GEOSCAN, résultats de la recherche


TitreA link between high-speed solar wind streams and explosive extratropical cyclones
AuteurPrikryl, P; Iwao, K; Muldrew, D B; Rusin, V; Rybansky, M; Bruntz, R
SourceJournal of Atmospheric and Solar-Terrestrial Physics vol. 149, (2016), 2016 p. 219-231,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20150487
Documentpublication en série
Mediapapier; en ligne; numérique
Sujetstempêtes; champs géomagnétiques; variations géomagnétiques; orages magnétiques; zone aurorale; magnétosphère; ionosphère; variations solaires; Temps (Météorologie); géologie extraterrestre
Illustrationslocation maps; graphs; bar graphs
ProgrammeNord du Canada, risque géoscience, Géoscience pour la sécurité publique
Résumé(disponible en anglais seulement)
A link between solar wind magnetic sector boundary (heliospheric current sheet) crossings by the Earth and the upper-level tropospheric vorticity was discovered in the 1970s. These results have been later confirmed but the proposed mechanisms remain controversial. Using a database of extratropical cyclones tracks obtained from two meteorological reanalysis datasets, superposed epoch analysis of time series of solar wind plasma parameters and the green coronal emission line intensity keyed by times of maximum growth of explosively developing extratropical cyclones is performed. The new statistical evidence corroborate the previously published results indicating that explosive extratropical cyclones tend to occur after arrivals of solar wind disturbances such as high-speed solar wind streams from coronal holes when large amplitude magneto-hydrodynamic waves couple to the magnetosphere-ionosphere system and modulate Joule heating and/or Lorentz forcing of the high-latitude thermosphere generating medium-scale atmospheric gravity waves. These aurorally-generated gravity waves propagate energy upward and downward through the atmosphere. At tropospheric level, in spite of significantly reduced amplitudes, they could provide a lift of unstable air to release the moist symmetric instability thus initiating slantwise convection and forming cloud/precipitation bands. The release of latent heat is known to provide energy for rapid development and intensification of extratropical cyclones.
Résumé(Résumé en langage clair et simple, non publié)
La météo spatiale fait référence aux conditions dynamiques du soleil et de l'environnement spatial qui peuvent influer sur les infrastructures essentielles. RNCan exploite le Centre canadien de météo spatiale et étudie les effets de la météo spatiale sur les systèmes d'alimentation électrique, les pipelines, les satellites, les installations de communications radio et le FGISM pour aider l'industrie canadienne à comprendre et à atténuer les effets de la météo spatiale.