general circulation model, definition of

A global, three-dimensional computer model of the climate system; GCM's are highly complex and they represent the effects of such factors as reflective and absorptive properties of atmospheric water vapor, greenhouse gas concentrations, clouds, annual and daily solar heating, ocean temperatures and ice boundaries. The most recent GCM's include global representations of the atmosphere, oceans, and land surface.

They are often used to model the effects of human induced climate change into the future; but the accuracy of the models are highly dependent upon:

• The accuracy of the initial starting conditions;
• The accuracy of how the climatic processes are modeled, and;
• The accuracy of the assumptions made in the model construction.

Related Tags: environment, climate, atmosphere