Characterization of Equatorial Ionization Anomaly at the African Southern Hemisphere During a High Solar Activity Period

Abstract

This study was carried out using Total Electron Content (TEC) data from Global Navigation satellite systems (GNSS) situated in the equatorial-low latitudes region to characterize the quiet-time equatorial ionization anomaly (EIA) over African sector during high solar activity year 2013. The day-to-day (TEC) and monthly (MTEC) variations generally exhibits minimum pre-sunrise (0400-0500 LT) hrs magnitudes that start rising gradually at sunrise (0600 LT) hrs to reach their peak around (1200-1700 LT) hrs respectively. The TEC generally exhibit random spread that is mild at the magnetic equator and intensified with increasing geomagnetic latitudes. MTEC magnitudes appear weak in summer months and increase through winter months with greater intensity in equinoctial months. At any particular month, the MTEC at the magnetic equator (BJCO) exhibit daytime flat surface in summer months and consistently maintained lower magnitudes relative to low-latitude stations considered in the study. The noontime bite-out peculiar to the equatorial region is not realistic at the magnetic equator (BJCO) of this study. This could be attributed to stronger daytime EXB drift associated to stronger fountain effect. Seasonal appearance of EIA crests were observed earlier in winter and at latter hours in summer solstice across all latitudes exception of MAL2. The results also reveal the presence of equinoctial asymmetry across the latitudes. The equinoxes had the highest TEC values and the least magnitudes in summer solstice across all the latitudes. The prevalent MTEC and seasonal nighttime TEC enhancements across all the latitudes is not realistic at the magnetic equator (BJCO) indication of possible interplay between pre-reversal enhancement of EXB drift and other mechanism. All other latitudinal characteristics of EIA in the African sector of this study are discussed in light of the potential source mechanisms and implications.