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The annual temperature cycle of the earth closely follows the annual cycle of solar flux. At temperate latitudes, both driving and response cycles are well described by a strong annual sinusoidal component and a non-vanishing semiannual…

Atmospheric and Oceanic Physics · Physics 2020-11-13 Yunxiang Song , Kyle B. Lawlor , Thomas A. Witten

To demonstrate a degree of correlation between periodicity in the solar activity and a multi-resonant system three examples are considered. Although only two base frequencies were employed a relatively close correlation was obtained for…

Astrophysics · Physics 2007-05-23 M. A. Vukcevic

After decades of effort, the solar activity cycle is exceptionally well characterized but it remains poorly understood. Pioneering work at the Mount Wilson Observatory demonstrated that other sun-like stars also show regular activity…

Solar and Stellar Astrophysics · Physics 2017-09-01 Travis S. Metcalfe , Jennifer van Saders

The so-called solar cycle is generally characterized by the quasi-periodic oscillatory evolution of the photospheric spots number. This quasi-periodic pattern has always been an intriguing question. Several physical models were proposed to…

Solar and Stellar Astrophysics · Physics 2015-05-14 Alexis Klutsch , Rubens Freire Ferrero

The near 155 days solar periodicity, so called Rieger periodicity, was first detected in solar flares data and later confirmed with other important solar indices. Unfortunately, a comprehensive analysis on the occurrence of this periodicity…

Solar and Stellar Astrophysics · Physics 2014-11-20 J. M. Vaquero , R. M. Trigo , M. Vazquez , M. C. Gallego

The existence of ~12-year and ~51-year periodicities in the north-south asymmetry of solar activity is well known. However, the origin of these as well as the well-known relatively short periodicities in the north-south asymmetry is not yet…

Solar and Stellar Astrophysics · Physics 2020-01-17 J. Javaraiah

Solar activity seems quite understandable when considered on the scales comparable with a solar cycle, i.e. about 11 years, and on a short time scale of about a year. A solar cycle looks basically (anti)symmetric with respect to the solar…

Solar and Stellar Astrophysics · Physics 2025-08-08 V. N. Obridko , A. S. Shibalova , D. D. Sokoloff , I. M. Livshits

Context. Solar activity, dominated by the 11-year cyclic evolution, has been observed directly since 1610. Before that, indirect cosmogenic proxy data are used to reconstruct it over millennia. Recently, the precision of radiocarbon…

Solar and Stellar Astrophysics · Physics 2026-04-22 Ilya Usoskin , Sami K. Solanki , Natalie A. Krivova , Theodosis Chatzistergos

A growing body of evidence suggests that multiple dynamo mechanisms can drive magnetic variability on different timescales, not only in the Sun but also in other stars. Many solar activity proxies exhibit a quasi-biennial ($\sim$2 year)…

Solar and Stellar Astrophysics · Physics 2015-10-14 Ricky Egeland , Travis S. Metcalfe , Jeffrey C. Hall , Gregory W. Henry

There have been numerous reports of quasiperiodicities in solar activity in the intermediate period range. However, no accepted explanation for the episodic occurrence of quasiperiodicities has emerged. This paper examines the possibility…

Solar and Stellar Astrophysics · Physics 2015-10-12 Ian Edmonds

Searches for periodicity in time series are often done with models of periodic signals, whose statistical significance is assessed via false alarm probabilities or Bayes factors. However, a statistically significant periodic model might not…

Earth and Planetary Astrophysics · Physics 2022-02-22 Nathan C. Hara , Jean-Baptiste Delisle , Nicolas Unger , Xavier Dumusque

The solar magnetic activity cycle is responsible for periodic episodes of severe space weather, which can perturb satellite orbits, interfere with communications systems, and bring down power grids. Much progress has recently been made in…

Astrophysics · Physics 2007-05-23 T. S. Metcalfe , T. J. Henry , M. Knolker , D. R. Soderblom

Aims. The Sun shows strong variability in its magnetic activity, from Grand minima to Grand maxima, but the nature of the variability is not fully understood, mostly because of the insufficient length of the directly observed solar activity…

Solar and Stellar Astrophysics · Physics 2014-02-24 I. G. Usoskin , G. Hulot , Y. Gallet , R. Roth , A. Licht , F. Joos , G. A. Kovaltsov , E. Thebault , A. Khokhlov

In 1844 Schwabe discovered that the number of sunspots increased and decreased over a period of about 11 years, that variation became known as the sunspot cycle. Almost eighty years later, Hale described the nature of the Sun's magnetic…

The Rieger periods are solar cycles with a time scale of months, which are present in both flaring activity and sunspot occurrence. These short-term periodicities, tentatively explained by equatorially trapped Rossby-type waves modulating…

Astrophysics · Physics 2009-11-10 M. Massi , J. Neidhoefer , Y. Carpentier , E. Ros

The sunspot number data during the past 400 years indicates that both the profile and the amplitude of the solar cycle have large variations. Some precursors of the solar cycle were identified aiming to predict the solar cycle. The polar…

Solar and Stellar Astrophysics · Physics 2015-06-15 Jie Jiang

Long-term records of sunspot number and concentrations of cosmogenic radionuclides (10Be and 14C) on the Earth reveal the variation of the Sun's magnetic activity over hundreds and thousands of years. We identify several clear periods in…

Solar and Stellar Astrophysics · Physics 2015-06-03 T. V. Zaqarashvili , R. Oliver , A. Hanslmeier , M. Carbonell , J. L. Ballester , T. Gachechiladze , I. G. Usoskin

The variation with time from 1956-2002 of the globally averaged rate of ionization produced by cosmic rays in the atmosphere is deduced and shown to have a cyclic component of period roughly twice the 11 year solar cycle period. Long term…

Geophysics · Physics 2009-11-13 A. D. Erlykin , T. Sloan , A. W. Wolfendale

The inherent stochastic and nonlinear nature of the solar dynamo makes the strength of the solar cycles vary in a wide range, making it difficult to predict the strength of an upcoming solar cycle. Recently, our work has shown that by using…

Solar and Stellar Astrophysics · Physics 2024-12-25 Akash Biswas

The solar cycle and its associated magnetic activity are the main drivers behind changes in the interplanetary environment and the Earth's upper atmosphere (commonly referred to as space weather). These changes have a direct impact on the…

Solar and Stellar Astrophysics · Physics 2013-04-12 Andrés Muñoz-Jaramillo , María Dasi-Espuig , Laura A. Balmaceda , Edward E. DeLuca