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gfdl's home page > gfdl on-line bibliography > 1988: Journal of Climate, 1(9), 841-866
Two stable equilibria of a coupled ocean-atmosphere model
| Manabe, S., and R. J. Stouffer, 1988: Two stable equilibria of a coupled ocean-atmosphere model. Journal of Climate, 1(9), 841-866. |
| Abstract: Two stable equilibria have been obtained from a global model of the coupled ocean-atmosphere system developed at the Geophysical Fluid Dynamics Laboratory of NOAA. The model used for this study consists of general circulation models of the atmosphere and the world oceans and a simple model of land surface. Starting from two different initial conditions, "asynchronous" time integrations of the coupled model, under identical boundary conditions, lead to two stable equilibria. In one equilibrium, the North Atlantic Ocean has a vigorous thermohaline circulation and relatively saline and warm surface water. In the other equilibrium, there is no thermohaline circulation, and an intense halocline exists in the surface layer at high latitudes. In both integrations, the air-sea exchange of water is adjusted to remove a systematic bias of the model that supresses the thermohaline circulation in the North Atlantic. Nevertheless, these results raise the intriguing possibility that the coupled system may have at least two equilibria. They also suggest that the thermohaline overturning in the North Atlantic is mainly responsible for making the surface salinity of the northern North Atlantic higher than that of the northern North Pacific. Finally, a discussion is made on the paleoclimatic implications of these results for the large and abrupt transition between the Allerod and Younger Dryas events which occurred about 11,000 years ago. |