HOW DOES THE GREENLAND ICE-SHEET GEOMETRY REMEMBER THE ICE-AGE

The response of the Greenland ice sheet geometry to glacial/interglacial climatic transition is studied by using a numerical ice sheet dynamical model. The possible contribution due to the increase in melting, snow accumulation, ice temperature and accumulation of harder ice during the Holocene is examined. The results imply that: (1) within 1000 years after the termination of the Ice Age, the present ice sheet became thicker than that during the Ice Age, mainly due to the increase in snow accumulation, (2) at present, about 10,000 years after the transition, the ice sheet is still reacting to the change in ice temperature and the advection of harder Holocene ice, effects which are partly compensating each other, (3) the central part of the ice sheet may be thinning slightly by about 4 mm per year because of the somewhat quicker response of the ice sheet to temperature change than to advection of the harder Holocene ice, (4) the influence due to the repetition of the ice age cycles is negligible. Since the rate of change at present is below the detection threshold, observation of the elevation change must be explained by the short-term climatic change.