A model which isolates the interaction between midlatitude ocean gyres and the wind-stress is formulated. The ocean and atmosphere are coupled through their respective heat balances, and global heat and momentum conservations are enforced. The oceanic contribution to the global heat balance steepens the midlatitude atmospheric temperature gradients resulting in a well-defined climatological storm-track.
Because of the delayed adjustement of the oceanic gyres to the wind-stress, the coupled system equilibrates into a state which is periodic in time, with a period of about eighteen years. The hallmark of this coupled mode of variability is that the oceanic and atmospheric northward heat transport anomalies are out of phase. This oscillatory state is characterized by equatorward propagation of alternating warm and cold anomalies of upper ocean temperature, suggesting that the tropics are modulated by midlatitude dynamics on decadal time scales.
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12th Conference on Atmospheric and Oceanic Fluid Dynamics