Simultaneous estimation of global present-day water transport and glacial isostatic adjustment
Simultaneous estimation of global present-day water transport and glacial isostatic adjustment
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DOI：
10.1038/ngeo938
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发表时间：
2010-08
影响因子：
18.3
通讯作者：
Xiaoping Wu;M. Heflin;H. Schotman;B. Vermeersen;D. Dong;R. Gross;E. Ivins;A. Moore;S. Owen
中科院分区：
文献类型：
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作者：
Xiaoping Wu;M. Heflin;H. Schotman;B. Vermeersen;D. Dong;R. Gross;E. Ivins;A. Moore;S. Owen
在从冰期到间冰期的过渡时期，海洋和大陆之间的全球水运输量巨大。粘弹性固体地球一直在响应这种卸载的大冰块与陆块的上升，在一个过程中被称为冰川均衡调整。此外，目前陆地/海洋水的分布发生了重大变化。由于现今冰/水厚度的变化和冰川均衡调整都影响空间大地测量，因此很难理清这两个过程的相对贡献。在这里，我们结合联合收割机重力测量和大地测量数据的表面移动的数据同化模式的海洋底部压力，同时估计现今的水输送和冰川均衡调整。我们确定了它们对地心运动的单独贡献，地心运动是对地球质量分布变化的响应，不确定性低于0.1 mm yr−1。根据我们的估计，2002年至2008年格陵兰、阿拉斯加/育空地区和南极洲西部的质量损失分别为104±23、101±23和64±32 Gt/年。我们对冰川均衡调整的估计表明，极向的地心速度很大，为-0.72 ±0.06 mm yr-1。我们的结论是，一个重大的修订目前的估计冰川均衡调整和陆-海水交换是必要的。
Global water transport between oceans and continents during the transition from glacial to interglacial times has been enormous. The viscoelastic solid Earth has been responding to this unloading of large ice masses with a rise of the land masses, in a process termed glacial isostatic adjustment. In addition, significant changes in the land/ocean water distribution occur at present. As both present-day changes in the ice/water thickness and glacial isostatic adjustment affect space geodetic measurements, it is difficult to untangle the relative contributions of these two processes. Here we combine gravity measurements and geodetic data of surface movement with a data-assimilating model of ocean bottom pressure to simultaneously estimate present-day water transport and glacial isostatic adjustment. We determine their separate contributions to movements in the geocentre, which occur in response to changes in the Earth’s mass distribution, with uncertainties below 0.1 mm yr−1. According to our estimates, mass losses between 2002 and 2008 in Greenland, Alaska/Yukon and West Antarctica are 104±23, 101±23 and 64±32 Gt yr−1, respectively. Our estimates of glacial isostatic adjustment indicate a large geocentre velocity of −0.72±0.06 mm yr−1in the polar direction. We conclude that a significant revision of the present estimates of glacial isostatic adjustments and land–ocean water exchange is required.