Shan Sun, NASA/GISS, and Rainer Bleck, LANL
Century-scale integrations of a global coupled model consisting of the latest GISS atmospheric model and an updated HYCOM ocean model are carried out, including a control run assuming fixed atmospheric composition, and a perturbation run assuming gradual doubling of CO2. The control run has a small but steady drift. In the global warming scenario, the Atlantic meridional overturning rate is reduced to half the strength of the control run. The mechanism for this reduction and the impact of Southern Ocean ice coverage changes on the meridional overturning circulation and poleward heat transport will be discussed.