Space Weather & Heliophysics

Periodicities Of Solar Activity And Solar Radiation Derived From Observations And Their Links With The Terrestrial Environment

By Keith Cowing
Status Report
January 19, 2023
Filed under , , , , , , , ,
Periodicities Of Solar Activity And Solar Radiation Derived From Observations And Their Links With The Terrestrial Environment
Top plots: Left – The averaged sunspot numbers N versus time in 1700-2020 including purely defined cycles. Right – The power bar for the wavelet spectrum. Bottom plots: Left – Wavelet spectrum with periods (Y-axis) derived from sunspot numbers, the black dashed line shows the Cone of Influence (COI) (see the text for details). Right – The global wavelet spectrum (the solid black line), Fourier spectrum (the indigo line). The COI shown by the black dashed line and the red-noise level at 95% shown by the red dashed line. A courtesy of Zharkova et al. (2022). —

Solar magnetic activity is expressed via variations of sunspots and active regions varying on different timescales. The most accepted is an 11-year period supposedly induced by the electromagnetic solar dynamo mechanism.

There are also some shorter or longer timescales detected: the biennial cycle (2-2.7 years), Gleisberg cycle (80-100 years), and Hallstatt’s cycle (2100-2300 years). Recently, using Principal Component Analysis (PCA) of the observed solar background magnetic field (SBMF), another period of 330-380 years, or Grand Solar Cycle (GSC), was derived from the summary curve of two eigenvectors of SBMF. In this paper, a spectral analysis of the averaged sunspot numbers, solar irradiance, and the summary curve of eigenvectors of SBMF was carried out using Morlet wavelet and Fourier transforms.

We detect a 10.7-year cycle from the sunspots and modulus summary curve of eigenvectors as well a 22 years cycle and the grand solar cycle of 342-350-years from the summary curve of eigenvectors. The Gleissberg centennial cycle is only detected on the full set of averaged sunspot numbers for 400 years or by adding a quadruple component to the summary curve of eigenvectors.

Another period of 2200-2300 years is detected in the Holocene data of solar irradiance measured from the abundance of 14C isotope. This period was also confirmed with the period of 2100 years derived from a baseline of the summary curve, supposedly, caused by the solar inertial motion (SIM) induced by the gravitation of large planets.

The implication of these findings for different deposition of solar radiation into the northern and southern hemispheres of the Earth caused by the combined effects of the solar activity and solar inertial motion on the terrestrial atmosphere are also discussed.

Valentina V. Zharkova, Irina Vasilieva, Simon Shepherd, Elena Popova

Comments: 30 pages, 15 figures
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (
Cite as: arXiv:2301.07480 [astro-ph.SR] (or arXiv:2301.07480v1 [astro-ph.SR] for this version)
Submission history
From: Valentina Zharkova
[v1] Wed, 18 Jan 2023 12:48:00 UTC (7,001 KB)
Astrobiology, space weather

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