thesisThis thesis reviews the techniques used to model the circulation of the atmosphere and oceans. Models of the atmospheric and oceanic circulation can be used to evaluate future and past conditions of the climate of the Earth. They can also be used to evaluate what affect any changes to the parameters for the Earth's environment might have on the climate of the Earth. For models of the atmosphere, physical properties of the air and of the rotating Earth are used to develop equations for the state and motion of the air in the atmosphere. These equations represent the relationships between the temperature, density, and wind speeds of the air in the atmosphere. The final equations are a set of nonlinear partial differential equations which require a numerical solution. There are several methods used to accomplish a numerical solution to these equations. Models of the ocean can be developed in much the same way as models of the atmosphere. The differences include the fact that sea water is essentially incompress- ible. The models are much more complicated as the oceans are much more limited by the shape of the continents and so do not cover the entire Earth like the atmosphere does. To aid in the understanding of ocean circulation, simpler models of the main circulation of the oceans have been developed as "boxes" of sea water connected by flows of sea water between the boxes which are driven by differences in density between the boxes of sea water. The density of the sea water is a function of the temperature and salinity of the water in each part of the ocean. These box models show that there are multiple equilibrium states for the circulation of the ocean
