Abstract
A coupled ocean-atmosphere model of El Nino and the Southern Oscillation is discussed. The model ocean is a reduced-gravity system that also includes an equation for the temperature of the layer, T. The model atmosphere is a linear, single-baroclinic mode system driven by convection, Q. The wind stress used to drive the model ocean is proportional to the wind velocity produced by the model atmosphere, while Q over the ocean is a function only of T. Some of the solutions also involve land as well as ocean; in that case, Q over land is either a fixed forcing function or it is set to zero.
For a broad range of model parameters, solutions oscillate at the long time scales associated with El Nino and the Southern Oscillation (ENSO). In all cases, the basic process causing the oscillation is the growth of unstable disturbances to finite amplitude and their subsequent slow eastward propagation. The dynamics of the instability are nicely illustrated in the simpler analyses of Lau (1981), Philander et al. (1984) and others.
Solutions compare favorably with observations of ENSO in several respects. For example, for a basin geometry that most resembles the Indian and Pacific Oceans, strong permanent convection exists in the eastern Indian Ocean, and there is a oscillation in the Pacific Ocean with a period of about five years. Associated with this oscillation is a patch of convection that develops in the central and western ocean and propagates into the eastern ocean before dissipating. Solutions do not compare favorably in other ways. A major limitation is that they do not simulate the rapid onset or intermittancy of ENSO.
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© 1986 D. Reidel Publishing Company, Dordrecht, Holland
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McCreary, J.P. (1986). Coupled Ocean-Atmosphere Models of El Nino and the Southern Oscillation. In: Willebrand, J., Anderson, D.L.T. (eds) Large-Scale Transport Processes in Oceans and Atmosphere. NATO ASI Series, vol 190. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-4768-9_7
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DOI: https://doi.org/10.1007/978-94-009-4768-9_7
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