El Nino Southern Oscillation as Sporadic Oscillations between Metastable States

TL;DR

This paper proposes a new self-organizing mechanism for ENSO, modeling it as sporadic oscillations between metastable states driven by coupled processes of sea surface temperature variations.

Contribution

It introduces a novel natural feedback mechanism for ENSO based on dynamic transition theory, explaining its sporadic oscillations as metastable state transitions.

Findings

ENSO exhibits metastable warm and cold states.

The interplay of coupled processes explains ENSO's variability.

A new feedback mechanism drives sporadic ENSO oscillations.

Abstract

The main objective of this article is to establish a new mechanism of the El Nino Southern Oscillation (ENSO), as a self-organizing and self-excitation system, with two highly coupled processes. The first is the oscillation between the two metastable warm (El Nino phase) and cold events (La Nina phase), and the second is the spatiotemporal oscillation of the sea surface temperature (SST) field. The interplay between these two processes gives rises the climate variability associated with the ENSO, leads to both the random and deterministic features of the ENSO, and defines a new natural feedback mechanism, which drives the sporadic oscillation of the ENSO. The new mechanism is rigorously derived using a dynamic transition theory developed recently by the authors, which has also been successfully applied to a wide range of problems in nonlinear sciences.