© 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

(1)

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

(2)

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

(3)

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

(4)

National Center for Atmospheric Research, Boulder, CO, USA

(5)

Lamont Doherty Earth Observatory, Palisades, NY, USA

(6)

Bureau of Meteorology Research Centre, Melbourne, Australia

(7)

Deutsches Klimarechenzentrum, Hamburg, Germany

(8)

LODYC-ISPL, Paris, France

(9)

Laboratoire de Meteorologie Dynamique, Paris, France

(10)

Canadian Centre for Climate Modelling and Analysis, Victoria, Canada

(11)

Naval Research Laboratory, Monterey, CA, USA

(12)

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

(13)

Center for Climate System Research, Tokyo, Japan

(14)

Meteorological Research Institute, Tsukuba, Japan

(15)

Geophysical Fluid Dynamics Laboratory, Princeton, NJ, USA

(16)

Max-Planck-Institut für Meteorologie, Hamburg, Germany

(17)

Earth Frontier Research System, Tokyo, Japan

(18)

University of California Los Angeles, USA

(19)

CERFACS, Toulouse, France

(20)

University of Hawaii, Honolulu, HI, USA

(21)

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.