Upper limits of HO2 in the atmosphere of Mars from the ExoMars Trace Gas Orbiter
Résumé
Odd-hydrogen (HOx ) species have a crucial role in regulating the chemistry of the atmosphere of Mars and are important to
understand some of the most fundamental aspects regarding its atmospheric composition such as the long-term stability of
CO2 . Despite the key role of these species for our understanding of the Martian photochemistry, there is little observational
evidence constraining their abundances. In this study, we use infrared solar occultation observations from the Atmospheric
Chemistry Suite aboard the ExoMars Trace Gas Orbiter to search for spectral signatures of HO2 in the atmosphere of Mars. In
our analysis of the data, we retrieve vertical profiles of pressure, temperature, and water vapour mixing ratio, but are unable to
confidently detect the presence of HO2 features in the spectra. We report upper limits of 15 ppbv (5σ ), which represents an order
of magnitude improvement with respect to previous investigations. Comparing the derived upper limits with the expectations
from 3-dimensional Global Climate Models, we find that approximately an order of magnitude improvement in the instrument
sensitivity would be required to detect this molecule and/or constrain the models.
Domaines
Planète et Univers [physics]| Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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