A 3-D thermomechanical ice-sheet/ ice-shelf/ lithosphere model was used to reconstruct the history of the Antarctic ice sheet over the last 8 glacial cycles. The glaciological model freely generates ice-sheet volume and extent, has a 20 km horizontal resolution, and is driven by changes of temperature, mass balance, and sea-level. The simulation is driven by a temperature record derived from the Dome C ice core and a sea level record derived from the Bassinot oceanic delta-18O record. Most importantly, we find a regime change in the dynamics of the Antarctic ice sheet centered around Stage 11. For the last 400000 years, the Antarctic ice sheet shows a clear and more or less regular pattern of glacial cycles with glacial-interglacial shifts characterised by waxing and waning of grounded ice over the Ross and Weddell basins. Such behaviour is lacking before Stage 11, when the Antarctic ice sheet stays mostly in glacial model, also during the warm intervals. This behaviour is not necessarily in contradiction with the forcing itself, as the sea-level stand during the interglacials between 750 and 400 ka does not rise above 20 to 25 m, which can be reconciled with a continuous maximum Antarctic ice sheet, but still nearly complete interglacials on the northern hemisphere continents.The presentation will summarize the results of this simulation by showing the evolution of key glaciological variables over the last 740000 years.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL1-Processes and interactions in the polar climate system
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL6-Earth climate variability since the Pliocene