Asymmetrical Distribution of Sunspot Groups in the Solar Hemispheres

Abstract

Abstract In the present work, the north–south asymmetry of solar activity was examined by analyzing statistically the hemispheric distribution of annual numbers of sunspot groups, using the Royal Greenwich Observatory data set from the year 1874 through 2000. An interesting phenomenon is found that the solar activity of a cycle usually has the same beginning and end times, but different maximum amplitudes at different maximum times in the hemispheres. Some characteristics of the asymmetry of solar activity were investigated and explained. For solar cycle 23, a dominance of solar activity is predicted to occur in the southern hemisphere in several forthcoming years.