Day 30

Passage 30

El Niño

① El Niño is an oceanic and atmospheric phenomenon in the Pacific Ocean, during which unusually warm ocean conditions appear along the western coast of Ecuador and Peru, causing climatic disturbances of varying severity. The term was originally used to describe the warm southward current that appears in the region every December, but is now reserved for occurrences that are exceptionally intense and persistent. These occur every three to seven years and can aff ect climates around the world for more than a year. The name El Niño, Spanish for “the Child”, refers to the infant Jesus Christ and is applied because the current usually begins during the Christmas season. Because of the fluctuations in air pressure and the wind patterns in the southern Pacific that accompany El Niño, the phenomenon is known as the El Niño Southern Oscillation, or ENSO.

② Normally, the warm waters are confined to the western tropical Pacific, with temperatures more than 10 Celsius degrees (18 Fahrenheit degrees) higher than the eastern waters of coastal Peru and Ecuador. The air pressure is quite low over the warmer waters. Moist air rises in the region, causing the clouds and heavy rainfall characteristic of Southeastern Asia, New Guinea, and Northern Australia. In the Eastern Pacific, the water is cold and air pressure is high, creating the typically arid conditions along coastal South America. The trade winds blow from east to west, pushing sun-warmed surface waters westward and exposing cold water to the surface in the east.

③However, during El Niño, the easterly trade winds collapse or even reverse. As the slight weakening of the winds causes a modest change in sea surface temperatures, the warm water of the Western Pacific flows back eastward and sea surface temperatures increase significantly off the western coast of South America. As this happens, the wet weather conditions normally present in the Western Pacific move to the east, and the arid conditions common in the east appear in the west. This brings heavy rains to South America and can cause droughts in Southeastern Asia, India, and Southern Africa. It can also bring unusual weather to large parts of the United States.

④The disturbances in the climate also have an eff ect on the economy of various countries. This is felt particularly in coastal Peru and Ecuador. These cold water zones normally support large populations of fish, especially anchovies. The fish are caught commercially and also provide food for seabirds, whose guano is an important component of the regional fertilizer industry. However, few of the fish can get accustomed to the warmer, nutrient-depleted water from the west during an El Niño. As a result, the fish and birds die or leave the area in search of food, thus upsetting the economy of the region.

⑤ ENSO conditions have actually occurred at two-to-seven-year intervals for at least the past 300 years, but most of them have been weak. There is also evidence for strong El Niño events during the early Holocene epoch 10,000 years ago. The first recorded El Niño is in the early 1500s, and it happened every four years at that time. It usually lasted for a few weeks, but major events lasted for a little longer than a year. The El Niño events that began in 1982 and in 1997 were the most severe of the 20th century. The 1982-to-1983 event caused severe droughts in Australia and Indonesia. On the other side of the Pacific Ocean, it brought an unusually large number of storms to California, USA. There were also violent rains and destructive floods in Ecuador and Peru.

——2012年8月17日北美机经

According to Paragraph 3, all the following happen in the eastern area during El Niño except____ .

A. the sea surface temperature increases

B. wet weather prevails

C. arid weather appears

D. warm water flows in

核心词汇：

词汇练习：

阅读下列句子，用所给单词（或词组）的正确形式填空：

reverse persistent modest fluctuation expose component collapse

1. To build up a better picture of____ appreciably further back in time requires us to use proxy records.(TPO-10:Variations in the Climate)

2. In areas where considerable soil still remains, though, a rigorously enforced program of land protection and cover-crop planting may make it possible to____ the present deterioration of the surface.(OG:Desert Formation)

3. Without this muscular action, inhaling is like sucking air out of a balloon—the narrow passages tend to____ .(TPO-24:Breathing During Sleep)

4. The scientists concluded that green icebergs form when a two-layer block of shelf ice breaks away and capsizes (turns upside down), ____the bubble-free shelf ice that was formed from seawater.(OG Test 2:Green Icebergs)

5. Horseshoe crabs kept in the dark continuously for a year were found to maintain a____ rhythm of brain activity that similarly adapts their eyes on a daily schedule for bright or for weak light.(TPO-13:Biological Clocks)

6. In these shops diff erences of rank were blurred as artisans and masters labored side by side in the same____ establishment, were usually members of the same guild and religious sect, lived in the same neighborhoods, and often had assumed (or real) kinship relationships. (TPO-16:Trade and the Ancient Middle East)

7. These characteristics make Spartina a valuable____ of the estuaries where it occurs naturally. The plant functions as a stabilizer and a sediment trap and as a nursery area for estuarine fish and shellfish.(TPO-22:Spartina)

参考答案：

1. fluctuations 2. reverse 3. collapse 4. exposing 5. persistent 6. modest 7. component