SOIROpenVenus · SOIR instrument Open science of the Venus upper atmosphere

Venus, our closest neighbour after the Moon, is an important planet to study: although it is very similar in size and Sun-distance when compared to the Earth, both planets evolved in very different manners. For this reason, studying the structure, dynamics, composition and chemistry of the Venus atmosphere is an major aspect of planetary science, as it helps to understand more about our Solar System in general. Indeed, many Venus atmosphere related questions remain unanswered, and this projects aims to address important open key questions.This project proposes a study of the Venus mesosphere and thermosphere at the terminator region, using solar occultation transmittance spectra that were measured by the SOIR instrument on board the ESA Venus Express spacecraft (2006-2014). The objectives of the proposed research project are (i) to characterize the two main Venus chemistry cycles, i.e. the sulfur and the carbon oxide cycles, and the deuterium/hydrogen ratio, and (ii) to study the wave dynamics, while (iii) making the results available to the community based on an open-science approach. Even though many species and temperature vertical profiles were retrieved during the mission timeframe using the SOIR spectra (CO2, CO, H2O, HDO, HCl, HF, SO2), some species absorbing in the SOIR wavenumber range were not studied (OCS, H2S, DCl, DF, NH3, HBr and HI); no cross-correlations between these species, which are involved in the different Venus chemical cycles, were examined. Furthermore, the observed short-term extreme variability in terms of species relative abundances and thermal structure was never characterized. We propose here (1) to complete the SOIR profiles molecular database, (2) to study the dependence between the species that contribute to the same chemical cycles and to characterize the variability, (3) to release the data products using existing open-base solutions and to disseminate the results through outreach activities.