Chapter 10 - Dust Devils: Stirring Up the Martian Surface

Abstract

Mars is a hyperarid planet with a thin atmosphere, large diurnal temperature variations, and abundant surface coverage of fine dust. These are ideal conditions for the formation of insolation-driven convective vortices, if laden with dust, called dust devils. Aerosols such as mineral dust play an important role in the atmosphere influencing the climate by reflection of incoming solar radiation and absorption of outgoing thermal radiation. In addition, they have significant effects on the atmospheric energy budget as they act as cloud condensation and ice nuclei. In the last decades, several thousand active dust devils and innumerable streaks on the surface caused by passages of dust devils have been imaged globally from orbit. At every landing site dust devils have been directly imaged and/or indirectly detected via meteorological signatures. From these large data sets it was able to constrain local, regional, and global statistics of the spatial and temporal occurrences of dust devils. The analysis of the current data sets indicates that dust devils are an important factor to loft dust in the martian atmosphere, replenishing the background dust haze.