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VOA慢速英语2013 Scientists Use Satellites to Identify Groundwater Losses in the Middle East

时间:2013-04-18 08:22:49

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Scientists Use Satellites to Identify Groundwater Losses in the Middle East

From VOA Learning English, this is SCIENCE IN THE NEWS. I'm Avi Arditti.

And I'm Faith Lapidus. Today we tell about a study of groundwater losses in the Middle East. We also tell how rising temperatures around the world may influence the intensity1 of storms. We report on an unusual way to make a microscope. And we tell about a huge, experimental airship.

Researchers have used Earth-orbiting satellites to identify losses of groundwater supplies in the Middle East. The researchers say the losses threaten to incite2 local water conflicts. And they warn that the situation could worsen as climate change on Earth puts those water resources at risk.

Two major rivers, the Tigris and Euphrates, flow through Syria and Iraq on their way to the Persian Gulf3. Both rivers begin in southeastern Turkey, which is home to many ethnic4 Kurds. Some Kurds have pushed for an independent state.

Katalyn Voss is with the University of Colorado. She says Turkey has built more than 20 dams on the rivers in an effort to help economic activity in the country's southeast.

"They have their own political reasons and social reasons for wanting to use as much water as possible."

Water used in Turkey does not always flow to its neighbors. In 2007, farm production fell sharply in Iraq and Syria because of dry weather. However, the drought had less of an effect on Turkish agriculture.

Katalyn Voss and her researcher team say Turkey's dams on the two rivers helped keep farms productive, but at a cost.

"Because they continued to use normal levels, or normal amounts of water during the drought, that resulted in a decline of stream flows into Syria and Iraq. And subsequently, those two countries had to find alternative water sources. And they turned to groundwater."

Information about water use and its availability in the Middle East are rare. So Katalyn Voss and her team turned to space. They studied information from man-made satellites that measure small differences in the pull of Earth's gravity. They found the upper Tigris and Euphrates river basin lost a lot of water between 2003 and 2009. The area lost an estimated 144 cubic kilometers of water, above and below ground, during that period.

Ms. Voss says that is almost equal to all the water in the Dead Sea. She thinks about two-thirds of that water was pumped from underground. She says this is not a good sign for the future, given the predicted effects of climate change.

"It only appears that this region is going to get drier and that the frequency of drought and severity of drought is only going to increase. And so this situation is only going to repeat itself, if not (get) worse."

She says this shows the need for Turkey, Iraq and Syria to agree on how water resources will be used in the future.

Todd Jarvis is head of the Institute for Water and Watersheds5 at Oregon State University. He says the satellite information needs to be confirmed with on-the-ground measurements. But that will be difficult to do, partly because the countries consider their water information an issue of national security.

Mr. Jarvis says the study is important because it does more than just publicize the problem.

"It also went beyond the step of assessing how much was potentially depleted6 to going to the next step, and that is, can we use this information to come up with a collaborative approach to managing the resources?"

He says this kind of information from space could provide a tool for policymakers as they look for better ways to share the world's water.

A new study has found that the intensity of hurricanes along the southeast coast of the United States may increase because of rising temperatures worldwide. Experts also expect rising temperatures to affect storm activity in the Pacific Ocean.

An international team of researchers studied weather records from 1923 to the present. They then created a statistical7 model based on this information.

The researchers say the model predicted a sharp increase in the number of Katrina-size hurricanes along the eastern coast of the United States. Hurricane Katrina was a Category 5 hurricane. The storm just about flattened8 the city of New Orleans, Louisiana, in August of 2005.

Tom Knutson works with the National Oceanic and Atmospheric9 Administration at Princeton University in New Jersey10. He is a specialist on extreme climate events. He uses a computer model to study hurricanes. This enables him to test different climactic conditions so that he can predict storm intensity.

"What our model suggests is that (if) you have a global warming due to increased greenhouse gases you have warmer sea surface temperatures. You also have a lot of warming in the atmosphere above the ocean. And these effects operate to gather stronger hurricanes in the warmer climate."

He says his modeling predicts fewer, but more intense hurricanes in the 21st century. He expects a 40 to 80 percent increase in the strongest Atlantic storms.

Tom Knutson says there has been a drop in the number of tropical cyclones11 in the western Pacific. But the storms that have taken place have brought stronger winds and more rainfall.

The Joint12 Typhoon Warning Center in Hawaii says there were just 19 named tropical storms in 2010. That is well below the historical average of 31 such storms. That was big news for Tom Knutson.

"Yeah, we were actually a little bit surprised to find this when we studied our climate simulations and even trying to figure out why we're getting this decrease in the models is actually a difficult research problem which we are struggling with".

Yet, even with an increase in the intensity of storm activity worldwide, he says, climatologists still cannot prove that human activity is to blame for the changes.

Microscopes are an important tool in identifying diseases. But they are not always easily available. Now, for a few dollars and a little work, the iPhone can become a microscope.

Dr. Isaac Bogoch is an infectious disease specialist at Toronto General Hospital in Canada.

"We got this idea from reading some of the medical literature. And we saw that some other groups had published neat images that were taken in the laboratory using smartphones and converting them into microscopes. But we thought this was a really neat concept and we wanted to take it to real world and practical settings."

Dr. Bogoch is the lead investigator13 of a study on the iPhone microscope. It appeared in the American Journal of Tropical Medicine and Hygiene14. He says he used an iPhone 4s because he happened to own one.

"But any smartphone with a decent camera and a zoom-in function should work just fine."

Isaac Bogosh and his teammates then bought a ball lens online for about eight dollars. They connected the special lens to the lens of the iPhone camera using two sided tape.

Dr. Bogosh and his colleagues from Massachusetts General Hospital and the Swiss Tropical and Public Health Institute tested the iPhone on Pemba Island in Tanzania. He says they looked for intestinal15 parasites16 in school age children. He says the infections affect more than one billion people on the planet.

"We took slides. We were looking for intestinal parasites, so these are stool samples. The slide had a little bit of cellophane covering the stool sample and we put the slide very close to our ball lens, which was stuck up against the iPhone. And we were able to zoom-in and we could see the parasites that we were looking for pretty easily."

Dr. Bogosh said results were better when the infections were more severe. But he thinks that will change when the technology improves.

Intestinal parasites include hookworms and roundworms. They can cause chronic17 anemia18, a lack of enough iron in the blood. They also lead to malnutrition19. Normally, intestinal parasites are identified by examining body waste through a traditional light microscope.

Dr. Bogoch says the next step is to improve the image quality. He says the smartphone microscope could greatly extend disease control in poor, rural areas. He says treatment for many intestinal parasites is generally widely available. He also says medical workers would be able to email an image to an expert for help in identification.

Recently, a huge helium-filled airship was shown to reporters in California. The airship is still experimental, but has possible military and other uses. Its developers say a full-sized working model should be finished in a few years.

The experimental airship is just half the size of the final working model. But it is huge -- about 75 meters from end to end. It is wide and flattened on the top, and covered with silver-colored Mylar, a strong, manmade substance.

The airship was built with 35 million dollars from the United States Department of Defense20 and the American space agency.

The airship is made of carbon fiber21 and aluminum22. It has rotating propellers23 for take-off and landing, and a ballast system that compresses helium gas to control the lift. Sometimes the airship is heavier than air, sometimes lighter24.

Igor Pasternak, an immigrant from Ukraine, created Aeros -- the company that developed the airship. He says the aircraft is not an airplane and not a traditional airship.

"It is really its own category. It is a new type of air vehicle."

He says the airship could reduce shipping25 costs if it works as planned.

"It is the workhorse of the air. It is the truck of the air."

The model airship rises up in the air and falls under its own power. It has been tested inside a hanger26 near Los Angeles. Company officials say they expect an outdoor test after the airship leaves the storage area sometime this year. If the ship works as planned, and possible users show interest, a commercial version could be produced in two or three years.


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1 intensity 45Ixd     
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。
2 incite kx4yv     
v.引起,激动,煽动
参考例句:
  • I wanted to point out he was a very good speaker, and could incite a crowd.我想说明他曾是一个非常出色的演讲家,非常会调动群众的情绪。
  • Just a few words will incite him into action.他只需几句话一将,就会干。
3 gulf 1e0xp     
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。
4 ethnic jiAz3     
adj.人种的,种族的,异教徒的
参考例句:
  • This music would sound more ethnic if you played it in steel drums.如果你用钢鼓演奏,这首乐曲将更具民族特色。
  • The plan is likely only to aggravate ethnic frictions.这一方案很有可能只会加剧种族冲突。
5 watersheds 12dac97dd0f3c330deb3ba24768943c9     
n.分水岭( watershed的名词复数 );分水线;转折点;流域
参考例句:
  • Hyetographs are important in estimating stormflow hydrographs from upstream watersheds. 降雨历线资料为上游集水区推估洪水流量历线的重要依据。 来自互联网
  • Sediments check dam in small watersheds in loess hilly gully area come from three proportion, i. 黄土丘陵沟壑区治沟骨干工程泥沙淤积来源于坡面侵蚀、沟道侵蚀和库区岸坡坍塌。 来自互联网
6 depleted 31d93165da679292f22e5e2e5aa49a03     
adj. 枯竭的, 废弃的 动词deplete的过去式和过去分词
参考例句:
  • Food supplies were severely depleted. 食物供应已严重不足。
  • Both teams were severely depleted by injuries. 两个队都因队员受伤而实力大减。
7 statistical bu3wa     
adj.统计的,统计学的
参考例句:
  • He showed the price fluctuations in a statistical table.他用统计表显示价格的波动。
  • They're making detailed statistical analysis.他们正在做具体的统计分析。
8 flattened 1d5d9fedd9ab44a19d9f30a0b81f79a8     
[医](水)平扁的,弄平的
参考例句:
  • She flattened her nose and lips against the window. 她把鼻子和嘴唇紧贴着窗户。
  • I flattened myself against the wall to let them pass. 我身体紧靠着墙让他们通过。
9 atmospheric 6eayR     
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。
10 jersey Lp5zzo     
n.运动衫
参考例句:
  • He wears a cotton jersey when he plays football.他穿运动衫踢足球。
  • They were dressed alike in blue jersey and knickers.他们穿着一致,都是蓝色的运动衫和灯笼短裤。
11 cyclones 17cc49112c36617738bb1601499ae56d     
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
12 joint m3lx4     
adj.联合的,共同的;n.关节,接合处;v.连接,贴合
参考例句:
  • I had a bad fall,which put my shoulder out of joint.我重重地摔了一跤,肩膀脫臼了。
  • We wrote a letter in joint names.我们联名写了封信。
13 investigator zRQzo     
n.研究者,调查者,审查者
参考例句:
  • He was a special investigator for the FBI.他是联邦调查局的特别调查员。
  • The investigator was able to deduce the crime and find the criminal.调查者能够推出犯罪过程并锁定罪犯。
14 hygiene Kchzr     
n.健康法,卫生学 (a.hygienic)
参考例句:
  • Their course of study includes elementary hygiene and medical theory.他们的课程包括基础卫生学和医疗知识。
  • He's going to give us a lecture on public hygiene.他要给我们作关于公共卫生方面的报告。
15 intestinal DbHzX     
adj.肠的;肠壁;肠道细菌
参考例句:
  • A few other conditions are in high intestinal obstruction. 其它少数情况是高位肠梗阻。 来自辞典例句
  • This complication has occasionally occurred following the use of intestinal antiseptics. 这种并发症偶而发生在使用肠道抗菌剂上。 来自辞典例句
16 parasites a8076647ef34cfbbf9d3cb418df78a08     
寄生物( parasite的名词复数 ); 靠他人为生的人; 诸虫
参考例句:
  • These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的,而与寄生虫无关。
  • Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。
17 chronic BO9zl     
adj.(疾病)长期未愈的,慢性的;极坏的
参考例句:
  • Famine differs from chronic malnutrition.饥荒不同于慢性营养不良。
  • Chronic poisoning may lead to death from inanition.慢性中毒也可能由虚弱导致死亡。
18 anemia joGy3     
n.贫血,贫血症
参考例句:
  • The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。
  • I was put on iron tablets for my anemia.我曾因贫血吃补铁药片。
19 malnutrition kAhxX     
n.营养不良
参考例句:
  • In Africa, there are a lot of children suffering from severe malnutrition.在非洲有大批严重营养不良的孩子。
  • It is a classic case of malnutrition. 这是营养不良的典型病例。
20 defense AxbxB     
n.防御,保卫;[pl.]防务工事;辩护,答辩
参考例句:
  • The accused has the right to defense.被告人有权获得辩护。
  • The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。
21 fiber NzAye     
n.纤维,纤维质
参考例句:
  • The basic structural unit of yarn is the fiber.纤维是纱的基本结构单元。
  • The material must be free of fiber clumps.这种材料必须无纤维块。
22 aluminum 9xhzP     
n.(aluminium)铝
参考例句:
  • The aluminum sheets cannot be too much thicker than 0.04 inches.铝板厚度不能超过0.04英寸。
  • During the launch phase,it would ride in a protective aluminum shell.在发射阶段,它盛在一只保护的铝壳里。
23 propellers 6e53e63713007ce36dac451344bb87d2     
n.螺旋桨,推进器( propeller的名词复数 )
参考例句:
  • The water was thrashing and churning about under the propellers. 水在螺旋桨下面打旋、翻滚。 来自辞典例句
  • The ship's propellers churned the waves to foam. 轮船的推进器将海浪搅出泡沫。 来自辞典例句
24 lighter 5pPzPR     
n.打火机,点火器;驳船;v.用驳船运送;light的比较级
参考例句:
  • The portrait was touched up so as to make it lighter.这张画经过润色,色调明朗了一些。
  • The lighter works off the car battery.引燃器利用汽车蓄电池打火。
25 shipping WESyg     
n.船运(发货,运输,乘船)
参考例句:
  • We struck a bargain with an American shipping firm.我们和一家美国船运公司谈成了一笔生意。
  • There's a shipping charge of £5 added to the price.价格之外另加五英镑运输费。
26 hanger hanger     
n.吊架,吊轴承;挂钩
参考例句:
  • I hung my coat up on a hanger.我把外衣挂在挂钩上。
  • The ship is fitted with a large helicopter hanger and flight deck.这艘船配备有一个较大的直升飞机悬挂装置和飞行甲板。

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