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A Regional climate model animation from NARCCAP

An animation ncepjan2000.mp4 (6.4Mb) of one of the NARCCAP regional climate models being forced by the global (and lower resolution) NCEP reanalysis field over the month of January 2000 (courtesy of Stephan Sain). See also NARCCAP for information of the sources of these data and model output.

The NCEP reanalysis is a gridded data product for the atmosphere that uses a weather forecast model with observations to give a physically balanced estimate of the physical variables of the atmopsphere on a 3-d grid. In this animiation the surface precipitation is indicated for NCEP although the actual variables driving (known as forcing) the region model in the interior are moisture, momentum and energy fluxes. This model particular regional model (ECPC) is unusual for a regional model in that it not only uses the fluxes at the domain boundaries but also nudges its interior values to the NCEP field. The finer resolution and more detailed structure in the regional model is considered to be a more accurate simulation of weather processes such as rainfall. The cliamte predicted by the model is found by simulating a long period of weather and averaging the values over time. A numerical simulation where a regional model is forced by observed weather, such as the NCEP reanalysis, is a test of how well the model can reproduced detailed climate under observed conditions. To determine possible changes in climate for the future the NCEP forcings are replaced by the fields from a global climate system that uses future scenarios of greenhouse emissions and other changes to simulate a different set of set of large scale conditions.