AN ADVECTIVE-REFLECTIVE CONCEPTUAL-MODEL FOR THE OSCILLATORY NATURE OF THE ENSO

Recent findings about zonal displacements of the Pacific warm pool req uired a notable modification of the delayed action oscillator theory, the current leading theory for the El Nino-Southern Oscillation (ENSO) . Simulations with a linearized coupled ocean-atmosphere model resulte d in 3- to 6-year ENSO-like oscillations, with many of the variable mo del parameters found to be very close to their observed values. This s imple model suggests that ocean processes that are ignored or underest imated in the delayed action oscillator theory, such as zonal current convergence, zonal advection of sea surface temperature, and equatoria l wave reflection from the eastern ocean boundary, are fundamental to the development of the ENSO, in particular to its manifestations in th e central equatorial Pacific.