Retrieval of CO Relative Column Abundance in the Martian Thermosphere From FUV Disk Observations by EMM EMUS

J. S. Evans , J. Correira , J. Deighan , S. Jain , H. Al Matroushi , H. Al Mazmi , M. Chaffin , S. Curry , S. England , F. Eparvier , M. Fillingim , F. Forget (1) , G. Holsclaw , R. Lillis , F. Lootah , E. Thiemann

1 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)

Carbon monoxide (CO) is a sensitive tracer of the thermal profile and winds in Mars' middle atmosphere and the chemistry that balances CO₂ in the whole atmosphere of Mars. The Emirates Ultraviolet Spectrometer (EMUS) onboard the Emirates Mars Mission Hope probe images Mars at ultraviolet wavelengths from approximately 100 to 170 nm. ΣCO/CO₂, the column density ratio of CO to carbon dioxide, provides a sensitive measure of CO relative variability within the Martian thermosphere. Derived from the heritage of ΣO/N₂ used at Earth, the ΣCO/CO₂ algorithm uses emission from the CO Fourth Positive Group band system to derive the relative column abundance of CO above ∼70 km. We describe the EMUS ΣCO/CO₂ algorithm, review the Level 3 data product, and discuss preliminary validation of the algorithm. The ΣCO/CO₂ algorithm produces column density ratios that characterize the spatial structure and relative variability of CO abundance in the Martian thermosphere.

Domaines: Planète et Univers [physics]

J. S. Evans, J. Correira, J. Deighan, S. Jain, H. Al Matroushi, et al.. Retrieval of CO Relative Column Abundance in the Martian Thermosphere From FUV Disk Observations by EMM EMUS. Geophysical Research Letters, 2022, 49, ⟨10.1029/2022GL099615⟩. ⟨insu-03847098⟩