2001 Reports

Seasonal Comparison of the Response of CCM3.6, ECHAM4.5 and COLA2.0 Atmospheric Models to Observed SSTs

Camargo, Suzana J.; Zebiak, Stephen E.; DeWitt, David G.; Goddard, Lisa M.

The main features of three atmospheric general circulation models forced with monthly-mean, observed sea surface temperature for the 1979-1995 period are analyzed and compared with observational data. The ensemble means and intra-ensemble standard deviations of several variables were investigated for the two seasons December-January-February and June-July-August. Correlations of the ensemble mean anomalies with observational data and with the indices Nino-3 and the Atlantic Dipole were also calculated. The probability distribution function of the precipitation at different regions was also examined, as well as the internal and external variance of the precipitation in the three models. No model has uniformly better characteristics than the others. On the contrary, each model has strengths and weaknesses that depend on the region and season.