22-Year Periodicity in the Solar Differential Rotation

[摘要] Using the data on sunspot groups compiled during 1879-1975, we determined variations in the differential rotation coefficients 𝐴 and 𝐵 during the solar cycle. The variation in the equatorial rotation rate 𝐴 is found to be significant only in the odd numbered cycles, with an amplitude ∼ 0.01 𝜇rads-1. There exists a good anticorrelation between the variations of the differential rotation rate 𝐵 derived from the odd and even numbered cycles, suggesting existence of a `22-year' periodicity in 𝐵. The amplitude of the variation of 𝐵 is ∼ 0.05 𝜇 rad s-1.

[学科分类] 天文学(综合)

[关键词] Sunspot group;solar cycle;solar rotation.