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FEATURE: 'Wind-chasing' missions help unlock typhoons' secrets

FEATURE: 'Wind-chasing' missions help unlock typhoons' secrets

By Lee Hsin-Yin, CNA staff reporter A high number of typhoons have threatened Taiwan this year, bad news for most residents of the island but a source of sustenance for an elite group of scientists who love nothing more than to chase the storms. They are with Dotstar (Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region), a research project started in 2003 involving 14 organizations, from Taiwan's Central Weather Bureau (CWB) to the United-States based National Oceanic and Atmospheric Administration. Their mission: get on a specially equipped plane whenever a typhoon approaches and track it at 43,000 feet to help forecasters figure out what it's up to. The operation is the first and only one in the northwestern Pacific and East Asia region to engage in aircraft surveillance of typhoons. "An intensive survey allows us to obtain more thorough data on how typhoons develop and how they could interact with each other," said Chen Hsin-gan, a member of the project and a researcher at National Taiwan University (NTU). Rarely have the scientists been busier than over the past week, when they flew four missions to follow Typhoon Tembin to the southeast and southwest Typhoon Bolaven further away to the northeast between Aug. 21 and Aug. 27. The two storms are now engaging in some atmospheric gymnastics, with Bolaven pulling Tembin back toward Taiwan after it went out to sea on Aug. 24 -- a phenomenon known as the Fujiwhara Effect. Flight crews of three meteorologists and two former Air Force pilots have been following the storms' antics, spending five hours at a time flying above and even into the very heart of the typhoons to collect data, said project member and CWB Weather Forecast Center Director Cheng Ming-dean. Cheng said that when the plane, a re-equipped business jet operated by the Taiwan-based Aerospace Industrial Development Corp., arrives above the storm, specially designed thermos-shaped devices, called "dropwindsondes," are released into its bands. Usually around 15 of these 40-centimeter-long measuring instruments are used to detect humidity, wind direction and velocity, a valuable resource for the CWB to determine a typhoon's often fickle path. After each flight is completed, all data is sent to the team's lab to identify the typhoon's steering flow in different time frames. "It's the most direct scientific data we can get, and we share our analysis with partners in Japan, the U.S. and Europe," Cheng said, noting that the project costs Taiwan NT$30 million (US$1 million) each year. Lin Po-hsiung, an NTU professor and the project's co-principal investigator, explained that each mission can improve the forecasting accuracy of a typhoon's path within the next 24 hours by 20 percent on average, according to their U.S. partners. Somewhat surprisingly, the operation only improves Taiwan's forecast accuracy by about 10 percent, Lin said, because the weather bureau's computers do not run the same model and crunch data relatively slowly. That should change, however, when the weather bureau takes delivery of a supercomputer later this year, Lin said. According to the CWB, the new system's speed will enable weather forecasters to run more than 20 weather patterns comprising large numbers of variables at one time, which should help enhance the mission's output in real-time. Any improvements in accuracy in the often imprecise world of typhoon forecasting can be particularly beneficial for Taiwan, which is often highly exposed to the storms. More accurately identifying a storm's path can result in more targeted evacuations of vulnerable communities, better disaster prevention preparations, and better decision-making by local governments on whether to close schools and businesses, all of which have sparked controversies in recent years. The mission has already made important contributions to the international study of the storms, Lin said. Its precise prediction in 2004 of the path of Typhoon Conson, which brushed Taiwan and battered Okinawa, was highly praised by the Japan Meteorological Agency, so much so that "Japanese meteorologists have since used the case to lobby their government to develop a similar program," he said. A consummate scientist who has confronted typhoons in the sky many times, Lin refuses to portray the missions as the white-knuckle adventures outsiders may imagine them to be. "I don't quite understand why people always ask me if it's scary. We've got everything under control," he said. But to others on the plane, the missions can be both physical and emotional roller coasters. Tsao Chia-hsiang, a 61-year-old pilot who has been with the team since its inception, said the flights require the highest level of piloting skills. "The most daunting part lies in the uncertainty because you are often headed to an extreme environment without knowing much about it," said Tsao, who has flown for the military and airlines for more than 30 years. He described the hail he usually encounters when passing a typhoon's eyewall as "shots and shells" and said the most important thing is to stay focused. "Many of my colleagues have described the experience like a scene in the Chinese movie 'Hero' where the trapped hero is showered with tens of thousands of arrows," he said. The most dangerous trip Tsao could recall was back in 2003, when he accidentally flew into the eye of the typhoon. "We were surrounded by complete darkness. The bands were like walls around us," he said, adding that the plane was severely damaged by hail and needed an overhaul. Nevertheless, NTU student-researcher Greg Chen said he was excited about joining future missions because of the chance to chase the wind. "I used to watch other students come back from a mission and sleep like there was no tomorrow," he said. "To me it's a 'must experience' for meteorologists, just as going on a military mission might appeal to soldiers."


Updated : 2021-03-01 11:53 GMT+08:00