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 show？the signature of a strength electrojet that is coupled with
intense counter electrojet in the afternoon. Under disturbed conditions,？mean intense electrojet is observed in winter？during fluctuating and recurrent activities. Intense counter
electrojet is seen under fluctuating and shock activities in all seasons
coupled with strength electrojet in autumn. In summer？and 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.
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Ouattara, F. and Zerbo, J.L. (2011) Ouagadougou Station F2 layer Parameters Yearly and Seasonal Variations during Severe Geomagnetic Storms Generated by CMEs and Fluctuating wind Streams. International Journal of Physical Sciences, 6, 4854-4860.
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Gnabahou, D.A., Elias, A.G. and Ouattara, F. (2013) Long-Term Trend of foF2 at a West-African Equatorial Station Linked to Greenhouse Gases Increase and Dip Equator Secular Displacement. Journal of Geophysical Research, 118, 3909-3913. http://dx.doi.org/10.1002/jgra.50381
Gnabahou, D.A., Ouattara, F., Nanéma, E. and Zougmoré, F. (2013) foF2 Diurnal Variability at African Equatorial Stations: Dip Equator Secular Displacement Effect. International Journal of Geosciences, 4, 1145-1150.
Ouattara, F., Gnabahou, A. and Mazaudier, C.A. (2012) Seasonal, Diurnal and Solar-Cycle Variations of Electron Density at Two West Africa Equatorial Ionization Anomaly Stations. International Journal of Geophysics, 2012, Article ID: 640463, 9 p.
Ouattara, F., Amory-Mazaudier, C., Fleury, R., Lassudrie-Duchesne, P., Vila, P. and Petitdidier, M. (2009) West African Equatorial Ionospheric Parameters Climatology Based on Ouagadougou Ionosonde Station Data from June 1966 to February 1998. Annales Geophysicae, 27, 2503-2514. http://dx.doi.org/10.5194/angeo-27-2503-2009
Dunford, E. (1967) The Relationship between the Ionosphere Equatorial Anomaly and the E-Region Current System. Journal of Atmospheric and Terrestrial Physics, 29, 1489-1498. http://dx.doi.org/10.1016/0021-9169(67)90102-X
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