Wednesday, June 12, 2013

Amount of Dust Blown Across the Western U.S. Is Increasing


The amount of dust being blown across the landscape has increased over the last 17 years in large swaths of the West, according to a new study led by the University of Colorado Boulder. The escalation in dust emissions -- which may be due to the interplay of several factors, including increased windstorm frequency, drought cycles and changing land-use patterns -- has implications both for the areas where the dust is first picked up by the winds and for the places where the dust is put back down. The increase in dust erosion matters, the researchers said, because it can impoverish the soil in the areas where dust is being lost. Wind tends to pick up the finer particles in the soils, and those are the same particles that have the most nutrients and can hold onto the most soil moisture, Brahney said. Increasing amounts of dust in the atmosphere also can cause people living in the rural West a variety of problems, including poor air quality and low visibility. In extreme cases, dust storms have shut down freeways, creating problems for travelers. The areas where the dust travels to are also affected, though the impacts are more mixed. When dust is blown onto an existing snowpack, as is often the case in the Rockies, the dark particles better absorb the sun's energy and cause the snowpack to melt more quickly. But the dust that's blown in also brings nutrients to alpine areas, and the calcium in dust can buffer the effects of acid rain...more

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