Monitoring And Analysis Of Ground Deformation In Permafrost Region Of Wudaoliang Based On SBAS-InSAR Technology

The cryosphere is one of the five major circles.Under the trend of climate warming,its changing trend will have a significant impact on the global environment,resources,energy cycle and socio-economic development.Permafrost,as an important part of the cryosphere,has been degraded to some extent in recent decades.The permafrost region of Qinghai-Tibet plateau,which is located in the area of the largest permafrost region in low latitude,is very sensitive to climate change and its degradation trend is more obvious.Based on the Sentinel-1 SAR data of the European space agency and SBAS-In SAR technology,the time series ground deformation information of the permafrost region of the Wudaoliang on the Qinghai-Tibet plateau from November 2014 to March 2017 is obtained.the results are in good agreement with the measured data of the leveling instrument.The results show that the ground surface of the Wudaoliang region shows a trend of subsidence with a relative error of 22.4 % and a root mean square error of 4.3 mm.It shows that In SAR technology can be used for deformation monitoring in permafrost regions.At the same time,combined with long-term real-time observation data of five beams,the influence of different environmental factors on sentinel-1 data acquisition of ground deformation information in permafrost region of Qinghai-Tibet plateau is analyzed.The results show that:(1)Vegetation type has a great influence on the ground deformation information obtained from sentinel-1 data.The better the vegetation development,the higher the coverage and the more serious the incoherent,which will affect the accuracy of sentinel-1 data acquisition.(2)The shape variables of different landforms in permafrost regions have spatial heterogeneity.There are vertical and north-south differences in mountainous areas with high plateau topographic relief.In permafrost regions,such as rivers and hot-melt lakes,the radar signal is seriously incoherent,which will affect the ability of acquiring the surface deformation information.(3)The effects of precipitation and daily freeze-thaw cycles on the ability of sentinel-1 to acquire ground deformation information in permafrost regions cannot be ignored.The continuous precipitation will affect the propagation of radar signal,which leads to a large error when using sentinel-1 data to obtain ground deformation information of permafrost.The daily freeze-thaw cycles will make the ground deformation in permafrost regions have a big difference between day and night,which is also the main reason for the relatively large error.