Vertical Accuracy Comparison And Ice Volume Analysis Of Byrd Glacier,Antarctica Based On Multi-Source DEM Data

High-precision ground elevation information of Antartica provides an important data basis for the Antartic topography expression and the analysis of driving force of the glacier,which is of great significance for monitoring the changes of Antartic ice sheet and its impact on sea level.The existing study of Antarctic DEM accuracy assessment is lack of the analysis for the complex terrain area,such as the Antartic groundingline,the coastline,the fast ice stream and the mountain area.In addition,the influence from muiltiple terrain factors on the DEM vertical accuracy,and the analysis of the ice reserves in the complex terrain area need to be further invesgated.This research quantitatively evaluates the accuracy of ICESat-1 DEM?RAMP V2 DEM?ASTER GDEM V2,and BEDMAP 2 surface DEM in Byrd Glacier,Antarctic,based on ICESat/GLAS data.The influence from elevation,slope,aspect and relief on the vertical accuracy for abovemened four DEMs is also discussed.Ice thickness distribution,as well as geomorphology and ice volume analysis of Byrd Glacier are conducted based on the result of the multi-source surface DEM precision analysis and BEDMAP 2 bed DEM data.The important conclusions are as follows:(1)The large anomalies in original ASTER GDEM V2 are corrected by using the contours correcting method.The result shows that the RMSE of the corrected ASTER GDEM is 18.77 m,which is lower than the RAMP V2 DEM(RMSE=100.53 m),ICESat-1 DEM(RMSE=121.24 m),and BEDMAP 2 Surface DEM(RMSE=80.11 m).It indicates that the corrected ASTER GDEM can be used as an ideal data source for analyzing the glacier dynamics and the material balance of the ice sheet in the Byrd glacier.(2)The vertical accuracy of the four DEMs decrease along with the increase of elevation,slope and relief levels.Especially,the vertical accuracy of ASTER GDEM V2 is much higher than the other three DEMs in different topographic conditions,and less affected by the terrain.The vertical accuracy of ICESat-1 DEM is seriously affected by terrain,and the more vigorously terrain changes,the faster the accuracy will decrease.The elevation value of RAMP V2 DEM is higher than that of reference data,and the accuracy is slightly lower than BEDMAP 2 Surface DEM.These four DEMs have higher vertical accuracy in the western and southern aspect than eastern and northern aspect.(3)The Byrd glacier shows the typical topographical characteristics of the Antarctic mountain glaciers.The distribution of ice is deep in the middle area,shallow in the upstream and downstream,and thicker from both sides to the main line of the glacier.The average ice thickness in the glacier area is 1969.34 m,and the total ice volume is about 5213.73 km~3.