To the description of long-term variations in the solar magnetic flux: The sunspot area index
- Cite this article as:
- Nagovitsyn, Y.A. Astron. Lett. (2005) 31: 557. doi:10.1134/1.2007032
We show that the Wolf sunspot numbers W and the group sunspot numbers GSN are physically different indices of solar activity and that it is improper to compare them. Based on the approach of the so-called “primary” indices from the observational series of W(t) and GSN(t), we suggest series of yearly mean sunspot areas beginning in 1610 and monthly mean sunspot areas beginning in 1749.