Dust is present everywhere on Mars, yet its abundance, physical properties and impact on the atmosphere have today only barely been understood. Dust is lifted from the surface up into the atmosphere by several processes. 3 transport regimes are usually considered: suspension (the grain remains aloft in the atmosphere), saltation (the particle will fall back to the surface), and creep (the particle undergoes rolling and sliding on the surface). When large particles return to the surface, they impact dust grains which in turn can be injected into the atmosphere.
Dust storms can span different spatial and time scales. Sometimes, Global Dust Storms occur. The processes that control the creation, expansion, and decay of global dust storms depend on the radiative–dynamic feedback between dust lifting, heating of the atmosphere, and circulation. The dust and water cycles are coupled through cloud condensation processes. Dust also modifies the thermal structure of the atmosphere.
The concept of the RoadMap project (ROle and impAct of Dust and clouds in the Martian AtmosPhere) is based on an integrated approach of different scientific aspects (laboratory, modelling, space data analysis) to improve our vision of the Martian atmosphere and provide a new generation of high-level data which will increase the science return of the past and current missions to Mars, but will also shape and help future planetary missions.
This will be done through the analysis of existing data to obtain abundances and properties of gases, dust and clouds through analysis tools improved thanks to laboratory experiments. General Circulation Models will be updated with the latest results from the lab (lifting, aggregation, radiative properties), to better understand the Martian atmosphere.
