A simple atmospheric model of relevance to El Nino

A linear, equatorial, beta-plane atmosphere model with heating parameterized in terms of SST anomalies is developed and used to simulate surface wind anomalies in the equatorial Pacific during El Nino. The model results show some similarity to observations with respect to movement of the major convergence zones, and equatorial wind anomaly patterns in the central and western Pacific. There is considerable discrepancy between the model results and observations in much of the eastern Pacific, especially in the South Pacific high and southeast trades regions. The results suggest that some additional mechanisms may be responsible for these apparently sizeable and spatially coherent fluctuations, but that a direct link between wind anomalies and SST anomalies may indeed exist in much of the equatorial Pacific.