Mars: Dust devil track survey in Argyre Planitia and Hellas Basin

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.