Chasing dust devils reveals secrets of desert cyclones

Joanna Carver, reporter

Walking into a cyclone of sand may seem dangerous, but the dust devils shown in this video are no more powerful than the weakest tornadoes. On Mars, however, they are larger and stronger, so studying them on Earth could give insight into how they feed dust storms and create lightning on the Red Planet.

Dust devils typically form in the desert, where hot air can quickly swirl up from a flat surface into a pocket of cooler air above. Colliding particles become charged, creating an electric field that lifts up more dust, making the swirling column of sand more powerful.

Nilton Renno from the University of Michigan in Ann Arbor and his team have been placing instruments in areas where dust devils are prevalent to investigate how they occur. In this video, captured in El Dorado valley near Boulder City, Nevada, and in Eloy, Arizona, the researchers measured wind direction, wind speed and electric fields as they waited for the devils to pass over them, swirling at velocities ranging from 70 to 95 kilometres per hour. "It's like being completely inundated with dust," says Doug Halleaux, a member of the team. "Like any blowing dust, you can get it in your eyes."

So far, the team has found that dust devils move forward faster than previously thought and that large ones can move just as quickly as smaller ones. Unlike the spiral-like trajectories of Martian dust devils, most of the Earthly ones appear to move in straight lines.

A new project starting in December will investigate how the phenomenon affects climate. Dust and aerosols suspended in the air can have a cooling or warming effect, so the team plans to look at how fast dust is ejected depending on the type of soil and atmospheric conditions. This time, the equipment will operate autonomously, sending back live images and data from within a dust devil.

If you enjoyed this video, see what it might be like to travel into a giant magnetic tornado on the sun or watch a time-lapse that lets you dive into a monster hurricane.

Source: http://feeds.newscientist.com/c/749/f/10897/s/2588a9d3/l/0L0Snewscientist0N0Cblogs0Cnstv0C20A120C110Cdust0Edevils0Bhtml0Dcmpid0FRSS0QNSNS0Q20A120EGLOBAL0Qonline0Enews/story01.htm

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