[en] We reconstruct the mass balance of the Greenland Ice Sheet using a comprehensive survey of thickness, surface elevation, velocity, and surface mass balance (SMB) of 260 glaciers from 1972 to 2018. We calculate mass discharge, D, into the ocean directly for 107 glaciers (85% of D) and indirectly for 110 glaciers (15%) using velocity-scaled reference fluxes. The decadal mass balance switched from a mass gain of +47 ± 21 Gt/y in 1972-1980 to a loss of 51 ± 17 Gt/y in 1980-1990. The mass loss increased from 41 ± 17 Gt/y in 1990-2000, to 187 ± 17 Gt/y in 2000-2010, to 286 ± 20 Gt/y in 2010-2018, or sixfold since the 1980s, or 80 ± 6 Gt/y per decade, on average. The acceleration in mass loss switched from positive in 2000-2010 to negative in 2010-2018 due to a series of cold summers, which illustrates the difficulty of extrapolating short records into longer-term trends. Cumulated since 1972, the largest contributions to global sea level rise are from northwest (4.4 ± 0.2 mm), southeast (3.0 ± 0.3 mm), and central west (2.0 ± 0.2 mm) Greenland, with a total 13.7 ± 1.1 mm for the ice sheet. The mass loss is controlled at 66 ± 8% by glacier dynamics (9.1 mm) and 34 ± 8% by SMB (4.6 mm). Even in years of high SMB, enhanced glacier discharge has remained sufficiently high above equilibrium to maintain an annual mass loss every year since 1998.
Disciplines :
Earth sciences & physical geography
Author, co-author :
Mouginot, Jérémie ; Department of Earth System Science, University of California, Irvine, CA 92617, erignot@uci.edu jmougino@uci.edu ; Institut des Géosciences de l'Environnement, Université Grenoble Alpes, CNRS, 38000 Grenoble, France
Rignot, Eric ; Department of Earth System Science, University of California, Irvine, CA 92617, erignot@uci.edu jmougino@uci.edu ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
Bjørk, Anders A; Department of Earth System Science, University of California, Irvine, CA 92617 ; Centre for GeoGenetics, University of Copenhagen, 1350 Copenhagen, Denmark
van den Broeke, Michiel ; Institute for Marine and Atmospheric Research Utrecht, Utrecht University, 3508 TA Utrecht, Netherlands
Millan, Romain; Department of Earth System Science, University of California, Irvine, CA 92617
Morlighem, Mathieu ; Department of Earth System Science, University of California, Irvine, CA 92617
Noël, Brice ; Université de Liège - ULiège > Département de géographie > Climatologie et Topoclimatologie ; Institute for Marine and Atmospheric Research Utrecht, Utrecht University, 3508 TA Utrecht, Netherlands
Scheuchl, Bernd; Department of Earth System Science, University of California, Irvine, CA 92617
Wood, Michael; Department of Earth System Science, University of California, Irvine, CA 92617
Language :
English
Title :
Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018.
Publication date :
07 May 2019
Journal title :
Proceedings of the National Academy of Sciences of the United States of America
NASA - National Aeronautics and Space Administration [US-DC] [US-DC]
Funding text :
ACKNOWLEDGMENTS. This work was performed at the University of California, Irvine, and at California Institute of Technology’s Jet Propulsion Laboratory under Contract NNX13AI84 A with the NASA Cryosphere Science Program. J.M. acknowledges funding from the French Centre National d’Etudes Spatiales (CNES) and French L’Agence Nationale de la Recherche (ANR) (Grant ANR-15-IDEX-02). M.v.d.B. and B.N. acknowledge funding from the Polar Program of the Netherlands Organization for Scientific Research and the Netherlands Earth System Science Center. A.A.B. acknowledges support from the Carlsberg Foundation (Grant CF17-0529). We acknowledge the European Space Agency (ESA), Canadian Space Agency (CSA), Japanese Space Agency (JAXA), Italian Space Agency (ASI), and German Space Agency (DLR) for the use of SAR data, NASA and US Geological Survey for the Landsat data, NASA’s OIB and IceSAT missions for the use of ice thickness and elevation data. We thank the Space Task Group and Polar Space Task Group for coordinating satellite data acquisition efforts during IPY and post-IPY, respectively. Worldview DEMs were provided by the Polar Geospatial Center under National Science Foundation OPP Awards 1043681, 1559691, and 1542736.This work was performed at the University of California, Irvine, and at California Institute of Technology’s Jet Propulsion Laboratory under Contract NNX13AI84 A with the NASA Cryosphere Science Program. J.M. acknowledges funding from the French Centre National d’Etudes Spatiales (CNES) and French L’Agence Nationale de la Recherche (ANR) (Grant ANR-15-IDEX-02). M.v.d.B. and B.N. acknowledge funding from the Polar Program of the Netherlands Organization for Scientific Research and the Netherlands Earth System Science Center. A.A.B. acknowledges support from the Carlsberg Foundation (Grant CF17-0529). We acknowledge the European Space Agency (ESA), Canadian Space Agency (CSA), Japanese Space Agency (JAXA), Italian Space Agency (ASI), and German Space Agency (DLR) for the use of SAR data, NASA and US Geological Survey for the Landsat data, NASA’s OIB and IceSAT missions for the use of ice thickness and elevation data. We thank the Space Task Group and Polar Space Task Group for coordinating satellite data acquisition efforts during IPY and post-IPY, respectively. Worldview DEMs were provided by the Polar Geospatial Center under National Science Foundation OPP Awards 1043681, 1559691, and 1542736.
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