Monitoring And Analysis Of Typical Tibet Glacier Displacement Period Based On High-resolution SAR

Under the influence of global warming,glaciers in many regions continue to intensify and shrink.The movement velocity of mountain glaciers is an important indicator for monitoring the glacier's response to climate.On the other hand,the geological disasters caused by glacier movement,such as glacier lake outburst caused by glacier collapse and subsequent floods,mudslides,etc.,deserve people's vigilance.Therefore,it is of great practical significance to monitor changes in glacier flow velocity.The paper collected a variety of high-resolution and different wavelength SAR satellite data,COSMO-Sky Med,Radar Sat-2,ALOS-2,and high-resolution DEM data,using synthetic aperture radar differential interferometry(DInSAR)and DEM-assisted offset tracking technology monitors the surface movement of different types of glaciers in Tibet.The research results and conclusions of this paper are as follows:1.Based on the COSMO-Sky Med data and offset tracking technology from September to October 2019 to detect changes in the flow rate of the Aru Glacier,and to perform the 1-day baseline COSMO-Sky Med data and the 14-day baseline ALOS-2 data DInSAR detection.The results show that the Aru Glacier moves at an average velocity of 8 cm/day from late September to early October,and the highest regional movement rate can reach 22 cm/day;the spatial distribution of glacier movement appears to decrease from the central axis to both sides,from the front of the glacier When the ice tongue diminishes,the area with the largest flow velocity and the area with the largest slope of the glacier are spatially consistent;the overall movement of the glacier is related to the existence of the lower glacial lake and local weather changes.2.Based on COSMO-Sky Med data and Radar Sat-2 data from March to November 2020,combined with offset tracking technology to detect Langcuo Glacier and G089323E27832 N Glacier.Analyze the changes in the time series of Langcuo Glacier and G089323E27832 N Glacier,and use the DInSAR method to analyze and verify.The results show that the maximum velocity of the Langcuo Glacier area can reach 30 cm/day,and the maximum velocity of the G089323E27832 N glacier is 10 cm/day,which both reach the highest velocity in summer;the two glaciers move slowly in April to May,and from June to August.Increased sharply,slowing down from September to November,showing seasonal changes;the overall movement of the glacier is related to changes in local temperature,rainfall and the roughness of the ice surface.Various factors cause changes in the overall movement rate of the glacier.By comparing the DInSAR results in the same season,at the end of April,the velocity of the G089323E27832 N glacier was greater than that of the Aru Glacier,which is consistent with the rule that the transitional glacier movement rate is generally greater than that of the continental glacier.3.Based on InSAR results and local topographic analysis,it is found that Langcuo Glacier is in danger of collapsing and inducing glacial lake outburst.Therefore,the Langcuo Glacier and its lower glacial lake are interpreted and analyzed by optical remote sensing.The interpretation found that the glaciers in this area are shrinking,and the glacial lakes are expanding;inferred the spatial impact of glacier collapse-glacial lake collapse,and provide a reference for geological disaster warning.