基于时序InSAR的东营地区地表沉降研究

黄河携带大量泥沙入海,河口三角洲覆盖20~50m厚的沉积层。沉积层的自然压实导致该地区的地表沉降。此外,黄河三角洲油气资源的开发和地下水的开采也加速地表的下陷。InSAR作为一种有效的空间大地测量工具,可以提供几十公里范围内的高精度地表形变场。时序InSAR技术在多幅雷达影像组成的干涉网络基础上,识别永久散射体(PS)等雷达回波信噪比高的像素。与传统的InSAR技术相比,时序InSAR技术削弱雷达影像去相干效应的影响,实现长期的形变序列提取。文中利用两组雷达影像:19幅ERS卫星1992年12月至1996年1月的SAR影像,17幅ENVISAT卫星2003年5月至2008年3月的SAR影像。影像主要覆盖山东省东营市及其周边部分区域。结果显示,东营地区存在每年15mm以上的地表沉陷,该地区的地表沉降与油气开采活动有关。

Subsidence in Dongying region based on time series InSAR

As its flowing water contains numerous sand and clay,the Yellow River forms a delta with sediments between 20 and 50 meters thick.Subsidence occurs at the Yellow River Delta as a result of the natural compaction of sediments,petroleum and gas extraction together with underground water withdrawal.Interferometric Synthetic Aperture Radar (InSAR)is an advanced geodetic tool with sub-centimetre precision.The InSAR time series technique combines information retrieved from multiple SAR images with a common master scene based on a PS network.The advantage of the PS time series technique indicates that it is more effective in circumventing decorrelation and forming a long-term series of observations than conventional InSAR techniques.Two groups of radar images acquired at different time intervals are used in this study.The time-series results suggest two subsidence areas with a rate of up to 1 5 mm/yr in Dongying region,which are probably caused by oil extraction.