English

Relationship between group sunspot number and Wolf sunspot number

Solar and Stellar Astrophysics 2015-05-19 v1

Abstract

Continuous wavelet transform and cross-wavelet transform have been used to investigate the phase periodicity and synchrony of the monthly mean Wolf (RzR_{z}) and group (RgR_{g}) sunspot numbers during the period of June 1795 to December 1995. The Schwabe cycle is the only one common period in Rg and Rz, but it is not well-defined in case of cycles 5-7 of Rg and in case of cycles 5 and 6 of RzR_{z}. In fact, the Schwabe period is slightly different in RgR_{g} and RzR_{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. RgR_{g} is found to fit RzR_{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, RgR_{g} is usually less than RzR_{z}. Asynchrony of RgR_{g} and RzR_{z} should somewhat agree with different sunspot cycle characteristics exhibited by themselves.

Keywords

Cite

@article{arxiv.1006.2203,
  title  = {Relationship between group sunspot number and Wolf sunspot number},
  author = {Kejun Li and Hongfei Liang},
  journal= {arXiv preprint arXiv:1006.2203},
  year   = {2015}
}
R2 v1 2026-06-21T15:34:48.049Z