Analysis and Detection of Groundwater Exploitation-Induced Urban Deformation Disaster Based on PS-lnSAR and GIS

摘要

Interferometric synthetic aperture radar (InSAR) is a very effective technique for measuring surface deformation, but the temporal and geometrical decorrelation and atmospheric disturbances can compromise strongly the accuracy of the results. Persistent scatterer InSAR (PS-lnSAR) overcomes the decorrelation and atmospheric disturbances problem. The results obtained by PS-lnSAR technique are not the field deformation information but persistent scatterers deformation. In this paper, PS-lnSAR and geographic information system (GIS) are used to investigate surface deformation caused by groundwater overexploitation in Nantong, China. For improving the accuracy of extracting the atmospheric effects in the PS-lnSAR technique, an automatic determining method of the best filter method and filter window size is proposed when extracting the atmospheric effects from the residual phase by filtering. The proposed method is based on structure function of residual phases. The linear deformation rate of permanent scatterers was analyzed by using ArcGIS tools to examine the distribution of data and detect outliers. The ground deformation rate was interpolated using kriging method, and a ground subsidence rate map with high resolution was developed. The experimental results show that the method can improve the accuracy of the extraction of atmospheric effects. A ground subsidence rate map of Nantong with high resolution was generated. The subsidence rate of most zones in Nantong is less than 8 mm/year, and the interpolation accuracy of subsidence rate can be improved by using the spatial analysis and interpolation tools of ArcGIS. Eight subsidence funnels are found in Nantong downtown during the period of 2006-2009; but there are no large subsidence funnels in Nantong downtown.