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 Annual Mean Precipitation as Simulated by a Global Climate Model, and Observed Values

A climate model is a tool that researchers use to understand the workings of the intricate systems that make up the earth’s climate. Climate researchers can’t conduct experiments in the real world to check their ideas. But computer simulations—which use equations to represent the physical processes of the climate—allow researchers to experiment with a virtual world.

Climate models are complex—like climate itself. To test a climate model, scientists compare the model’s predictions to observations made in the real world. This process, known as validation, allows researchers to see where a model’s predictions match reality—and where the model goes astray.

Researchers working with the climate model that generated the top map recognize that this model distorts annual patterns of precipitation in central Europe. To improve the model’s performance, they are working to incorporate equations that will better represent the effects related to the role of clouds and water vapor in the atmosphere.


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Annual Mean Precipitation

Annual Mean Precipitation as Simulated by a Global Climate Model, and Observed Values - The top map shows the annual mean precipitation simulated by a climate model; the lower map shows observed values of precipitation over the same period. Source: Massachusetts Institute of Technology Center for Global Change Science Climate Modeling Initiative

 questions about the data 

question If we can't predict whether it will rain next week, how can anyone predict what precipitation will be years from now?

email Email your own questions about this data set. 

 research connection  

Comparing predictions with actual outcomes is a fundamental tool of science. Comparing the scenario generated by a climate model with real world conditions is a test for the model—and for the understanding of natural processes that the model represents.

 related sites  

Los Alamos National Laboratory/Global Warming: An Update - This report on global warming includes a discussion of climate models, their limitations, and work being done to improve them.

Uncertainty In Climate Change Policy Analysis - This report includes a map showing how four climate models in their assessment of how global warming affect precipitation in North America.

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