Periodicity Analysis of SMMF in Solar Maximum and Minimum

Using the data observed by Wilcox Solar Observatory from 1975 to 2010,the short periodicity of the solar mean magnetic field(SMMF) in solar maximum and minimum is analyzed.The result shows that SMMF has main periods about 9 days,13.5 days,and 27 days.During the solar maximum,the SMMF has the most dominant period near 27 days. However,in solar minimum,the 13.5-day periodicity is most significant except in 1984-1986. These results show that the solar active region distribution in the solar maximum is quite different from that in solar minimum.