Applications Of CryoSat-2 Satellite Altimetry In Antarctic Ice Sheet

The polar region is an important unit of the earth's climate system,including the whole process of the interaction of atmosphere,ocean,land,ice,snow and biology.Through these interactions,the high latitude of the earth is constantly driving global change,but also by the impact of global change.As global warming and sea level rise,further understanding of the polar ice sheet ablation and its response to global change has become the focus of global change research.The emergence of the CryoSat-2 satellite provides a new possibility for the further understanding of the relationship between the cryosphere and the world.Based on the CryoSat-2 Altimetry Data,This paper established the regional DEM and the Antarctic DEM,and the elevation of the Thwaites glacier is calculated.The main research contents and results are as follows:(1)This paper compares the results of three kinds of waveform reset algorithms in CryoSat-2 LRM mode,The results in antarctic Dome A region and Zhongshan Station-dome A section show that the OCOG algorithm is more suitable for the LRM algorithm in CryoSat-2 baseline C data.(2)Based on the CryoSat-2 satellite data from September 2010 to May 2016,the Antarctic Digital Elevation Model with a resolution of 1km north and a coverage of 88 °s was established,the accuracy verification results in the east Antarctic Taishan Station show that the mean value of CryoSat-2 DEM is 1.23m,the standard deviation is 2.02m,shows the precision is higher than the other four DEM;The results of precision verification of Thwaites region in west Antarctic show that the mean value of CryoSat-2 DEM is-2.84m which is the smallest,the standard deviation is 16.71m,and the verification accuracy is comparable to ICESat DEM.The accuracy verification results in Zhongshan Station-Dome A section showed the CryoSat-2 DEM has a minimum mean value of about 0.01 m and a standard deviation of 8.17 m.The verification accuracy is equivalent to the Bamber 1 km DEM.The results of regional DEM and the Antarctic DEM show that the CryoSat-2 DEM is the best,and the precision of ICESat DEM and Bamber 1 km DEM is slightly worse,and the precision of GLB97 DEM and RAMPv2 is the worst.The digital elevation model of the antarctic Dome A area is constructed by using the GPS data and CryoSat-2 data,results show dynamic GPS data verification is-0.10 ± 0.43m,the accuracy of the DEM is improved by about 30%by compare with the DEM which was established only by CryoSat-2 data,shows the precision control of satellite altimetry data by using distributed GPS data can effectively improve the accuracy of DEM.(3)In this paper,the CryoSat-2 data from September 2010 to May 2016 were processed by using the method of repeated track analysis,and the elevation variation of Thwaites glacier area was obtained,the result of height variation is-1.34m/yr,which is equal to result of ice bridge elevation variation in the same period,the result of ice bridge elevation variation is-1.38m/yr;the elevation change of ice bridge data is inserted into the CryoSat-2 grid,and the results show that the difference between the two methods is-0.02 ± 0.82m/yr,it is shown CryoSat-2 can effectively monitor the elevation changes in the edge of the ice sheet.