Long-Term Solar Variability and the Solar Cycle in the 21st Century

Bonev, B. P.; Penev, K.; Sello, Stefano

doi:10.1086/420695

Cited by 30 publications

(30 citation statements)

References 28 publications

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“…Thus with the present data set we cannot unambiguously state that there is an 80 year Gleissberg cycle. Previous studies also show that an 80 year Gleissberg cycle need not be 80 year long and may be a cycle of 100 years (Rozelot 1994;Bonev et al 2004).…”

Section: Data and Resultsmentioning

confidence: 97%

The solar cycle as a forced and damped harmonic oscillator: long-term variations of the amplitudes, frequencies and phases

Hiremath¹

2006

A&A

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We model solar activity cycle as a forced and damped harmonic oscillator consisting of two parts, sinusoidal and transient. The amplitudes, frequencies, phases and decay factors of such a harmonic oscillator are determined by fitting the equation of the sinusoidal and transient parts to the sunspot data for the years 1755-1996 (cycles 1-22) with the results: (i) there is a long-term decreasing trend in the phase, while the amplitude and the frequency (or period of ∼11 yr) of the sinusoidal part remain constant for all the solar cycles; (ii) the amplitude of the transient part is phase locked with the phase of the sinusoidal part; (iii) for all the cycles, the period and decay factor (that is much less than 1) of the transient part remain approximately constant; (iv) except in cycles 6 and 15, the phases of the transient part are approximately constant with a magnitude of ∼π/2 radians and; (v) for cycles 6 and 15, the simultaneous change in magnitude of phase difference (∼2π radians) between the transient and sinusoidal parts and of very low sunspot activity may be due to the Maunder minimum type of oscillations. The constancy of the amplitudes and the frequencies of the sinusoidal part and a very small decay factor from the transient part suggests that the solar activity cycle mainly consists of a persistent oscillatory part that might be compatible with long-period (∼22 yr) Alfven oscillations.

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Section: Data and Resultsmentioning

confidence: 97%

The solar cycle as a forced and damped harmonic oscillator: long-term variations of the amplitudes, frequencies and phases

Hiremath¹

2006

A&A

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“…There are long term variations in the solar activity and irradiance (e.g., Tapping et al 2007;Fröhlich 2009;Shapiro et al 2011). In particular, because the Sun apparently had an unusually active period in the last couple of decades (Usoskin et al 2003;Bonev et al 2004), we cannot completely rule out the existence of a long term trend. However, in spite of suggestions that cycle No.…”

Section: Implications For the Solar Irradiancementioning

confidence: 96%

Variation in sunspot properties between 1999 and 2011 as observed with the Tenerife Infrared Polarimeter

Rezaei

Beck

Schmidt

2012

A&A

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“…The scenarios based on the observed data are in serious contradiction. On the contrary, predictions based on indirect "historical" data are in agreement for the forthcoming supercentennial solar minimum during the 21st century (Komitov and Bonev, 2001;Kaftan, 2003, 2004;Solanki et al, 2004;Bonev et al, 2004;Ogurtsov, 2005) and it is independent from what types of historical data (14C, 10Be or Schove series data) or methods have been used. Komitov and Kaftan's studies are based on multiple periodicity.…”

Section: Long Time-scale Variationsmentioning

confidence: 97%

Prediction of solar cycle 24 based on the Gnevyshev-Ohl-Kopecky rule and the three-cycle periodicity scheme

Kane

2008

Ann. Geophys.

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Abstract. An examination of the maximum yearly values of the conventional sunspot number Rz of all cycles revealed fluctuations of various intervals in the high periodicity region (exceeding 11 years), namely 2 cycles (Hale, 22 years), 3 cycles (TRC, three-cycle) and longer intervals. The 2-cycle spacings had the smallest amplitudes. According to the G-O (Gnevyshev-Ohl) rule (Gnevyshev and Ohl, 1948), the even-numbered series of the maxima of annual mean Wolf sunspot numbers Rz are followed by higher amplitude odd-numbered series. Kopecky (1950) generalized this relation to annual mean Wolf numbers corresponding to equivalent phases of the adjacent even-odd 11-year cycles. Therefore, we would call it the G-O-K rule. For the data of 28 cycles (cycle −4 to cycle 23), it was found that four pairs (~29%) from the fourteen even-odd pairs showed failure of the G-O-K rule. In the remaining ten pairs, the magnitudes of the odd cycles were well-correlated with the magnitudes of the preceding even cycles, but it was impossible to tell whether it would be a normal pair following the G-O-K rule or a possible case of failure. A much stronger sequence was the three-cycle sequence (TRC, low, high, higher). The 2-cycle oscillations were embedded into the TRC until the G-O-K rule failures occurred as in cycle 23. The patterns of cycle 17 (low), 18 (high), 19 (higher); 20 (low), 21 (high), 22 (higher) were noticed and used by Ahluwalia (1995, 1998) to predict a low value for cycle 23, which was accurate. However, in the earlier data, the preceding sequence (14, 15, 16) was rather uncertain, and before that for seven cycles (cycles 8-14), there were no TRC sequences at all. During the twelve cycles −4 to 7, there were only three isolated TRC sequences (one doubtful). In view of this chequered history of TRC, it is doubtful whether the present TRC pattern (cycles 17–23) would persist in the near future. Spectral analysis showed that in the first half (cycles −4 to 9), larger periodicities (reminiscent of the Gleissberg cycle of ~80 years) prevailed. but in the latter half, periodicities were different (3-year cycle was predominant) and the matching was not good. In particular, the points for the recent cycles 21, 22 seemed to deviate considerably from the constructed series, thus introducing unreliability in predictions for the future by using extrapolation of periodicities.

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Long-Term Solar Variability and the Solar Cycle in the 21st Century

Cited by 30 publications

References 28 publications

The solar cycle as a forced and damped harmonic oscillator: long-term variations of the amplitudes, frequencies and phases

The solar cycle as a forced and damped harmonic oscillator: long-term variations of the amplitudes, frequencies and phases

Variation in sunspot properties between 1999 and 2011 as observed with the Tenerife Infrared Polarimeter

Prediction of solar cycle 24 based on the Gnevyshev-Ohl-Kopecky rule and the three-cycle periodicity scheme

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