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We have used data from two equatorial stations in the African longitude sector to study the monthly variability of foF2. Diurnal, seasonal, and solar activity effects were investigated. The data established by this study are proposed as equatorial input values for the development of a variability model for the International Reference Ionosphere. [Copyright &y& Elsevier]

Abstract: The recent availability of new data sets during the recent extreme solar minimum provides an opportunity for testing the performance of the International Reference Ionosphere in historically undersampled regions. This study presents averages and variability of topside ionospheric densities over Africa as a function of season, local time, altitude, and magnetic dip latitude as measured by the Communication/Navigation Outage Forecast System (C/NOFS) satellite. The results are compared to the three topside model options available in IRI-2007. Overall, the NeQuick model is found to have the best performance, though during the deepest part of the solar minimum all three options significantly overestimate density. [Copyright &y& Elsevier]