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  3. EI Nino is the term used for the period when sea surface temperatures are ab

EI Nino is the term used for the period when sea surface temperatures are ab

游客2025-04-16  28
问题     EI Nino is the term used for the period when sea surface temperatures are above normal off the South American coast along the equatorial Pacific, sometimes called the Earth’s heartbeat, and is a dramatic but mysterious climate system that periodically rages across the Pacific.
    El Nino means "the little boy" or "the Christ child" in Spanish, and is so called because its warm current is felt along coastal Peru and Ecuador around Christmas. But the local warming is just part of an intricate
set of changes in the ocean and atmosphere across the tropical Pacific, which covers a third of the Earth’s circumference. Its intensity is such that it affects temperatures, storm tracks and rainfall around the world.
    Droughts in Africa and Australia, tropical storms in the Pacific, torrential rains along the Californian coast and lush greening of Peruvian deserts have all been ascribed to the whim of EI Nino. Until recently it has been returning about every three to five years. But recently it has become more frequent--for the first time on record it has returned for a fourth consecutive year--and at the same time a giant pool of unusually warm water has settled down in the middle of the Pacific and is showing no signs of moving.
    Climatologists don’t yet know why, though some are saying these aberrations may signal a worldwide change in climate. The problem is that nobody really seems sure what causes the EI Nino to start, and what makes some stronger than others. And this makes it particularly hard to explain why it as suddenly started behaving so differently.
    In the absence of EI Nino and its cold counterpart, La Nina, conditions in the tropical eastern Pacific are the opposite of those in the west: the east is cool and dry, while the west is hot and wet. In the east, it’s the winds and currents that keep things cool. It works like this. Strong, steady winds, called trade winds, blowing west across the Pacific drag the surface water along with them. The varying influence of the Earth’s rotation at different latitudes, known as the Coriolis effect, causes these surface winds and water to veer towards the poles, north in the northern hemisphere and south in the southern hemisphere. The surface water is replaced by colder water from deeper in the ocean in a process known as upwelling.
    The cold surface water in mm chills the air above it. This cold dense air cannot rise high enough or water vapor to condense into clouds. The dense air creates an area of high pressure so that the atmosphere over the equatorial eastern Pacific is essentially devoid of rainfall. [br] It can be inferred that when EI Nino and La Nina occurs simultaneously, ______
选项 A、the Coriolis effect may make the wind blow to the poles.
B、the atmosphere in the Pacific will be short of rainfall.
C、the conditions in the eastern Pacific may be hot and wet.
D、the cold dense vapor will rise high enough to form droplets.
答案 C
解析 题干问：“从文中可以得知当厄尔尼诺和拉尼娜现象同时发生时……”。此题为段落考察题，正确选项为C“东太平洋的气候状况湿润闷热”，定位在第5自然段第1句。而选项A“科里奥利力的作用导致了风往极向运动”，这不是厄尔尼诺现象直接造成的结果。选项B“太平洋地区缺乏雨”和选项D“冷的高密度的蒸汽升空后会形成雨滴”这都是对原文编造的答案。
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