Vertical distributions of CO, H₂O, HDO, and temperature in the atmosphere of Mars after a year of observations with the ExoMars Trace Gas Orbiter (TGO) Atmospheric Chemistry Suite mid-infrared (ACS MIR) solar occultation spectrometer

Kevin Olsen (1) , J. Alday (2) , Lucio Baggio (1) , D. Belyaev (3) , A. Fedorova (3) , A. Grigoriev (3) , Franck Lefèvre (1) , O. Korablev (3) , Franck Montmessin (1) , A. Patrakeev (3) , Loïc Rossi (1) , A. Shakun (3) , Alexander Trokhimovskiy (3)

1 PLANETO - LATMOS
2 Department of Physics [Oxford]
3 IKI - Space Research Institute of the Russian Academy of Sciences

The ExoMars Trace Gas Orbiter (TGO) began its nominal science phase in April 2018 after arriving at the red planet in October 2016 and undergoing a lengthy aerobraking campaign. It carries a stereo camera (CaSSIS), a neutron detector (FREND), and two spectrometer suites aimed at investigating the atmosphere: the Atmospheric Chemistry Suite (ACS), and the Nadir and Occultation for Mars Discovery (NO-MAD). This presentation focuses on data analysis for the mid-infrared (MIR) channel of ACS, operating exclusively in solar occultation mode. We will describe work done to produce a Level 2B data product of calibrated transmission spectra and then show results from performing trace gas retrievals on target gas species, such as H₂O, HDO, CO, and CH₄. ACS MIR is a cross dispersion spectrometer consisting of an echelle grating with a wide blaze angle and a secondary, steerable diffraction grating (Ko-rablev et al., 2018). The secondary grating is used to separate high diffraction orders and access a spectral range of 2300-4400 cm −1. The simultaneous spectral range observed during an occultation is around 200 cm −1 wide, and the spectral resolution is around 0.04 cm −1.

Domains: Sciences of the Universe [physics]

Kevin Olsen, J. Alday, Lucio Baggio, D. Belyaev, A. Fedorova, et al.. Vertical distributions of CO, H₂O, HDO, and temperature in the atmosphere of Mars after a year of observations with the ExoMars Trace Gas Orbiter (TGO) Atmospheric Chemistry Suite mid-infrared (ACS MIR) solar occultation spectrometer. EPSC-DPS Joint Meeting 2019, Sep 2019, Geneva, Switzerland. pp.EPSC-DPS2019-1463-3. ⟨insu-02291450⟩