Analysis of SAR visibility and sensitivity based on Sentinel-1A images - a case study of Fengjie, the Three Gorges Region of China

The Three Gorges Region is one of the regions with the most geological disasters in China. Fengjie county, located in the Chongqing section of the Three Gorges Region, is one of the most complicated areas of geological hazards in northeast of Chongqing. Synthetic Aperture Radar Interferometry (InSAR) technology has been proven to be an effective method for surface deformation monitoring, such as the earthquake, landslide and land subsidence etc. Nevertheless, the application of InSAR technology in landslide monitoring is limited by observation blind areas. These blind areas are mainly caused by the large scale of slope in the study area and the direction of satellite. And, these blind areas are also caused by the land cover changes. In this paper, we obtained the observation capability of Sentinel-1A ascending data in Fengjie county, and projection of true surface deformation in the line of sight direction by calculating the relationship of synthetic aperture radar data and digital elevation model data. And we analyzed the relationship about visibility, sensitivity and InSAR monitoring points. It provides a priori assessment of SAR image selection for geological disaster monitoring in the Three Gorges Region, and a regional interpretation method of InSAR deformation values for mountainous areas with significant terrain fluctuation.