Antarctic contribution to sea level rise observed by GRACE with improved GIA correction
Antarctic contribution to sea level rise observed by GRACE with improved GIA correction
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DOI：
10.1002/jgrb.50208
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发表时间：
2013-06-01
影响因子：
3.9
通讯作者：
Simon, Karen M.
中科院分区：
文献类型：
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作者：
Ivins, Erik R.;James, Thomas S.;Simon, Karen M.
在过去的21000年里，南极体积的变化比以前认为的要小，在这里，我们构建了一个冰盖历史，推动了冰川均衡调整（GIA）重力信号的正演模型预测。新的模型，反过来，应该给出受最近隆起数据约束的预测。GIA信号对重力恢复和气候实验（GRACE）南极物质平衡估算的影响取决于所使用的具体GRACE分析方法。对于本文描述的方法，通过考虑修订的冰史模型和对垂直运动预测的参数搜索，GIA对地表表观质量变化的贡献被重新评估为+5513 Gt/yr，该预测最适合18个高质量站点的GPS观测。尽管GIA模型涵盖了一系列可能的地球流变结构值，但这些数据还不足以求解上下地幔粘度的优选值，也不足以求解岩石圈厚度的优选值。GRACE每月的解决方案来自空间研究中心发布的第04版（CSR-RL04），从2003年1月到2012年1月初发布的时间序列，未经GIA校正，得出冰质量率为+2.9 29 Gt/年。新的GIA校正将南极洲的已解冰质量不平衡增加到-5734 Gt/年。修正后的GIA修正值比过去的GRACE估计值小约50至90 Gt/年。2003年至2012年期间，南极冰盖海平面上升的新上限平均约为0.160.09毫米/年。
Antarctic volume changes during the past 21 thousand years are smaller than previously thought, and here we construct an ice sheet history that drives a forward model prediction of the glacial isostatic adjustment (GIA) gravity signal. The new model, in turn, should give predictions that are constrained with recent uplift data. The impact of the GIA signal on a Gravity Recovery and Climate Experiment (GRACE) Antarctic mass balance estimate depends on the specific GRACE analysis method used. For the method described in this paper, the GIA contribution to the apparent surface mass change is re-evaluated to be +5513 Gt/yr by considering a revised ice history model and a parameter search for vertical motion predictions that best fit the GPS observations at 18 high-quality stations. Although the GIA model spans a range of possible Earth rheological structure values, the data are not yet sufficient for solving for a preferred value of upper and lower mantle viscosity nor for a preferred lithospheric thickness. GRACE monthly solutions from the Center for Space Research Release 04 (CSR-RL04) release time series from January 2003 to the beginning of January 2012, uncorrected for GIA, yield an ice mass rate of +2.9 29 Gt/yr. The new GIA correction increases the solved-for ice mass imbalance of Antarctica to -5734 Gt/yr. The revised GIA correction is smaller than past GRACE estimates by about 50 to 90 Gt/yr. The new upper bound to the sea level rise from the Antarctic ice sheet, averaged over the time span 2003.0-2012.0, is about 0.160.09 mm/yr.