Earth surface deformation in the North China Plain detected by joint analysis of GRACE and GPS data.
Earth surface deformation in the North China Plain detected by joint analysis of GRACE and GPS data.
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利用 GRACE 和 GPS 技术研究华北平原的地表形变
DOI：
10.3390/s141019861
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发表时间：
2014-10-22
期刊：
影响因子：
--
通讯作者：
Li Z
中科院分区：
文献类型：
--
作者：
Liu R;Li J;Fok HS;Shum CK;Li Z
地球的质量重新分布引起可变载荷，使固体地球变形。虽然最近利用大地测量技术进行的研究大多集中在由于水文负荷而具有1-4厘米量级的大的季节性变形幅度的区域（如亚马逊河流域和尼泊尔喜马拉雅山），但很少对季节性变形幅度只有其一半的区域进行这类研究。在这里，我们使用联合GPS和GRACE数据，调查由于水文负荷在华北平原，其中显着的地下水枯竭的垂直变形。我们发现，GPS和GRACE导出的长期趋势和季节信号是一致的，与隆升幅度为1-2毫米/年，相关性为85.0%-98.5%，分别。这一上升速率与GRACE数据和早期报告研究中的地下水原位测量结果估计的地下水消耗速率一致;而季节性水文变化反映了人类在春季抽取地下水用于农业灌溉的行为，导致夏季储水量低于冬季。然而，不到20%的加权均方根（WRMS）减少检测到所有选定的GPS站时，GRACE派生的季节性变形去除趋势的GPS高度时间序列。这种差异可能是因为GRACE导出的季节信号是大尺度的，而GPS导出的信号是局部点测量。
Mass redistribution of the Earth causes variable loading that deforms the solid Earth. While most recent studies using geodetic techniques focus on regions (such as the Amazon basin and the Nepal Himalayas) with large seasonal deformation amplitudes on the order of 1–4 cm due to hydrologic loading, few such studies have been conducted on the regions where the seasonal deformation amplitude is half as large. Here, we use joint GPS and GRACE data to investigate the vertical deformation due to hydrologic loading in the North China Plain, where significant groundwater depletion has been reported. We found that the GPS- and GRACE-derived secular trends and seasonal signals are in good agreement, with an uplift magnitude of 1–2 mm/year and a correlation of 85.0%–98.5%, respectively. This uplift rate is consistent with groundwater depletion rate estimated from GRACE data and in-situ groundwater measurements from earlier report studies; whereas the seasonal hydrologic variation reflects human behavior of groundwater pumping for agriculture irrigation in spring, leading to less water storage in summer than that in the winter season. However, less than 20% of weighted root-mean-squared (WRMS) reductions were detected for all the selected GPS stations when GRACE-derived seasonal deformations were removed from detrended GPS height time series. This discrepancy is probably because the GRACE-derived seasonal signals are large-scale, while the GPS-derived signals are local point measurements.