Diurnal variation of F2-layer critical frequency under solar activity recurrent conditions during solar cycles 21 and 22 at Ouagadougou Station: Prediction with IRI-2012

Abstract

This paper presents foF2 data recorded at Ouagadougou Ionosonde Station and compares them with IRI-2012 model results through its two subroutines, Union Radio Scientifique Internationale (URSI) and Comite Consultatif International des Radio Communications (CCIR) during recurrent solar activity. Except for the solar cycle maximum period, measured data profiles corroborate with the signatures of E×B drift. IRI- 2012 subroutine URSI is not consistent with observed electrodynamics during any solar cycle phase, while CCIR predictions are consistent with the measured data during the solar maximum and declining phases. Investigation on the relative deviation module mean (RDMM) shows poor agreement between measurements and predictions with IRI most of the time. However, the deviation percentages indicate good correlation between URSI predictions and data from the ionosonde, except for solar ascending phase. Good correlation with CCIR is only obtained during the solar cycle minimum and maximum phases. From a quantitative point of view, this study shows that predictions with URSI are closer to experimental measurements. The investigations show good agreement between model and in situ measurement during the day. Significant differences are recorded at night, especially from midnight to sunrise. There is necessity to improve IRI model for equatorial regions to better predict foF2 variation. Key words: Ionosphere, foF2, Solar cycle, IRI model.