Near-Surface Water Vapor Content Based on SPICAV IR/VEx Observations in the 1.1 and 1.18 μm Transparency Windows of Venus

The SPICAV IR spectrometer aboard the Venus Express orbiter measured spectra of the 1.1 and 1.18 μm atmospheric transparency windows at the Venus night side in 2006–2014. The long-term measurements encompassed the major part of the Venus globe, including polar latitudes. For the first time, the H<...

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Main Authors: Daria Evdokimova, Anna Fedorova, Nikolay Ignatiev, Oleg Korablev, Franck Montmessin, Jean-Loup Bertaux
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Atmosphere
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Online Access:https://www.mdpi.com/2073-4433/16/6/726
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author Daria Evdokimova
Anna Fedorova
Nikolay Ignatiev
Oleg Korablev
Franck Montmessin
Jean-Loup Bertaux
author_facet Daria Evdokimova
Anna Fedorova
Nikolay Ignatiev
Oleg Korablev
Franck Montmessin
Jean-Loup Bertaux
author_sort Daria Evdokimova
collection DOAJ
description The SPICAV IR spectrometer aboard the Venus Express orbiter measured spectra of the 1.1 and 1.18 μm atmospheric transparency windows at the Venus night side in 2006–2014. The long-term measurements encompassed the major part of the Venus globe, including polar latitudes. For the first time, the H<sub>2</sub>O volume mixing ratio in the deep Venus atmosphere at about 10–16 km has been retrieved for the entire SPICAV IR dataset using a radiative transfer model with multiple scattering. The retrieved H<sub>2</sub>O volume mixing ratio is found to be sensitive to different approximations of the H<sub>2</sub>O and CO<sub>2</sub> absorption lines’ far wings and assumed surface emissivity. The global average of the H<sub>2</sub>O abundance retrieved for different parameters ranges from 23.6 ± 1.0 ppmv to 27.7 ± 1.2 ppmv. The obtained values are consistent with recent studies of water vapor below the cloud layer, showing the H<sub>2</sub>O mixing ratio below 30 ppmv. Within the considered dataset, the zonal mean of the H<sub>2</sub>O mixing ratio does not vary significantly from 60° S to 75° N, except for a 2 ppmv decrease noted at high latitudes. The H<sub>2</sub>O local time distribution is also uniform. The 8-year observation period revealed no significant long-term trends or periodicities.
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spelling doaj-art-571fc2055f6a40ef90d9400481e4225d2025-08-20T03:26:21ZengMDPI AGAtmosphere2073-44332025-06-0116672610.3390/atmos16060726Near-Surface Water Vapor Content Based on SPICAV IR/VEx Observations in the 1.1 and 1.18 μm Transparency Windows of VenusDaria Evdokimova0Anna Fedorova1Nikolay Ignatiev2Oleg Korablev3Franck Montmessin4Jean-Loup Bertaux5Space Research Institute of the Russian Academy of Sciences, Moscow 117997, RussiaSpace Research Institute of the Russian Academy of Sciences, Moscow 117997, RussiaSpace Research Institute of the Russian Academy of Sciences, Moscow 117997, RussiaSpace Research Institute of the Russian Academy of Sciences, Moscow 117997, RussiaLaboratoire Atmosphères, Observations Spatiales (LATMOS), Centre National de la Recherche Scientifique (CNRS), Université de Versailles-Saint-Quentin-en-Yvelines (UVSQ) Université Paris-Saclay, 78280 Guyancourt, FranceLaboratoire Atmosphères, Observations Spatiales (LATMOS), Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005 Paris, FranceThe SPICAV IR spectrometer aboard the Venus Express orbiter measured spectra of the 1.1 and 1.18 μm atmospheric transparency windows at the Venus night side in 2006–2014. The long-term measurements encompassed the major part of the Venus globe, including polar latitudes. For the first time, the H<sub>2</sub>O volume mixing ratio in the deep Venus atmosphere at about 10–16 km has been retrieved for the entire SPICAV IR dataset using a radiative transfer model with multiple scattering. The retrieved H<sub>2</sub>O volume mixing ratio is found to be sensitive to different approximations of the H<sub>2</sub>O and CO<sub>2</sub> absorption lines’ far wings and assumed surface emissivity. The global average of the H<sub>2</sub>O abundance retrieved for different parameters ranges from 23.6 ± 1.0 ppmv to 27.7 ± 1.2 ppmv. The obtained values are consistent with recent studies of water vapor below the cloud layer, showing the H<sub>2</sub>O mixing ratio below 30 ppmv. Within the considered dataset, the zonal mean of the H<sub>2</sub>O mixing ratio does not vary significantly from 60° S to 75° N, except for a 2 ppmv decrease noted at high latitudes. The H<sub>2</sub>O local time distribution is also uniform. The 8-year observation period revealed no significant long-term trends or periodicities.https://www.mdpi.com/2073-4433/16/6/726Venus atmosphereinfrared spectroscopy
spellingShingle Daria Evdokimova
Anna Fedorova
Nikolay Ignatiev
Oleg Korablev
Franck Montmessin
Jean-Loup Bertaux
Near-Surface Water Vapor Content Based on SPICAV IR/VEx Observations in the 1.1 and 1.18 μm Transparency Windows of Venus
Atmosphere
Venus atmosphere
infrared spectroscopy
title Near-Surface Water Vapor Content Based on SPICAV IR/VEx Observations in the 1.1 and 1.18 μm Transparency Windows of Venus
title_full Near-Surface Water Vapor Content Based on SPICAV IR/VEx Observations in the 1.1 and 1.18 μm Transparency Windows of Venus
title_fullStr Near-Surface Water Vapor Content Based on SPICAV IR/VEx Observations in the 1.1 and 1.18 μm Transparency Windows of Venus
title_full_unstemmed Near-Surface Water Vapor Content Based on SPICAV IR/VEx Observations in the 1.1 and 1.18 μm Transparency Windows of Venus
title_short Near-Surface Water Vapor Content Based on SPICAV IR/VEx Observations in the 1.1 and 1.18 μm Transparency Windows of Venus
title_sort near surface water vapor content based on spicav ir vex observations in the 1 1 and 1 18 μm transparency windows of venus
topic Venus atmosphere
infrared spectroscopy
url https://www.mdpi.com/2073-4433/16/6/726
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