Instabilities in the coupled equatorial ocean atmosphere system

Abstract

The large-scale interaction between the ocean and atmosphere is one of the impor- tant factors of natural climate variability.The El-Niño/Southern Oscillation (ENSO) phenomenon in the Tropical Pacific is one of the most prominent examples of climate variability on interannual time scales.ENSO has large effects on climate,even far outside the Pacific basin and occurs at relatively short time scales.Therefore,it is one of the best studied climate phenomena,both observational and theoretical.ENSO is now known as an oscillatory mode in the coupled ocean-atmosphere system,arising through large scale instabilities involving the sea surface temperature,the low level atmospheric winds and movements of the ocean-atmosphere interface.After an intro- duction into the phenomenon and its basic physics,the remainder of the paper focusses on the nature of the instability causing the oscillation.