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TitleStudying correlations between coronal hole area, soalr wind velocity, and local magnetic indices in the Canadian region during the decline phase of cycle 23
AuthorShugai, Y S; Veselovsky, I S; Trichtchenko, L D
SourceInternational Journal of Geomagnetism and Aeronomy vol. 49, no. 4, 2009 p. 415-424,
Alt SeriesEarth Sciences Sector, Contribution Series 20100380
Mediapaper; on-line; digital
Subjectsgeophysics; solar variations; geomagnetism; geomagnetic fields; geomagnetic variations
Illustrationstables; histograms; plots
ProgramTargeted Hazard Assessments in Northern Canada, Public Safety Geoscience
AbstractGeomagnetic 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.