| Abstract: | Characteristics of the sunspot cycle described by the international sunspot numbers are investigated based on the results obtainned by Hathaway, Wilson, and Reichmann (1994). A long period of about 90 years is found to possibly exist for the sunspot number time series. Cycles that take less time to rise from minimum to maximum of cycle amplitude tend to have large amplitude, and those that have small maximum amplitude tend to run a long time to get ended. It is also found in this paper that the more recent cycles are larger in amplitude and shorter both in cycle length and the rising time of solar cycle than the earlier ones. |
