Comparison of solar activity proxies: eigenvectors versus averaged sunspot numbers

ABSTRACT We explore the links between averaged sunspot numbers (SSN) and a modulus summary curve (MSC) of two largest eigenvectors solar background magnetic field (SBMF) derived from principal component analysis. MSC has rather close correspondence with whole set SSN revealing cycle timings, duration, maxima times for cycles 12–24, 6, 7, −4, −3, while few in mid-18th mid-19th centuries there are discrepancies maximum amplitudes, durations, maxima. Possible reasons these related to uncertainties observations 18th–19th centuries, definition different activity entities they represent: toroidal poloidal fields, discussed. Wavelet Fourier spectral analysis series reveal within 95 per cent confidence levels same prominent period 10.7 yr, whereas show 101 yr 342 or above red-noise level. The correlation coefficients vary 0.25 data (from 1700), 0.56 sets 1860, 0.67 1900 when all restorations agree. These confirmed be closely but not identically representing dynamo. Use SBMF can provide additional information better understanding activity.