Detecting Ground Settlement of Shanghai Using Interferometric Synthetic Aperture Radar (insar) Techniques

Differential (D) and persistent scatterer (PS) interferometric synthetic aperture radar (InSAR) (DInSAR and PSInSAR) techniques are arguably the most cost effective and efficient methods today for ground surface deformation monitoring since their invention in the last quarter of the twentieth century. They overcome the limitations of traditional methods of deformation monitoring with regards to cost, time, man power and environmental conditions. A study has been conducted using the above techniques to investigate the land subsidence phenomena in Shanghai. Data from both the European Remote Sensing (ERS) Satellite 1 and 2 (ERS-1/2) and the Japanese Earth Resource Satellite 1 (JERS-1) were used. Results of ground surface subsidence using (i) the DInSAR technique with the L-band JERS-1 SAR data, and (ii) the PSInSAR technique with the C-band ERS-1/2, have been produced for Shanghai. Consistent deformation rates for each dataset used have been produced using the DInSAR and the PSInSAR techniques. Qualitative analysis of the differential interferograms produced from L-band JERS-1 SAR data yields a more accurate and consistent land subsidence pattern in Shanghai. Three stages of land subsidence are revealed by a series of L-band JERS-1 differential interferograms covering Shanghai from 1992-1998. The results obtained from PSInSAR processing, although a bit noisy, are also in agreement with both the results obtained from the DInSAR processing, and land subsidence map of Shanghai produced from other survey techniques. * Corresponding author