The Wolf number and total solar irradiance variations during 21–23 solar cycles
In this work, the numerical sequences of the total solar irradiance data and the corresponding values of the international sunspot index, both for the same time interval (about 25 years), are compared. The data are analysed by means of two methods: continuous wavelet transformation and Fourier spectrum decomposition. Special attention is given to short periods of approximately 27 days. It is shown that the 27 day periodicity, caused by rotation of the active regions, is demonstrated well in the Wolf number spectrum, while in the total solar irradiance spectrum a time interval of about 15–60 days is displayed. The peaks at about 1 year and the weaker quasibiennial peaks (2–2.5 years) are noticeable in both spectra.
Document Type: Research Article
Affiliations: Sternberg Astronomical Institute, Universitetskij Prospekt 13, Moscow, 119992, Russia
Publication date: 2006-08-01