Ehinlafa, O. E., Abdulsalam et al. (13 contributing authors)
In this study, f o F2 variability diurnally, seasonally and annually was investigated during a Low Solar Epoch (LSE) over Ilorin (latitude 8.31°N, longitude 4.34°E, dip latitude 2.95 o ), a low latitude station along the equatorial anomaly trough. The percentage variability index () was used for the analysis. The percentage variability index () is lowest during the day (2-17%); increases during night to (8-55%); and attained the highest magnitude during pre-sunrise phase (17-68%), for the period of LSE. Two major peaks were noticed in V R : the pre-sunrise peak, which is higher, and the post-sunset peak. Annually, peaks at 44% for the pre-sunrise phase, and 37% for the post-sunset phase, during the LSE. The rapid electron drift away from the equator coincides with subsequent rise in the percentage variability index immediately after sunset for all the seasons.
Critical frequency (foF2)Variability index () 
Ehinlafa, O. E., Johnson et al. (10 contributing authors)
The F2 region critical frequency ( f o F2 ) and peak electron density ( N m F2 ) morphology was investigated over Ilorin (latitude 8.31°N, longitude 4.34°E) during a Low Solar Epochs (LSE), a station along the equator anomaly trough. Diurnally, f o F2 and N m F2 are visibly more prominent during the day than at night with two characteristic peaks: pre-noon and post-noon peaks. The f o F2 and N m F2 pre-noon peak magnitude range: (7.7–8.3 MHz) and (7.3–8.6) × 10 11 /m -3 respectively is less compared to the f o F2 and N m F2 post-noon peak magnitude range: (7.3–9.7 MHz) and (6.7–11.7) ×10 11 /m -3 respectively. Seasonally, the highest values were attained during the post-noon peak in the equinoctial months compared to the solstices months, and also, annually, the post-noon peak is higher than the pre-noon peak. The rapid electron drift away from the equator is responsible for the sharp drop in f o F2 and N m F2 after sunset in all seasons. Seasonal peaks in f o F2 and N m F2 are suspected to be controlled by the enhanced E × B drifts and the onset and turn-off of solar ionization, which is consistent with some earlier results obtained at some stations in the African region during low solar epoch periods.
