Atmospheric Dust on Mars: A Review

The Martian environment is characterized by airborne mineral dust extending between the surface and up to 80 km altitude. This dust plays a key role in the climate system and in the atmospheric variability. It is a significant issue for any system on the surface. The atmospheric dust content is highly variable in space and time. In the past 20 years, many investigations have been conducted to better understand the characteristics of the dust particles, their distribution and their variability. However, many unknowns remain. We still don't know precisely the composition of the dust particles and notably their density, a key parameter when modeling their abrasion. The occurrence of local, regional and global dust storms are better documented and modeled, but they remain very difficult to predict. The vertical distribution of dust, characterized by detached layers exhibiting large diurnal and seasonal variations, remains quite enigmatic and very poorly modeled. Near the surface the actual dynamics of saltating dust in the surface layer (where landers and astronauts operate) is also a topic of ongoing research. We will review our current knowledge on these subjects and discuss the implication for future exploration projects.