Abstract:
SUMMARY: Here, we compare the sunspot counts and the number of sunspot
groups (SGs) with variations of total solar irradiance (TSI), magnetic activity, Ca
II K-flux, faculae and plage areas. We applied a time series method for extracting
the data over the descending phases of solar activity cycles (SACs) 21, 22 and 23,
and the ascending phases 22 and 23. Our results suggest that there is a strong
correlation between solar activity indices and the changes in small (A, B, C and
H-modified Zurich Classification) and large (D, E and F) SGs. This somewhat
unexpected finding suggests that plage regions substantially decreased in spite of
the higher number of large SGs in SAC 23 while the Ca II K-flux did not decrease
by a large amount nor was it comparable with SAC 22 and relates with C and DEF
type SGs. In addition to this, the increase of facular areas which are influenced by
large SGs, caused a small percentage decrease in TSI while the decrement of plage
areas triggered a higher decrease in the magnetic field flux. Our results thus reveal
the potential of such a detailed comparison of the SG analysis with solar activity
indices for better understanding and predicting future trends in the SACs.
