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BOULDER-- While athletes from around the world compete for the gold in this month's Olympic Games in Sydney, an elite team of automated forecast tools is going head to head with Australia's weather. Human forecasters will use advanced software furnished by Australia, Canada, Great Britain, and the United States to help provide automated short-term forecasts for the Olympics.
One of the five team members is an "Auto-nowcaster" developed at the National Center for Atmospheric Research (NCAR) and installed in Sydney last year with funding from the U.S. Weather Research Program.
The system uses 30 different computational procedures to predict the birth, growth, and decay of thunderstorms. Outlooks are issued every five minutes for periods of up to an hour. NCAR's primary sponsor is the National Science Foundation.
The Olympics forecasts are part of a broader exercise running from September 2 to November 21 to see how much of a boost the automated tools can provide to flesh-and-blood forecasters. After November an international verification team will assess whether the automated systems actually improved the Sydney forecasts.
Australia's Bureau of Meteorology will issue official Olympic forecasts by mixing and matching output from NCAR's Auto-nowcaster and the four other automated systems and then applying their own insight. Their outlooks will go to emergency managers, flight controllers at Sydney Airport, venue managers at the Olympics, and personnel in charge of the Sydney Harbor Bridge Climb, a tourist attraction.
By tracking convergence lines (gust fronts, sea breezes, and other zones where air masses collide), the Auto-nowcaster anticipates where the next storm might form. "The idea is to do better than if you just extrapolate from the existing storms," explains Wilson, who has worked on short-term forecasts since the mid-1980s.
The nowcaster is automated because often there's too much going on at once for a person to monitor every possible interaction in short-term forecasts. "It doesn't take long for the human to wear out and make mistakes," says Wilson.
But automation is no piece of cake. "To get a machine to see what your eye can see is extremely difficult," he explains. NCAR and the Massachusetts Institute of Technology's Lincoln Laboratories have been working for the past ten years to develop step-by-step computational procedures to automatically detect convergence lines observed on radar. They've settled on a technique to be tested in Sydney in which a person will input the convergence line's location and the Auto-nowcaster will do the rest.
The U.S. National Weather Service plans to bring Auto-nowcaster concepts into severe-storm and flash-flood warnings once the agency has sufficient computing power to accommodate the package. In November a workshop in Sydney sponsored by the World Meteorological Organization's World Weather Research Program will provide developing countries a chance to obtain first-hand experience with the advanced systems.
The other automated forecast tools operating in Sydney this fall were developed by the National Oceanic and Atmospheric Administration's National Severe Storms Laboratory, Environment Canada, the U.K. Meteorology Office, and the University of Salford, England.
The experiment will draw on data from two Doppler radars, three wind profilers, about 20 weather stations, and four daily radiosonde launches from Sydney Airport. Satellite data, which are important for seeing the first cumulus clouds as a new storm develops, are available only once an hour because of the recent loss of a weather satellite.
The Auto-nowcaster was funded by the Federal Aviation Administration, the National Weather Service, the National Science Foundation, the U.S. Army, and the U.S. Weather Research Program.
Writers: Bob Henson, Anatta
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