Dust affects on climate to be examined

HUNTSVILLE, Ala., Sept. 13 (UPI) -- U.S. scientists say they will spend three years studying the impact about 770 million tons of dust wafting from the Sahara Desert each year has on the climate.

Scientists at the University of Alabama will use data from several research satellites to determine the affect the dust has on Earth's climate by reflecting sunlight back into space, a university release said Monday.

Some Saharan dust falls back to Earth before it leaves Africa while much of it streams out over the Atlantic Ocean or Mediterranean Sea, carried on the winds as far away as South America and the southeastern United States, researchers say.

"The people who build climate models make some assumptions about dust and its impact on the climate," Sundar Christopher, a professor of atmospheric science at UA, said. "We want to learn more about the characteristics of this dust, its concentrations in the atmosphere and its impact on the global energy budget so we can replace those assumptions with real data."

The composition of dust varies depending on which part of the Sahara it comes from, researchers say, and some of it absorbs more solar energy than others.

"One thing we want to do is calculate how reflective dust is, because not all dust is created equal," Christopher said. "We're trying to calculate reflectivity so we can say with precision how much sunlight is being reflected."

"Climate models are not very sophisticated in the way they handle dust. We want to nail down those values."