Response of global and regional electron content to solar activity changes.

The global electron content (GEC) as a new ionospheric parameter was proposed for the first time in the work by Afraimovich et al., DAN, 2006, 409A, 399. GEC is equal to the total number of electrons in the near-Earth space. GEC better reflects the global response to solar activity changes than local parameters. It is shown that during the 23rd cycle of solar activity, the dynamics of GEC follows analogous changes as the UV radiation of the Sun and the F10.7 index, including the 11-year cycle and 27-day variations.: The dynamics of the regional electron content (REC) is considered for three belts, the equatorial and two mid-latitudinal ones in the northern and southern hemispheres (±30° and from 30 to 65° geomagnetic latitude, respectively). Unlike the GEC, the annual component of the REC is clearly expressed for the northern and southern mid-latitudinal belts. The REC amplitude is comparable to the scope of seasonal variations in the northern hemisphere and exceeds the scope of seasonal variations in the southern hemisphere by 1.7 times. The ratio R(t) of the REC of the day side of the Earth to the REC of the night side at the equator is 1.5 times lower than for GEC that indicates a higher degree of night ionization, especially during the period of maximum solar activity. The mid-latitudes are characterized by a clear annual cycle with a maximum value R(t) of about 8.0 for the southern hemisphere in winter and for the northern hemisphere in summer.

E.I., Zhivetyev I.V., Oynats A.V., Yasyukevich Yu.V. Response of global and regional electronic content to changes in solar activity. //Geomagnetism and Aeronomy, 2008, Vol.48, No.2, 195-208.