domingo, 22 de agosto de 2010


El Niño and La Niña are the names of two atmospheric-oceanic phenomena that occur cyclically varying periods of 2-7 years. Have a higher incidence in the Pacific Ocean and around the latitude of Ecuador. Its effects are regional and global status as transforming the climate of almost the entire Earth. For example, during the 1997-1998 El Niño event in Mongolia temperature reached 42 ° C and precipitation in central Europe caused a major flood of the century.

This phenomenon severely affects the social, economic and political status of countries, altering its production cycle and socio-economic growth. In humid areas usually originate prolonged droughts in arid areas are produced torrential rains and waves of heat or cold in different parts of the world.
Usually, this means heavy losses in economic activities, especially in primary activities, so much more to affect developing countries where they are the foundation of its economy. For example:

• drought, increase the mortality of livestock and forest fires that pollute the environment and cause loss of biodiversity.

• Torrential rains cause severe flooding and mudslides and rocks; increasing the temperature of the water away from some fishing grounds important fish species for their commercial value thus impeding fishing.

• other activity is tourism affected, source of income for these countries.

Now, how is the atmosphere-ocean circulation in normal times?

The trade winds blow from east to west and drag the warm waters of the Pacific Ocean to its western sector. For this reason, Asian and Australian coasts, the sea is about 50 cm. higher and 70 C to 90 C warmer than on the American coasts. This causes:

• off the coast of Southeast Asia during the summer, has increased evaporation of water. The monsoon winds carry moisture causing rainfall over the continent, and allow the practice of intensive agriculture, which provides food for millions of people;

off the American coast, where the cold currents circulating in California and Humboldt, it is hard to evaporation. This produces a climate on the coast is arid and warm surface waters are not very thick. This process allows the rise of deep waters with nutrients that feed the abundant fish, generating one of the most productive fishing areas in the world

When El Niño occurs is an alteration in atmospheric pressure over the Pacific Ocean near Tahiti decreases and increases in northern Australia. The trade winds weaken or even disappear resulting in both the atmosphere and oceans, large anomalies. The trade winds are not strong to drag warm surface waters to the coasts of Asia, then return to American shores forming the counter El Niño. This results in atmospheric and oceanic effects contrary to those normal times. That is, in the Asian coasts are droughts, forest fires and so forth. In turn, on the American coasts are unleashed major tropical storms, landslides and floods that carry.

The girl in turn, causes a reverse mechanism that produced El Niño atmospheric pressure in Tahiti and low rises in Australia, restoring the normal flow direction but more strongly. The trade winds blow more strongly than the normal crawling toward the western Pacific larger volume of water, causing it to draw out more of cold water in the eastern Pacific. This leads to above normal rainfall in Asia, Australia and even South Africa. Meanwhile, the temperature drops on the American coasts and increasing aridity and the frequency of hurricanes in the U.S. central plains

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