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Brazil - What is El Niņo?
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Stormclouds massing above the rainforest |
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Photo: Mike Goldwater/Oxfam
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The waters off the west coast of South America are normally much
colder than would be expected for their position on the globe. At
Lima, Peru, ocean temperatures vary from about 16°C in the winter
to about 20°C in the summer. This cold current of water extends
nearly to the equator before turning to the west. Normally, for
a period of just a few weeks around Christmas each year, this cold
water is replaced by a warm current. This event is called El Niņo,
Spanish for "the child." Every two to seven years, however,
this warm water event lasts much longer and is much more pronounced.
Then it is called a major El Niņo event.
During a major El Niņo, the normally cold water off the west coast
of South America becomes much warmer, while the waters in the western
Pacific cool. These changes are accompanied by a change in the surface
atmospheric pressure patterns. Unseasonal and catastrophic storms,
torrential rain, floods, and even drought in Africa, have been linked
to El Niņo.
A study in 1982-83 showed that the effects of an El Niņo can be
felt far beyond the Pacific and that the phenomenon probably influences
events worldwide.
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