Simulation of glacial cycles with a climate-ice sheet model of intermediate complexity
Dr. Andrey Ganopolski
Reinhard Calov, Andrey Ganopolski
Climate Research Potsdam Institute for Climate Impact Research
Simulations of the last four glacial cycles were performed with the coupled climate-ice sheet model of intermediate complexity CLIMBER-2 using the orbital variations and greenhouse gases concentrations as prescribed forcings. The model reproduces a number of important aspects of glacial climate variability both on orbital and millennial time scales, including dominating 100-kyr cycle and numerous abrupt climate changes resembling in temporal and spatial dynamics Dansgaard-Oeschger and Heinrich events. The role of dust-snow albedo and CO2 feedbacks are studied in a suite of sensitivity experiments. Results of model simulations also help to explain some phase relationships between different climate proxies seen in paleoclimate record. Overall, our modeling results suggest that a considerable portion of glacial climate variability arises from the direct and strongly nonlinear response of the northern hemisphere ice sheets to the variations in Earths orbital parameters amplified by a number of positive feedbacks and an intrinsic instability of the Atlantic thermohaline circulations and the ice sheets.
