| Antarctica is the earth's freezing,affecting the global climate change,and the ice sheet of thousands of meters thick in Antarctica is rich in water resources,the ice sheet small changes can cause global sea level fluctuations,under the background of global warming,Antarctic ice sheet has been at the melting state of large area,the coastal regions of the human social development pose a threat,so the real-time monitoring of the Antarctic mass balance is of great significance to the development of the global climate and humankind.Using Cryo Sat-2 data from July 2011 to July 2019,a 1km resolution Antarctic DEM was established based on a model fitting method.Using the cryosat-2 data from November 2010 to October 2019,the elevation change of Antarctica was estimated by using the method of model fitting.Based on the results of the estimated Antarctic elevation change,the mass balance of Antarctica was estimated with the help of Firn Densification Model(FDM),Regional Atmospheric Climate Model(RACMO)and ERA-interim reanalysis data.The main conclusions are as follows:DEM contains 94 percent of the ice sheet and 98 percent of the ice shelf.Ice Bridge data was used to assess the accuracy of DEM.By comparing the grid cells of the two data sets,the mean,median,and root mean square elevation differences between DEM and Ice Bridge data were-0.30 m,-0.47 m,and 10.55 m,respectively.The region with the greatest elevation difference was the ice sheet margins of cryosat-2 in SARIn model.The region with the smallest elevation differences are the low-slope Ross and filcher-ronne ice shelf,RMS is only 4.03 m.Elevation change of Pine Island Glacier(PIG)and Thwaites Glacier(TWG)is the most vigorous in the AS region in West Antarctica and maximum elevation change is-11.3 m/yr,elevation change of West Antarctica is-11.4 ± 0.5 cm/yr.Elevation change of most of the area in East Antarctica is small,isolated regions(TG and TOG)appear larger decline trend and Dronning Maud Land(DML)appear abnormal rising trends,elevation change of East Antarctica is-0.5 ± 0.3 cm/yr.Antarctic peninsula inland is rising,edge appear larger decline trend,elevation change of Antarctic peninsula is-22.2±3.1 cm/yr.Most of the regions with drastic elevation change are accompanied by large amount of snow fall and fast ice velocity.It is concluded that most of the regions with drastic change in Antarctica are mainly caused by ice movement,and the change caused by snowfall accumulation are smaller than ice movement,and there are also some areas where change are mainly caused by snowfall(such as DML).Elevation change of Most Antarctic basins compared with elevation change in other periods appeared to accelerate decline trend,decline trend also increased in East Antarctica,West Antarctica and Antarctic peninsula,On the whole,elevation change trend of Antarctica from 2010 to 2019 is-2.5 ± 0.5cm/yr,while elevation change from 2010 to 2013 is-1.9 ± 0.2cm/yr,indicating that the overall decline rate of Antarctica has increased in recent years.Mass change of the Antarctic ice sheets from 2010 to 2019 is 235.5 ± 53.7 Gt/yr,this result was twice as fast as the rate of-101 ± 15 Gt/yr between 2003 and 2009.Mass balance in each basin is also in a state of accelerated loss in recent years.Mass balance from 2010 to 2016 was calculated using GRACE data,which showed a large gap with the results of this study.By comparison with other studies,it was found that the accuracy of GRACE data in estimating mass balance was relatively poor.The main reasons are the anomaly of the earth's gravitational field and the coarse resolution. |
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