DAY-TO-DAY VARIABILITY IN SOME IONOSPHERIC PARAMETERS IN THE QUIET EQUATORIAL IONOSPHERE (CASE STUDY: IONOSPHERIC CRITICAL FREQUENCY OF THE E-REGION, fOE)

Abstract

Day- to -day variability in some ionospheric parameters in the quiet equatorial ionosphere, case
study: foE is hereby presented. The diurnal variation of foE shows a symmetrical one with a peak
value at noon. The seasonal variation curve of foE has two maximum points in the months of April
and August. It is also shown that for short time variation, the day-to-day variability in the E -
region of the ionospheric critical frequency, foE, is not due to season nor relative sunspot number
Rz. The test of significance carried out between the standard errors of foE before and after
correction shows no significant difference at 95% level of significance.