Cool Roofs May Lead to Dry Roofs

Study suggests that light-colored roofs may reduce regional rainfall.

In recent years, many cities have explored light-colored roofs -- so-called "cool roofs" -- as a way to deal with the heat-producing impacts of dark and impermeable urban surfaces. A new study by Arizona State University researchers suggests that although light roofs reduce urban temperatures, they may have the unexpected result of altering rainfall patterns by reducing evapotranspiration rates of urban vegetation.

Researcher Matei Georgescu, whose research was based on computer modeling of Arizona's "Sun Corridor" of Phoenix, Tucson, Prescott, and Nogales, emphasizes that the study is not a condemnation of cool roofs.

"Does that suggest that cool roofs are a negative? I think what this leads to is future research to see how they should place cool roofs to minimize impacts," Georgescu said. "Certain regions might be more appropriate for cool roofs than others."

Thanks to Rachel Proctor May

Full Story: Cool roofs may have side effects on regional rainfall


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