Seasonal Variability of foE and Nocturnal Winter Anomaly in E-layer during Solar Cycles 21 and 22 at the Ouagadougou Station

Abstract

This paper aims to study the variability of foE during two solar cycles 21 (SC21) and 22 (SC22) at Ouagadougou station (lat = 12.4°N, long = 358.5°E, local time (LT) = universal time (UT)), to give visibility on the behavior of foE in this station. We used International Reference Ionosphere (IRI-2016) to collect data from five (5) quiet days of each characteristic month of each season. This study reveals that in this station located at the ionospheric equator, the variability of foE follows the evolution of the sun intensity during the day. There is a correlation between foE and the solar cycle phase, the season, and the time of day. During the day [0500 LT-1900LT], the foE profile does not show a winter anomaly, contrary to what is observed in the F2 layer  at the minimum and maximum  SC21 and SC22. On the other hand, a nocturnal winter anomaly was observed related to that observed in the F2 layer in the same periods. The study of foE at the Ouagadougou station will allow ionospheric physicists to have visibility on the seasonal variability of foE in this station.