Wetter Cities | Green Energy News

May 25, 2003 – Vol.8 No.9

WETTER CITIES.

The U.S. Megalopolis, which spans much of the East Coast, was under cloudy conditions and rain for most of the month of May. Was this a natural phenomenon or is the heavily built-up, long coastal region now creating it own dreary weather?

A new study funded by U.S. National Aeronautics and Space Administration (NASA) concludes that cities and urban sprawl have increased local and downwind rainfall.

According to the study, growing cities, especially those in coastal areas receive more rainfall because of the heat island effect. As more and more surfaces are paved over and more buildings constructed, more heat rises from the sunlight absorbing surfaces - dark pavement and rooftops - to create thermals which help create clouds. Coastal cities especially, with greater humidity and sea breezes, combined with the heat island effect have an increased the chance for rain and thunderstorms.

Methods considered to reduce this effect have been to use more sunlight reflective materials for roofs, roadways and parking lots as well as more green spaces.

The research paper was published by the American Meteorological Society and the American Geophysical Union’s journal Earth Interactions. For a review visit NASA Earth Observatory at http://earthobservatory.nasa.gov/ click News, Media Alerts. See Coastal Cities Turn Up Heat on Rainfall.