Problems and solutions in climate modeling
Although the dramatic increase in computational power, a complete description of the Earth’s climate by means of solutions of the equations of motion is far from being achieved.
Most of the problems arise because the sought solution mostly depend on the second order processes associated with the dynamic and thermodynamic instability processes that plague the system. These instabilities are, in fact, such that the observed behavior strongly departs from the forced response of the atmosphere to the forcing associated with the energy input.
In illustrating the nature of the problem, we shall discuss the Atmospheric General Circulation, i. e. the circulation obtained by averaging the atmospheric motion along the west to east coordinate. Although in this case the description of the motion appears greatly simplified, we will show, both by considering the observed motion and some theoretical model, that the solution requires the parameterization of the momentum and heat fluxes associated to the baroclinic instability of the full three dimensional field.
Moreover, we shall discuss how the sought parameterization strongly depends on the detailed nature of the external parameters.
As a conclusion, some speculations on the nature of the closure needed for this problem will be offered.