青藏高原西北缘时序InSAR对流层延迟改正方法评估  

Evaluation of Time-Series InSAR Tropospheric Delay Correction Methods over Northwestern Margin of the Qinghai-Tibet Plateau

作　　者：高梦瑶 许才军[1,2,3] 刘洋[1,2,3] GAO Mengyao;XU Caijun;LIU Yang(School of Geodesy and Geomatics,Wuhan University,Wuhan 430079,China;Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,Wuhan University,Wuhan 430079,China;Key Laboratory of Geophysical Geodesy,Ministry of Natural Resources,Wuhan University,Wuhan 430079,China)

机构地区：[1]武汉大学测绘学院,湖北武汉430079 [2]武汉大学地球空间环境与大地测量教育部重点实验室,湖北武汉430079 [3]武汉大学自然资源部地球物理大地测量重点实验室,湖北武汉430079

出　　处：《武汉大学学报（信息科学版）》2021年第10期1548-1559,共12页Geomatics and Information Science of Wuhan University

基　　金：国家自然科学基金(41721003,41874011);国家重点研发计划(2018YFC1503603)。

摘　　要：合成孔径雷达干涉测量(interferometric synthetic aperture radar, InSAR)的时序分析是监测大面积地表缓慢形变的重要手段,但对流层延迟相位大大影响了形变监测的精度。以青藏高原西北缘为研究区域,分析了经验模型线性改正、通用型InSAR大气校正在线服务(generic atmospheric correction online service for InSAR, GACOS)改正和欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts, ECMWF)最新发布的ERA5(ECMWF reanalysis v5)数据集改正3种方法在时序InSAR反演形变速率中的改正效果。通过掩模技术计算非形变区的速率标准差,分析形变速率与地形的相关性,并与GPS数据进行比较分析后发现,自西向东的3个研究区域76.5°E~79.7°E(D136)、80.5°E~83.7°E(D165)、84.9°E~88.1°E(D19)范围内,其线性改正后标准差分别降低了41.05%、59.21%、25.13%,而GACOS改正后标准差分别降低了38.76%、55.97%、30.73%,ERA5改正后其标准差分别降低了10.05%、30.11%、20.15%。此外,InSAR与GPS站视线向形变速率比较显示线性改正、GACOS改正与ERA5改正后3个研究区域内其均方根误差分别降低了46.07%、51.28%和35.51%。对于青藏高原西北缘,3种方法均可削弱对流层延迟效应,其中线性改正和GACOS改正的效果好,适用性更高,ERA5受地面监测站点密度影响,在该区域改正效果稍差。Objectives:Time-series analysis of interferometric synthetic aperture radar(InSAR) plays an important role in monitoring large-scale surface slow deformation.However,the impact of tropospheric delay limits the accuracy of mapping deformation.Tropospheric delay correction is crucial to InSAR deformation rate inversion objective.Methods:We focus on the northwestern margin of the Qinghai-Tibet Plateau and use three methods which are the empirical model linear correction,generic atmospheric correction online service for InSAR(GACOS) and ERA5 dataset released by the European Centre for Medium-Range Weather Forecasts(ECMWF) in the time-series InSAR inversion of deformation rate to study their applicability in this region.Results:By calculating the standard deviation in the non-deformation region with the mask technique,analyzing the correlation between deformation rate and topography,and comparing with the GPS data,the results show that three study areas from west to east,in the range of D136(76.5°E—79.7°E),D165(80.50 E-83.7°E) and D19(84.9°E—88.1°E),the standard deviations of linear corrected are decreased by 41.05%,59.21% and 25.13%.The standard deviations of GACOS corrected are reduced by38.76%,55.97% and 30.73%,and those of ERA5 corrected are decreased by 10.05%,30.11% and20.15%,respectively.Besides,the correlation coefficients between deformation rate and elevation of the three profiles are 0.68,0.93 and 0.60,respectively.With the increase of correlation coefficients,the advantage of linear correction becomes obvious.In addition,the comparison of LOS deformation rates between InSAR and GPS projected shows that the root mean square error of linear correction,GACOS correction and ERA5 correction in the three study areas are reduced by 46.07%,51.28% and 35.51% respectively.Conclusions:The northwestern margin of the Qinghai-Tibet Plateau,all three methods can mitigate tropospheric effects,and the linear correction and GACOS correction perform better and have higher applicability.While the performance of ERA5

关 键 词：时序InSAR 线性改正 GACOS ERA5数据集 

分 类 号：P237[天文地球—摄影测量与遥感]