Relationship between group sunspot numbers and Wolf sunspot numbers

Continuous wavelet transform and cross‐wavelet transform have been used to investigate the phase periodicity and synchrony of the monthly mean Wolf ( R z ) and group ( R g ) sunspot numbers during the period of June 1795 to December 1995. The Schwabe cycle is the only one common period in R g and R z , but it is not well‐defined in case of cycles 5–7 of R g and in case of cycles 5 and 6 of R z . In fact, the Schwabe period is slightly different in R g and R z before cycle 12, but from cycle 12 onwards it is almost the same for the two time series. Asynchrony of the two time series is more obviously seen in cycles 5 and 6 than in the following cycles, and usually more obviously seen around the maximum time of a cycle than during the rest of the cycle. R g is found to fit R z better in both amplitudes and peak epoch during the minimum time time of a solar cycle than during the maximum time of the cycle, which should be caused by their different definition, and around the maximum time of a cycle, R g is usually less than R z . Asynchrony of R g and R z should somewhat agree with different sunspot cycle characteristics exhibited by themselves (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)