Study On The Surface Deformation Of Permafrost Along Transportation Corridor In Plateau Based On Sentinel-1A Satellite Interferometric Data

The Qinghai-Tibet Railway and the Qinghai-Tibet Highway run through the permafrost area,forming a transportation corridor.The deformation of frozen soil will change with the temperature and season,lead to the settlement and uplift of the surface along the transportation corridor,which have a harmful effect on the stability of the roadbed.Therefore,it is particularly important to monitor the surface deformation of the permafrost transportation corridor in the Qinghai-Tibet Plateau.In the past,we monitor surface deformation by using leveling and GPS surveying,and achieve some results.However,in the harsh environmental conditions of the Qinghai-Tibet Plateau,both the traditional leveling and GPS surveying need a lot of manpower and material costs,so the operating efficiency is low.This article is based on the InSAR technology,using the radar images captured by the ESA-launched Sentinel satellite to monitor the study area,and using the two-track D-InSAR method and the SBAS method to monitor the transportation corridor from Ningzhong to Wumatang in Dangxiong County.The main tasks of this article are:(1)According to the research status of InSAR technology at home and abroad,this paper summarizes the remote sensing satellite data currently applicable for InSAR,analyzes the basic principle of Synthetic Aperture Radar(SAR),interferometric measurement InSAR and differential interferometry D-InSAR technique,analyzes the sensitivity of D-InSAR monitoring,and points out the influence factors of D-InSAR monitoring surface deformation.In particular,the whole decoherence factors have been studied.(2)This paper selects the the Qinghai-Tibet line which from Ningzhong to Wumatang as the study area and focus on the key steps of D-InSAR such as image registration,interferogram filtering,and phase unwrapping.By comparing these methods,the paper chooses Goldstein filtering algorithm and the Minimum Cost Flow algorithm.(3)This paper selects four pairs of interference pairs,according to the seasons of the study area,and performs four pairs of D-InSAR differential interferometry to obtain the deformation results after the geocoding.The profiles along the transportation corridor can be drawn by the GIS spatial analysis.This paper analyzes the surface deformation of the frozen soil of the Qinghai-Tibet Plateau will change with the seasons,the temperature will increase from spring to summer,then the permafrost will thaw,and the surface will settle;the temperature will fall from autumn to winter,then the frost heave will swell,and start to raise.(4)This paper analyzes the limitation of conventional D-InSAR monitoring deformation,using SBAS-InSAR in the study area with 8 scenes of Sentinel-1A radar image,the 8 scene data are combined into 28 interferometry pairs,and obtained through SBAS technical process.The paper obtains deformation time-sequence map after geocoding and average deformation rate map.(5)This paper selects four key areas in order to analyze,and obtains the historical deformation maps for each area.Research shows that the SBAS monitoring surface deformation can reach millimeter accuracy.Based on the monitoring results,specific suggestions for reducing the impact of deformation on the project were put forward.