Has the maximum of Solar Cycle 23 appeared?
In this note, we define firstly a compositive parameter as an index describing the level of solar activity in a solar cycle. The parameter is derived from a combination of the smoothed monthly mean sunspot number with the fluctuation of the associated monthly mean sunspot numbers to the smoothed one. Then, a method is developed for estimating the time of the appearance of a solar maximum based on the conception of similar cycles. An application of the method to the 23rd solar cycle shows that the maximum of the cycle should have appeared in the period from April to August 2000, and the descending phase of Cycle 23 has come.
Keywordssolar cycle sunspot number estimate of peak time 23rd solar cycle
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