Research On The Mass Budeget Of The Lambert Glacier Basin And The Basal Ice Flux Beneath The Amery Ice Shelf, East Antarctica

Our study area is the Lambert Glacier Basin and the Amery Ice Shelf, which is often called The Lambert Glacier-Amery Ice Shelf system together. It is one of the biggest glacier system of Antarctica and accounts for about 16% of the East Antarctic area. The Amery ice shelf drains the grounded ice from the interior of the Lambert Glacier Basin and discharges at the ice shelf front, which is less than 200 km. Therefore, the research on the mass budget of the Lambert Glacier Basin and the Basal ice flux beneath the Amery Ice Shelf is very import to the study about sea level rise and the ice-ocean interaction.In this thesis, the following research is conducted in the key research region of Antarctica: Firstly, a new DEM with high accuracy is generated for the Amery ice shelf, using kriging to interpolate the data from ICESat altimetry. Secondly, the mass budget of Lambert Glacier Basin is assessed by the differences between total accumulation of the basin and the corresponding ice flux through the grounding line, which could decrease the uncertainty of the mass budget of Antarctica. Thirdly, the thickness of marine ice, the basal melting and refreezing rates with their distributions are estimated, using the new DEM and MAMM InSAR velocity data etc. The main results are as follows:I. The ice flux across the grounding line and the total accumulation of the Lambert Glacier Basin are 88.9±8.9 Gt ? a -1 and 84.8±4.2 Gt ? a -1 respectively. The mass budget of the basin is -4.2±9.8 Gt ? a -1. The median and the west of Lambert Glacier Basin have negative imbalances of 2.6±7.9 Gt ? a -1 and 2.5±2.8 Gt ? a -1 respectively, while the eastern has positive imbalance of 0.9±2.3 Gt ? a -1. II. The Amery Ice Shelf marine ice, up to 230m thick, is concentrated in the northwest of the ice shelf. Its mean thickness is 90.4m. The volume of the marine ice is 2.38×103 km3 and accounts for about 5.6% of the shelf volume. The marine ice distribution is consistent with accretion zones obtained from modeling the three-dimensional ocean circulation beneath the Amery Ice Shelf. The thickest marine ice occurs in the two longitudinal bands, oriented along the ice flow direction.III. The detailed distribution map of basal melting and refreezing rate is figured out. The total area of basal melting is 3.44×104 km2. The melting rate is up to 25.0±0.4 m a-1 near the southern grounding line, which decreases rapidly downstream, and transits to refreezing at around 280 km from the southern extremity of the ice shelf. Mean refreezing rates are around 0.6±0.1～2.4±0.4 m a-1. Our estimates of the total basal melting, refreezing and net basal mass losses are 62.4±9.4 Gt a-1, 15.3±2.3 Gt a-1, 47.1±7.1 Gt a-1 respectively. The mean melting rate of the whole ice shelf is 0.75 m a-1.