Solar forcing on the ionosphere: Global model of the F2 layer peak parameters driven by re-calibrated sunspot numbers

Abstract

Global empirical models (GMF2 – the F2 layer Global Model) of the critical frequency, foF2, of the ionospheric F2-layer and the peak height, hmF2, are built up with the re-calibrated sunspot number time series, SSN2, for the quiet geomagnetic conditions (ap < 15 nT). The input parameters of the model are the geographic coordinates, time UT, day, month, year, and the sunspot number SSN2. Two options of solar proxy are presented by 12-month smoothed SSN212 and the 27-day integral index SSN2(τ) of solar activity (τ = 0.96) for a given day. The effect of the saturation of foF2 at high solar activity is taken into account by a combination of linear and logarithmic dependences of foF2 on SSN2. The GMF2 model is incorporated into the IRI-Plas system to provide 3-D electron density profile and total electron content TEC through the ionosphere and plasmasphere. GMF2 and IRI-Plas model predictions are compared with foF2, hmF2 and TEC observations and other models for low, medium and high solar activity demonstrating improved accuracy by 20–50% as compared to other modelling results.