Keeping Cities Cool

Keeping Cities Cool

INDIANAPOLIS, Indiana, (ENS)

20th September 2006

When researchers with Indiana State University's Center for Urban and Environmental Change decided to investigate the urban heat effect, the logical first place to investigate was the state capital's, Indianapolis.

The nation's 12th largest city is undergoing changes that center on concrete, asphalt and brick - all materials that contribute to the urban heat effect, retaining heat and not allowing rain water to pass through to the soil beneath.

The investigation is part of an effort by the researchers to examine methods that could help large cities stay just a little bit cooler by planting trees to spread their shading branches over streets and sidewalks.

In the first year of the three-year project, Qihao Weng, associate professor of geography at Indiana State and director of the Center for Urban and Environmental Change, and his students have already begun to look at other metropolitan areas in the United States, including New York; Chicago; Los Angeles; Houston; and a location that might be called an "urban super heat island," Phoenix.

"Satellite images provide global coverage. By using remote-sensing measurements, we can do urban heat detection and monitoring for all major cities in the world," Weng said.

"One of our goals is to apply the methodology we develop here in Indianapolis to other cities."

Weng believes the layout of urban landscapes - from lawns, trees, parks and cemeteries to streets, parking lots and buildings - plays a role in determining the urban heat island effect.

Indianapolis' White River State Park, for example, gently curves along the banks of its namesake. Weng has a theory that such a layout holds the key to reducing the urban heat island effect, even if by just a few degrees.

"Theoretically speaking, a park with a square or rectangular shape is going to generate more heat than a park of the same total area with a circular shape because it has more heat interactions with the surrounding area of impervious surfaces," he said.

Weng contends Indianapolis and Indiana State University are leading the way in conducting such research and developing ways to minimize the effects of urban heat islands.

"We intend to develop a very comprehensive database. Other cities, to my knowledge, haven't developed this kind of comprehensive knowledge," he said. "The city's Park and Recreation Department has collected a tree inventory database, and using that database, combined with our records obtained through field work, we will soon be able to develop a very comprehensive urban land cover database to use in our urban heat island studies and other kinds of urban ecosystems studies in the future."