Atmos. Chem. Phys. Discuss., 8, 10873-10911, 2008
© Author(s) 2008. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Quantitative performance metrics for stratospheric-resolving chemistry-climate models
D. W. Waugh1 and V. Eyring2
1Department of Earth and Planetary Science, Johns Hopkins University, Baltimore, MD, USA
2Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany

Abstract. A set of performance metrics is applied to stratospheric-resolving chemistry-climate models (CCMs) to quantify their ability to reproduce key processes relevant for stratospheric ozone. The same metrics are used to assign a quantitative measure of performance ("grade") to each model-observations comparison shown in Eyring et al. (2006). A wide range of grades is obtained, both for different diagnostics applied to a single model and for the same diagnostic applied to different models, highlighting the wide range in ability of the CCMs to simulate key processes in the stratosphere. No model scores high or low on all tests, but differences in the performance of models can be seen, especially for transport processes where several models get low grades on multiple tests. The grades are used to assign relative weights to the CCM projections of 21st century total ozone. However, only small differences are found between weighted and unweighted multi-model mean total ozone projections. This study raises several issues with the grading and weighting of CCMs that need further examination, but it does provide a framework that will enable quantification of model improvements and assignment of relative weights to the model projections.

Citation: Waugh, D. W. and Eyring, V.: Quantitative performance metrics for stratospheric-resolving chemistry-climate models, Atmos. Chem. Phys. Discuss., 8, 10873-10911, doi:10.5194/acpd-8-10873-2008, 2008.
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