Geodetic measurements reveal similarities between post-Last Glacial Maximum and present-day mass loss from the Greenland ice sheet.
Geodetic measurements reveal similarities between post-Last Glacial Maximum and present-day mass loss from the Greenland ice sheet.
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DOI：
10.1126/sciadv.1600931
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发表时间：
2016-09
期刊：
影响因子：
13.6
通讯作者：
Munneke PK
中科院分区：
文献类型：
--
作者：
Khan SA;Sasgen I;Bevis M;van Dam T;Bamber JL;Wahr J;Willis M;Kjær KH;Wouters B;Helm V;Csatho B;Fleming K;Bjørk AA;Aschwanden A;Knudsen P;Munneke PK
目前格陵兰海洋部门的不稳定可能会在未来几个世纪内增加海平面。由于关键区域的现场观测稀少，准确量化格陵兰冰盖千年尺度的物质平衡及其对全球海平面上升的贡献仍然具有挑战性。冰川均衡调整(GIA)是固体地球对末次冰盛期(LGM；约21000年前)以来冰川和海洋负荷变化的持续响应，可用于约束GRIS的冰川消融历史。我们使用格陵兰全球定位系统网络的数据来直接测量GIA，并估计自末次盛冰期以来整个流域的质量变化。在格陵兰岛东南部发现了出人意料的巨大GIA隆起速率，每年+12毫米。这些速率是由于该地区的上地幔粘度较低，从大约4000万年前格陵兰岛越过冰岛热点开始。这一软流变学集中区对重建格陵兰的冰川消退史有着深远的影响。我们重新评估了末次冰期以来GRIS的演变，得到西北和东南部海平面损失相当于1.5米。这些同样的行业正在主导现代的质量损失。我们认为，这些海洋部门目前的不稳定可能会在未来几个世纪内使海平面上升。我们新的冰川消退史和GIA隆起估计表明，使用重力恢复和气候实验卫星任务来推断GIA现今变化的研究可能错误地修正了GIA，并低估了大约200亿吨/年的质量损失。
Present destabilization of marine-based sectors in Greenland may increase sea level for centuries to come. Accurate quantification of the millennial-scale mass balance of the Greenland ice sheet (GrIS) and its contribution to global sea-level rise remain challenging because of sparse in situ observations in key regions. Glacial isostatic adjustment (GIA) is the ongoing response of the solid Earth to ice and ocean load changes occurring since the Last Glacial Maximum (LGM; ~21 thousand years ago) and may be used to constrain the GrIS deglaciation history. We use data from the Greenland Global Positioning System network to directly measure GIA and estimate basin-wide mass changes since the LGM. Unpredicted, large GIA uplift rates of +12 mm/year are found in southeast Greenland. These rates are due to low upper mantle viscosity in the region, from when Greenland passed over the Iceland hot spot about 40 million years ago. This region of concentrated soft rheology has a profound influence on reconstructing the deglaciation history of Greenland. We reevaluate the evolution of the GrIS since LGM and obtain a loss of 1.5-m sea-level equivalent from the northwest and southeast. These same sectors are dominating modern mass loss. We suggest that the present destabilization of these marine-based sectors may increase sea level for centuries to come. Our new deglaciation history and GIA uplift estimates suggest that studies that use the Gravity Recovery and Climate Experiment satellite mission to infer present-day changes in the GrIS may have erroneously corrected for GIA and underestimated the mass loss by about 20 gigatons/year.
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影响因子：
4
作者：
Fleming, K;Lambeck, K
通讯作者：
Lambeck, K
影响因子：
56.9
作者：
Fahnestock, M;Abdalati, W;Gogineni, P
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作者：
Dietrich, R;Rülke, A;Scheinert, M
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Scheinert, M
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作者：
Altamimi, Z.;Metivier, L.;Collilieux, X.
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