Abstract

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. Results show obvious a quasi ~500-year cycle exists in the past solar activity. Three reconstructed solar activity series from ¹⁴C variations confirm the periodic signals.

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