Numerical Resolution and Modeling of the Global Atmospheric Circulation: A Review of Our Current Understanding and Outstanding Issues

Abstract

This chapter presents a survey of published literature related to the issue of how the simulation of climate and atmospheric circulation by global models depend on numerical spatial resolution. To begin the basic question of how the zonalmean tropospheric circulation in atmospheric general circulation models (AGCMs) vary with changing horizontal and vertical grid spacing is considered. The appropriate modification of subgrid-scale parameterizations with model resolution is discussed. Advances in available computational power have recently spurred work with quite fine resolution global AGCMs, and the issue of how well such models simulate mesoscale aspects of the atmospheric circulation is considered. Experience has shown that the AGCM simulated circulation is particularly sensitive to resolution in the stratosphere and mesosphere, and so studies related to the middle atmospheric circulation are considered in some detail. Finally, the significance of atmospheric model resolution for coupled global ocean—atmosphere models and the simulated climate sensitivity to large-scale perturbations is discussed.