Incomplete separability of Antarctic plate rotation from glacial isostatic adjustment deformation within geodetic observations
Incomplete separability of Antarctic plate rotation from glacial isostatic adjustment deformation within geodetic observations
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DOI：
10.1093/gji/ggv461
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发表时间：
2015
影响因子：
2.8
通讯作者：
Matt A. King;P. Whitehouse;W. Wal
中科院分区：
文献类型：
--
作者：
Matt A. King;P. Whitehouse;W. Wal
南极固体地球变形的大地测量包括来自板块旋转和冰川均衡调整 (GIA) 的信号。通过模拟，我们研究了这些信号在水平 GPS 站点速度内的可分离程度，这些速度通常定义板块旋转估计，并为 GIA 模型带来新的约束。使用一套结合一维和三维地球流变学的 GIA 模型预测，我们表明，考虑到南极洲东部 GPS 站点的当前位置，GPS 速度中未建模或错误建模的 GIA 信号会产生对板块旋转的有偏差的估计。当从 GPS 速度中去除有偏差的板块旋转时，会引入高达 0.8 mm yr−1 的误差；通常大于预测的 GIA 信号幅度的值。在缺乏可靠的板块旋转或 GIA 正演模型的情况下，南极大地测量速度不能完全且明确地限制这两个过程，尤其是 GIA。
Geodetic measurements of Antarctic solid Earth deformation include signals from plate rotation and glacial isostatic adjustment (GIA). Through simulation, we investigate the degree to which these signals are separable within horizontal GPS site velocities that commonly define plate rotation estimates and that promise new constraints on models of GIA. Using a suite of GIA model predictions that incorporate both 1-D and 3-D Earth rheologies, we show that, given the present location of GPS sites within East Antarctica, unmodelled or mismodelled GIA signal within GPS velocities produces biased estimates of plate rotation. When biased plate rotation is removed from the GPS velocities, errors as large as 0.8 mm yr−1 are introduced; a value commonly larger than the predicted GIA signal magnitude. In the absence of reliable forward models of plate rotation or GIA then Antarctic geodetic velocities cannot totally and unambiguously constrain either process, especially GIA.