A comparison of annual vertical crustal displacements from GPS and Gravity Recovery and Climate Experiment (GRACE) over Europe
A comparison of annual vertical crustal displacements from GPS and Gravity Recovery and Climate Experiment (GRACE) over Europe
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DOI：
10.1029/2006jb004335
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发表时间：
2007-03
影响因子：
--
通讯作者：
T. Dam;J. Wahr;D. Lavallée
中科院分区：
文献类型：
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作者：
T. Dam;J. Wahr;D. Lavallée
[1] 我们将大约 3 年的 GPS 高度残差（相对于国际陆地参考系）与来自欧洲站重力恢复和气候实验 (GRACE) 重力场的垂直表面位移预测进行比较。适合剩余月高度的年度信号，针对大气压力和正压海洋载荷效应进行校正，应主要代表由于水储存的长波长变化而导致的表面位移。对欧洲各地 GPS 和 GRACE 的年度高度信号进行比较表明，在大多数地点，年度信号的幅度或相位不一致。我们发现，与 GRACE 预测的年度信号不同，GPS 高度中的年度信号在该地区并不连贯，显示出不同地点的显着变化。对 GRACE 数据的信心以及 GRACE 数据未捕获的载荷场中大振幅小尺度特征的可能性不大，使我们得出结论，GPS 和 GRACE 观测值之间的一些差异是由于 GPS 数据处理中的技术错误造成的。 GPS 和 GRACE 之间的分歧在沿海地区最大，半日海洋潮汐载荷信号的错误建模可能会导致虚假的年度信号，这一事实证明了这一点。
[1] We compare approximately 3 years of GPS height residuals (with respect to the International Terrestrial Reference Frame) with predictions of vertical surface displacements derived from the Gravity Recovery and Climate Experiment (GRACE) gravity fields for stations in Europe. An annual signal fit to the residual monthly heights, corrected for atmospheric pressure and barotropic ocean loading effects, should primarily represent surface displacements due to long-wavelength variations in water storage. A comparison of the annual height signal from GPS and GRACE over Europe indicates that at most sites, the annual signals do not agree in amplitude or phase. We find that unlike the annual signal predicted from GRACE, the annual signal in the GPS heights is not coherent over the region, displaying significant variability from site to site. Confidence in the GRACE data and the unlikely possibility of large-amplitude small-scale features in the load field not captured by the GRACE data leads us to conclude that some of the discrepancy between the GPS and GRACE observations is due to technique errors in the GPS data processing. This is evidenced by the fact that the disagreement between GPS and GRACE is largest at coastal sites, where mismodeling of the semidiurnal ocean tidal loading signal can result in spurious annual signals.