Revisit of short-term periodicities in solar mean magnetic field

Short-term variations of the solar mean magnetic field (SMMF) were investigated through re-analyzing the data from the Wilcox Solar Observatory during the last four solar activity cycles using continuous wavelet transforms. We demonstrated the time-variable characters of short-term periods of SMMF. Our results indicate that the SMMF has main periods of about 27 and 13.5 days not only in the minimum and maximum years of each activity cycle, but also in the increase and decrease of the solar cycle. The result is partly different from the conclusion that the SMMF has dominant period of about 27 days during the solar maxima and about 13.5 days during the solar minimum years (Ye et al. in Solar Phys 279:411–418, 2012). The entire time span of SMMF was investigated and discussed further.