The Research On Elevation Change Of Greenland Ice Sheet Based On Cryosat-2 Altimeter Data

The greenhouse effect of global warming is becoming intensifying,this leads to the ice sheet including the Greenland ice sheet and the Antarctic ice sheet melting accelerating,and then the sea level rise.This may trigger the chain reaction related to the climate worldwide.The Greenland ice sheet,which is especially sensitive to temperature,is the second biggest continent ice sheet,only second to the Antarctic ice sheet changes,so it is important to carry out research on monitoring the ice sheet.The Cryosat-2 satellite can do measurement on Greenland ice sheet with high large range,multi-mode and high accuracy.In this paper,the digital elevation model?DEM?of Greenland ice sheet is constructed based on a total of 3 cycles level2 SIR_GDR₂A Cryosat-2 altimeter data,the time span is 2010.10²013.10,and the elevation changes of the Greenland ice sheet is calculated.The main research contents are as follows:?1?Study the spatial distribution characteristics of Cryosat-2 altimeter data by comparison with the multi-satellite altimeter data,do the cross_over adjustment on the sub_cycle Cryosat-2 altimeter data using the posteriori condition adjustment method.Statistic and analysis the cross_over points differences before and after the cross_over adjustment,the mean cross_over points differences decreased by about 0.8m,the RMS decreased about 1.2m,compared with the ATM?Airborne Topographic Mapper?data on the Greenland ice sheet using the interpolation method,the mean differences is 3.5m,and the RMS value is 5.8m.?2?Point out the current lack of the Greenland ice sheet DEM,and the DEM with the spatial resolution of 5km×5km of Greenland ice sheet is constructed.The value of about 82.4% of Greenland area is less than 1.5m,and the RMS value is less than 4.3m.?3?Carry out the study about the ice sheet elevation changes monitoring motheod and the fitting method,the results show that the cross_over points method and the autoregressive model?AR?can get the best linear variation trend of ice sheet,and calculate the elevation change of Greenland ice sheet,the results show that the elevation above 2000 m dominated by growth,and the elevation below 2000 m dominated by melting,the ice sheet changes from melting to growth as the elevation and latitude increase.