Periodicities in Solar Activity, Solar Radiation and Their Links with Terrestrial Environment

Abstract

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-year-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 14 C isotope. This period was also confirmed with the period of about 2000 -2100 years derived from a baseline of the solar background magnetic field, 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 is also discussed.

ENSO Index Variations and Links with Solar and Volcanic Activity

“…The most puzzling is the larger period of 12 years in the ENSO index, which is detected with a high accuracy within 95% confidence interval. This period is not clearly linked to any solar activity indices shown in Section 2.2, which within in the same duration of the data have a period of about 10.7 years [23,29]. Hence, this 12-year period of the ENSO index oscillation is outside the standard effects of solar activity as was also clearly shown in the previous Section 2.2.…”

“…The effect of the solar system planet gravitation on the motion even of the star of the system, the Sun, leading to the solar inertial motion (SIM) about the barycentre of the solar system, has been reported by many authors [42][43][44] while only recently these effects have been linked to the changes in Sun-Earth distances on the orbit in different years, centuries or even millennia reporting the two-millennial variations of solar irradiance (Hallstaat's cycle) caused by SIM [27][28][29]. In this millennium the Sun is shown to move closer to the Earth's orbit during passing the orbit about the spring equinox in the Northern hemisphere.…”

“…On the other hand, in the past few hundred years, the Sun has been shown to provide some additional radiation to the Earth by moving closer toward the Earth's orbit because of the solar inertial motion (SIM) caused by the gravitation of the large planets [27][28][29]. These periodic variations of the Sun-Earth distance, and the solar irradiance, occur every 2100 -2200 years, called Hallstatt's cycles, which were independently derived from the isotope abundances in the terrestrial biomass [30,31].…”

“…These periodic variations of the Sun-Earth distance, and the solar irradiance, occur every 2100 -2200 years, called Hallstatt's cycles, which were independently derived from the isotope abundances in the terrestrial biomass [30,31]. In the current Hallstatt's millennial cycle, the Sun-Earth distances are decreasing from the MM until 2600 that leads to the increase of solar irradiance deposited to the atmosphere of the Earth (and other planets [28,29]. Natural Science This SIM effect is shown to contribute to the terrestrial atmosphere heating [28,29], in addition to any heating considered in the terrestrial models.…”

“…In the current Hallstatt's millennial cycle, the Sun-Earth distances are decreasing from the MM until 2600 that leads to the increase of solar irradiance deposited to the atmosphere of the Earth (and other planets [28,29]. Natural Science This SIM effect is shown to contribute to the terrestrial atmosphere heating [28,29], in addition to any heating considered in the terrestrial models. However, the most notable effect of the Sun in the next few decades will come from a reduction of solar activity, in spite of SIM or any other reason for global warming, that is caused by the modern grand solar minimum (GSM), which started in 2020 and will last until 2053 [20,32].…”