One-Day-Shock, Two-Days-Shock and Three-Days-Shocks foF2 Diurnal Variation with Solar Cycle Phases at Ouagadougou Station from 1966 to 1998. Comparison with IRI 2012 Predictions

Abstract

The present work concerns foF2 time variation at Ouagadougou station for three solar cycles (from cycle 20 to cycle 22). We not only investigate solar cycle phase dependence under shock activity that is divided into one-shock-activity, two-shock-activity and three-shock-activity but also compare the IRI 2012 model values with the data carried out at Ouagadougou station. This study reveals that there is no one-day-shock during solar minimum phase. For the other solar cycle phases IRI 2012 reproduces the ionosphere electrodynamics at daytime except during the increasing phase. During night time the model is not suitable. The best subroutine under one-day-shock activity is URSI for increasing and decreasing phases. During the maximum phase it is CCIR. For two-days-shock activity IRI 2012 reproduces the ionosphere electrodynamics during the minimum and the increasing phases. The best subroutine is CCIR during the minimum phase and URSI for the other solar cycle phases. For three-days-shock activity IRI 2012 is not suitable. The best model is URSI for all solar cycle phases.

foF2 diurnal variation at Dakar station during the period of geomagnetic shock of variable duration over solar cycle 21 and 22: Prediction with IRI 2016

“…Experimental data show a night-time peak indicating the signature of a pre-reversal of the electric field in the equatorial region during the increasing phase, but the IRI model does not show this signature. The same result was reported by Sawadogo et al (2019) and Segda et al (2019), during their studies at the Ougadougou station. The quantitative study through the percentage of deviation shows that the prediction is good during the day compared to night.…”

“…The IRI 2012 version also provides poor predictions during nighttime (Ouattara, 2013;Ouattara and Nanema, 2014). However, during geomagnetic shock periods, the 2012 version of the IRI model reproduces the electrodynamic phenomenon (vertical drift EXB) during the daytime (Segda et al, 2019). A quantitative study based on deviation percentages indicates a good correlation between the URSI subprogramme forecasts and ionosonde data, except during the increasing phase.…”

“…Considering the findings from previous studies, it becomes necessary to investigate the diurnal variation of foF2 during disturbed geomagnetic periods with predictions from the IRI model at the Dakar station, which is situated near the Equatorial Ionization Anomaly (EIA). It has been noted that the URSI model provides better predictions for all phases of the solar cycle, with values approaching experimental measurements compared to CCIR in the African equatorial sector (Segda et al, 2019;Sawadogo et al, 2019). The objective of this article is to assess the predictability of the IRI 2016 model on days with varying durations of geomagnetic shocks (one-day shock, two-day shock, and three-day shocks) using data from the Dakar station during all phases of solar cycles 21 and 22.…”