Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018
Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018
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DOI：
10.1073/pnas.1904242116
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发表时间：
2019-05-07
影响因子：
11.1
通讯作者：
Wood, Michael
中科院分区：
文献类型：
--
作者：
Mouginot, Jeremie;Rignot, Eric;Wood, Michael
我们通过对1972年至2018年260个冰川的厚度、表面高程、速度和表面物质平衡(SMB)的综合调查，重建了格陵兰冰盖的物质平衡。我们使用速度尺度的参考通量计算了107个冰川(D的85%)直接进入海洋的质量流量D和110个冰川(15%)的间接质量流量D。十年质量平衡从1972-1980年的+47+/-21Gt/y转变为1980-1990年的51+/-17Gt/y。质量损失从1990-2000年的41+/-17千吨/年增加到2000-2010年的187+/-17千吨/年，到2010-2018年增加到286+/-20千吨/年，或自1980年代以来的6倍，或平均每十年80+/-6千吨/年。由于一系列寒冷的夏季，质量损失的加速从2000-2010年的正值转为2010-2018年的负值，这表明将短期记录推断为长期趋势是困难的。自1972年以来，对全球海平面上升的贡献最大的是格陵兰西北部(4.4+/-0.2 mm)、东南部(3.0+/-0.3 mm)和中西部(2.0+/-0.2 mm)，冰盖总计13.7+/-1.1 mm。冰川动力学(9.1 mm)控制质量损失为66+/-8%，SMB(4.6 mm)控制质量损失为34+/-8%。即使在SMB较高的年份，自1998年以来，增加的冰川流量仍高于平衡水平，足以维持每年的质量损失。
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.