高分辨率TerraSAR-X时序差分干涉沉降监测及精度验证

Land subsidence monitoring based on differential interferometry using time series of high-resolution TerraSAR-X images and monitoring precision verification

城市地面沉降属于缓慢性地质灾害,其对社会经济和人类生活具有持续性负面影响,对城市沉降进行广域高效监测具有重要现实意义。选取天津市为研究区域,以2009年4月7日—2010年12月14日获取的34幅高分辨率TerraSAR-X SAR影像为数据源,采用基于相干点目标分析(interferometric point target analysis,IPTA)的时序差分干涉处理方法进行沉降监测,使用精密水准数据进行精度验证,并提出一种基于最小二乘拟合的沉降时间序列验证方法,最后基于验证后的结果进行沉降分析和解释。与水准数据对比表明,IPTA解算沉降速率、时间序列最小二乘拟合沉降速率的均方根误差分别为3.15 mm/a和-3.25 mm/a。对沉降结果进行分析表明,实验区总体沉降呈不均匀性,最大沉降速率为-128.41 mm/a,沉降时空分布与研究区地表覆盖类型及地下水开采相关。

Urban land subsidence is a kind of slowly developing geological disaster and has sustained negative impacts on the social economy and human life.Therefore,it is of great significance to carry out effective and wide-area urban subsidence monitoring.With 34 high-resolution TerraSAR-X SAR images obtained from April 07,2009 to December 14,2010 as data sources,the land subsidence in Tianjin City was monitored using the differential interferometry of time series based on interferometric point target analysis(IPTA)in this study.Then the monitoring precision was verified using the precise leveling data,and a verification method of subsidence time series based on least-squares fitting was adopted.Finally,subsidence analysis and interpretation were carried out based on the verification results.Compared to the leveling data,the root mean square errors of the subsidence rates obtained using IPTA and that using the least squares-fitting of time series were 3.15 mm/a and-3.25 mm/a,respectively.According to the analysis of subsidence results,the overall subsidence of the study area is significantly uneven,the maximum subsidence rate is-128.41 mm/a,and the spatial-temporal distribution of the land subsidence correlates highly with surface cover types and groundwater exploitation.