El Niño

El Niño is a band of warm ocean water temperatures that periodically develops off the Pacific coast of South America.

El niño is Spanish for "the boy", and the capitalized term El Niño refers to the Christ Child, Jesus, because periodic warming in the Pacific near South America  is usually noticed around Christmas

There is a phase of 'El Niño– Southern Oscillation' (ENSO), which refers to variations in the temperature of the surface of the tropical eastern Pacific Ocean and in air surface pressure in the tropical western Pacific.

The two variations are coupled: the warm oceanic phase, El Niño, accompanies high air surface pressure in the western Pacific, while the cold phase, La Niña, accompanies low air surface pressure in the western Pacific.

Mechanisms that cause the oscillation remain under study


The first signs of an El Niño are:

1. Rise in surface pressure over the Indian Ocean,Indonesia and Australia 
2. Fall in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean
3. Trade Windsin the south Pacific weaken or head east
4. Warm air rises near Peru, causing rain in the northern Peruvian deserts
5. Warm water spreads from the west Pacific and the Indian Ocean to the east Pacific. It takes the rain with it, causing extensive drought in the western Pacific and rainfall in the normally dry eastern Pacific