Increased West Antarctic and unchanged East Antarctic ice discharge over the last 7 years

被引:347
作者
Gardner, Alex S. [1 ]
Moholdt, Geir [2 ]
Scambos, Ted [3 ]
Fahnstock, Mark [4 ]
Ligtenberg, Stefan [5 ]
van den Broeke, Michiel [5 ]
Nilsson, Johan [1 ]
机构
[1] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA
[2] Fram Ctr, Norwegian Polar Inst, N-9296 Tromso, Norway
[3] Univ Colorado, NSIDC, Boulder, CO 80303 USA
[4] Univ Alaska Fairbanks, Inst Geophys, Fairbanks, AK 99775 USA
[5] Univ Utrecht, Inst Marine & Atmospher Res Utrecht IMAU, Utrecht, Netherlands
基金
美国国家航空航天局;
关键词
GROUNDING LINE RETREAT; AMUNDSEN SEA EMBAYMENT; SURFACE MASS-BALANCE; PINE ISLAND GLACIER; RECONCILED ESTIMATE; KOHLER GLACIERS; MELT RATES; FLOW; SHELF; GREENLAND;
D O I
10.5194/tc-12-521-2018
中图分类号
P9 [自然地理学];
学科分类号
0705 ; 070501 ;
摘要
Ice discharge from large ice sheets plays a direct role in determining rates of sea-level rise. We map present-day Antarctic-wide surface velocities using Landsat 7 and 8 imagery spanning 2013-2015 and compare to earlier estimates derived from synthetic aperture radar, revealing heterogeneous changes in ice flow since similar to 2008. The new mapping provides complete coastal and inland coverage of ice velocity north of 82.4 degrees S with a mean error of < 10 m yr(-1), resulting from multiple overlapping image pairs acquired during the daylight period. Using an optimized flux gate, ice discharge from Antarctica is 1929 +/- 40 Gigatons per year (Gt yr(-1)) in 2015, an increase of 36 +/- 15 Gt yr(-1) from the time of the radar mapping. Flow accelerations across the grounding lines of West Antarctica's Amundsen Sea Embayment, Getz Ice Shelf and Marguerite Bay on the western Antarctic Peninsula, account for 88% of this increase. In contrast, glaciers draining the East Antarctic Ice Sheet have been remarkably constant over the period of observation. Including modeled rates of snow accumulation and basal melt, the Antarctic ice sheet lost ice at an average rate of 183 +/- 94 Gt yr(-1) between 2008 and 2015. The modest increase in ice discharge over the past 7 years is contrasted by high rates of ice sheet mass loss and distinct spatial patters of elevation lowering. The West Antarctic Ice Sheet is experiencing high rates of mass loss and displays distinct patterns of elevation lowering that point to a dynamic imbalance. We find modest increase in ice discharge over the past 7 years, which suggests that the recent pattern of mass loss in Antarctica is part of a longer-term phase of enhanced glacier flow initiated in the decades leading up to the first continent-wide radar mapping of ice flow.
引用
收藏
页码:521 / 547
页数:27
相关论文
共 81 条
[1]  
Allison I., 2010, AMERY ICE SHELF COMP
[2]  
[Anonymous], 1987, USGS PROF PAP
[3]   Mass loss of Larsen B tributary glaciers (Antarctic Peninsula) unabated since 2002 [J].
Berthier, Etienne ;
Scambos, Ted A. ;
Shuman, Christopher A. .
GEOPHYSICAL RESEARCH LETTERS, 2012, 39
[4]   SATELLITE-IMAGE-DERIVED VELOCITY-FIELD OF AN ANTARCTIC ICE STREAM [J].
BINDSCHADLER, RA ;
SCAMBOS, TA .
SCIENCE, 1991, 252 (5003) :242-246
[5]   Ice-sheet model sensitivities to environmental forcing and their use in projecting future sea level (the SeaRISE project) [J].
Bindschadler, Robert A. ;
Nowicki, Sophie ;
Abe-Ouchi, Ayako ;
Aschwanden, Andy ;
Choi, Hyeungu ;
Fastook, Jim ;
Granzow, Glen ;
Greve, Ralf ;
Gutowski, Gail ;
Herzfeld, Ute ;
Jackson, Charles ;
Johnson, Jesse ;
Khroulev, Constantine ;
Levermann, Anders ;
Lipscomb, William H. ;
Martin, Maria A. ;
Morlighem, Mathieu ;
Parizek, Byron R. ;
Pollard, David ;
Price, Stephen F. ;
Ren, Diandong ;
Saito, Fuyuki ;
Sato, Tatsuru ;
Seddik, Hakime ;
Seroussi, Helene ;
Takahashi, Kunio ;
Walker, Ryan ;
Wang, Wei Li .
JOURNAL OF GLACIOLOGY, 2013, 59 (214) :195-224
[6]  
Blankenship D. D., 2012, IceBridge HiCARS 2 L2 Geolocated Ice Thickness, Version 1", Distributed by
[7]   Snowfall-driven mass change on the East Antarctic ice sheet [J].
Boening, Carmen ;
Lebsock, Matthew ;
Landerer, Felix ;
Stephens, Graeme .
GEOPHYSICAL RESEARCH LETTERS, 2012, 39
[8]  
Bouzinac C., 2015, CRYOSAT PRODUCT HDB
[9]   Transition of flow regime along a marine-terminating outlet glacier in East Antarctica [J].
Callens, D. ;
Matsuoka, K. ;
Steinhage, D. ;
Smith, B. ;
Witrant, E. ;
Pattyn, F. .
CRYOSPHERE, 2014, 8 (03) :867-875
[10]   Mass balance of the Sor Rondane glacial system, East Antarctica [J].
Callens, Denis ;
Thonnard, Nicolas ;
Lenaerts, Jan T. M. ;
van Wessem, Jan M. ;
van de Berg, Willem Jan ;
Matsuoka, Kenichi ;
Pattyn, Frank .
ANNALS OF GLACIOLOGY, 2015, 56 (70) :63-69