Adapted from Ray, A.J., J.A. Barsugli, K.B. Averyt, M. Hoerling, and K. Wolter, 2008, Climate Change in Colorado: A Synthesis to Support Water Resources Management and Adaptation for the Colorado Water Conservation Board
In a virtual system, climate models attempt to integrate as much as possible the known factors that influence climate, from the transfer of atmospheric heat into the oceans to the reflection of solar rays by polar and mountain ice. From the climate modeler’s standpoint, the processes that control the climate can be expressed by mathematical equations derived from scientific laws, empirical data, and observations. These equations are converted into computer language and, along with information about the Earth’s geography - such as topography and vegetation - form the basis of a climate model.
To understand how a climate model is constructed, it helps to think of the Earth’s climate as a complex system of many interacting parts that include the atmosphere, oceans, land surface, and sea and land ice. Atmosphere models are the oldest and evolved during the 1960s. They have at their core the equations for fluid motion, which describe air movement, and the first law of thermodynamics, which relates to the conservation of energy, including heat.
Ocean component models followed atmospheric models and were built to simulate ocean currents, salinities, and temperatures. By 1970, the first model integrated the atmosphere and ocean components into what is commonly referred to as atmosphere-ocean general circulation models, or coupled GCMs. Researchers continue to refine these coupled GCMs, by improving their resolution, for example. Models that go beyond climate, such as Earth system models, remain more experimental.
Adapted by Melanie Lenart, University of Arizona
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