Climatic conditions for modelling the Northern Hemisphere ice sheets throughout the ice age cycle
نویسنده
چکیده
The ice sheet-climate interaction as well as the climatic response to orbital parameters and atmospheric CO 2 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 5 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 10 the plausible range of parameters related to these processes, the ice sheet response to orbital parameters and atmospheric CO 2 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.
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