Continuously accelerating ice loss over Amundsen Sea catchment, West Antarctica, revealed by integrating altimetry and GRACE data
Continuously accelerating ice loss over Amundsen Sea catchment, West Antarctica, revealed by integrating altimetry and GRACE data
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DOI：
10.1016/j.epsl.2011.12.040
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发表时间：
2012-03
影响因子：
5.3
通讯作者：
H. Lee;C. Shum;I. Howat;A. Monaghan;Y. Ahn;J. Duan;Junyi Guo;C. Kuo;Lei Wang
中科院分区：
文献类型：
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作者：
H. Lee;C. Shum;I. Howat;A. Monaghan;Y. Ahn;J. Duan;Junyi Guo;C. Kuo;Lei Wang
卫星测高和重力恢复和气候实验（GRACE）测量提供了当代但截然不同的南极冰盖质量平衡估计。高度测量不提供有关雪松密度的信息，而 GRACE 数据受到约束不良的冰川均衡调整信号的显着影响。在这里，我们结合了南极洲西部阿蒙森海 (AS) 区域的 Envisat 雷达测高和 GRACE 数据，来估计季节性时间尺度内全盆地的平均雪和冷杉柱密度。从 Envisat 观测到的冰盖海拔变化中去除冰雪变化信号，揭示了底层冰层更快速的动态变薄。我们报告称，2002年至2006年期间AS扇区的净质量变化率估计为−47±8Gtyr−1，2007年至2009年期间估计为−80±4Gtyr−1，分别相当于海平面上升0.13和0.22mmyr−1。加速是由于2007年之后降雪积累减少（2002-2006年为+13Gtyr−1，2007-2009年为-6Gtyr−1）和冰动态变薄增强（2002-2006年为−60±10Gtyr−1，2007-2009年为−74±11Gtyr−1）。由于过去21年（1989年至2009年）没有明显的降雪趋势，并且冰流速度有所增加（2003年至2010年），加速的质量损失可能会持续下去。
Satellite altimetry and Gravity Recovery and Climate Experiment (GRACE) measurements have provided contemporary, but substantially different Antarctic ice sheet mass balance estimates. Altimetry provides no information about firn density while GRACE data is significantly impacted by poorly constrained glacial isostatic adjustment signals. Here, we combine Envisat radar altimetry and GRACE data over the Amundsen Sea (AS) sector, West Antarctica, to estimate the basin-wide averaged snow and firn column density over a seasonal time scale. Removing the firn variability signal from Envisat-observed ice-sheet elevation changes reveals more rapid dynamic thinning of underlying ice. We report that the net AS sector mass change rates are estimated to be −47±8Gtyr−1between 2002 and 2006, and −80±4Gtyr−1between2007 and 2009, equivalent to a sea level rise of 0.13 and 0.22mmyr−1, respectively. The acceleration is due to a combination of decreased snowfall accumulation (+13Gtyr−1in 2002–2006, and −6Gtyr−1in 2007–2009) and enhanced ice dynamic thinning (−60±10Gtyr−1in 2002–2006, and −74±11Gtyr−1in 2007–2009) after 2007. Because there is no significant snowfall trend over the past 21yr (1989–2009) and an increase in ice flow speed (2003–2010), the accelerated mass loss is likely to continue.