Accueil > Actualités > Séminaires > Séminaire de Jörg GUMBEL au LATMOS


Titre : Satellite observations of mesospheric clouds as tracers for global atmospheric dynamics
Nom du conférencier : Jörg GUMBEL
Son affiliation : Stockholm University, Department of Meteorology, Stockholm, Sweden
Laboratoire organisateur : LATMOS
Date et heure : 26-01-2012 14h00
Lieu : LATMOS/OVSQ, amphithéâtre Gérard Mégie, 11 boulevard d'Alembert, 78280 Guyancourt
Résumé :

Noctilucent Clouds (or Polar Mesospheric Clouds) occur during summer at altitudes near 80 km as the highest clouds in our atmosphere. These clouds are extremely sensitive to variations of their mesospheric environment. The state of the mesosphere is in turn connected to the lower atmosphere through various dynamical coupling processes. Ten years of noctilucent cloud data from the Swedish/French/Finnish/Canadian Odin satellite have been analyzed as tracers for such processes. Inter-hemispheric coupling from the winter stratosphere and troposphere is found to have a major influence on the summer mesosphere. Intra-hemispheric coupling from the spring/summer stratosphere, on the other hand, can control the onset of the noctilucent cloud season. Proposed mechanisms for these "teleconnections" are based on the effect of lower atmospheric circulation on gravity wave filtering and, thus, on the dynamical forcing of the mesospheric circulation. This presentation provides both an introduction on noctilucent clouds and a discussion of global dynamics studies than can be based on their observation.