Assessment of Contemporary Antarctic GIA Models Using High-Precision GPS Time Series
Assessment of Contemporary Antarctic GIA Models Using High-Precision GPS Time Series
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DOI：
10.3390/rs14051070
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发表时间：
2022-02
期刊：
影响因子：
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通讯作者：
Wenhao Li;Fei Li;C. Shum;Chanfang Shu;Feng Ming;Shengkai Zhang;Qingchuan Zhang;Wei Chen
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文献类型：
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作者：
Wenhao Li;Fei Li;C. Shum;Chanfang Shu;Feng Ming;Shengkai Zhang;Qingchuan Zhang;Wei Chen
过去由于地球对冰川消融和冰川周期的粘弹性响应而导致的地球质量的重新分配反映了被称为冰川均衡调整(GIA)的过程。全球定位系统数据可以有效地限制GIA的速度，只要这些数据是准确的，有足够的空间覆盖，并考虑到相互竞争的地球物理过程，包括冰/雪消融/积累的弹性载荷。GPS解算受共模误差(CME)和最佳噪声模型选择的影响很大，并且主要由于地球的弹性响应而受到其他地球物理信号的污染。利用独立分量分析去除日冕物质抛射，利用Akaike信息准则确定南极79个GPS站点的最佳噪声模型，这些站点主要分布在南极洲西部和南极半岛。其次，使用高分辨率的表面质量变化模型来修正弹性变形。最后，我们使用改进的GPS解对7个当代GIA南极洲正演模式的精度进行了评估。结果表明，剔除日冕物质抛离和噪声分析后，GPS地壳位移速度最大偏差达到4.0mmyr−1，平均偏差为0.4mmyr−1。所有GIA模型预测的速度都被系统地低估了阿蒙森海湾GPS观测的速度。此外，南极半岛北部的GPS垂直速度大于南极半岛南部的GPS垂直速度，大多数正演模型低估了GIA对南极半岛的影响。
Past redistributions of the Earth’s mass resulting from the Earth’s viscoelastic response to the cycle of deglaciation and glaciation reflect the process known as glacial isostatic adjustment (GIA). GPS data are effective at constraining GIA velocities, provided that these data are accurate, have adequate spatial coverage, and account for competing geophysical processes, including the elastic loading of ice/snow ablation/accumulation. GPS solutions are significantly affected by common mode errors (CMEs) and the choice of optimal noise model, and they are contaminated by other geophysical signals due primarily to the Earth’s elastic response. Here, independent component analysis is used to remove the CMEs, and the Akaike information criterion is used to determine the optimal noise model for 79 GPS stations in Antarctica, primarily distributed across West Antarctica and the Antarctic Peninsula. Next, a high-resolution surface mass variation model is used to correct for elastic deformation. Finally, we use the improved GPS solution to assess the accuracy of seven contemporary GIA forward models in Antarctica. The results show that the maximal GPS crustal displacement velocity deviations reach 4.0 mm yr−1, and the mean variation is 0.4 mm yr−1 after removing CMEs and implementing the noise analysis. All GIA model-predicted velocities are found to systematically underestimate the GPS-observed velocities in the Amundsen Sea Embayment. Additionally, the GPS vertical velocities on the North Antarctic Peninsula are larger than those on the South Antarctic Peninsula, and most of the forward models underestimate the GIA impact on the Antarctic Peninsula.