Temporal Variations of the Solar Rotation Determined by Sunspot Groups

摘要: The extended Greenwich data set consisting of positions sunspot groups is used for the investigation cycle-related variations solar rotation in years 1874–1981. Applying residual method, which yields a single number each year describing average deviation from mean value rotation, dependence velocity on phase cycle investigated. A secular deceleration was found: slope being statistically significant at 3σ level. Periods 33, 22, 11, 5.2, and 3.5 can be identified power spectra. residuals were averaged all with same relative to nearest preceding minimum. variation pattern reveals higher than minimum activity and, lesser extent, also around maximum activity. analysis repeated several changes reduction such as elimination trend, application statistical weights, different cutoffs central meridian distance, division latitude into subregions treating minima separately. results obtained are compared those literature, an interpretation observed phenomena proposed.