Ground Subsidence of Shanghai from 2009 to 2010 Monitored by PSI Technique

This study focuses on the monitoring by Persistent Scatterer Interferometry(PSI) technique and analyzes the reason of surface settlement.By the analysis of the PS amplitude and phase detection method,the experiments of subsidence monitoring and a detailed analysis of surface settlement are performed using 16 high resolution SAR images collected by the X-band radar sensor onboard the German satellite TerraSAR-X over Shanghai between 28 March 2009 and 30 January 2010.We obtained the following main conclusions.Firstly,there are obvious subsidence signatures in the entire study area,which can be attributed to large-scale urban construction,excessive withdrawal of groundwater,industrial production,transportation and so forth.The maximum relative subsidence rate in the study area is as high as-47 mm/yr and the averaged subsidence rate is-16.96 mm/yr.Secondly,previous settlement center in 2008 has been effectively controlled.At this stage,three centers of subsidence are more obvious,namely Baoshan Industrial Park in Luo Jing Town which an average sedimentation rate is-29.8 mm/year,Hongkou Football Stadium which an average sedimentation rate is-24.58 mm/year,and Minhang Economic and Technological Development Zone which an average sedimentation rate is-32.2 mm/year.Thirdly,the land subsidence has gradually extended to north,south,southwest,and southeast along with urban construction.Lastly,the experiment results have been validated with leveling data and the accuracy is ±6 mm,which shows that the PSI technique can be used to monitor urban ground deformation.