双极化Sentinel-1数据在城市沉降监测中的对比研究

Comparative study of dual-polarized Sentinel-1 data in urban subsidence monitoring

目的 针对地面沉降监测仅考虑VV极化Sentinel-1数据而忽略VH极化数据的问题,方法采用PS-InSAR和SBAS-InSAR技术处理延安新区2018年8月—2021年5月的84景双极化Sentinel-1数据,获取地面沉降信息,对比两种极化的沉降监测结果,探讨VH极化在不同实验方法中的意义,并提出一种双极化时序InSAR融合监测新方法。结果 结果表明,新区大部分区域为较稳定区域,形变速率为-8~8 mm/a,此外,还探测到3个较大的沉降区,分别位于桥儿沟流域、高家沟流域和新区东北部填方区域;Sentinel-1不同极化数据的监测结果相关性较高,形变趋势一致;VV极化数据整体优于VH极化,但部分区域VH极化数据得到的地表形变信息更详细;VV-VH极化PS-InSAR形变监测中,VH极化数据能够有效补充VV极化数据监测结果的不足,使结果更加密集,因此,与单一极化监测结果相比,VV-VH极化PS-InSAR形变监测更加详细地反演了地表变形情况;VV-VH极化SBAS-InSAR形变速率结果比单一极化数据相干性和稳定性更高。结论 基于双极化Sentinel-1数据的时序InSAR融合监测技术可以获得比单一极化数据更好的城市地表形变监测结果。

Objectives To address the problem of the ground subsidence only considering the VV polarization Sentinel-1 data and ignoring the VH polarization data,Methods in this paper,PS-InSAR and SBASInSAR techniques were used to process the 84-view dual-polarization Sentinel-1 data in Yan'an New Area from August 2018 to May 2021,obtain the ground settlement information,compare the results of the settlement monitoring of the two polarizations,explore the significance of the VH polarization in different experimental methods,and put forward a new dual-polarized time-series InSAR fusion monitoring method.Results The results show that most of the new area is relatively stable with deformation rate of -8~8 mm/a;in addition,three larger subsidence areas are detected,located in Qiaoergou Basin,Gaojiagou Basin,and the northeastern filling area of the new area.The monitoring results of Sentinel-1 with different polarization data have high correlation and consistent deformation trends.The overall VV polarization data is better than the VH polarization,but in some areas,the VH polarization data can get more detailed surface deformation.VH polarization data in some areas can get more detailed surface deformation information.In the VV-VH polarization PS-InSAR deformation monitoring,the VH polarization data can effectively supplement the insufficiency of the VV polarization data monitoring results,making the results more intensive,and therefore reflecting a more detailed inversion of surface deformation compared with the results of a single polarization monitoring.The VV-VH polarization SBAS-InSAR deformation rate results have higher coherence and stability compared to a single polarization data.Conclusions The time-series InSAR fusion monitoring technique based on dual-polarized Sentinel-1 data can obtain better urban surface deformation monitoring results than singlepolarized data.