Early Identification Of Landslides Based On In Sar With Elevation Related Atmospheric Correction

A landslide is a geological hazard that is extremely harmful.The western Sichuan area is mostly alpine canyons with large terrain and complex geological environment.And it leads to the development of landslide geological disasters,there are many inducing factors,which seriously threaten the lives and property safety and economic development of the local people.Therefore,early identification and monitoring of landslides in the western Sichuan area is necessary.As an advanced space-to-ground monitoring method,InSAR has high spatial-temporal resolution and monitoring accuracy.This method can effectively monitor the spatial and temporal changes of the research object,and has great advantages in large-scale deformation monitoring.It has been widely used in geological disaster prevention and monitoring.InSAR technology has the characteristics of high precision,wide coverage and freedom from weather in landslide monitoring.However,in the mountainous area of western Sichuan with a complex topography and changeable meteorological environment,the monitoring accuracy of InSAR is greatly challenged.Atmospheric phase correction related to elevation in mountainous areas is one of the main research contents of this paper.In this paper,the national road G317 Wenchuan-Lixian section in western Sichuan region is taken as the key research area,and the early identification of potential landslides in mountainous areas are conducted by SBAS-InSAR.And the elevation-related atmospheric effects are significantly weakened and the monitoring accuracy is improved.The main research contents and achievements are as follows:(1)Correction of the atmosphere associated with elevation.Due to the steep terrain and complex and changeable meteorology in the study area,there are obvious atmospheric interferences related to elevation in InSAR monitoring results.This paper conducts atmospheric correction based on three different atmospheric correction methods: high/low pass filtering method,linear model correction method and external data method(GACOS).The degree of different correction methods on the results of unwrapping interferograms and deformation rate are analyzed to obtain the best atmospheric correction results in the research area.(2)With the data of Sentinel-1 images covering the Wenchuan-Lixian in western Sichuan region section of national highway G317,and time span is one year.The SBAS-InSAR technology integrated with elevation related atmospheric correction is used for early identification of landslides,11 obvious geological disaster points of collapse and slide be identified.And the annual average deformation rate and time series deformation results of disaster points were obtained.And the meteorological data was used in the analysis of the deformation characteristics of unstable regions.Furthermore,based on the optical remote sensing data,the topographic and geomorphic information of the landslides area was extracted,and the risk analysis of the landslide body was carried out by combining with the deformation information.(3)Deformation key analysis of Xishan landslide was carried out based on deformation results corrected by elevation-related atmospheric effects,and the reliability of the correction of elevation-related atmospheric effect by GACOS was verified.Based on the results of deformation calculation of ascending and descending track data corrected by atmosphere correction,the two-dimensional deformation decomposition of Xishan village landslide is emphasized to obtain the deformation results along the slope direction and in the vertical direction.The real deformation characteristics and causes of deformation of Xishan village landslide during the monitoring period are analyzed.