© Springer-Verlag 2001

STOIC: a study of coupled model climatology and variability in tropical ocean regions

M. K. Davey1, Contact Information, M. Huddleston1, K. R. Sperber2, P. Braconnot3, F. Bryan4, D. Chen5, R. A. Colman6, C. Cooper1, U. Cubasch7, P. Delecluse8, D. DeWitt5, L. Fairhead9, G. Flato10, C. Gordon1, T. Hogan11, M. Ji12, M. Kimoto13, A. Kitoh14, T. R. Knutson15, M. Latif16, H. Le Treut9, T. Li11, S. Manabe17, C. R. Mechoso18, G. A. Meehl4, S. B. Power6, E. Roeckner16, L. Terray19, A. Vintzileos9, R. Voss7, B. Wang20, W. M. Washington4, I. Yoshikawa21, J. -Y. Yu18, S. Yukimoto14 and S. E. Zebiak5


Meteorological Office, Bracknell, London Road, Bracknell RG12 2SZ, UK


PCMDI, Lawrence Livermore National Laboratory, Livermore, CA, USA


Laboratoire de Modelisation du Climat et de l'Environnement, France


National Center for Atmospheric Research, Boulder, CO, USA


Lamont Doherty Earth Observatory, Palisades, NY, USA


Bureau of Meteorology Research Centre, Melbourne, Australia


Deutsches Klimarechenzentrum, Hamburg, Germany


LODYC-ISPL, Paris, France


Laboratoire de Meteorologie Dynamique, Paris, France


Canadian Centre for Climate Modelling and Analysis, Victoria, Canada


Naval Research Laboratory, Monterey, CA, USA


National Centers for Environmental Prediction, Camp Springs, MD, USA


Center for Climate System Research, Tokyo, Japan


Meteorological Research Institute, Tsukuba, Japan


Geophysical Fluid Dynamics Laboratory, Princeton, NJ, USA


Max-Planck-Institut für Meteorologie, Hamburg, Germany


Earth Frontier Research System, Tokyo, Japan


University of California Los Angeles, USA


CERFACS, Toulouse, France


University of Hawaii, Honolulu, HI, USA


Japan Meteorological Agency, Tokyo, Japan

Abstract. We describe the behaviour of 23 dynamical ocean-atmosphere models, in the context of comparison with observations in a common framework. Fields of tropical sea surface temperature (SST), surface wind stress and upper ocean vertically averaged temperature (VAT) are assessed with regard to annual mean, seasonal cycle, and interannual variability characteristics. Of the participating models, 21 are coupled GCMs, of which 13 use no form of flux adjustment in the tropics. The models vary widely in design, components and purpose: nevertheless several common features are apparent. In most models without flux adjustment, the annual mean equatorial SST in the central Pacific is too cool and the Atlantic zonal SST gradient has the wrong sign. Annual mean wind stress is often too weak in the central Pacific and in the Atlantic, but too strong in the west Pacific. Few models have an upper ocean VAT seasonal cycle like that observed in the equatorial Pacific. Interannual variability is commonly too weak in the models: in particular, wind stress variability is low in the equatorial Pacific. Most models have difficulty in reproducing the observed Pacific 'horseshoe' pattern of negative SST correlations with interannual Nino3 SST anomalies, or the observed Indian-Pacific lag correlations. The results for the fields examined indicate that several substantial model improvements are needed, particularly with regard to surface wind stress.