The impact of coronal mass ejections on the seasonal variation of the ionospheric critical frequency f₀F2

We investigated the relations between the monthly average values of the critical frequency (f₀F2) and the physical properties of the coronal mass ejections (CMEs), then we examined the seasonal variation of f₀F2 values as an impact of the several CMEs properties. Given that, f₀F2 were detected by PRJ18 (Puerto Rico) ionosonde station during the period 1996–2013. We found that the monthly average values of f₀F2 are varying coherently with the sunspot number (SSN). A similar trend was found for f₀F2 with the CMEs parameters such as the CME energy (linear correlation coefficient R = 0.73), width (R = 0.6) and the speed (R = 0.6). The arrived CMEs cause a plasma injection into the ionosphere, in turn, increasing the electron density, and consequently, f₀F2 values. This happens in the high latitudes followed by the middle and lower latitudes. By examining the seasonal variation of f₀F2, we found that the higher correlation between f₀F2 and CMEs parameters occurs in the summer, then the equinoxes (spring and autumn), followed by the winter. However, the faster CMEs affect the ionosphere more efficiently in the spring more than in the summer, then the winter and the autumn seasons.