Sunspot time series: spectrum from square law modulation of the Hale cycle

Journal Article · Wed Dec 01 04:00:00 EST 1982 · Geophys. Res. Lett.; (United States)

DOI:https://doi.org/10.1029/GL009i012p01313· OSTI ID:6524726

Sonett, C P

The spectrum of the sunspot index can be qualitatively accounted for by a very simple time series model which the Hale 22 year cycle dominates; the series is amplitude modulated at the 90 year Gleissberg period with an index of 25%. The square of the modulated Hale cycle reproduces all of the spectral lines of the Zurich sunspot index spectrum, provided that a small offset is included in the Hale carrier. Without this, evidence of the 22 year periodicity disappears. The squaring explains the dominance of the 11 year cycle which is an artifact of the modulation as is the 45 year line. The offset suggests a small relict magnetic field in the Sun's core. Lastly Gilliland (1981) finds a radial eigenmode in the Sun with period of 76 +- 8 years suggestive of a physical basis for the Gleissberg modulation.

• Research Organization: Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721
• OSTI ID: 6524726
• Journal Information: Geophys. Res. Lett.; (United States), Journal Name: Geophys. Res. Lett.; (United States) Vol. 9:12; ISSN GPRLA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
FREQUENCY DEPENDENCE
FUNCTIONS
MATHEMATICS
RESOLUTION
SOLAR ACTIVITY
SOLAR CYCLE
SPECTRAL DENSITY
SPECTRAL FUNCTIONS
SUNSPOTS
TIME-SERIES ANALYSIS