Icarus http://doi.org/jc6 (2012)

Credit: © NASA

Dust devils — swirling updrafts of air and dust — have been observed whirling across arid landscapes on Earth and Mars. Measurements of dust devils on Earth suggest that the paths and speeds of these whirlwinds are directed by the ambient winds at the site.

Matthew Balme at the Planetary Science Institute, USA, and colleagues used a stereo camera system to image more than a hundred dust devils in two study areas in southwestern USA. They combined their field measurements of the dust storms' positions through time with local meteorological data to calculate the horizontal velocity of the dust devils as a function of ambient wind velocity. They found that the dust devils move in the direction of the ambient winds, at the same speed as winds at 20–30 metres above the surface. The horizontal velocities of dust devils should therefore reflect the local wind conditions during periods of dust devil activity.

Because the paths of dust devils are frequently captured in spacecraft imaging of Mars, the researchers suggest that they can be used to assess local surface winds on the red planet.