Strong fluctuations in sunspot indices
Abstract
Strong fluctuations in the relative numbers and total areas of sunspots over Carrington solar rotations (27.3 days) and months are examined based on data obtained from 1878-1964. A catalog of strong positive and negative fluctuations of Wolf numbers and total areas is presented for solar cycles 12 through 19 and discussed in terms of the solar 11-year and 80-90 year activity cycles. Strong index fluctuations are shown to depend on the phase of the 11-year cycle, with positive fluctuations most often apparent 1 to 5 years after maximum and negative fluctuations predominantly occurring 1 year after maximum. Inverse variations in positive and negative index fluctuations are observed at the epochs of maximum and minimum of the 80-90 year solar cycle, and anomalous fluctuation behaviors are noted in solar cycle 16. The characteristics of long-period variations in solar activity are thus shown to be fundamentally determined by differences in the fluctuations of the relative numbers and total areas of sunspots, in part by the mean values of these fluctuations over months and solar rotations.
- Publication:
-
Izvestiya Glavnoj Astronomicheskoj Observatorii v Pulkove
- Pub Date:
- 1980
- Bibcode:
- 1980IzPul.198...50V
- Keywords:
-
- Long Term Effects;
- Secular Variations;
- Solar Cycles;
- Sunspots;
- Anomalies;
- Solar Rotation;
- Tables (Data);
- Twenty-Seven Day Variation;
- Solar Physics