Large-scale Long Time-series InSAR Land Subsidence Research in the Pearl River Estuary

Abstract

Due to the influence of human activity and changes in natural conditions, the Pearl River Estuary (PRE) has emerged as a large-scale area of land subsidence, which represents a serious threat to the quality of human life and sustainable socio-economic development. In response to the problems associated with the lack of man-made targets of traditional time-series Interferometric Synthetic Aperture Radar (InSAR) in estuaries and other coastal areas, a distributed scatterers (DS) InSAR method based on a spatially adaptive filter and an eigendecomposition algorithm to estimating the optimal phase of statistically homogeneous DS was applied to obtain subsidence data using 67 scenes Sentinel-1A SAR images covering the PRE. The temporal and spatial distribution characteristics of land subsidence were analyzed. The results suggest that land subsidence in the PRE was widespread and unevenly distributed with large differences between 2015 and 2018. The northwest and southeast are the main subsidence areas, with a maximum sedimentation rate greater than 25 mm/year.