GACOS的SBAS-InSAR小尺度大气延迟改正及沉降监测

Small scale atmospheric delay correction of SBAS-InSAR based on GACOS in subsidence monitoring

针对以往一般在大尺度区域开展大气对合成孔径雷达干涉测量(InSAR)沉降监测的影响研究的问题,该文基于通用型大气校正在线服务(GACOS)探讨小尺度区域的改正效果,分析大气校正前后对InSAR沉降观测量的影响。以山东省济南市某矿区为研究区,采用2017年5月至2019年8月期间27景Sentinel-1A构成的75组干涉对为例,选取其中两对校正前后的相位解缠结果进行对比,发现校正后的相位图标准差分别降低15%和16%。基于差分干涉测量短基线集时序分析技术(SBAS-InSAR)对校正和未校正的干涉对进行处理,经过校正的SBAS-InSAR沉降速率和累积沉降量分别为-166.3 mm/a和-373.8 mm,未经校正的SBAS-InSAR的沉降速率和累积沉降量分别为-167.1 mm/a和-372.8 mm。通过与水准监测数据对比发现,经过GACOS大气校正可以去除大气噪声相位,对于小区域长时间形变监测具有一定的适用性。

In view of the problem that the researches on the influence of atmosphere on the interferometric synthetic aperture radar(InSAR)subsidence monitoring are generally carried out for largescale areas,the correction effect in a small scale area was discussed based on the generic atmospheric correction online service(GACOS)and the influence of atmospheric correction on InSAR subsidence observed before and after was analyzed in this paper.Taking a mining area in Jinan,Shandong Province as the research area,75 interference pairs consisting of 27 Sentinel-1A interferometers from May 2017 to August 2019 were used as examples.The phase unwrapping results of two pairs before and after correction were selected for comparison.The results showed that the standard deviation of the corrected phase diagram decreased by 15%and 16%,respectively.Based on the processing of the corrected and uncorrected interference pairs by SBAS-InSAR,the corrected SBAS-InSAR settlement rate and cumulative settlement amount were-166.3 mm/a and-373.8 mm,respectively.The uncorrected settlement rate and cumulative settlement of SBAS-InSAR were-167.1 mm/a and-372.8 mm,respectively.By comparing with the level monitoring data,it was found that the atmospheric noise phase could be removed by GACOS atmospheric correction,which had certain applicability to the long-term deformation monitoring in small areas.