Composition of the Venus mesosphere measured by Solar Occultation at Infrared on board Venus Express
Vandaele, A. C.; Montmessin, F.; Fedorova, A.; Korablev, O.; Bertaux, J. -L.; Wilquet, V.; Drummond, R.; Mahieux, A.; Belyaev, D.; Neefs, E.; De Mazière, M.
Belgium, Russia, France
Abstract
Solar Occultation at Infrared (SOIR), which is a part of the Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV) instrument on board Venus Express, combines an echelle-grating spectrometer with an acoustooptical tunable filter. It performs solar occultation measurements in the IR region at a high spectral resolution better than all previously flown planetary spectrometers. The wavelength range probed allows for a detailed chemical inventory of the Venus atmosphere above the cloud layer, with an emphasis on the vertical distribution of the gases. A general description of the retrieval technique is given and is illustrated by some results obtained for CO2 and for a series of minor constituents, such as H2O, HDO, CO, HCl, and HF. Detection limits for previously undetected species will also be discussed.