The Relative Phase Asynchronization between Sunspot Numbers and Polar Faculae

Abstract

The monthly sunspot numbers compiled by Temmer et al. and the monthly polar faculae from observations of the National Astronomical Observatory of Japan, for the interval of March 1954 to March 1996, are used to investigate the phase relationship between polar faculae and sunspot activity for total solar disk and for both hemispheres in solar cycles 19, 20, 21 and 22. We found that (1) the polar faculae begin earlier than sunspot activity, and the phase difference exhibits a consistent behaviour for different hemispheres in each of the solar cycles, implying that this phenomenon should not be regarded as a stochastic fluctuation;(2) the inverse correlation between polar faculae and sunspot numbers is not only a long-term behaviour, but also exists in short time range; (3) the polar faculae show leads of about 50-71 months relative to sunspot numbers, and the phase difference between them varies with solar cycle; (4) the phase difference value in the northern hemisphere differs from that in the southern hemisphere in a solar cycle, which means that phase difference also existed between the two hemispheres. Moreover, the phase difference between the two hemispheres exhibits a periodical behaviour. Our results seem to support the finding of Hiremath (2010).

The Long-Term Hemispheric Variation of Polar Faculae

“…A cross-correlation analytic method adopted by Deng et al (2011) and Yan et al (2011) is used to study the N-S asynchrony of the polar faculae. The cross-correlation coefficient between the numbers of the polar faculae in the northern and southern hemispheres is defined as: …”

Signatures of Chaotic Naturein Astronomical Data with Nonlinear Analysis Techniques

“…Moreover, they are applied to deterministic dynamical systems which are a periodic and exhibit sensitive dependence on initial conditions. During the last three decades, a great deal of studies employed these theories to distinguish, model, and forecast the dynamical behavior of various natural phenomena, such as geophysics, economics, meteorology, material science, ethology, astronomy, and so on [4][5][6]. The outstanding achievements of these studies are very encouraging, because they not only demonstrated that the nonlinear dynamics of irregular systems can be described from a chaotic point of view but also made it develop in to a useful technique or method to solve physical problems in many other science fields, in particular for solar-activity variations [7][8][9].…”

An investigation of north-south asynchrony of solar filament activity: Wavelet transform analyses

“…The traditional frequency-space methods have a limitation: they assume that the underlying processes should be stationary in time. Linear analysis approaches may generate artifacts when they are applied to analysis of real-world processes, therefore nonlinear analysis approaches should be adopted to study the non-linear behaviour of solar activity [9]- [10]. Many advanced analysis approaches, such as the cross-wavelet transform, wavelet coherence, cross-recurrence plot and line of synchronization, are widely used to study the nonlinear behaviour of solar time series [11]- [12].…”