SEASONAL EFFECT ON FoF2 VARIABILITY DURING ONE-DAY-SHOCK AT OUAGADOUGOU STATION DURING SOLAR CYCLES 20, 21 AND 22

The seasonal effect on the F2 sublayer critical frequency of the ionosphere (foF2), during one-day-shock, at Ouagadougou station during three solar cycles (20, 21, and 22) is examined in this work. It appears that summer has an effect tending to decrease the values ​​of foF2 in the maximum, ascending and descending phase. At solar cycle maximum, winter and autumn do not modify the foF2 amplitudes. At solar cycle minimum, winter decreases foF2 values ​​in the morning (08:00 a.m. to 1:00 p.m.), while spring amplifies them (09:00 a.m. to 1:00 p.m.). In the ascending phase, winter, spring and autumn increase foF2 values ​​in the morning. In the descending phase, winter and autumn do not modify the foF2 values ​​while spring increases them.