TITLE:
Statistical Study of foF2 Diurnal Variation at Dakar Station from 1971 to 1996: Effect of Geomagnetic Classes of Activity on Seasonal Variation at Solar Minimum and Maximum
AUTHORS:
Ali Mahamat Nour, Ouattara Frédéric, Zerbo Jean Louis, Gyébré Aristide Marie Frédéric, Nanéma Emmanuel, Zougmoré François
KEYWORDS:
foF2 Diurnal Variation, Solar Cycle Phases, Geomagnetic Activity Classes, Seasonal Effects, E Region Electric Currents
JOURNAL NAME:
International Journal of Geosciences,
Vol.6 No.3,
March
11,
2015
ABSTRACT: The statistical study of F2 layer critical frequency at Dakar
station from 1971 to 1996 is carried out. This paper shows foF2 statistical
diurnal for all geomagnetic activities and all seasons and that during solar
maximum and minimum phases. It emerges that foF2 diurnal variation graphs at
Dakar station exhibits the different types of foF2 profiles in African EIA
regions. The type of profile depends on solar activity, season and solar phase.
During solar minimum and under quiet time condition, data showthe signature of a strength electrojet that is coupled with
intense counter electrojet in the afternoon. Under disturbed conditions,mean intense electrojet is observed in winterduring fluctuating and recurrent activities. Intense counter
electrojet is seen under fluctuating and shock activities in all seasons
coupled with strength electrojet in autumn. In summerand spring under all geomagnetic activity condition, there is
intense counter electrojet. During solar maximum, in summer and spring there is
no electrojet under geomagnetic activity conditions.Winter shows a mean intense electrojet. Winter and autumn are
marked by the signature of the reversal electric field.