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什么是厄爾尼諾和拉尼娜現(xiàn)象
[ 2007-10-17 16:08 ]
專題推薦：詞解十七大
大家對厄爾尼諾這個詞應(yīng)該都不陌生，它指的是赤道中、東太平洋海水表面溫度偶爾增暖并導致氣候異常的現(xiàn)象；而拉尼娜現(xiàn)象正好和它相反，指的是赤道附近東太平洋水溫異常下降并導致氣候異常的現(xiàn)象。這兩種現(xiàn)象都會給人類帶來很大的災(zāi)難。
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| Pic from NASA |
The El Nino of '97-98 was one of the most devastating weather cycles, bringing with it more energy than a million Hiroshima bombs. It killed nearly 2,100 people worldwide. As if that wasn't bad enough, El Nino was followed by one of the worst La Nina cycles in recent history - the very next year.
El Nino is a weather pattern that passes through the Equatorial Pacific Ocean every couple of years. In the past 98 years, there have been 23 El Nino systems recorded. El Nino is associated with warmer ocean currents but that's not all that happens when this system passes through.
Air pressure changes during El Nino cause higher temperatures and when they are combined with warmer ocean currents, evaporation takes place at a greater speed. All these elements combined lead to drastic changes in normal weather patterns and abnormal amounts of rain during an El Nino cycle. These rainstorms take place within the Equatorial Pacific Ocean - causing massive flooding for the countries in that area, including the United States, Peru and other parts of South and Central America. While the Eastern Pacific area is being pummeled by extra rain, areas like Australia, Indonesia and India deal with severe drought. This is because much of the moisture that is normally dispersed around the world is evaporating too quickly and staying within the Eastern Pacific Ocean.
Just like everything in the world, El Nino has an opposite, too. La Nina is a weather system that hits the Pacific Ocean between December and March. While there are mild winters and flooding associated with El Nino, the complete opposite is true when La Nina arrives. La Nina brings harsh winters with drought and abnormally low temperatures.
There was a time when these two weather patterns were responsible for thousands of deaths. During the El Nino cycle in 1789, 600,000 people died in one region of India due to severe drought. Thanks to modern science, scientists are now able to predict when we will see these weather systems pass through. This doesn't mean we can necessarily lessen the physical damage they cause but hopefully their predictions will help to save more lives in the future.
Hiroshima bombs:廣島原子彈
Equatorial:赤道附近的
Pummel:連續(xù)擊打
（來源：coolquiz.com 英語點津 Annabel 編輯）
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