Long-term changes in the north-south asymmetry of solar activity: A nonlinear dynamics characterization using visibility graphs

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Date
2014
Volume
21
Issue
6
Journal Title
Title
Series Titel
Publisher
Göttingen : Copernicus GmbH
Abstract

Solar activity is characterized by complex dynamics superimposed onto an almost periodic, approximately 11-year cycle. One of its main features is the presence of a marked, time-varying hemispheric asymmetry, the deeper reasons for which have not yet been completely uncovered. Traditionally, this asymmetry has been studied by considering amplitude and phase differences. Here, we use visibility graphs, a novel tool of nonlinear time series analysis, to obtain complementary information on hemispheric asymmetries in dynamical properties. Our analysis provides deep insights into the potential and limitations of this method, revealing a complex interplay between factors relating to statistical and dynamical properties, i.e., effects due to the probability distribution and the regularity of observed fluctuations. We demonstrate that temporal changes in the hemispheric predominance of the graph properties lag those directly associated with the total hemispheric sunspot areas. Our findings open a new dynamical perspective on studying the north-south sunspot asymmetry, which is to be further explored in future work.

Description
Keywords
graphical method, probability, solar activity, sunspot, temporal variation, time series analysis
Citation
Zou, Y., Donner, R. V., Marwan, N., Small, M., & Kurths, J. (2014). Long-term changes in the north-south asymmetry of solar activity: A nonlinear dynamics characterization using visibility graphs. 21(6). https://doi.org//10.5194/npg-21-1113-2014
License
CC BY 3.0 Unported