Fof2 prediction with IRI-2016 at Dakar Station during quiet activity over solar cycles 21 and 22

This study deals with comparison between Dakar station ionospheric’s F2 layer critical frequency (foF2) data and the two subroutines (CCIR and URSI) of IRI-2016 model predictions. Comparisons are made for very quiet geomagnetic activity during the four phases of the solar cycles 21 and 22 (minimum, increasing, maximum and decreasing). Model's predictions are suitable with observed data by day than by night. The accuracy is better during increasing phase and poor during the other solar cycle phases. During minimum, maximum and decreasing solar phases, both model subroutines do not express the signature of E×B and on other hand they express an intense counter-electrojet instead of a medium intensity electrojet. Key words: Solar cycle, geomagnetic quiet activity, ionosphere electrodynamic phenomena, IRI-2016 model prediction.