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TitreStudying correlations between the coronal hole area, solar wind velocity, and local magnetic indices in the Canadian region during the decline phase of cycle 23
AuteurShugai, Y S; Veselovsky, I S; Trichtchenko, L D
SourceInternational Journal of Geomagnetism and Aeronomy vol. 49, no. 4, 2009 p. 415-424,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20100380
Documentpublication en série
Mediapapier; en ligne; numérique
Sujetsvariations solaires; géomagnétisme; champs géomagnétiques; variations géomagnétiques; géophysique
Illustrationstables; histograms; plots
ProgrammeTargeted Hazard Assessments in Northern Canada, Géoscience pour la sécurité publique
Diffusé2009 07 28
Résumé(disponible en anglais seulement)
Geomagnetic disturbances in the Canadian region are compared with their solar and heliospheric sources during the decline phase of solar activity, when recurrent solar wind streams from low-latitude coronal holes were clearly defined. A linear correlation analysis has been performed using the following data: the daily and hourly indices of geomagnetic activity, solar wind velocity, and coronal hole area. The obtained correlation coefficients were rather low between the coronal hole areas and geomagnetic activity (0.17 - 0.48), intermediate between the coronal hole areas and the solar wind velocity (0.40 - 0.65), and rather high between the solar wind velocity and geomagnetic activity (0.50 - 0.70). It has been indicated that the correlation coefficient values can be considerably increased (by tens of percent in the first case and by a factor of 2 - 4 in the second case) if variations in the studied parameters related to changes in the ionosphere (different illumination during a year) and variations in the heliolatitudinal shift of the coordinate system between the Earth, the Sun, and a spacecraft are more accurately taken into account.