基于改进时序InSAR技术的填海区地面沉降监测:以中国深圳前海填海区为例OA

To enhance the reliability of permanent scatterer(PS)points selection for monitoring land subsid-ence in reclaimed areas,a multi-threshold joint PS point optimization method was proposed.This method in-troduced a sidelobe threshold for joint constraint,building upon the traditional dual-threshold approach based on amplitude dispersion and coherence coefficient.Different threshold combinations were tested using a con-trolled variable approach,and the effect of different threshold combinations was validated by comparing with leveling measurement data.The optimal threshold combination was ultimately determined to be an amplitude dispersion threshold of 0.8,a mean coherence coefficient threshold of 0.5,and a sidelobe threshold of 0.25.The proposed method was applied to monitor the Qianhai reclaimed area in Shenzhen,using high-resolution COSMO-SkyMed data from 2021 to 2023.The results show that the average annual vertical deformation rate in the region ranges from-45.61 to 10.56 mm/a,with a maximum cumulative settlement of 97.8 mm.Sig-nificant subsidence is mainly concentrated in areas such as Mawan and Guiwan.Cross-validation with Senti-nel-1A data yields a determination coefficient of 0.86 between the two sets of monitoring results,indicating high reliability and consistency of the proposed method.This study provides an effective technical approach for PS point optimization in land subsidence monitoring over reclaimed areas,and offers data support and a methodological reference for deformation monitoring and risk assessment in similar regions.