OMEGA albedo map of Mars

Ground albedo is a key parameter controlling the radiative budget of a planet. A precise knowledge of Mars surface albedo is required to predict the climate of Mars and to assess the thermo-physical properties of the ground. The TES instrument provided a reference albedo map with a 3 km spatial resolution, based on data gathered under clear atmospheric conditions from 1999 to 2004. While universally used, this dataset could contain biases: why do simultaneous retrievals of albedo and thermal inertia by IRTM yield to different albedo values compared to separate retrievals performed by TES? How do aerosols modify estimates of surface albedo? Is TES albedo representative of recent missions measurements? Our goal is to retrieve an independent, calibrated albedo map of the surface of Mars with a 1 km spatial resolution using OMEGA spectral reflectance measurements from 0.3 μm to 2.5 μm. This study will account for aerosols contribution, which cannot be neglected even under clear atmospheric conditions. Bidirectional reflectance properties of the surface of Mars will also be considered to derive albedo from single viewing geometry measurements. First results indicate albedo differences between OMEGA and TES up to 50%. Such variations significantly impact climate predictions and ground thermal inertia estimates.