Detection Of Antarctic Subglacial Lakes Activities Using Satellite Altimetry Data

Antarctica is the major resource of the global largest glaciers and fresh water.As an essential part of the Cryosphere,the Antarctic ice sheet plays an important role in the study of the global climate and environment change.Antarctic subglacial lakes which form an important component of the subglacial hydrological system have existed for millions years and have the potential to study the history of the ice sheet and the global climate change.Besides,the activities of some subglacial lakes have great impacts on ice sheet dynamic,ice-flow velocity,mass balance of ice sheet and sea level changes.It's very significant to study the movement of the subglacial lakes.It's difficult to get direct observation of the subglacial lakes since they were located at the base of the ice sheet.However,the activities of the subglacial lakes which caused height changes of the ice sheet surface can be captured by the satellite altimetry data.Therefore,the changes of the subglacial lakes can be detected according to the deformation of the ice sheet based on the ICESat and CryoSat-2 altimetry data.The main research on monitoring the subglacial lakes in this paper is as follows:(1)Since the laser altimetry satellite ICESat and radar altimetry satellite CryoSat-2 operated on different principles,a detailed description of the basic principles and key technologies of monitoring subglacial lakes with repeat-track algorithm based on ICESat altimetry data and differential DEM based on CryoSat-2 altimetry data are presented.(2)Using the BEDMAP 2 dataset and CryoSat-2 altimetry data,the Antarctic potential subglacial lakes including the numbers and areas as well as drainage pathways were respectively detected.The similarities and differences of the results according to the two different datasets were compared.Besides,the distribution between the drainage pathways and the subglacial lakes were analyzed based on the drainage basins.(3)Combined with the ICESat and CryoSat-2 altimetry data,the long-term dynamic changes of the CookE2 and the Engelhardt subglacial lakes were obtained from October 2003 to June 2016.Besides,the boundaries of the two lakes were extracted automatically according to the CryoSat-2 data.The strengths and weaknesses of the two different altimetry data to detect the subglacial lakes were introduced.(4)Based on the ICESat and Cryosat-2 satellite altimetry data,the long time series activities of the subglacial lakes in the Totten and Byrd glacier catchment were analyzed.According to the characteristic of the lakes activities and the drainage pathways,the connection between these lakes were analyzed.