El Niño is the name given to a change in the flow of water currents in the Pacific Ocean near the equator. El Niño in Spanish means the child. It was given that name because if often occurs around Christmas. Although El Niño takes place in a small portion of the Pacific, it can affect the weather in large parts of Asia, Africa, Indonesia, and North and South America.
The rotation of Earth and the exchange of heat between the atmosphere and the oceans create wind and ocean currents. At the equator, trade winds blow westward over the Pacific, pushing surface water away from South America toward Australia and Indonesia. These strong trade winds bring life giving monsoons to eastern Asia. As warm surface water moves west, cold water from the deep in the ocean rises to replace it.
Every three to five years, the trade winds slacken or reverse direction allowing winds from the west to push warm surface water eastward toward South America. This change is called the Southern Oscillation and is caused by a shifting pattern of air pressure between the eastern and western ends of the Pacific Ocean. The warm, moist air that slams into South America coast brings heavy rains and storms. At the same time, countries on the western Pacific, such as Australia, Indonesia, and the Philippines, have dry weather.
Another type of weather that follows El Niño is La Niña which in Spanish means the girl. La Niña and El Niño are opposite. El Niño is a warming trend that raises the water temperature as much as 5.6 degrees Celsius above normal and La Niña is a cooling of the waters that drops the temperature of the water as much as 8 degrees Celsius below normal.
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