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.
Solar activity has a profound influence upon geodynamics processes, and the Sun directly or indirectly affects some terrestrial phenomena on the Earth. Some studies showed variation of solar activity closely relates to global and regional climate change (Rasmus, 2006; Miyahara et al., 2008; Mendoza & Velasco, 2009; Ogurtsov et al., 2013; Dergachev et al., 2016). After analyzing the solar variation, global and regional sea-surface temperature, Weng (2005) concluded that inter-annual and centennial climate change signals were not purely internal, but also external because of the existence of the solar activity cycle. Kilcik et al. (2008) made use of surface air temperature, pressure and tropospheric absorbing aerosol data as climate parameters and solar flare index data as solar activity indicator, to study effect of solar activity on the surface air temperature of Turkey. With Indian temperature series of more than one-hundred years, Aslam (2014) investigated the influence of solar activity on regional climate. Results indicated that the solar variation may still be contributing to ongoing climate change.