環(huán)球英語 — 385：Measuring Cyclones
Voice 1
Thank you for joining us for today’s Spotlight program. I’m Liz Waid.
Voice 2
And I’m Ryan Geertsma. Spotlight uses a special English method of broadcasting. It is easier for people to understand, no matter where in the world they live.
Voice 1
In May of 2008, cyclone Nargis hit the coastal areas of Myanmar. The damage this cyclone caused was horrible. It took many weeks for aid workers to report all of the damage. And it took weeks to find the thousands of people who were injured or killed by the cyclone. Tropical cyclones are very powerful storms. Just one strong tropical cyclone can kill thousands of people. And the damage it creates can cost millions of dollars. Each year, tropical cyclones hit many towns and villages along ocean coasts. In different parts of the world, tropical cyclones are also called hurricanes or typhoons.
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Tropical cyclones develop in warm ocean areas. They form when the surface temperature of the water increases. The water then quickly heats the air. And this process creates an area of low pressure. The area of low pressure causes water to fill the air. And wind begins to circle around this low pressure area.
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This process usually happens over eighty [80] times in one year. Sometimes the process creates minor tropical storms. However, the process often creates severe tropical cyclones. These severe storms have wind speeds of one hundred eighteen [118] kilometres per hour or greater. In fact, some tropical cyclones have wind speeds of more than two hundred fifty [250] kilometres per hour.
Voice 2
Severe tropical cyclones cause terrible damage if they reach land. The damage is caused by the strong winds, rain and flooding. Tropical cyclones are most harmful when they hit villages, towns or cities. When this happens, many people die. And the cyclone also destroys many homes, schools and businesses.
Voice 1
People cannot prevent tropical cyclones. However, early warning about a severe tropical cyclone could save many lives. If warned, people could move away from the coast before a cyclone hits. They could also move important things away from the coast. And some people can even protect their homes by covering windows and doors with wood. However, a cyclone can also be very minor. And moving people away from the coast when it is not necessary can cost a lot of money. Nicholas Makris is a leading scientist at MIT. He explains,
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“You need to know, do you tell people to move away from the coast or not? Both ways, if you get it wrong, there can be big problems.”
Voice 2
Warning people about severe cyclones is very important. But how do scientists know if a cyclone will be severe or minor? How can they tell how powerful it is? Satellites can show scientists clearly the path of a cyclone. But, they can not tell scientists the wind speed or power of the cyclone. Measuring the wind speed of a cyclone is very difficult.
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To measure the wind speed of a cyclone, someone must fly a special airplane into the strongest part of the storm. This is very dangerous. The special airplane costs one hundred million dollars [$100,000,000]. And each airplane trip into the cyclone costs fifty thousand dollars. [$50,000]. To measure just one cyclone, the airplane may make twelve [12] or more trips into the storm.
Voice 2
This airplane technology measures cyclones well. However, only the richest countries can pay so much money to measure cyclones. Scientists do try to work together to warn all countries about cyclones. However, it can be difficult to communicate quickly between countries. And other times, foreign scientists and country leaders do not trust each other. That is why one group of scientists decided to research a new way of measuring cyclones. The scientists are based at the well-known technology school, Massachusetts Institute of Technology or MIT.
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The scientists at M I T decided to try and listen to the sound a cyclone makes under water. They believed that the sound of a cyclone would relate to its wind speed.
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Scientists have been listening to underwater sound for many years. During World War Two, they found ways to use sound to find enemy ships. By listening underwater, sailors could tell how far away the ship was. They could also tell which way it was moving, and how fast.
Voice 1
The MIT scientists believed they could use the same technology with cyclones. Their idea was to record cyclone sounds using underwater microphones. From these sound recordings, they believed they could judge wind speed. The theory seemed good, but they needed to prove that it could work.
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The MIT scientists were in luck! They soon discovered that underwater cyclone sounds had already been recorded. In nineteen ninety nine [1999], a cyclone called “Hurricane Gert” had passed directly over an underwater microphone. The microphone was being used to record underwater earthquake sounds, not cyclones. However, the microphone was in the perfect place. It provided a clear and useful recording.
Voice 1
There was even more good news for the MIT scientists. Special airplanes had also measured Hurricane Gert’s wind speed. So, the scientists had the underwater sounds of the cyclone. And they had the exact wind speeds measured by the airplanes. They compared the two. By doing this, they were able to prove that the underwater sound of a cyclone did relate to the wind speed. And they were able to find which sounds were equal to which wind speeds. The lead MIT scientist, Nicholas Makris said,
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“There was an almost perfect relationship between the power of the wind and the power of the underwater wind noise.”
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So, what would this mean? It would mean that the expensive airplanes could be a thing of the past! Underwater microphones could measure cyclones just as well. And they would be safer and cheaper! The cost of underwater microphones would be within the reach of developing countries. Even if a cyclone happens where there is not a microphone, this new technology could still be used. A normal airplane could drop an underwater microphone in the path of a cyclone. This airplane would not have to enter the cyclone.
Voice 1
The MIT scientists will continue to research this new technology. It still needs more testing. And like all new technology, it can always be improved. However, for people living in areas where tropical cyclones hit, this technology can bring much hope. Instead of fear, the people would have knowledge - their greatest weapon in the face of natural tragedies. It is this weapon that will protect, and save their lives.
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