Geomagnetic Effects of the Equatorial Counter-Electrojet and Their Extension to Non-Equatorial Latitudes

Abstract

Variation of the additional magnetic field due to the counter-electrojet is examined over the latitudes from the dip equator to Sabhawala (dip=45°) separately for January and the summer months. The additional field is derived from a set of days on which intense afternoon counter-electrojet events have been recorded at Trivandrum near the dip equator, during the period 1965-1977. An almost a reversal in the pattern of field variation in declination is observed between January and summer at all the stations. An approximate representation of the overhead current vectors during the daytime hours in summer months, under the assumption that the field effects result from an additional current system, suggests a vortex in the afternoon with a clockwise rotation and an oppositely directed vortex in the forenoon.