View Online

Excessive groundwater exploitation is common through the Taiyuan basin, China, and is well known to result in ground subsidence. However, most ground subsidence studies in this region focus on a single place (Taiyuan city), and thus fail to demonstrate the regional extent of the deformation phenomena in the whole basin. In this study, we used Interferometric Synthetic Aperture Radar (InSAR) time series analysis to investigate land subsidence across the entire Taiyuan basin region. Our data set includes a total of 75 ENVISAT ASAR images from two different frames acquired from August 2003 to September 2010 and 33 TerraSAR-X scenes spanning between March 2009 and March 2010. ERA-Interim reanalysis was used to correct the stratified delay to reduce the bias expected from the systematic components of tropospheric delay. The residual delay after correction of stratified delay can be considered as a stochastic component and be mitigated through spatial-temporal filtering. A comparison with MERIS (Medium-Resolution Imaging Spectrometer) measurements indicates that our atmospheric corrections improved agreement over the conventional spatial-temporal filtering by about 20%. The displacement results from our atmosphere-corrected time series InSAR were further validated with continuous GPS data. We found eight subsiding centers in the basin and a surface uplift to the north of Taiyuan city. The causes of ground deformation are analyzed and discussed in relation to gravity data, pre-existing faults, and types of land use.

过度的地下水开采在中国太原盆地普遍存在，并且众所周知会导致地面沉降。然而，该地区的大多数地面沉降研究仅集中在单一地点（太原市），因此未能展示整个盆地范围内的变形现象。在本研究中，我们使用干涉合成孔径雷达（InSAR）时间序列分析方法研究了整个太原盆地地区的地面沉降。我们的数据集包括2003年8月到2010年9月期间获取的两帧共75幅ENVISAT ASAR影像，以及2009年3月到2010年3月期间的33幅TerraSAR-X影像。我们使用ERA-Interim再分析数据进行分层延迟修正，以减少来自对流层延迟系统成分的偏差。修正分层延迟后的残余延迟可以视为一个随机成分，通过时空滤波进行缓解。与MERIS（中分辨率成像光谱仪）数据的比较表明，我们的大气校正方法比传统的时空滤波方法提高了约20%的一致性。我们使用大气校正后的时间序列InSAR位移结果进一步通过连续GPS数据进行了验证。研究发现盆地内存在八个沉降中心，而太原市北部则出现了地面抬升。地面变形的原因通过与重力数据、预存断层以及土地利用类型的分析和讨论进行了探讨。

Graphical Abstract