Analysis of Sunspot Variability Using the Hilbert – Huang Transform

摘要

The Hilbert – Huang transform is a relatively new data analysis technique, which is able to analyze the cyclic components of a potentially nonlinear and nonstationary data series. Monthly sunspot number data from 1749 to 2010 were analyzed using this technique, which revealed the different variability inherent in the data including the 11-year (Schwabe), 20 – 50-year (quasi-Hale) and 60 – 120-year (Gleissberg) cycles. The results were compared with traditional Fourier analysis. The Hilbert – Huang transform is able to provide a local and adaptive description of the intrinsic cyclic components of sunspot number data, which are nonstationary and which are the result of nonlinear processes.