Retrieving cloud, dust and ozone abundances in the Martian atmosphere using SPICAM/UV nadir spectra

Abstract : We present the retrieval algorithm developed to analyse nadir spectra from SPICAM/UV aboard Mars-Express. The purpose is to retrieve simultaneously several parameters of the Martian atmosphere and surface: the dust optical depth, the ozone total column, the cloud opacity and the surface albedo. The retrieval code couples the use of an existing complete radiative transfer code, an inversion method and a cloud detection algorithm. We describe the working principle of our algorithm and the parametrisation used to model the required absorption, scattering and reflection processes of the solar UV radiation that occur in the Martian atmosphere and at its surface. The retrieval method has been applied on 4 Martian years of SPICAM/UV data to obtain climatologies of the different quantities under investigation. An overview of the climatology is given for each species showing their seasonal and spatial distributions. The results show a good qualitative agreement with previous observations. Quantitative comparisons of the retrieved dust optical depths indicate generally larger values than previous studies. Possible shortcomings in the dust modelling (altitude profile) have been identified and may be part of the reason for this difference. The ozone results are found to be influenced by the presence of clouds. Preliminary quantitative comparisons show that our retrieved ozone columns are consistent with other results when no ice clouds are present, and are larger for the cases with clouds at high latitude. Sensitivity tests have also been performed showing that the use of other a priori assumptions such as the altitude distribution or some scattering properties can have an important impact on the retrieval.
Type de document :
Article dans une revue
Planetary and Space Science, Elsevier, 2017, 142, pp.9-25. 〈10.1016/j.pss.2017.04.011〉
Liste complète des métadonnées

Littérature citée [64 références]  Voir  Masquer  Télécharger

https://hal-insu.archives-ouvertes.fr/insu-01512630
Contributeur : Catherine Cardon <>
Soumis le : lundi 29 mai 2017 - 10:18:45
Dernière modification le : mercredi 21 mars 2018 - 18:58:00
Document(s) archivé(s) le : mercredi 6 septembre 2017 - 10:28:43

Fichier

PSS Lefevre.pdf
Fichiers éditeurs autorisés sur une archive ouverte

Identifiants

Collections

Citation

Y. Willame, A. C. Vandaele, C. Depiesse, Franck Lefèvre, V. Letocart, et al.. Retrieving cloud, dust and ozone abundances in the Martian atmosphere using SPICAM/UV nadir spectra. Planetary and Space Science, Elsevier, 2017, 142, pp.9-25. 〈10.1016/j.pss.2017.04.011〉. 〈insu-01512630〉

Partager

Métriques

Consultations de la notice

109

Téléchargements de fichiers

27