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Advanced ENSO Theory: The Delayed Oscillator

Introduction
The Simplified Tropical Pacific Ocean
Perturbing the Ocean
Kelvin and Rossby Waves
Evolution of Kelvin and Rossby Waves
The Coupled System
What Happens During El Niño?
References

Introduction

Here we present a more technical discussion of the essential physical mechanism leading to the El- Niño Southern Oscillation (ENSO). The theory described here for the ENSO mechanism was originally postulated in a series of papers that were published in the late 1980's (Schopf and Suarez, 1987; Battisti, 1988; Suarez and Schopf, 1988; Battisti and Hirst, 1989). This theory is known as the delayed oscillator. In order to illustrate the central aspects of the delayed oscillator, we will rely on some idealized numerical calculations. After the basics of the theory have been shown in the idealized setting we will show observational evidence that the delayed oscillator is operating in the tropical Pacific Ocean. This section also makes use of ideas originally put forward in the papers of Wakata and Sarachik (1991), Philander et al. (1984), and Zebiak and Cane (1987).