Variability of NmF2 and its correlation with solar and geomagnetic variations at an equatorial station in the African sector

Abstract

This study focuses on the variability of NmF2 and the impact of the solar and geomagnetic activity on the variability of NmF2 over Ouagadougou, an equatorial ionisation anomaly station in the African sector. The daily hourly values of the critical frequency (foF2) covering two different solar cycles are used to study the variability of NmF2. The solar and geomagnetic data are used to examine their effect on the variability of NmF2. The results show that NmF2 displays obvious diurnal, seasonal and solar cycle effects. The semi-annual variation, winter and annual anomalies of NmF2 are clearly seen at all levels of solar activities. There is equinoctial asymmetry in NmF2. NmF2 is also characterized by two peaks namely pre-noon and post-noon peaks and noontime bite-out. The SSN is observed to have major effects on the variability of NmF2.