Development of Efficient, Dynamical Ocean-Atmosphere Models for Climatic Studies

Abstract

Abstract Three ocean-atmosphere models are constructed and evaluated for further studies of climatic variability and climatic sensitivity. All the models are based on the two-layer, highly truncated spectral atmospheric model of Held and Suarez modified to have a seasonal cycle of solar forcing and to interact with simple geographical distributions of land and sea. For simplicity, a 120° sector configuration is adopted. The first coupled model has as its oceanic component two motionless layers, connected by vertical diffusion and convective adjustment. This is chosen to represent the seasonal cycle in the upper ocean more realistically than a constant-thickness mixed layer. The effect of wind stirring on mixed-layer thickness is added in the second coupled model. The third coupled model is one in which three-dimensional ocean circulation is included, using a relatively fine oceanic grid (1.5°). Long integrations of the three coupled models are carried out in order to understand their intrinsic dynamics. T...