Dynamics of the Last Glacial Maximum Antarctic ice-sheet and its response to ocean forcing

Published: Nov 1, 2012 by The PISM Authors

Retreat of the Last Glacial Maximum (LGM) Antarctic ice sheet is thought to have been initiated by changes in ocean heat and eustatic sea level from northern ice sheets melted under rising atmospheric temperatures. The extent to which spatial variability in ice dynamics may have modulated the resultant pattern and timing of decay of the Antarctic ice sheet has so far received little attention, however. We use a 5-km resolution whole-continent PISM model to assess whether differences in the mechanisms governing ice sheet flow could account for discrepancies between geochronological studies in different parts of the continent. We simulate the geometry and flow characteristics of an equilibrium LGM ice sheet. Then we perturb the system with sea level and ocean heat flux increases to investigate ice-sheet vulnerability. We find that although ocean warming and sea-level rise bring about localized glacier acceleration, drawdown of ice from neighboring areas leads to widespread thinning of entire glacier catchments.