Climatic conditions for modelling the Northern Hemisphere ice sheets throughout the ice age cycle

A. Abe-Ouchi (1, 2) , T. Segawa (2) , F. Saito (2)

1 CCSR - Center for Climate System Research [Kashiwa]
2 FRCGC - Frontier Research Center for Global Change

The ice sheet-climate interaction as well as the climatic response to orbital parameters and atmospheric CO₂ content are examined in order to drive an ice sheet model throughout an ice age cycle. Feedback processes between ice sheet and atmosphere are analyzed by numerical experiments using a high resolution General Circulation Model (GCM) under different conditions at the Last Glacial Maximum. Among the proposed processes, the ice albedo feedback, the elevation-mass balance feedback and the desertification effect over ice sheet were found to be the dominant processes for the ice-sheet mass balance. The temperature lapse rate over the ice sheet is proposed to be about 5 °C km^?1, which is weaker than assumed in other studies. Within the plausible range of parameters related to these processes, the ice sheet response to orbital parameters and atmospheric CO₂ content for the last glacial/interglacial cycle was simulated in terms of both ice volume and geographical distribution, using a three-dimensional ice-sheet model. Careful treatment related to climate-ice sheet feedback is essential for a reliable simulation of ice sheet changes during ice age cycles.

Domaines: Interfaces continentales, environnement; Sciences de la Terre

A. Abe-Ouchi, T. Segawa, F. Saito. Climatic conditions for modelling the Northern Hemisphere ice sheets throughout the ice age cycle. Climate of the Past Discussions, 2007, 3 (1), pp.301-336. ⟨hal-00298176⟩