Diagnosis of the mean simulated climate of the Community Climate System Model (CCSM2.0) is performed by calculating a normalized root mean square difference between model output and accepted observational datasets or their proxies [1]. We display these results for numerous atmospheric fields over a selection of temporal and spatial regions in order to provide a comprehensive multivariate view of the model's performance. We also calculate the change in these diagnostic quantities from previous versions of coupled models developed at the National Center for Atmospheric Research (NCAR). Although highly averaged, such changes illustrate how a model simulation may have improved or degraded relative to the observations and provide a useful roadmap to further investigation into model performance changes. Our preliminary findings indicate general improvement of the CCSM2.0 control run simulation over results from two previous models, the NCAR Climate System Model Version 1 and the Parallel Climate Model.

This work was performed under auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48 and by the University of California Lawrence Berkeley National Laboratory under contract No. DE-AC03-76SF00098.

[1] Curt Covey, Krishna M. AcutaRao, Michael Fiorino, Peter J. Gleckler, Karl E. Taylor and Michael F. Wehner, Intercomparison of Climate Data Sets as a Measure of Observational Uncertainty, PCMDI Report #69, LLNL Report UCRL-ID-147371, April 2002. Available on the Web at http://www-pcmdi.llnl.gov/pcmdi/pubs/pdf/rpt69.pdf.