Observations of thermal tides in the middle atmosphere of Mars by the SPICAM instrument

Paul Withers 1 Robert Pratt 1 Jean-Loup Bertaux 2 Franck Montmessin 2
2 IMPEC - LATMOS
LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales
Abstract : We use vertical profiles of Martian atmospheric density, pressure, and temperature from the Mars Express SPICAM UV spectrometer to study thermal tides in the poorly studied middle atmosphere region at 70-120 km. Here we show that nonmigrating tides cause zonal pressure variations of tens of percent and zonal temperature variations on the order of 10 K in these observations. Wave-2 and wave-3 components are dominant, consistent with previous work at lower and higher altitudes and with theoretical predictions. Normalized pressure amplitudes tend to increase with altitude for the cases and altitudes studied here. Phases of the pressure variations vary little with altitude, indicating long vertical wavelengths for the underlying tidal modes. We derive theoretical relationships between zonal variations in temperature and in pressure and find that they are generally satisfied. Failure of these relationships can be used to infer the presence of multiple tidal modes contributing to a single observed wave component. The wave-2 component is dominated by the diurnal Kelvin wave 1 (DK1) above about 80 km but contains multiple tidal modes below this altitude. In one unusual instance, 40°S-30°S, Ls = 150°-180°, and local time of 22-24 h, the usually strong wave-2 component is extremely weak. The wave-3 component is always dominated by a single tidal mode, which for tropical and extratropical latitudes we identify as the diurnal Kelvin wave 2 (DK2).
Keywords : Mars Tides Atmosphere
Liste complète des métadonnées

Littérature citée [53 références]  Voir  Masquer  Télécharger

https://hal.archives-ouvertes.fr/hal-00642614
Contributeur : Catherine Cardon <>
Soumis le : samedi 12 novembre 2016 - 16:30:18
Dernière modification le : lundi 29 mai 2017 - 15:08:26
Document(s) archivé(s) le : jeudi 16 mars 2017 - 11:40:59

Fichier

Withers_et_al-2011-Journal_of_...
Fichiers éditeurs autorisés sur une archive ouverte

Identifiants

Collections

Citation

Paul Withers, Robert Pratt, Jean-Loup Bertaux, Franck Montmessin. Observations of thermal tides in the middle atmosphere of Mars by the SPICAM instrument. Journal of Geophysical Research. Planets, Wiley-Blackwell, 2011, 116 (E11), pp.E11005. 〈10.1029/2011JE003847〉. 〈hal-00642614〉

Partager

Métriques

Consultations de la notice

186

Téléchargements de fichiers

19