NASA SATELLITE CONFIRMS URBAN HEAT ISLANDS INCREASE RAINFALL AROUND CITIES

NASA researchers have for the first time used a rainfall-measuring satellite to confirm that "urban heat-islands" create more summer rain over and downwind of major cities, including Atlanta, Dallas, San Antonio and Nashville.

Dr. J. Marshall Shepherd and colleagues at NASA's Goddard Space Flight Center, Greenbelt, Md., found that urban areas with high concentrations of buildings, roads and other artificial surfaces retain heat and lead to warmer surrounding temperatures, and create urban heat-islands. This increased heat may promote rising air and alter the weather around cities

"Cities tend to be one to 10 degrees Fahrenheit [.56 to 5.6 Celsius] warmer than surrounding suburbs and rural areas and the added heat can destabilize and change the way air circulates around cities," said Shepherd. Rising warm air may help produce clouds that result in more rainfall around urban areas.

http://www.gsfc.nasa.gov/topstory/20020613urbanrain.html