Space Science Reviews, 2024; https://doi.org/10.1007/s11214-024-01054-5

Colin F. Wilson, Emmanuel Marcq, Cédric Gillmann, Thomas Widemann, Oleg Korablev, Nils T. Mueller, Maxence Lefèvre, Paul B. Rimmer, Séverine Robert & Mikhail Y. Zolotov

Abstract

This work reviews possible signatures and potential detectability of present-day volcanically emitted material in the atmosphere of Venus. We first discuss the expected composition of volcanic gases at present time, addressing how this is related to mantle composition and atmospheric pressure. Sulfur dioxide, often used as a marker of volcanic activity in Earth’s atmosphere, has been observed since late 1970s to exhibit variability at the Venus’ cloud tops at time scales from hours to decades; however, this variability may be associated with solely atmospheric processes. Water vapor is identified as a particularly valuable tracer for volcanic plumes because it can be mapped from orbit at three different tropospheric altitude ranges, and because of its apparent low background variability. We note that volcanic gas plumes could be either enhanced or depleted in water vapor compared to the background atmosphere, depending on magmatic volatile composition. Non-gaseous components of volcanic plumes, such as ash grains and/or cloud aerosol particles, are another investigation target of orbital and in situ measurements. We discuss expectations of in situ and remote measurements of volcanic plumes in the atmosphere with particular focus on the upcoming DAVINCI, EnVision and VERITAS missions, as well as possible future missions.

Proceedings Volume 11128, Infrared Remote Sensing and Instrumentation XXVII; 1112804 (2019) https://doi.org/10.1117/12.2529248

J. Helbert, A. C. Vandaele, E. Marcq, S. Robert, C. Ryan, G. Guignan, Y. Rosas-Ortiz, E. Neefs, I. R. Thomas, G. Arnold, G. Peter, T. Widemann, L. Lara

Abstract

The VenSpec instrument suite is part of the payload for the ESA M5 mission proposal EnVision which is currently in a competitive Phase A study. VenSpec consists of three channels: VenSpec-M, VenSpec-H and VenSpec-U. VenSpec-M will provide near-global compositional data on rock types, weathering, and crustal evolution by mapping the Venus surface in five atmospheric windows. VenSpec-H will be dedicated to extremely high-resolution atmospheric measurements. The main objective of the VenSpec-H instrument is to detect and quantify SO2, H2O and HDO in the lower atmosphere, to enable characterization of volcanic plumes and other sources of gas exchange with the surface of Venus, complementing VenSAR and VenSpecM surface and SRS subsurface observations. VenSpec-U will monitor sulphured minor species (mainly SO and SO2) and the as yet unknown UV absorber in Venusian upper clouds and just above. In combination, VenSpec will provide unprecedented insights into the current state of Venus and its past evolution. VenSpec will perform a comprehensive search for volcanic activity by targeting atmospheric signatures, thermal signatures and compositional signatures, as well as a global map of surface composition.

Journal of Quantative Spectroscopy and Radiative Transfer, 2024; https://doi.org/10.1016/j.jqsrt.2024.109026

É. Ducreux, B. Grouiez, S. Robert, M. Lepère, B. Vispoel, R.R. Gamache, L. Régalia

Abstract

H2O is an important molecule in the quest to better understand the evolution of solar system. In the study of Venus and Mars CO2-rich atmospheres (around 96 % of their composition) and because of the space instruments constant improvements, the planetary community needs spectroscopic data as accurate as possible.

Continuing from our previous study [JQSRT 231, 126(2019)], new spectra of H2O perturbed by CO2 were measured with our new experimental set-up in the 2.7 µm region to compare with the previous results. After the improvement in the determination of the partial pressure of water vapor, the line parameters were then determined with a multispectrum fitting procedure using a Voigt profile in the same way as in [JQSRT 231, 126(2019)]. This led to characteristic W-shape residuals that have been improved using beyond-Voigt profiles. Our investigation showed that considering the speed dependence of collisional line parameters is essential to obtain better line-shape parameters in the considered experimental conditions.

BIRA-IASB wants to acknowledge the support of BELSPO (Belgian Science Policy Office) to the mission and in particular to the VenSpec-H instrument.