Solar Activity Indices for Ionospheric Parameters in the 23rd and 24th Cycles
Abstract
Characteristics of changes in the solar activity indices (the flux of the solar radio emission at a wavelength of 10.7 cm F and the new version of the relative sunspot number Ri) and the ionospheric index of this activity T in the 23rd and 24th solar cycles, which were low by the amplitude of solar and geomagnetic activity, are analyzed. The running mean over 12 months and smoothed (by a 24-month filter) values of these indices are considered in the analysis. It is found that the relation between the T and F indices was on average stable for these cycles and did not differ from the previous solar cycles. The relation between the T and Ri indices changed with time in the 23rd and 24th cycles and was different from the previous cycles. Moreover, a distinct hysteresis effect in the dependence of the smoothed values of T on Ri was observed in the 24th cycle when different values of T corresponded to a fixed value of Ri in the growing and declining phases of the solar cycle. This effect was absent in the dependence of T on F. Thus, it is confirmed that the F index is a more exact indicator of solar activity for the ionosphere than Ri.</sec>
- Publication:
-
Geomagnetism and Aeronomy
- Pub Date:
- April 2020
- DOI:
- 10.1134/S0016793220010053
- Bibcode:
- 2020Ge&Ae..60....1D