Article,
Mars: Dust devil track survey in Argyre Planitia and Hellas Basin
Journal of Geophysical Research-Planets, 108 (E8): 5086 (2003)
Abstract
Dust devils and dust devil tracks have been frequently observed in
Viking Orbiter and Mars Orbiter Camera (MOC) images, but the parameters
that control their distribution have been poorly constrained. Here
we investigate the abundance of dust devil tracks in two large study
areas, Argyre Planitia and Hellas Basin, using a survey of over 3000
MOC narrow-angle (NA) images. We report the effect of season, elevation,
and surface properties on track distribution using measurements of
dust devil track density (the number of dust devil tracks per square
kilometer). In both areas, dust devil tracks occur predominantly
in summer and are rarely observed in winter. The lifetime of dust
devil tracks is inferred to be short (i.e., less than a few months).
There is no unambiguous correlation of abundance with elevation;
rather the spatial distribution follows albedo patterns, suggesting
that dust availability controls the abundance of dust devil tracks.
We estimate the total dust lifting potential of dust devils using
the average dust devil track density for Argyre and Hellas and conclude
that, unless the average dust devil track is greater than 20 m wide,
longer than 2 km, and more than 40 mm deep, they cannot account for
the estimated global sedimentation rate. In addition, by comparing
2 Mars years of observations, we find no evidence of an increase
in dust devil track density prior to the global dust storm that occurred
in June 2001. We conclude that dust devils did not trigger this storm.
