Can increase of chaos be a precursor of the epoch of low solar activity?
IPGP - Îlot Cuvier
Séminaires communs Géomagnétisme-Paléomagnétisme
Scientists give controversial predictions of the maximum of the current solar cycle. The previous cycle, which has been the longest cycle in more than 150 years, is characterized by numerous anomalies. These anomalies might signal the end of the Modern Maximum of solar activity. We compute a quantity (known as the Lyapunov exponent in the theory of dynamical systems) that reflects the order/disorder of the sunspot number time series. This Lyapunov exponent computed for the daily data within a sliding window significantly changes its behaviour twice: during 1910-1930 and at the present time. During the first change the order of the series has increased and now it seems to return onto the level seen before 1910. This phenomenon might be connected with other anomalies of the last solar cycles.