A global coupled atmosphere-ocean model

Abstract

A low-resolution version of the European Centre for Medium Range Weather Forecasts global atmosphere model has been coupled to a global ocean model developed at the Max Planck Institut in Hamburg. The atmosphere model is driven by the sea surface temperature and the ice thickness calculated by the ocean model, which, in turn, is driven by the wind stress, the heat flux and the fresh-water flux diagnosed by the atmosphere model. Even though each model reaches stationarity when integrated on its own, the coupling of both creates problems, because the fields calculated by each model are not consistent with those the other model has to have to stay stationary, as some of the fluxes are not balanced. In the coupled experiment the combined ocean-atmosphere system drifts towards a colder state. To counteract this problem a flux correction has been applied, which balances the mean biases of each model. This method makes the climate drift of the coupled model smaller, but additional work has to be done to perfect this method.