基于SBAS InSAR方法的苏州地区2007-2010年地表形变时空变化研究

Spatial-Temporal Ground Deformation Study of Suzhou Area from 2007 to 2010 Based on the SBAS InSAR Method

苏州地区位于中国苏锡常地面沉降带,地面沉降严重影响了该地区的经济社会发展,因此对其进行地面沉降监测具有重要的意义。本文基于SBAS In SAR方法,利用27景ERS-2 SAR数据,反演了苏州地区2007-2010年地表年平均沉降速率分布图和时序沉降变化图,分析了该时间段地表沉降的时空演化特征。结果表明,在整个研究观测期,苏州地区整体呈现出＂老区沉降趋缓,新区沉降较快＂的特点。老城区（姑苏区及邻近的吴中区）地面沉降趋于缓和,年平均沉降速率在10 mm/a以下,无明显的沉降中心;而相对新发展的区域（相城区、工业园区和吴江区）则表现出明显的沉降特征,沉降速率普遍大于10 mm/a。其中,相城区年平均沉降速率大约为10-20 mm/a,局部地区沉降严重,速率可达或超过20 mm/a;工业园区年平均沉降速率约20 mm/a,最大累计沉降量在50 mm左右。吴江区地面沉降最为严重,表现出面积广、速率大的特点,其年平均沉降速率在20 mm/a左右,最大累计沉降量可达60 mm以上。

The city of Suzhou is located in the well known Suzhou-Wuxi-Changzhou subsidence zone in China, which suffers from serious land subsidence. Land subsidence occurring in this area can cause conspicuous social and economic lost, thus a proper investigation is necessary for this region. In order to understand the spatial- temporal evolution of land subsidence in Suzhou, we applied the Small Baseline Subset（SBAS） Interferometric Synthetic Aperture Radar（In SAR） technique to 27 C-band ERS-2 SAR images acquired between 2007 and 2010 by European Space Agency（ESA）. The results show that during the observation period,the downtown and uptown areas show a relatively slow subsidence rate, while an exceptionally rapid subsidence is detected in 3suburb areas. The downtown area such as Gusu district and the uptown area such as Wuzhong district are characterized by their generally low subsidence rates, which are less than 10 mm/a, and there is no subsidence center detected. Land subsidence mainly occurs in Xiangcheng district, Wujiang district and the industrial park, which are the newly developed zones characterized by the subsidence rates of greater than 10 mm/a. We observe the prevalence of ground subsidence phenomena ranging from 10 mm/a up to20 mm/a in Xiangcheng district, while in certain towns and streets, the subsidence phenomenon is significantly severe with a rate close to 20 mm/a or higher. The maximum accumulative subsidence in the industrial park reaches 50 mm, and the average subsidence rate of this area is approximately 20 mm/a. Rapid subsidence with an average rate being up to 20 mm/a is observed in Wujiang district, which is located in the southern part of Suzhou. The land subsidence in this area is the severest within the whole research area, featured by its large coverage and high subsidence rate, and the maximum accumulative subsidence displacement can reach 60 mm or more.