基于Sentinel-1A数据的天津地区PS-InSAR地面沉降监测与分析

Land Subsidence Monitoring in Tianjin with PS-InSAR Technique based on Sentinel-1 Data

为有效预防地面沉降带来的灾害,利用2015年4月~2018年2月天津地区的24景Sentinel-1A数据,进行了永久散射体干涉测量处理,并使用高精度轨道数据和TanDEM-X DEM修正残差相位,提取了3 a的地面沉降结果,结合土地利用类型、水文、地质和交通等数据,分析了多处沉降地区的特征和形成原因,最后和小基线集方法的监测结果进行对比分析。结果表明:近3 a来天津城区沉降治理效果显著,平均沉降速率在8 mm/a以内,郊区沉降仍然严重,沉降速率在50~70 mm/a,沉降最为严重的区域为武清区王庆坨镇,3 a累计沉降量超过200 mm,并且有和其他沉降漏斗连成片的趋势。地面沉降发生的区域与地下水漏斗形成的区域基本一致,且两种方法得到的累积形变量差值95%在5 mm以内,说明本研究结果可以为天津市地质灾害防治提供数据支撑和决策依据。

Land Subsidence is one of the most important geological hazards in many areas.In order to prevent disasters caused by land subsidence efficiently,24 Sentinel-1 A images covering area of Tianjin are choosed from 2015 to 2018.Based on Persistent Scatterers InSAR technique,the results of land subsidence for three years are extracted using the precise orbit data and TanDEM-X DEM and compared with the monitoring results of SBAS(Small Baseline Subset)method.Combined with land use types,hydrogeological and traffic data,the characteristics and formation reasons of several subsidence areas are analyzed.The experimental results show that:(1)In recent three years,the land subsidence in Tianjin urban area is relatively slow,with an average speed of less than 8 mm/a.However,suburban land subsidence is still serious with an average speed between 50 mm/a^70 mm/a.The most serious land subsidence area was Wangqingtuo Town in Wuqing district,the total land subsidence was over 200 mm.And there is a trend of connectivity in these subsidence areas.(2)Land subsidence and the falling of groundwater levels have a very high spatial correlation and the difference between the cumulative shape variables obtained by the two methods of SBAS and PSInSAR is less than 5 mm.The results of this study can provide data support for the government of Tianjin.