Correlations between minor species in the Venus mesosphere from the SOIR/Venus Express spectrograph

The Solar Occultation in the Infrared (SOIR) instrument was an infrared echelle grating spectrometer on board the Venus Express spacecraft of ESA that sounded the Venus mesosphere using the solar occultation technique [1] from 2006 to 2014. Working at very high resolution, it performed 500+ solar occultations during which many species could be targeted, wherein CO [1], H₂O [2], HDO [3], HCl, HF [4], SO₂ [5], OCS, SO₃, H₂S, CS [6], etc., aside from CO₂ [7], the main atmosphere constituent. From the measured spectra, we could derive vertical profiles covering the 65 to 160 km region at maximum extent, each species being detected in specific altitude ranges, depending on the strength of their respective spectral absorption bands and concentrations. Temperature profiles were also derived considering the CO₂ vertical profiles and the hydrostatic equation [7]. During each solar occultation, SOIR could measure up to four spectral intervals corresponding to the diffraction orders of the echelle grating, allowing us to simultaneously target specific species in different altitude regions.

 

In this work, we are seeking correlations between the concentrations of the minor species, and between the minor species and the temperature profiles, that were measured simultaneously. We will summarize those possible concentration dependencies focusing on possible latitude or time trends. We will also report on possible temperature dependence on the concentrations of those species.

 

[1] Vandaele , A.C., et al. (2016), Icarus, 272.

[2] Chamberlain, S., et al. (2020), Icarus, 346.

[3] Fedorova, A., et al. (2008), J. Geophys. Res., 113.

[4] Mahieux, A., et al. (2015), Planet. Space Sci., 113-114.

[5] Mahieux, A., et al. (2015), Planet. Space Sci., 113-114.

[6] Mahieux, A., et al. (2023), Icarus, Under review.

[7] Mahieux, A., et al. (2015), Planet. Space Sci., 113-114.