Lihua Ma, Zhiqiang Yin, Yanben Han. Quasi 500-Year Cycle Signals in Solar Activity, Earth Science Research; Vol. 7, No. 1; 2018
Direct observations of solar activity are available for the past four century, so some proxies reflecting solar activity such as 14C, 10Be and geomagnetic variations are used to reconstruct solar activity in the past. In this present paper, the authors use rectified wavelet power transform and time-averaged wavelet power spectrum to investigate long-term fluctuations of the reconstructed solar activity series. The results show an obvious quasi 500-year cycle exists in the past solar activity. Three reconstructed solar activity series from 14C variations confirm the periodic signals.