Thermal Structure and Aerosols in Mars’ Atmosphere From TIRVIM/ACS Onboard the ExoMars Trace Gas Orbiter: Validation of the Retrieval Algorithm

The Atmospheric Chemistry Suite (ACS) onboard the ExoMars Trace Gas Orbiter (TGO) monitors Martian atmosphere through different spectral intervals in infrared light. We present a retrieval algorithm tailored to analysis of spectra acquired nadir geometry by TIRVIM, thermal channel ACS. Our simultaneously retrieves vertical profile atmospheric temperature up 50 km, surface temperature, and integrated optical depth dust water ice clouds. specificity TIRVIM dataset lies its capacity resolve diurnal cycle over 54 sol period. However, it is uncertain what extent can desired quantities be accurately estimated at times day. Here we first an Observing System Simulation Experiment (OSSE). produce synthetic observations various latitudes, seasons local run our on these data, evaluate robustness. Different sources biases are documented, particular regarding aerosol retrievals. retrievals found robust even when and/or cloud opacities not well OSSE. then apply April-May, 2018 perform cross-validation retrieved opacity comparisons with thousands co-located Mars Climate Sounder (MCS) Most differences between MCS temperatures attributed sensitivity. Daytime agree each other, while nighttime from this season.