Reversals of Gnevyshev-Ohl rule

TL;DR

This study analyzes long-term variations in sunspot cycle parameters, revealing reversals of the Gnevyshev-Ohl rule over different epochs, indicating complex solar activity patterns.

Contribution

It uncovers long-term periodicity and reversals in the Gnevyshev-Ohl rule through historical sunspot data analysis.

Findings

Long-term variation with ~20 cycle period.

Positive correlation between consecutive cycle parameters.

Reversal of Gnevyshev-Ohl rule in earlier epochs.

Abstract

This paper considers the changes of average number of sunspots groups per day, aggregated by activity cycles Gn within the period since 1610 till present time. The relation of parameter Gn of the preceding and the following activity cycles has a long-term variation with the period of about 20 activity cycles. There is a positive correlation between the parameter Gn in the current cycle and analogous parameter in the following cycle Gn+1. For cycles N 10-21 for a pair of even and odd cycles the relation of parameter Gn corresponds to Gnevyshev-Ohl rule Godd/Geven>1. But in previous epochs the odd cycles could be less than the preceding even cycles, and it only proves the reversal of Gnevyshev-Ohl rule.