One Martian year of solar occultation observations of dust and water ice aerosols performed by ACS/TGO
Résumé
Dust and water ice aerosols play an essential role in the atmospheric circulation, energy budget, and climate of Mars. Dust particles cause changes in atmospheric dynamics and inflation of the atmosphere through the solar heating of the atmosphere. Water ice clouds are an integral part of the water cycle, altering the global transport of water vapor. They influence the atmosphere radiatively and alter the dust distribution through the scavenging of dust particles due to the condensation of ice. Knowledge of the spatial and temporal distribution of dust and water ice aerosols is, therefore, crucial for a better understanding of main atmospheric cycles on Mars. The Atmospheric Chemistry Suite (ACS) instrument onboard the ESA-Roscosmos Trace Gas Orbiter (TGO) mission is monitoring spatial and vertical distributions of dust and water ice aerosols in the Martian atmosphere since April 2018. Solar occultation observations of Thermal InfraRed (TIRVIM), Middle InfraRed (MIR), and Near InfraRed (NIR) channels of ACS in the 0.7−6 μm spectral range allow unambiguous retrieval of key aerosol parameters (effective radius, effective variance, number density, and mass loading) for both water ice and dust. We will present results on the vertical dependence and the temporal evolution of these parameters for more than one Martian year (MY), from LS = 170° of MY 34 (May 2018) to LS = 240° of MY 35 (July 2020). The work was supported by the Russian Science Foundation (project No. 20-42-09035).