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TitreTropospheric weather influenced by solar wind through atmospheric vertical coupling downward control
AuteurPrikryl, P; Bruntz, R; Tsukijihara, T; Iwao, K; Muldrew, D B; Rusin, V; Rybanský, M; Turna, M; Stastný, P
SourceJournal of Atmospheric and Terrestrial Physics ., https://doi.org/10.1016/j.jastp.2017.07.023
Séries alt.Ressources naturelles Canada, Contribution externe 20170092
ÉditeurElsevier
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1016/j.jastp.2017.07.023
Mediapapier; en ligne; numérique
Formatspdf
Illustrationsgraphs; plots
ProgrammeNord du Canada, risque géoscience, Géoscience pour la sécurité publique
Résumé(disponible en anglais seulement)
Occurrence of severe weather in the context of solar wind coupling to the magnetosphere-ionosphere-atmosphere (MIA) system is investigated. It is observed that significant snowfall, wind and heavy rain, particularly if caused by low pressure systems in winter, tend to follow arrivals of high-speed solar wind. Previously published statistical evidence that explosive extratropical cyclones in the northern hemisphere tend to occur within a few days after arrivals of high-speed solar wind streams from coronal holes (Prikryl et al., 2009; 2016) is corroborated for the southern hemisphere. Cases of severe weather events are examined in the context of the magnetosphere-ionosphere-atmosphere (MIA) coupling. Physical mechanism to explain these observations is proposed. The leading edge of high-speed solar wind streams is a locus of large-amplitude magneto-hydrodynamic waves that modulate Joule heating and/or Lorentz forcing of the high-latitude lower thermosphere generating medium-scale atmospheric gravity waves that propagate upward and downward through the atmosphere. Simulations of gravity wave propagation in a model atmosphere using the Transfer Function Model (Mayr et al., 1990) reveal that propagating waves originating in the lower thermosphere can excite a spectrum of gravity waves in the lower atmosphere. In spite of significantly reduced amplitudes but subject to amplification upon reflection in the upper troposphere, these gravity waves can provide a lift of unstable air to release instabilities in the troposphere and initiate convection to form cloud/precipitation bands. It is primarily the energy provided by release of latent heat that leads to intensification of storms. These results indicate that vertical coupling in the atmosphere exerts downward control from solar wind to the lower atmospheric levels influencing tropospheric weather development.
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'ndustrie canadienne à comprendre et à atténuer les effets de la météo spatiale.
GEOSCAN ID302706