Evidence of 6 000-Year Periodicity in Reconstructed Sunspot Numbers
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- Xapsos, M.A. & Burke, E.A. Sol Phys (2009) 257: 363. doi:10.1007/s11207-009-9380-3
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Reconstructed sunspot data are available that extend solar activity back to 11 360 years before the present. We have examined these data using Hurst analysis, a moving average filter, and Fourier analysis. All of the procedures indicate the presence of a long term (≈6 000 year) cycle not previously reported. A number of shorter cycles formerly identified in the literature by using Fourier analysis, Bayes methods, and maximum entropy methods were also detected in the reconstructed sunspot data.