VOA标准英语2013--Doppler on Wheels Rolls Into Tornados

 

Doppler on Wheels Rolls Into Tornados²

Doppler radar³ reads the weather based on reflections from items moving through the air. Joshua Wurman was the first to put the technology on wheels and drive it directly into the path of a tornado¹.

“I invented Doppler on Wheels in the 1990s because I was frustrated⁴ that I couldn’t see enough detail inside tornados and hurricanes," Wurman said. "We had blurry⁵ images of all these things and in order to really understand the physics, the math of what is going on inside a tornado, how exactly are they forming, how strong are the winds right at the surface are, we need to get up very, very, close."

Storm Chaser

Wurman, who directs the Center for Severe Weather Research, deploys⁶ Doppler on Wheels to chase storms. His fleet consists of large panel trucks with rotating antenna⁷ dishes mounted on the back.

Those high-powered antennas⁸ send out radio waves that reflect objects in the air from raindrops to birds. Wurman and his team watch the weather patterns in real time from inside the truck.

“I’m seeing it through computers and through the radar screens, which are making three dimensional images of the wind and the debris⁹ and the hail, flowing around the storm,” Wurman said.

Weather forecasts, based on data from satellites, fixed¹⁰ radar networks and computer models, help guide the trucks to the precise location of a storm that could spawn¹¹ a tornado. Doppler on Wheels has driven into more than 200 tornados so far.

“When we get up close to a storm while it’s in the process of making a tornado, we can look at the evolution of the winds near the surface, how that relates to the winds aloft, how the precipitation, the rain and the hail, influences whether the air is going up or down, whether it’s cold or warm, and how that is causing or not causing a tornado to form,” Wurman said.

Lifecycle of tornados

The analysis combines the Doppler images and 3D maps with data from steel weather pods, large heavy metal discs with measuring instruments inside. The pods are placed in the path of a storm to collect data from the ground, below the range of the radar.

“That’s where we live. We live right near the ground," Wurman said. "Buildings are built right on the ground and we need to understand more about how the winds do damage, how the debris field interacts with the winds and does damage.”  

That data could lead to better building design in storm prone¹² areas.  

As they observe the life cycle of tornados, scientists are getting a better understanding of which storms develop into tornados and which die away.  One factor revealed by the radar is a secondary wind surge that Wurman says could trigger the tornado.  

“The scientific process is that we need to now observe that and repeat that observation in maybe a dozen or more other thunderstorms, and in maybe a dozen or more thunderstorms that aren’t making tornados, to really see if that surge causes tornados and if there is no surge, whether there is no tornado,” he said.

Mobile scientific laboratory 

Doppler on Wheels is an advanced mobile scientific laboratory. Along with hundreds of twisters, it has also chased several hurricanes, expanding what we know about those storms.

Positioned on the Louisiana coast for Hurricane Gustav in 2008, the fleet captured high resolution measurements as the hurricane came ashore¹³. The images show winds in surprising corkscrew rolls.

“And that corkscrewing motion does two things," Wurman said. "One, it brings strong winds down to the surface and those stronger winds have a much greater potential to cause damage. But in addition, on the way back up, those winds are carrying heat and moisture from the ocean, which is basically the food, the fuel for a hurricane.”

For tornados, the false alarm forecast rate has hovered¹⁴ around 75 percent for decades. Looking at those winds could give forecasters a better idea of the intensity¹⁵ of the storm, which could translate into more accurate forecasts.  And that, Wurman says, can save lives.

1 tornado   

n.飓风，龙卷风

参考例句：

• A tornado whirled into the town last week.龙卷风上周袭击了这座城市。
• The approaching tornado struck awe in our hearts.正在逼近的龙卷风使我们惊恐万分。

2 tornados   

n.龙卷风，旋风( tornado的名词复数 )

参考例句：

• And the national weather service reports several tornados touch down. 国家气象中心报告预测龙卷风将来袭。 来自互联网
• They had stock footage of lightning, tornados, and hurricanes. 他们存有关于闪电、龙卷风和飓风的电影胶片。 来自互联网

3 radar   

n.雷达，无线电探测器

参考例句：

• They are following the flight of an aircraft by radar.他们正在用雷达追踪一架飞机的飞行。
• Enemy ships were detected on the radar.敌舰的影像已显现在雷达上。

4 frustrated   

adj.挫败的，失意的，泄气的v.使不成功( frustrate的过去式和过去分词 )；挫败；使受挫折；令人沮丧

参考例句：

• It's very easy to get frustrated in this job. 这个工作很容易令人懊恼。
• The bad weather frustrated all our hopes of going out. 恶劣的天气破坏了我们出行的愿望。 来自《简明英汉词典》

5 blurry   

adj.模糊的；污脏的，污斑的

参考例句：

• My blurry vision makes it hard to drive. 我的视力有点模糊，使得开起车来相当吃力。 来自《简明英汉词典》
• The lines are pretty blurry at this point. 界线在这个时候是很模糊的。 来自《简明英汉词典》

6 deploys   

（尤指军事行动）使展开( deploy的第三人称单数 )； 施展； 部署； 有效地利用

参考例句：

• It then deploys "decoy" programs designed to attract the virus. 然后，它释放“诱饵”去吸引病毒。
• But when that doesn't work, he deploys his secret defense mechanism. 但没有效果，它要施展绝密自卫武器了。

7 antenna   

n.触角，触须；天线

参考例句：

• The workman fixed the antenna to the roof of the house.工人把天线固定在房顶上。
• In our village, there is an antenna on every roof for receiving TV signals.在我们村里，每家房顶上都有天线接收电视信号。

8 antennas   

[生] 触角，触须（antenna的复数形式）

参考例句：

• Marconi tied several antennas to kites. 马可尼在风筝上系了几根天线。 来自超越目标英语 第3册
• Radio astronomy today is armed with the largest antennas in the world. 射电天文学拥有世界上最大的天线。

9 debris   

n.瓦砾堆，废墟，碎片

参考例句：

• After the bombing there was a lot of debris everywhere.轰炸之后到处瓦砾成堆。
• Bacteria sticks to food debris in the teeth,causing decay.细菌附着在牙缝中的食物残渣上，导致蛀牙。

10 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

11 spawn   

n.卵，产物，后代，结果；vt.产卵，种菌丝于，产生，造成；vi.产卵，大量生产

参考例句：

• The fish were madly pushing their way upstream to spawn.鱼群为产卵而疯狂地向上游挤进。
• These fish will lay spawn in about one month from now.这些鱼大约一个月内会产卵。

12 prone   

adj.(to)易于…的，很可能…的；俯卧的

参考例句：

• Some people are prone to jump to hasty conclusions.有些人往往作出轻率的结论。
• He is prone to lose his temper when people disagree with him.人家一不同意他的意见,他就发脾气。

13 ashore   

adv.在(向)岸上，上岸

参考例句：

• The children got ashore before the tide came in.涨潮前，孩子们就上岸了。
• He laid hold of the rope and pulled the boat ashore.他抓住绳子拉船靠岸。

14 hovered   

鸟( hover的过去式和过去分词 )； 靠近（某事物）； （人）徘徊； 犹豫

参考例句：

• A hawk hovered over the hill. 一只鹰在小山的上空翱翔。
• A hawk hovered in the blue sky. 一只老鹰在蓝色的天空中翱翔。

15 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。