VOA慢速英语2012 SCIENCE IN THE NEWS - Severe Ocean Storms: The Science of Nature's Power

 

SCIENCE IN THE NEWS - Severe Ocean Storms: The Science of Nature's Power

This is SCIENCE IN THE NEWS, in VOA Special English. I’m Barbara Klein.

And I’m June Simms. Today we tell about the science of severe ocean storms. Severe storms that develop over the Indian Ocean are called cyclones¹. Storms that form over the northwestern Pacific Ocean are typhoons. And storms that form over the eastern Pacific and the Atlantic Ocean are hurricanes. 

A storm named Isaac recently brought death and destruction² to the United States and islands in the Atlantic and Caribbean Sea. Wide, slow-moving Isaac came to life over waters near the island of Puerto Rico. At the time, the storm was not yet a hurricane. Instead, it was called a tropical³ depression. Then it grew in strength and size, was declared a tropical storm, and stayed that way for days. 

Isaac passed over Haiti, killing⁴ at least twenty-nine people. Five people were confirmed dead from the storm in the Dominican Republic.

Weather experts finally declared Isaac a hurricane as it moved toward⁵ the southern United States. Parts of Louisiana were still recovering from Hurricane Katrina, a powerful storm seven years earlier.

Isaac’s strong winds and rains cut electricity to nine hundred thousand homes and businesses in the state. Damage to agriculture was estimated⁶ in the millions of dollars. The storm also struck hard in Mississippi, Arkansas and other states.

The city of New Orleans largely⁷ escaped severe damage. But areas near it, like Plaquemines Parish, suffered huge floods. Plaquemines is on a piece of land shaped like a finger. It runs along the Mississippi River into the Gulf⁸ of Mexico. That is where Isaac – and Katrina before it -- made landfall. Plaquemines also suffered major damage during Katrina.

Isaac caused a number of tornadoes⁹, powerful wind storms, in states as far away as Illinois and Missouri. By the time it was over, nine people were reported dead in the United States. 

How did Isaac get its name? Naming storms and other natural events has been a tradition for centuries. For example, the name “Thor” was given to the mythical¹⁰ Norse god of thunder, the loud sound that follows lightning in the sky. 

An Australian scientist began calling storms by women's names before the end of the nineteenth century. During World War Two, scientists called storms by the names of their wives or girlfriends.

American weather experts started to use women's names for storms in nineteen fifty-three. In nineteen seventy-nine, they began to use men's names, too.

Scientists choose the names of storms many years before they are used. They decide on them at meetings of the World Meteorological Organization. The National Hurricane Center in Miami, Florida has one list for each of six years for Atlantic storms. Its experts name storms when they reach wind speeds of sixty-two kilometers an hour. That is true even if they never grow stronger.

The first name used in a storm season begins with the letter A. The second begins with B and so on. The letters Q, V, X, Y and Z are never used. And the same list of names is not used again for at least six years. And different lists are used for different parts of the world. A name is retired¹¹ when the storm with this name has been very destructive¹², like Hurricane Katrina in two thousand five.

That same year, Greek letters had to be used for the first time to name storms in the Atlantic. That was the plan -- to call storms Alpha, Beta and so on -- if there were ever more than twenty-one named storms in a season. As it happened, there were twenty-eight.

Ocean storms develop when the air temperature in one area is different from the temperature nearby. Warmer air rises, while cooler air falls. These movements create a difference in atmospheric¹³ pressure. 

If the pressure changes over a large area, winds start to blow in a huge circle. High-pressure air is pulled toward a low-pressure center. Thick clouds form and heavy rains fall as the storm gains speed and moves over the ocean. Storms can get stronger as they move over warm ocean waters.

The strongest, fastest winds of a hurricane blow in the area known as the eyewall. It surrounds the center, or eye, of the storm. The eye itself is calm by comparison¹⁴. 

Wind speeds in the most severe ocean storms can reach more than two hundred fifty kilometers an hour. Up to fifty centimeters of rain can fall. Some storms have produced more than one hundred fifty centimeters of rain.

These storms also cause high waves and ocean surges¹⁶. A surge¹⁵ is a continuous¹⁷ movement of water that may reach as high as six meters or more. The water strikes low coastal¹⁸ areas. Surges are commonly responsible for about ninety percent of all deaths from ocean storms.

The National Hurricane Center in Miami keeps close watch on severe storms. It works¹⁹ with government officials and with radio and television stations to keep people informed. Experts believe this early warning system has helped reduce deaths from ocean storms in recent years. 

But sometimes people cannot or will not flee the path of a storm. That is what happened in some parts of Louisiana when Hurricane Isaac struck.

Studies have found that some people do not leave a storm-threatened area because they have no transportation or money for transportation. Another reason is that they fear their property will be damaged by other people, if not by the storm. Yet another reason is that people do not want to leave their farm animals or pets. Today, more plans exist for animal care during severe storms than in years before. 

Weather experts use computer programs to create models that show where a storm might go. The programs combine information such as temperatures, wind speed, atmospheric pressure and the amount of water in the atmosphere.

Scientists collect the information with satellites, weather balloons and devices²⁰ floating in the oceans. They also receive information from ships and passenger airplanes and other flights. Government scientists use specially-equipped planes to fly into and around storms. The crews drop instruments tied to parachutes. The instruments collect information about temperature, pressure and wind speed.

Scientists use the Saffir-Simpson Hurricane Scale to measure the intensity²¹ of storms based on wind speed. This provides an idea of the amount of coastal flooding and property damage that might be expected. The scale is divided into five groups or categories.

The mildest hurricane is a category one, which is what Isaac was at its strongest. A hurricane called “Cat One” has winds of about one hundred twenty to one hundred fifty kilometers an hour. This storm can damage trees and lightweight structures. It can also cause flooding.

Wind speeds in a category two hurricane can reach close to one hundred eighty kilometers an hour. These storms are often powerful enough to break windows or blow the tops off houses.

Winds between about one hundred eighty and two hundred fifty kilometers an hour represent categories three and four. A more powerful storm is a category five hurricane. Researchers say forces other than wind speed help cause extensive²² destruction. And the lower the air pressure, the stronger the storm. Water caused Hurricane Isaac’s worst damage. Flooding drowned human victims. It also killed millions of dollars’ worth of valuable farm animals.

Some scientists believe climate change affects major storms. They say the warming of Earth’s atmosphere is already making the storms worse. Other scientists have published studies that dispute²³ this.

In two thousand ten, a special committee of the World Meteorological Organization reported on severe storms. The committee’s work appeared in the journal²⁴ “Nature Geoscience.” Ten scientists wrote the report. They represented both sides of the debate about climate change. The scientists reached no clear answer about whether rising temperatures on Earth had already intensified²⁵ storms. Still, they made some predictions.

The committee said the changing climate might cause more powerful ocean storms in the future. It said the overall²⁶ strength of storms measured by wind speed might increase two to eleven percent by the year twenty-one hundred. And there might be an increase in the number of the most severe storms. But there might be fewer weak and moderate²⁷ storms.

1 cyclones   

n.气旋( cyclone的名词复数 )；旋风；飓风；暴风

参考例句：

• The pricipal objective in designing cyclones is to create a vortex. 设计旋风除尘器的主要目的在于造成涡旋运动。 来自辞典例句
• Middle-latitude cyclones originate at the popar front. 中纬度地区的气旋发源于极锋。 来自辞典例句

2 destruction   

n.破坏，毁灭，消灭

参考例句：

• The enemy bombs caused widespread destruction.敌人的炸弹造成大面积的破坏。
• Overconfidence was his destruction.自负是他垮台的原因。

3 tropical   

adj.热带的，热带的，炎热的

参考例句：

• You must grow these tropical flowers in a glasshouse.你必须把这些热带花卉种在温室里。
• This disease is widespread in tropical areas.这种疾病在热带地区蔓延很广。

4 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

5 toward   

prep.对于，关于，接近，将近，向，朝

参考例句：

• Suddenly I saw a tall figure approaching toward the policeman.突然间我看到一个高大的身影朝警察靠近。
• Upon seeing her,I smiled and ran toward her. 看到她我笑了，并跑了过去。

6 estimated   

adj．根据估计的

参考例句：

• She estimated the breadth of the lake to be 500 metres. 她估计湖面大约有500米宽。
• The man estimated for the repair of the car. 那人估算了修理汽车的费用。

7 largely   

adv.大部分，主要地

参考例句：

• It is largely dependent on the weather.这多半取决于天气情况。
• Their conclusions were largely founded on guesswork.他们的结论大部份基于猜测。

8 gulf   

n.海湾；深渊，鸿沟；分歧，隔阂

参考例句：

• The gulf between the two leaders cannot be bridged.两位领导人之间的鸿沟难以跨越。
• There is a gulf between the two cities.这两座城市间有个海湾。

9 tornadoes   

n.龙卷风，旋风( tornado的名词复数 )

参考例句：

• Tornadoes, severe earthquakes, and plagues create wide spread havoc. 龙卷风、大地震和瘟疫成普遍的毁坏。 来自互联网
• Meteorologists are at odds over the working of tornadoes. 气象学者对龙卷风的运动方式看法不一。 来自互联网

10 mythical   

adj.神话的；虚构的；想像的

参考例句：

• Undeniably,he is a man of mythical status.不可否认，他是一个神话般的人物。
• Their wealth is merely mythical.他们的财富完全是虚构的。

11 retired   

adj.隐退的，退休的，退役的

参考例句：

• The old man retired to the country for rest.这位老人下乡休息去了。
• Many retired people take up gardening as a hobby.许多退休的人都以从事园艺为嗜好。

12 destructive   

adj.破坏（性）的，毁灭（性）的

参考例句：

• In the end,it will be destructive of our whole society.它最终会毁灭我们整个社会。
• It is the most destructive storm in 20 years.这是20年来破坏性最大的一次风暴。

13 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

14 comparison   

n.比较，对照；比拟，比喻

参考例句：

• They make a comparison of New York to a beehive.他们把纽约比作一个蜂巢。
• This dress is really cheaper by comparison.比较起来，这件衣服确实便宜。

15 surge   

n.汹涌，澎湃；vi.汹涌，强烈感到，飞涨；vt.放开，松手

参考例句：

• The surge travelled southwards along the coast.浪涛沿着海岸向南涌去。
• It failed to stimulate a surge of investment in industry.这没有能刺激工业投资的激增。

16 surges   

n.奔涌向前( surge的名词复数 )；（数量的）急剧上升；（感情等）洋溢；浪涛般汹涌奔腾v.（波涛等）汹涌( surge的第三人称单数 )；（人群等）蜂拥而出；使强烈地感到

参考例句：

• The Yellow River surges onward like ten thousand horses galloping. 黄河以万马奔腾之势滚滚向前。 来自《现代汉英综合大词典》
• The raging tide of revolution surges forward. 革命怒潮汹涌澎湃。 来自《现代汉英综合大词典》

17 continuous   

adj.继续的，连续的，持续的，延伸的

参考例句：

• She finally got in after 10 years'continuous effort.坚持不懈地努力了十年后，她终于当选了。
• We must be continuous to study.我们必须不断学习。

18 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

19 works   

n.作品，著作；工厂，活动部件，机件

参考例句：

• We expect writers to produce more and better works.我们期望作家们写出更多更好的作品。
• The novel is regarded as one of the classic works.这篇小说被公认为是最优秀的作品之一。

20 devices   

n.设备；装置( device的名词复数 )；花招；（为实现某种目的的）计划；手段

参考例句：

• electrical labour-saving devices around the home 节省劳力的各种家用电器
• modern labour-saving devices such as washing machines and dishwashers 诸如洗衣机和洗碗机之类的现代化省力设备

21 intensity   

n.强烈，剧烈；强度；烈度

参考例句：

• I didn't realize the intensity of people's feelings on this issue.我没有意识到这一问题能引起群情激奋。
• The strike is growing in intensity.罢工日益加剧。

22 extensive   

adj.广泛的，广阔的，广大的

参考例句：

• The story had an extensive popularity among American readers.这本小说在美国读者中赢得广泛的声望。
• The museum offers extensive facilities for study.这个博物馆提供了许多供研究的设备。

23 dispute   

n.争端，分歧；v.争论，争吵，辩论，辩驳

参考例句：

• They are trying to find a way of settling the dispute.他们正设法寻找解决争端的办法。
• The parties to the dispute should be more polite to each other.争执双方应相互礼貌些。

24 journal   

n.日志，日记；议事录；日记帐；杂志，定期刊物

参考例句：

• He kept a journal during his visit to Japan.他在访问日本期间坚持记日记。
• He got a job as editor of a trade journal.他找到了一份当商业杂志编辑的工作。

25 intensified   

v.（使）增强， （使）加剧( intensify的过去式和过去分词 )

参考例句：

• Violence intensified during the night. 在夜间暴力活动加剧了。
• The drought has intensified. 旱情加剧了。 来自《简明英汉词典》

26 overall   

n.工作服，工装裤；全面的，全体的

参考例句：

• The shop assistant was wearing a white overall.那店员穿着白色的工作服。
• How much will it cost overall?一共多少钱？

27 moderate   

adj.适度的，稳健的，温和的，中等的；v.节制，使...稳定，使...缓和；n.稳健的人

参考例句：

• You should moderate your language when children are present.在孩子面前，你说话应该有节制。
• The wind is moderate today.今天的风很柔和。