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EXPLANATION TEXT ABOUT EL NINO AND LA NINA

The converse of the Niño effect is the La Niña effect, which is an exaggeration of normal conditions. This takes place when trade winds blow strongly and consistently across the Pacific towards Australia. This pushes the warm waters from the central Pacific, off the northern Australian coast, to build up into a mass that is bigger than normal.


The El Niño and La Niña Phenomena
Deviations from normal temperature patterns of the southern Pacific Ocean, between Australia and South America, result in the phenomenon called El Niño. Under normal conditions, eastern trade winds blows across the Pacific. These drive the sun-warmed surface water from the central Pacific to the coast of northern Australia. When clouds form above this area of warm water and move over Indonesia, Papua New Guinea, and Australia, they bring rain with them. Every two to seven years, however, this pattern is interrupted by the El Niño event. During El Niño, the Pacific Ocean of Australia does not warm as much as it normally does. Instead, it becomes warmer right up to the coast of Peru in South America. At the same time, the easterly trade winds that blow across the Pacific reverse their direction. This causes high-pressure systems to build up to the north of and across the Australian Continent, preventing moist tropical air reaching the continent. These conditions in turn result in storms, and in rain falling in the eastern Pacific Ocean and in South America instead of in Australia, Papua New Guinea, and Indonesia, which suffer drought conditions.

EXPLANATION TEXT ABOUT HOW EL NINO AND LA NINA HAPPENED
The combined influence of land, sea and air on weather conditions can create a global climate rhythm. In the Pacific Ocean, for example (A), trade winds normally blow from east to west.(1) along the Equator, "dragging" sun–warmed surface waters into a pool of North Australia and there by the thermocline–the boundary between warm surface waters and the cooler layers beneath (2). High cumulus clouds form above these warm waters, bringing rain in the summer wet season (3). Cooler, nutrient-rich waters rise to surface off Southern America (4). supporting extensive shoals of anchovies on which a vast fishing industry has developed. The weather over this cold water region is dry.