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Atlanta, Georgia RELATED VIDEO CNN's Marsha Walton gives an urban climate report Real 28K 80K Windows Media 28K 80K Dale Quattrochi of NASA describes the foliage loss in metro Atlanta Real 28K 80K Windows Media 28K 80K

April 30, 1999
Web posted at: 10:16 a.m. EDT (1416 GMT)

ATLANTA (CNN) -- In Atlanta, one of the fastest growing urban areas of the United States, the economy isn't the only thing that's heating up. The city itself has become an island of hot pavement in a sea of green.

Scientists say the temperature increase, in turn, is causing Atlanta to produce its own weather.

The findings are based on studies that took place during the 1996 Olympics, when Atlanta was equipped with the latest technology to do spot forecasting for the Games.

What they found was that during a period of less than two weeks in 1996, Atlanta's heat island caused convective thunderstorms, causing it to rain on the city or to the south and southeast about 50 or 60 miles, says Dale Quattrochi of NASA's Marshall Space Flight Center.

Atlanta's urban sprawl has doubled the land used for housing and commercial development since 1973.

The Atlanta area includes four of the nation's top 10 fastest-growing counties. Developers are clearing an average of 50 acres of tree-covered land per day, which amounts to an area larger than Manhattan each year.

Pavement and buildings make the city 10 degrees hotter than surrounding areas

As the green canopy surrounding Atlanta recedes, temperatures are going up. The moisture in vegetation serves as a coolant. So with fewer trees and more people, the city that looks deceptively cool and shady from the air is up to 10 degrees hotter than the surrounding areas.

"What you find is that with pavement and buildings replacing forest land and agricultural land ... it is raising the overall heat that is emanated from the city," Quattrochi says.

Researchers say they will now try to determine whether all the additional pavement is affecting regional weather as well.

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