NUMERICAL SIMULATION OF SHIRASE GLACIER, EAST QUEEN MAUD LAND, ANTARCTICA

• Main Authors: Frank PATTYN, Hugo DECLEIR
• Format: Report
• Language: English
• Published: Department of Geography, Vrije Universiteit Brussel 1995
• Subjects: Mizuho; Queen Maud Land; Mizuho Plateau; Shirase Glacier; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Polar meteorology and glaciology; Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3882; http://id.nii.ac.jp/1291/00003882/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3882&item_no=1&attribute_id=18&file_no=1

Recent observations in Shirase Drainage Basin, East Queen Maud Land, Antarctica show that the ice sheet is thinning at a considerable rate and that this thinning started about a few thousand years ago. In order to improve insight into the present transient behavior of the ice sheet in Shirase Drainage Basin, a two-dimensional time-dependent flow line model was developed. The ice sheet system model takes into account a coupled ice shelf, longitudinal stress in the ice sheet and grounding zone domain, basal sliding and local isostatic bedrock adjustment. The two-dimensional temperature field is fully coupled to the velocity field. The model is numerically solved on a fine grid, which is unequally spaced both in the horizontal and the vertical directions. By simulating the evolution of the ice sheet during a complete glacial-interglacial cycle it was possible to obtain better insight into the reaction of the ice sheet to environmental changes (temperature, sea-level and mass balance) and to calculate the present local imbalance. Investigation of the role of geothermal heating at the ice sheet base showed that changes in geothermal heat flux and the inclusion of bedrock heating did not alter significantly the overall ice sheet geometry. The dynamical experiments revealed that the present modeled imbalance is much lower than the observed rate of change. Also, a significant discrepancy between the observed and the modeled surface velocities in the stream area could point to a model deficiency in treating the present ice dynamics at the grounding line and the ice tongue. Since the modeled ice dynamics at Mizuho Plateau are more or less in accord with the observed dynamics, we are of the opinion that changes in the dynamic behavior of the ice stream area are a possible cause for the enhanced ice sheet thinning.