LATITUDINAL EXTENT OF ELECTROMAGNETIC INDUCTION EFFECTS ALONG AFRICAN LONGITUDES

Abstract

Daily magnetic records obtained from 10 geomagnetic observatories along African longitudes between September 2008 and August 2009 were employed to investigate the electromagnetic inductive responses as a result of solar radiation during quiet days. The variation of the solar quiet daily variation of horizontal intensity (H) and vertical intensity (Z) were estimated to deduce the inductive response (𝑑𝑍𝑑𝐻) of the Earth's magnetic field. The result revealed that the variation pattern of dH followed the diurnal variation of ionospheric conductivity in the upper atmosphere. At some of the stations considered, induction effects were noticed during the day time as shown in Lusaka (LSK) and Hermanus (HER) in September 2008. This phenomenon occurred only during the night time, for stations like Addis Ababa (AAB) and Nairobi (NAB) in October 2008. At some other stations it occurred both at night time and day time. The seasonal variation of inductive response was maximum in D-season, followed by J-season and the least was recorded during E-season.