Impact of Dust on Mars Surface Albedo and Energy Flux with LMD General Circulation Model

Abstract:

Mars, just like Earth experience different seasons because of its axial tilt (about 25°). This causes growth and retreat of snow cover (primarily CO₂) in Martian Polar regions. The perennial caps are the only place on the planet where condensed H₂O is available at surface. On Mars, as much as 30% atmospheric CO₂ deposits in each hemisphere depending upon the season. This leads to a significant variation on planet’s surface albedo and hence effecting the amount of solar flux absorbed or reflected at the surface. General Circulation Model (GCM) of Laboratoire de Météorologie Dynamique (LMD) currently uses observationally derived surface albedo from Thermal Emission Spectrometer (TES) instrument for the polar caps. These TES albedo values do not have any inter-annual variability, and are independent of presence of any dust/impurity on surface. Presence of dust or other surface impurities can significantly reduce the surface albedo especially during and right after a dust storm. This change will also be evident in the surface energy flux interactions. Our work focuses on combining earth based Snow, Ice, and Aerosol Radiation (SNICAR) model with current state of GCM to incorporate the impact of dust on Martian surface albedo, and hence the energy flux. Inter-annual variability of surface albedo and planet’s top of atmosphere (TOA) energy budget along with their correlation with currently available mission data will be presented.