The cyclic activity of the sun from observations of the activity indices at different time scales

Abstract

With the time—frequency analysis of the series of observations of one of the global indices of solar activity, viz., the radio flux F10.7 at a wavelength of 10.7 cm (2.8 GHz), the most probable value of the main cycle period has been determined. This value is 10.2 yr, which is consistent with the generally accepted estimates. Simultaneously with the main cycle of activity, several low-amplitude cycles with cyclicity periods from 1.3 to 100 yr were identified. With the method of continuous wavelet transform with Morlet mother wavelets, we analyzed the other solar indices that are associated with the radiation at different heights in the solar atmosphere: the relative number of sunspots, SSN, the chromospheric index, Mg II, at 280 nm, the fluxes in the coronal line at 530.3 nm, F530, the Flare Index, and the index of a total number of flares, Counts of flares. The obtained time—frequency characteristics turned out to be generally similar. Differences in the results for the solar indices occur during the strengthening of stochastic processes in the maxima and minima of the main cycle.