An evidence of rapid hydrogen chloride uptake on water ice in the atmosphere of Mars

In 2020, hydrogen chloride (HCl) in the gas phase was discovered in the atmosphere of Mars with the Atmospheric Chemistry Suite (ACS) onboard the Trace Gas Orbiter (TGO) mission (Korablev et al., 2021). Its volume mixing ratio (VMR) shows a seasonal increase of up to 5 ppbv during the perihelion sea...

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Bibliographic Details
Published in:arXiv.org 2023-12
Main Authors: Luginin, Mikhail, Trokhimovskiy, Alexander, Taysum, Benjamin, Fedorova, Anna A, Korablev, Oleg, Olsen, Kevin S, Montmessin, Franck, Lefèvre, Franck
Format: Article
Language:English
Subjects:
Abundance
Atmosphere
Atmospheric chemistry
Hydrochloric acid
Hydrogen chloride
Mars atmosphere
Mixing ratio
Perihelions
Trace gases
Vapor phases
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Summary:In 2020, hydrogen chloride (HCl) in the gas phase was discovered in the atmosphere of Mars with the Atmospheric Chemistry Suite (ACS) onboard the Trace Gas Orbiter (TGO) mission (Korablev et al., 2021). Its volume mixing ratio (VMR) shows a seasonal increase of up to 5 ppbv during the perihelion season, followed by a sudden drop to undetectable levels, contradicting previous estimations of the HCl lifetime of several months. In the Earth's stratosphere, heterogeneous uptake of HCl onto water ice is known to be a major sink for this species. Modelling of associated chemistry involving heterogeneous reactions indicates that H2O ice becomes the most effective sink for HCl above 20 km with the characteristic time shorter than 12 hours. In this work, we use simultaneous measurements of water ice particles and HCl abundance obtained by the ACS instrument and show particular structures in the vertical profiles, forming detached layers of gas at the ice free altitudes ('ice-holes'). We demonstrate that the heterogeneous uptake of HCl onto water ice operates on Mars and is potentially a major mechanism regulating the HCl abundance in the atmosphere of Mars.
ISSN:2331-8422
DOI:10.48550/arxiv.2312.07209