A prediction of the onset of solar cycle 24

Aims: This paper aims to search for a method to estimate the onset of a new solar cycle by re-investigating the relationship between descending and ascending phase durations in terms of weighted extremum times. Methods. The lagged cross-correlation method is used to analyze their relationship. Results. The descending phase durations are found to be anti-correlated (correlation coefficient, -0.77) with the ascending phase durations three cycles earlier, in the 13-month running mean sunspot numbers since cycle 8. From linear regression analysis, the descending phase duration of cycle 23 is estimated to be 78 +/- 7 months; thus, cycle 24 should start near March 2007, where the error bar equals +/- standard error.