El Nino While some forecasting methods had limited SUCCESS predicting the 1997 E1 Nino - 试题答案网问答

第1题

El NinoWhile some forecasting methods had limited success predicting the 1997 El Nino a fe

El Nino

While some forecasting methods had limited success predicting the 1997 El Nino a few months in advance, the Columbia University researchers say their method call predict large El Nino events up to two years in advance. That would be good news for governments, farmers and others seeking to plan for the droughts and heavy rainfall that El Nino can produce in various parts of the world.

Using a computer the researchers matched sea-surface temperatures to later El Nino occurrences between 1980 and 2000 and were then able to anticipate El Nino events dating back to1857, using prior sea-surface temperatures. The results were reported in the latest issue of the journal Nature.

The researchers say their method is not perfect, but Bryan C. Weare. a meteorologist at the University of California, Davis, who was not involved in the work, said it "suggests'El Nino is indeed predictable.'"

"This will probably convince others to search around more for even better methods." said Weare. He added that the new method "makes it possible to predict El Nino at long lead.times." Other models also use sea-surface temperatures, but they have not looked as far back because they need other data, which is only available for recent decades, Weare said.

The ability to predict the warming and cooling of the Pacitic is of immense importance. The 1997 El Nino, for example, caused an estimated $ 20 billion in damage worldwide, offset by beneficial effects in other areas, said David Anderson, of the European Centre for Medium Range Weather Forecasts in Reading England. The 1877 El Nino, meanwhile, coincided with a failure of the Indian monsoon and a famine that killed perhaps 40 million in India and China, prompting the development of seasonal forecasting, Anderson said.

When El Nino hit in 1991 and 1997, 200 million people were affected by flooding in China alone, according to a 2002 United Nations report.

While predicting smaller El Nino events remains tricky, the ability to predict larger ones should be increased to at least a year if the new method is confirmed.

El Nino tends to develop between April and June and reaches its peak between December and February. The warming tends to last between 9 and 12 months and occurs every two to seven years

The new forecasting method does not predict any major El Nino events in the next two years, although a weak warming toward the end of this year is possible.

El Ninon. 厄尔尼诺现象

equatorial adj.赤道的

occurrence n. 发生

meteorologist n.气象学家

offset v. 抵销

lead adj. 提前的

monsoon n.季风

tricky adj.难以捉摸的

The method used by the Columbia University researchers can predict El Nino a few months in advance.

A．Right

B．Wrong

C．Not mentioned

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第2题

What is an El NinoAn El Nino is a temporary change in the climate of the Pacific Ocean, in

What is an El Nino

An El Nino is a temporary change in the climate of the Pacific Ocean, in the region around the equator. You can see its effects in both the ocean and atmosphere, generally in Northern Hemisphere winter. Typically, the ocean surface warms up by a few degrees Celsius. At the same time, the place where strong thunderstorms occur on the equator moves eastward. Although those might seem like small differences, it nevertheless can. have big effects on the world's climate.

What muses it？

Usually, the wind blows strongly from east to west along the equator in the Pacific. This actually piles up water (about half a meter's worth) in the western part of the Pacific. In the eastern part, deeper water (which is colder than the sunwarned surface water) gets pulled up from below to replace the water pushed west. So, the normal situation is warm water (about 30 ℃; ) in the west, cold (about 22℃ ) in the east. In an El Nine, the winds pushing that water around get weaker. As a result, some of the warm water piled up in the west slumps hack down to the east, and not as much cold water gets pulled up from below. Both these tend to make the water in the eastern Pacific warmer, which is one of the signs of an El Nine. But it doesn't stop there. The warmer ocean then affects the windsit makes the winds weaker! So if the winds get weaker, then the ocean gets warmer, which makes the winds get weaker, which makes the ocean get warmer... This is called a positive feedback, and is what makes an El Nino grow.

So what makes it stop growing？

The ocean is full of waves, but you might not know how many kinds of waves there are. There's one called a Rossby wave that is quite unlike the waves you see when you visit the beach. It is more like a distant cousin to a tidal wave. The difference is that a tidal wave goes very quickly, with all the water moving pretty much in the same direction. In a Rossby wave, the upper part of the ocean, say the top 100 meters or so, will be leisurely sliding one way, while the lower part, starting at 100 meters and going on down, will be slowly moving the other way. After a while they switch directions. Everything happens very slowly and inside the ocean, and you can't even see them on the surface. These things are so slow; they can take months or years to cross the oceans. If you had the patience to sit there while one was going by, you'd hardly notice it; the water would be moving 100 times slower than walking speed. But they are large, hundreds or thousands of kilometers in length (Not height! Remember, you can hardly see them on the surface), so they can have an effect on things. Another wave you rarely hear about is called a Kelvin wave, and it had some characteristics in common with Rosaby waves, but is somewhat faster and can only exist closer to the equator (say, within about 5 degrees of latitude around the equator).

El Ninos often start with a Kelvin wave spreading from the western Pacific over towards South America. Perhaps you saw, on the TV news, the movie (produced by JPL) for the El Nine of 1997/98？ It showed a whitish blob(白色团状物) (indicating a sea level some centimeters higher than usual) moving along the equator from Australia to South America. That is one of the hallmarks of a Kelvin wave, the early part of the El Nino process.

When an El Nino gets going in the middle or eastern part of the Pacific, it creates Rossby waves that drift slowly towards Southeast Asia. After several months of traveling, they finally get near the coast and reflect back. The changes in interior ocean temperature that these waves carry with it "cancel out" the original temperature changes that made the El Nino in the first place. The main point is that it shuts off when these funny interiorocean waves travel all the way ever to the coast of Asia, get reflected, and travel hack, a process that can take many months.

What effects does i

A．Y

B．N

C．NG

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第3题

In an El Nino, the winds pushing the water around get weaker. As a result, some of the war

m water piled up in the west slumps back down to the east, and not as much cold water gets pulled up from below.

A．Y

B．N

C．NG

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第4题

Intensive research is yielding important insight into E1 Nino, a periodic warming of tropi

cal waters in the Pacific that can trigger devastating drought and flooding. Scientists are finding that the phenomenon exists in reverse; some call it La Nina. Typically E1 Nino, like the calamitous 1982 - 1983 event that brought misery to places as far apart as Ecuador, Australia, and southern Africa (National Geographic, February 1984), announces itself with strong westerly winds along the Equator, accompanied by a warm current that usually arrives off western South America around Christmas, which led to its name, Spanish for "the Child". Ocean fisheries suddenly collapse, and coastal deserts reel under torrential rains that sweep away villages.

Scientists now believe that between E1 Ninos there often are La Ninas: one-or-two-year periods when the surface water of the equatorial Pacific becomes cooler. Experts detected the onset of La Nina in the spring of 1988, leading some to link it to last summers' drought in the United States, flooding in Bangladesh, and the abnormal cold winter in Alaska and western Canada.

The early detection of E1 Ninos and La Ninas is an invaluable tool for long-range weather forecasting.

The best title for the passage would be ______.

A．E1 Nino

B．La Nina

C．La Nina or E1 Nino？

D．A Companion for El Nino

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第5题

El Nino occurs irregularly and we sometimes can ______.

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第6题

What's the best title for this passage？A．El NinoB．How Does El Nino HappenC．What Is El Nino

What's the best title for this passage？

A．El Nino

B．How Does El Nino Happen

C．What Is El Nino

D．The Effects of El Nino

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第7题

This passage is devoted to introduction to ______.A．the causes and effects of El Nino weat

This passage is devoted to introduction to ______.

A．the causes and effects of El Nino weather phenomena

B．the worldwide monitoring network set up to predict El Nino

C．the relationship between the ocean temperatures and climate patterns

D．El Nino phenomena and destructive effects of one El Nino event on Ica

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第8题

What can be the possible cause of the changes of El Nino？A．Greenhouse warming.B．Inaccurate

What can be the possible cause of the changes of El Nino？

A．Greenhouse warming.

B．Inaccurate weather forecast.

C．Famine.

D．Accurate forecasts.

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第9题

When El Nino reaches a place, the temperature there would change a great deal.A．YB．NC．NG

When El Nino reaches a place, the temperature there would change a great deal.

A．Y

B．N

C．NG

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第10题

Weare's contribution in predicting El Nino was highly praised by other meteorologists.A．Ri

Weare's contribution in predicting El Nino was highly praised by other meteorologists.

A．Right

B．Wrong

C．Not mentioned

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