How well are subgrid-scale processes described in climate models?

Gunilla Svensson
Department of Meteorology
Stockholm University


The global temperature climate is determined by the energy fluxes at the top of the atmosphere of the earth. The general circulation takes care of the uneven distribution of solar energy. When the climate is in balance, the energy from the sun is balanced by the outgoing radiation. Factors determining the incoming and outgoing radiation is how much of the solar radiation that is reflected by the atmosphere and the earth's surface and the outgoing radiation is depending on the temperature. For both radiation fluxes clouds are very important. When there is a change in the forcing of the climate system, by natural or anthropogenic cause, the system adjust and feed-back systems act. Many of these occur through small-scale processes that are acting on scales much smaller than the computational grid in a climate model. This talk will describe how a few of these small-scale processes, such as boundary-layer turbulence and clouds, are described in climate models and how well they are able to represent the observed climate.