Seasonal Changes in the Vertical Structure of Ozone in the Martian Lower Atmosphere and Its Relationship to Water Vapor

Kevin S. Olsen (1) , A. A. Fedorova (2) , A. Trokhimovskiy (2) , Franck Montmessin (3) , Franck Lefèvre (3) , Oleg Korablev (2) , Lucio Baggio (3) , Francois, Forget (4) , E. Millour (4) , A. Bierjon (4) , J. Alday (1, 5) , C. F. Wilson (1, 6) , P. G. J. Irwin (1) , D. A. Belyaev (2) , A. Patrakeev (2) , A. Shakun (2)

1 Department of Physics [Oxford]
2 IKI - Space Research Institute of the Russian Academy of Sciences
3 PLANETO - LATMOS
4 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
5 School of Physical Sciences [Milton Keynes]
6 ESTEC - European Space Research and Technology Centre

Ozone on Mars is part of the so-called odd-oxygen family of reactive, oxidizing gases. It is part of many chemical cycles that help convert one type of gas into another, facilitating the transfer of carbon or hydrogen. Odd-oxygen is crucial to linking the cycles of water vapour and carbon dioxide, or the destruction of trace gases, such as methane. With the Atmospheric Chemistry Suite (ACS) onboard the ExoMars Trace Gas Orbiter (TGO), we are able to study the vertical structure of ozone in the Martian atmosphere and make direct comparisons between it and water vapour and temperature. We have observed ozone abundances several times larger than predicted, suggesting that the oxidizing power of the Martian atmosphere is stronger or faster than expected. We have also observed and measured the relationship between these products: temperature controls the abundance of water vapour, and when the atmosphere cools and water condenses, ozone is able to build up. It is the by-products of when water vapour breaks down in sunlight that remove odd-oxygen from the atmosphere.

Mots clés: Planetary Atmosphere; Ozone; Mars; Water Vapour

Domaines: Planète et Univers [physics]

Kevin S. Olsen, A. A. Fedorova, A. Trokhimovskiy, Franck Montmessin, Franck Lefèvre, et al.. Seasonal Changes in the Vertical Structure of Ozone in the Martian Lower Atmosphere and Its Relationship to Water Vapor. Journal of Geophysical Research. Planets, 2022, 127 (10), pp.e2022JE007213. ⟨10.1029/2022je007213⟩. ⟨insu-03685666v2⟩