Difference analysis of temporal evolution and shape of hemispheric sunspot cycles

Abstract

This paper focuses on the temporal evolution and shape of northern and southern hemispheric sunspot number. The comparisons, whether from time-varying spectral analysis or global power spectrum before and after filtering, imply the similarity and difference in the characteristics of periods between the northern and southern hemispheres. We have decomposed monthly hemispheric standardized sunspot of cycles 19–24 using principal component (PC) analysis and reconstructed based on the three principal components. These exhibit different characteristics of variation. And the main determinant of variation in various cycles is the second and third PC, whatever the hemisphere is. The comparisons we have outlined imply the hemispheric asymmetry. The difference analysis of the temporal evolution, shape of hemispheric sunspot cycles, and asymmetry is of great importance in understanding the global cycle variation and its evolution to fully understand the physical mechanism of the solar periodic variation and hemispheric asymmetry.