The Cryosphere Discussions www.the-cryosphere-discuss.net 1994-0432 1994-0440 4 3 2010 10.5194/tcd-4-1307-2010 http://www.the-cryosphere-discuss.net/4/1307/2010/ http://www.the-cryosphere-discuss.net/4/1307/2010/tcd-4-1307-2010.html http://www.the-cryosphere-discuss.net/4/1307/2010/tcd-4-1307-2010.pdf 1307 1341 2010-08-18 The Potsdam Parallel Ice Sheet Model (PISM-PIK) – Part 2: Dynamic equilibrium simulation of the Antarctic ice sheet M. A. Martin R. Winkelmann M. Haseloff T. Albrecht E. Bueler C. Khroulev A. Levermann anders.levermann@pik-potsdam.de Earth System Analysis, Potsdam Institute for Climate Impact Research, Potsdam, Germany Institute of Physics, Potsdam University, Potsdam, Germany Dept. of Physics, Humboldt-University, Berlin, Germany Dept. of Mathematics and Statistics, University of Alaska, Fairbanks, USA Geophysical Institute, University of Alaska, Fairbanks, USA We present a dynamic equilibrium simulation of the ice sheet-shelf system on Antarctica with the Potsdam Parallel Ice Sheet Model (PISM-PIK). The simulation is initialized with present-day conditions for topography and ice thickness and then run to steady state with constant present-day surface mass balance. Surface temperature and basal melt distribution are parameterized. Grounding lines and calving fronts are free to evolve, and their modeled equilibrium state is compared to observational data. A physically-motivated dynamic calving law based on horizontal spreading rates allows for realistic calving fronts for various types of shelves. Steady-state dynamics including surface velocity and ice flux are analyzed for whole Antarctica and the Ronne-Filchner and Ross ice shelf areas in particular. The results show that the different flow regimes in sheet and shelves, and the transition zone between them, are captured reasonably well, supporting the approach of superposition of SIA and SSA for the representation of fast motion of grounded ice. This approach also leads to a natural emergence of streams in this new 3-D marine ice sheet model. Albrecht,~T., Martin,~M A., Winkelmann,~R., Haseloff,~M., and Levermann,~A.: Parametrization for subgrid-scale motion of ice-shelf calving-fronts, The Cryosphere Discuss., submitted, 2010. 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