Multi-scale land surface deformation monitoring and driving factors analysis with intermittent SBAS in Bohai Bay, China

With the acceleration of global warming, coastal cities with high populations and rapid urban construction are more vulnerable to the combined effects of sea level rise and land subsidence. In the Bohai Bay region, which is characterized by significant urbanization and natural resource extraction, monitoring land subsidence is crucial for risk mitigation. This study first validated the InSAR results by comparing them with Global Navigation Satellite System (GNSS) data, showing an average RMSE of 7.22 mm. We then used Intermittent Small Baseline Subsets (ISBAS) InSAR techniques to monitor multi-scale surface deformation over Bohai Bay, employing 662 Sentinel-1A/B images from January 2020 to June 2023. The Independent Component Analysis (ICA) method and Okada model were used to extract deformation components and analyze the mechanisms. Results show significant subsidence in the Yellow River Delta (YRD), with a maximum deformation rate of 235 mm/a. This study provides crucial insights for land subsidence prevention in the Bohai Bay region.