NASA: Cities, Cars Increase Storms

NASA is claiming that cars and cities may increase storms -- without counting pollution that may lead to Global Warming.

An article last week in National Geographic says that large cities have the ability to cause stronger summer thunderstorms. J. Marshall Shepherd, a meteorologist who worked at NASA and who is now at the University of Georgia in Athens, says this is partly due to the extra heat that builds up in cities due to dark and reflective surfaces (known as the heat island effect, which up until now was supposed to only make cities a little warmer than their surrounding areas).

He also says that the rough surfaces like tall buildings increase air convergence, and pollution may play a factor (because raindrops have to form around small particles). To borrow another NASA article, things like green roofs are seen as a possible cure for these problems.

The Urban Heat Island (NASA)

A little research uncovers a report that Shepherd issued in 2002 indicated that satellite data showed increased rainfall rates downwind of major cities, but this report used urban sprawl and rainfall data, input into a computer forecast model.

Even more bizarre, during research for this entry, I found this article in National Geographic claiming that weekdays really are more rainy because rain is driven by traffic patterns (again, the pollution). This study was done by Thomas Bell, also working at NASA.