Open Access

Sunspot variability and an attempt to predict solar cycle 23 by adaptive filtering

Earth, Planets and Space201450:BF03352090

DOI: 10.1186/BF03352090

Received: 7 July 1997

Accepted: 5 January 1998

Published: 6 June 2014

Abstract

The series of annual mean relative sunspot numbers (Rz) for 1749–1996 is subjected to the recently developed methodology of Singular Spectrum Analysis (SSA). This technique also enables data-adaptive filtering of the individual spectral components. Low order autoregressive modelling of the components are combined to provide a basis for predicting the solar cycle 23.

The Rz series is largely dominated by a doublet with periods 11.13 and 10.35 yr. close to the nominal solar cycle periodicity, a longer period variation (~110 yr.) which is the envelope of the amplitude maxima and two clusters of periodicities centred around 8 yr. and 5.5 yr. The solar magnetic cycle has no detectable component. The predicted maximum for cycle 23 will have a magnitude of ~130 and the epoch of maximum is expected between late 2000 A.D. and early 2001 A.D.