Global Distribution of Dust Devil Tracks on Mars

Abstract

Dust devils are dust-raising atmospheric vortices that leave tracks of surface disturbance. In the first high-resolution global survey of martian dust devil tracks (DDTs), we find them in 4% of High Resolution Imaging Science Experiment images 2014–2018. They are concentrated near ±60° latitude and peak in local summer, more frequently in the southern hemisphere summer (L_S ∼ 250°–320°), coinciding with peak heating. DDT formation does not correlate with elevation, indicating it does not depend on ambient atmospheric pressure. 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, 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.