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Mars Arizona
11/08/2002
Listen in RealAudio 
If you were going to pick a U.S. state for studying the atmosphere on Mars, which one would
you pick? Hi, I'm Bryan Yeaton for The Weather Notebook.
Dust devils are one of the main features of Martian climate so scientists recently traveled to
a state where you can expect lots of hot, dusty summer weather: Arizona. In a study called
MATADOR, they aimed an instrument-laden pickup truck directly at dust devils to measure their
physical and electrical properties. Most dust devils on Earth are smaller than a city block.
On Mars they can range as wide as a half mile, and their winds can blow at over 140 miles an
hour. However, the MATADOR scientists are finding a lot of similarities between dust devils
on our green planet and those on the red one.
On both Earth and Mars, dust devils are most likely in the spring and summer, and they tend to
occur from late morning to mid-afternoon. That's when the sun's rays are at their strongest,
and parcels of hot air called thermals bubble up from above dry, dusty ground. One of the
MATADOR scientists is James Smith from the University of Arizona. Smith led the creation of a
camera that took dramatic photos of Mars in 1997 on NASA's Pathfinder mission. In that
project, Smith and colleagues detected 30 dust devils over 83 Martian days.
In Arizona, the team probed dust devils with lidar, a sibling of radar that uses laser beams
instead of microwaves. The results from MATADOR should help scientists create instruments to
withstand the strong electric fields that Martian dust devils can spin up… not to mention all
that sandblasting.
Thanks to today's contributing correspondent Bob Henson. The Weather Notebook is brought to
you from The Mount Washington Observatory, with major support from Subaru of America, and The
National Science Foundation.
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