Preliminary characterization of the upper haze by SPICAV/SOIR solar occultation in UV to mid-IR onboard Venus Express

Abstract : The Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus/Solar Occultation at Infrared (SPICAV/SOIR) suite of instruments onboard the Venus Express spacecraft comprises three spectrometers covering a wavelength range from ultraviolet to midinfrared and an altitude range from 70 to >100 km. However, it is only recently (more than 1 year after the beginning of the mission) that the three spectrometers can operate simultaneously in the solar occultation mode. These observations have enabled the study of the properties of the Venusian mesosphere over a broad spectral range. In this manuscript, we briefly describe the instrument characteristics and the method used to infer haze microphysical properties from a data set of three selected orbits. Discussion focuses on the wavelength dependence of the continuum, which is primarily shaped by the extinction caused by the aerosol particles of the upper haze. This wavelength dependence is directly related to the effective particle radius (cross section weighted mean radius) of the particles. Through independent analyses for the three channels, we demonstrate the potential to characterize the aerosols in the mesosphere of Venus. The classical assumption that the upper haze is only composed of submicron particles is not sufficient to explain the observations. We find that at high northern latitudes, two types of particles coexist in the upper haze of Venus: mode 1 of mean radius 0.1 ≤ rg ≤ 0.3 μm and mode 2 of 0.4 ≤ rg ≤ 1.0 μm. An additional population of micron-sized aerosols seems, therefore, needed to reconcile the data of the three spectrometers. Moreover, we observe substantial temporal variations of aerosol extinction over a time scale of 24 h.
Liste complète des métadonnées

Littérature citée [20 références]  Voir  Masquer  Télécharger
Contributeur : Catherine Cardon <>
Soumis le : jeudi 25 février 2016 - 14:59:50
Dernière modification le : dimanche 9 décembre 2018 - 01:25:38
Document(s) archivé(s) le : dimanche 13 novembre 2016 - 03:38:26


Fichiers éditeurs autorisés sur une archive ouverte




V. Wilquet, Anna Fedorova, Franck Montmessin, R. Drummond, A. Mahieux, et al.. Preliminary characterization of the upper haze by SPICAV/SOIR solar occultation in UV to mid-IR onboard Venus Express. Journal of Geophysical Research. Planets, Wiley-Blackwell, 2009, 114 (E9), pp.E00B42. 〈10.1029/2008JE003186〉. 〈hal-00379299〉



Consultations de la notice


Téléchargements de fichiers