用英文介绍一下 厄尔尼诺现象

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问题描述:

谁可以帮我用英文解释介绍一下厄尔尼诺气候现象啊？

解析:

El Ni·?o

A warming of the ocean surface off the western coast of South America that occurs every 4 to 12 years when upwelling of cold, nutrient-rich water does not occur. It causes die-offs of plankton and fish and affects Pacific jet stream winds, altering storm tracks and creating unusual weather patterns in various parts of the world.

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El Ni?o

In general, an invasion of warm water into the central and eastern equatorial Pacific Ocean off the coast of Peru and Ecuador, with a return period of 4–7 years. El Ni?o events e in various strengths: weak, moderate, strong, very strong, and extraordinary. The size of an El Ni?o event can be determined using various criteria: the amount of warming of sea surface temperatures in the central and eastern Pacific from their average condition; the areal extent of that warm water anomaly; and the length of time that the warm water lingers before being replaced by colder-than-average sea surface temperatures in this tropical Pacific region.

Under normal conditions the winds blow up the west coast of South America and then near the Equator turn wesard to Asia. The surface water is piled up in the western Pacific, and the sea level there is several tens of centimeters above average while the sea level in the eastern Pacific is below average. As the water is pushed toward the west, cold water from the deeper part of the ocean along the Peruvian coast wells up to the surface to replace it. This cold water is rich with nutrients, making the coastal upwelling region along western South America among the most productive fisheries in the world. See also Upwelling.

Every 4–7 years those winds tend to die down and sometimes reverse, allowing the warm surface waters that piled up in the west to move back toward the eastern part of the Pacific Basin. With reduced wesard winds the surface water also heats up. Sea level drops in the western Pacific and increases in the eastern part of the basin. El Ni?o condition can last for 12–18 months, sometimes longer, before the wesard flowing winds start to pick up again. Occasionally, the opposite also occurs: the eastern Pacific bees cooler than normal, rainfall decreases still more, atmospheric surface pressure increases, and the wesard winds bee stronger. This irregular cyclic swing of warm and cold phases in the tropical Pacific is referred to as ENSO (El Ni?o Southern Oscillation).

El Ni?o is considered to be the second biggest climate-related influence on human activities, after the natural flow of the seasons. Although the phenomenon is at least thousands of years old, its impacts on global climate have only recently been recognized. Due to improved scientific understanding and forecasting of El Ni?o's interannual process, societies can prepare for and reduce its impacts considerably. See also Climatology; Maritime meteorology; Tropical meteorology.

Numerical models that couple the atmosphere to the ocean have been used to successfully predict the sea surface temperature of the tropical Pacific a year or so in advance. The basic reason that the cycle is predictable is that ENSO evolves slowly and regularly. If the initial state of the atmosphere-ocean system can be characterized accurately, the classification of this state in the ENSO sequence is made (even if it is not pletely recognizable in each system separately), and the future evolution of the cycle can be predicted.