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Simulating El Niņo: How Are the Models Doing?
Latif, M., Sperber, K., Arblaster, J., Braconnot, P., Chen, D., Colman, A., Cubasch, U., Cooper, C., Delecluse, P., DeWitt, D., Fairhead, L., Flato, G., Hogan, T., Ji, M., Kimoto, M., Kitoh, A., Knutson, T., Le Treut, H., Li, T., Manabe, S., Marti, O., Mechoso, C., Meehl, G., Power, S., Roeckner, E., Sirven, J., Terray, L., Vintzileos, A., Voss, R., Wang, B., Washington, W., Yoshikawa, I., Yu, J. and Zebiak, S.  2001.  ENSIP: the El Niņo simulation intercomparison project.  Climate Dynamics 18: 255-276.

What was done
The authors compared 24 coupled ocean-atmosphere climate models with respect to their ability to correctly simulate the annual mean state, the seasonal cycle, and the interannual variability of sea surface temperatures (SSTs) in the tropical Pacific Ocean.

What was learned
In the words of the authors, "almost all models (even those employing flux corrections) still have problems in simulating the SST climatology."  They also note that "only a few of the coupled models simulate the El Niņo/Southern Oscillation (ENSO) in terms of gross equatorial SST anomalies realistically."  And they state that "no model has been found that simulates realistically all aspects of the interannual SST variability."

What it means
What is particularly scary about these findings is that they apply to what the authors call "a key region which affects many regions on the globe and which may also be of great importance within the framework of global change."  For this important task, i.e., attempting to anticipate future global change, the authors say "there appears to be a large potential to improve the coupled models, even if very basic diagnostics are considered."  We totally agree with them, concluding further that until these "large improvements" are made, we should not place great confidence in what they imply about the future.

Reviewed 26 June 2002