The East Antarctic Lambert Glacier Basin Upstream Material Balance Temporal And Spatial Variation Study

Antarctic Ice Sheet mass balance plays an important role on global sea level change. It is of great concern and one of the top priorities in polar research field. Lambert Glacier-Amery Ice Shelf System is one of the largest glacier-ice-shelf system in Antarctica. Lambert Glacier Basin, the interior grounded ice region, is an important drainage basin in terms of the overall mass balance of Antarctica.Based on small drainage basins, in this thesis, I analyze the temporal and spatial variations in the mass balance of Lambert Glacier Basin at high elevations in GIS environment, using ICESat GLAS data,Antarctic DEMs,Vaughan and Giovinetto accumulation compilations,ice fluxes obtained by previous studies and Davis dH/dt data. Major conclusions are as follows:(1) By comparing ICESat GLAS data with four Antarctic DEMs, Bamber-DEM is used to divide Lambert Glacier Basin into 17 drainage basins. The total research area is 941989.0㎞²;(2) Mass budgets of the small drainage basins are assessed using component approach, and then converted to dH/dt. The mass budget for the whole Lambert Glacier Basin at high elevations is 5.4±6.4 Gt a^-1;dH/dt is 16.2±19.6mm a^-1。(3) dH/dt for the small drainage basins is estimated using integrated approach, and then converted to mass budgets. The dH/dt for the whole Lambert Glacier Basin at high elevations is 25.6±3.7 mm a^-1;the mass budget is 8.2±1.2Gt a^-1.(4) The results of mass balance between component and integrated approaches have relatively smaller differences. From 1992 to 2003, the difference is 9.4±19.9mm a^-1 in dH/dt,and 2.8±6.5 Gt a^-1 in mass budget.(5) It is found that the entire research region has a positive imbalance with larger spatial variability. The results obtained using component approach show that the 1st, 2nd, 9th, 10th, 14th, 15th and 16th small drainage basin has a negative imbalance, their total mass budget is -4.51±0.99Gt a^-1;the others have a positive imbalance, with a total mass budget of 10.2±1.3Gt a^-1. The results by integrated method show all small drainage basins has a positive imbalance, with a total mass budget of 8.2±1.2 Gt a^-1; and the 15th small drainage basin has the largest positive imbalance of 1.24±0.19Gt a^-1,the 3rd is the least, 0.06±0.009Gt a^-1.(6) Recently, the entire study region is thickening. The results by component approach show it is thickening at a rate of 16.2±19.6 mm a^-1. It is thickening at a rate of 25.6±3.7 mm a^-1 from 1992 to 2003 by integrated approach.