Dynamic Characteristics of Area Variations of Small and Large Sunspots and Quasi-Biennial Oscillations in Solar Activity

Resumo

The spatiotemporal and chaotic dynamics of variations in area of sunspot groups related conventionally to small (area <50 Msh) and large (area >50 Msh) populations is analyzed. The Greenwich Observatory–Marshall Space Flight Center data were used. The results show that both sunspot populations have a single initial source, which is a magnetic flux generated by the dynamo process (presumably at the bottom of the convective zone) and is responsible for the 11—22-year periodicity of solar activity. A possible explanation of the revealed different behavior of the considered populations is that the magnetic flux is partially involved in another process responsible for the shaping of primarily very large sunspot groups. This process develops presumably in the upper layer of the convective zone with an unstable amplitude and a period varying within 1–2 years. The analysis of power spectrum of the Wolf number time series has indicated the difference between dynamic characteristics of the two studied processes.