SA, Nettles M. Spatial and temporal variations in Greenland glacial-earthquake activity, 1993-2010. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jf002412] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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5
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Seale A, Christoffersen P, Mugford RI, O'Leary M. Ocean forcing of the Greenland Ice Sheet: Calving fronts and patterns of retreat identified by automatic satellite monitoring of eastern outlet glaciers. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jf001847] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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6
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Amundson JM, Fahnestock M, Truffer M, Brown J, Lüthi MP, Motyka RJ. Ice mélange dynamics and implications for terminus stability, Jakobshavn Isbræ, Greenland. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jf001405] [Citation(s) in RCA: 258] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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7
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van de Wal RSW, Boot W, van den Broeke MR, Smeets CJPP, Reijmer CH, Donker JJA, Oerlemans J. Large and rapid melt-induced velocity changes in the ablation zone of the Greenland Ice Sheet. Science 2008; 321:111-3. [PMID: 18599784 DOI: 10.1126/science.1158540] [Citation(s) in RCA: 258] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Continuous Global Positioning System observations reveal rapid and large ice velocity fluctuations in the western ablation zone of the Greenland Ice Sheet. Within days, ice velocity reacts to increased meltwater production and increases by a factor of 4. Such a response is much stronger and much faster than previously reported. Over a longer period of 17 years, annual ice velocities have decreased slightly, which suggests that the englacial hydraulic system adjusts constantly to the variable meltwater input, which results in a more or less constant ice flux over the years. The positive-feedback mechanism between melt rate and ice velocity appears to be a seasonal process that may have only a limited effect on the response of the ice sheet to climate warming over the next decades.
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Affiliation(s)
- R S W van de Wal
- Institute for Marine and Atmospheric research Utrecht, Utrecht University, Netherlands.
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Joughin I, Howat I, Alley RB, Ekstrom G, Fahnestock M, Moon T, Nettles M, Truffer M, Tsai VC. Ice-front variation and tidewater behavior on Helheim and Kangerdlugssuaq Glaciers, Greenland. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jf000837] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Nick FM, van der Veen CJ, Oerlemans J. Controls on advance of tidewater glaciers: Results from numerical modeling applied to Columbia Glacier. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jf000551] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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10
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Velicogna I, Wahr J. Acceleration of Greenland ice mass loss in spring 2004. Nature 2006; 443:329-31. [PMID: 16988710 DOI: 10.1038/nature05168] [Citation(s) in RCA: 291] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Accepted: 08/14/2006] [Indexed: 11/09/2022]
Abstract
In 2001 the Intergovernmental Panel on Climate Change projected the contribution to sea level rise from the Greenland ice sheet to be between -0.02 and +0.09 m from 1990 to 2100 (ref. 1). However, recent work has suggested that the ice sheet responds more quickly to climate perturbations than previously thought, particularly near the coast. Here we use a satellite gravity survey by the Gravity Recovery and Climate Experiment (GRACE) conducted from April 2002 to April 2006 to provide an independent estimate of the contribution of Greenland ice mass loss to sea level change. We detect an ice mass loss of 248 +/- 36 km3 yr(-1), equivalent to a global sea level rise of 0.5 +/- 0.1 mm yr(-1). The rate of ice loss increased by 250 per cent between the periods April 2002 to April 2004 and May 2004 to April 2006, almost entirely due to accelerated rates of ice loss in southern Greenland; the rate of mass loss in north Greenland was almost constant. Continued monitoring will be needed to identify any future changes in the rate of ice loss in Greenland.
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Affiliation(s)
- Isabella Velicogna
- Department of Physics and CIRES, University of Colorado, Boulder, Colorado 80309-0390, USA.
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Abstract
Future sea-level rise is an important issue related to the continuing buildup of atmospheric greenhouse gas concentrations. The Greenland and Antarctic ice sheets, with the potential to raise sea level approximately 70 meters if completely melted, dominate uncertainties in projected sea-level change. Freshwater fluxes from these ice sheets also may affect oceanic circulation, contributing to climate change. Observational and modeling advances have reduced many uncertainties related to ice-sheet behavior, but recently detected, rapid ice-marginal changes contributing to sea-level rise may indicate greater ice-sheet sensitivity to warming than previously considered.
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Affiliation(s)
- Richard B Alley
- Department of Geosciences and Earth and Environmental Systems Institute, Pennsylvania State University, Deike Building, University Park, PA 16802, USA.
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Johannessen OM, Khvorostovsky K, Miles MW, Bobylev LP. Recent ice-sheet growth in the interior of Greenland. Science 2005; 310:1013-6. [PMID: 16239440 DOI: 10.1126/science.1115356] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A continuous data set of Greenland Ice Sheet altimeter height from European Remote Sensing satellites (ERS-1 and ERS-2), 1992 to 2003, has been analyzed. An increase of 6.4 +/- 0.2 centimeters per year (cm/year) is found in the vast interior areas above 1500 meters, in contrast to previous reports of high-elevation balance. Below 1500 meters, the elevation-change rate is -2.0 +/- 0.9 cm/year, in qualitative agreement with reported thinning in the ice-sheet margins. Averaged over the study area, the increase is 5.4 +/- 0.2 cm/year, or approximately 60 cm over 11 years, or approximately 54 cm when corrected for isostatic uplift. Winter elevation changes are shown to be linked to the North Atlantic Oscillation.
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Affiliation(s)
- Ola M Johannessen
- Mohn-Sverdrup Center for Global Ocean Studies and Operational Oceanography, Nansen Environmental and Remote Sensing Center, Bergen, 5006, Norway.
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Joughin I, Abdalati W, Fahnestock M. Large fluctuations in speed on Greenland's Jakobshavn Isbrae glacier. Nature 2005; 432:608-10. [PMID: 15577906 DOI: 10.1038/nature03130] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2004] [Accepted: 10/08/2004] [Indexed: 11/09/2022]
Abstract
It is important to understand recent changes in the velocity of Greenland glaciers because the mass balance of the Greenland Ice Sheet is partly determined by the flow rates of these outlets. Jakobshavn Isbrae is Greenland's largest outlet glacier, draining about 6.5 per cent of the ice-sheet area, and it has been surveyed repeatedly since 1991 (ref. 2). Here we use remote sensing data to measure the velocity of Jakobshavn Isbrae between 1992 and 2003. We detect large variability of the velocity over time, including a slowing down from 6,700 m yr(-1) in 1985 to 5,700 m yr(-1) in 1992, and a subsequent speeding up to 9,400 m yr(-1) by 2000 and 12,600 m yr(-1) in 2003. These changes are consistent with earlier evidence for thickening of the glacier in the early 1990s and rapid thinning thereafter. Our observations indicate that fast-flowing glaciers can significantly alter ice discharge at sub-decadal timescales, with at least a potential to respond rapidly to a changing climate.
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Affiliation(s)
- Ian Joughin
- Jet Propulsion Lab, California Institute of Technology, USA.
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15
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Affiliation(s)
- Mark Fahnestock
- Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH 03824, USA.
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16
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Abstract
Recent advances in the determination of the mass balance of polar ice sheets show that the Greenland Ice Sheet is losing mass by near-coastal thinning, and that the West Antarctic Ice Sheet, with thickening in the west and thinning in the north, is probably thinning overall. The mass imbalance of the East Antarctic Ice Sheet is likely to be small, but even its sign cannot yet be determined. Large sectors of ice in southeast Greenland, the Amundsen Sea Embayment of West Antarctica, and the Antarctic Peninsula are changing quite rapidly as a result of processes not yet understood.
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Affiliation(s)
- Eric Rignot
- Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 300-235, Pasadena, CA 91109, USA.
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Davis CH, McConnell JR, Bolzan J, Bamber JL, Thomas RH, Mosley-Thompson E. Elevation change of the southern Greenland ice sheet from 1978 to 1988: Interpretation. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001jd900167] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Rignot E, Gogineni S, Joughin I, Krabill W. Contribution to the glaciology of northern Greenland from satellite radar interferometry. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001jd900071] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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20
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Thomas RH. Program for Arctic Regional Climate Assessment (PARCA): Goals, key findings, and future directions. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001jd900042] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Thomas R, Csatho B, Davis C, Kim C, Krabill W, Manizade S, McConnell J, Sonntag J. Mass balance of higher-elevation parts of the Greenland ice sheet. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001jd900033] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Drinkwater MR, Long DG, Bingham AW. Greenland snow accumulation estimates from satellite radar scatterometer data. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001jd900107] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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