EGU21-14406, updated on 04 Mar 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

CO and O2 in the Martian atmosphere with ACS NIR onboard TGO.

Anna Fedorova1, Franck Lefèvre2, Alexander Trokhimovskiy1, Oleg Korablev1, Franck Montmessin2, Francois Forget3, Kevin Olsen4, Mikhail Luginin1, Alexander Lomakin1, Nikolay Ignatiev1, Denis Belyaev1, Andrey Patrakeev1, and Juan Alday4
Anna Fedorova et al.
  • 1Space Research Institute (IKI) RAS, Physics of planets, Moscow, Russian Federation (
  • 2LATMOS-UVSQ, Guyancourt, France
  • 3Laboratoire de Météorologie Dynamique, Sorbonne Université, Paris, France
  • 4AOPP, Oxford University, Oxford, United Kingdom

The molecular oxygen (O2) and carbon oxide (CO) are minor constituents of the Martian atmosphere with the annual mean mixing ratio of (1560 ± 60 ppm) and (673 ± 2.6 ppm), respectively (Krasnopolsky, 2017). Both are non-condensable species and their latitudinal variations are induced by condensation and sublimation of CO2 from the polar caps that result in enrichment and depletion and seasonal variations are following the total CO2 amount in the atmosphere.

The Atmospheric Chemistry Suite (ACS) is a set of three spectrometers (-NIR, -MIR, and -TIRVIM) intended to observe Mars atmosphere onboard the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission (Korablev et al., 2018). The near infrared channel (NIR) is a compact spectrometer operating in the range of 0.7–1.7 µm with a resolving power of λ/Δλ ~ 25,000. It is designed to operate in nadir and in solar occultation modes. The simultaneous vertical profiling of the O2 and CO density at altitudes of 10-60 km based on 0.76 µm and 1.57 µm bands, respectively, is a unique feature of the ACS NIR science in occultation. In this work we present the seasonal and latitudional distribution of the O2 and CO mixing ratios obtained for period of 2018-2020 (MY34 and35) and the comparison with the LMD General Circulation model. We report the averaged mixing ratio for CO of ~950 ppm and for O2 of~1800 ppm at low altitudes (~20 km). Also, we detected extremely enriched CO layer at 10-15 km in the southern polar region at Ls=100-200° both for MY34 and MY35.

How to cite: Fedorova, A., Lefèvre, F., Trokhimovskiy, A., Korablev, O., Montmessin, F., Forget, F., Olsen, K., Luginin, M., Lomakin, A., Ignatiev, N., Belyaev, D., Patrakeev, A., and Alday, J.: CO and O2 in the Martian atmosphere with ACS NIR onboard TGO., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14406,, 2021.

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