Modelling the Atmospheric, Oceanic and Coupled System

A model of the coupled system consists of component models of the atmosphere and of the ocean as well as software to link the two. The atmosphere must see the slowly evolving ocean sea surface temperature (SST) while the ocean must see the rapidly changing weather, in the form of the surface exchange of momentum, heat and freshwater. Although one should consider the coupled system as a whole, much progress has been made by considering aspects of the atmosphere and ocean modules separately. Computer restrictions mean that both the atmospheric and oceanic components have to be simplified. Many processes in both media take place at scales smaller than can be resolved by the component models and so must be parameterised as they cannot be explicitly resolved. Methods to deal with limitations to parameterisation are discussed. A variety of ways of validating testing and improving atmospheric general circulation models is considered.