Global Distribution of Dust Devil Tracks on Mars

Dust devils are dust-raising atmospheric vortices that leave surface tracks of dust disturbance. In the first high-resolution global survey of martian dust devil tracks (DDTs), we find them in 4% of HiRISE images 2014-2018. They are concentrated near ±60° latitude and peak in local summer, more frequently in the southern hemisphere summer (LS ~250-320), coinciding with peak heating. Based on their elevations, atmospheric pressure does not appear to influence their formation. Locations and timing of DDTs are similar to active dust devils, with several regional exceptions. DDTs are most common in areas characterized by low albedo and moderate thermal inertia. DDTs most readily form where thin layers of dust overlie larger-grained material that provides an albedo contrast when uncovered by the passage of an atmospheric vortex. In addition to revealing the nature and formation of DDTs, this study has implications for solar-powered exploration of Mars, identifying potential dust-clearing event regions.