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Abstract:
he Northern Patagonian Ice Field (NPI), Chile, is the second-largest ice body in the Southern Hemisphere outside Antarctica, and one of the two remnant parts of the Patagonian ice sheet that existed during the last glacial period. It is located in the Southern Andes, a region that was identified to have one of the most negative specific mass balances of the world’s glacierized regions. The NPI is a highly dynamic ice body, characterized by large accumulation/ablation rates, and also a large contribution of calving to the overall mass balance produced by both ocean- and lake-terminating glaciers. We set up the ice-sheet model SICOPOLIS (SImulation COde for POLythermal Ice Sheets, for the NPI with horizontal resolutions of 450 and 900 m. The main input data are the present-day surface and bed topography (the latter generated by a mass conservation algorithm) and a simulated surface mass balance . For validation purposes, distributions of the surface velocity as well as the change of surface elevation, both obtained by satellite measurements, are available. Forcing the model with a constant present-day surface mass balance a steady state is achieved which shows much similarity with the current state of the icefield. When forcing the model with a moderate climate change scenario, constant mass loss during the 21st century and a stabilization of the icefield at slightly more then half of its current ice volume is observed during the 22nd century. The greatest challenge of the simulations is to reproduce the behavior of the calving glacier tongues.
