Evidence for a tri-centennial cycle in solar proxies based on cosmogenic isotopes

Proxies of solar activity, based on radiocarbon and beryllium, covering most of the Holocene were statistically analysed using both wavelet and Fourier approaches. It was shown that a significant tri-centennial (300–400 yr) cyclicity is present in the both series. Evidence for the same kind of variation was found in data on flux of 10Be in Dye-3 (South Greenland, ad 1424–1985) and NGRIP (Central Greenland, ad 1389–1994) ice cores. Possible origins of the revealed quasi-300-year periodicity are discussed.