Solar activity forecast with a dynamo model

Jiang, Jingyang; Chatterjee, Piyali; Choudhuri, Arnab Rai

doi:10.1111/j.1365-2966.2007.12267.x

Cited by 197 publications

(242 citation statements)

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“…The conventional view of solar science has been that solar magnetic and radiant variability are driven by internal solar dynamics alone, characterized by hydromagnetic solar dynamo models (Tobias, 2002;Jiang et al, 2007). However, current solar dynamo models assume that the Sun is an isolated system and have been unable to explain and/or forecast solar variability including the emergence of the Schwabe 11-year cycle and of its multidecadal, secular and millennia modulations.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, although solar dynamo theories do predict the emergence of generic solar oscillations, the reason why, among all possible theoretical frequencies, the Sun oscillates at the specific observed frequencies and phases has eluded researchers so far. For example, periods of low solar activity such as the Maunder and Dalton minima, and the intra-annual oscillations larger than the monthly solar differential rotation cycles are essentially not predicted by the solar dynamo models, which require an arbitrary choice of specific free parameters even for reproducing an 11-year major oscillation (Jiang et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

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Empirical evidences for a planetary modulation of total solar irradiance and the TSI signature of the 1.09-year Earth-Jupiter conjunction cycle

Scafetta

Willson²

2013

Astrophys Space Sci

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The time series of total solar irradiance (TSI) satellite observations since 1978 provided by ACRIM and PMOD TSI composites are studied. We find empirical evidence for planetary-induced forcing and modulation of solar activity. Power spectra and direct data pattern analysis reveal a clear signature of the 1.09-year Earth-Jupiter conjunction cycle, in particular during solar cycle 23 maximum. This appears to suggest that the Jupiter side of the Sun is slightly brighter during solar maxima. The effect is observed when the Earth crosses the Sun-Jupiter conjunction line every 1.09 years. Multiple spectral peaks are observed in the TSI records that are coherent with known planetary harmonics such as the spring, orbital and synodic periods among Mercury, Venus, Earth and Jupiter: the Mercury-Venus spring-tidal cycle (0.20 year); the Mercury orbital cycle (0.24 year); the Venus-Jupiter spring-tidal cycle (0.32 year); the Venus-Mercury synodic cycle (0.40 year); the Venus-Jupiter synodic cycle (0.65 year); and the Venus-Earth spring tidal cycle (0.80 year). Strong evidence is also found for a 0.5-year TSI cycle that could be driven by the Earth's crossing the solar equatorial plane twice a year and may indicate a latitudinal solar-luminosity asymmetry. Because both spring and synodic planetary cycles appear to be present and the amplitudes of their TSI signatures appear enhanced during sunspot cycle maxima, we conjecture that on annual and sub-annual scales both gravitational and electro-magnetic planet-sun interactions and internal non-linear feedbacks may be modulating solar activity. Gravitational tidal forces should mostly stress spring cycles while electro-magnetic forces could be linked to the solar wobbling dynamics, and would mostly stress the synodic cycles. The observed statistical coherence between the TSI records and the planetary harmonics is confirmed by three alternative tests.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Empirical evidences for a planetary modulation of total solar irradiance and the TSI signature of the 1.09-year Earth-Jupiter conjunction cycle

Scafetta

Willson²

2013

Astrophys Space Sci

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“…Most of the present day predictions are based on statistical analyses of solar activity in the past (Hathaway et al 1999;Hathaway 2009). A more physics-based approach is offered by models of the evolution of the Sun's magnetic field, although recent dynamo computations have given controversial results for cycle 24 (Dikpati & Gilman 2006;Choudhuri et al 2007;Jiang et al 2007). …”

Section: Introductionmentioning

confidence: 99%

Sunspot group tilt angles and the strength of the solar cycle

Dasi-Espuig¹,

Solanki

Krivova³

et al. 2010

A&A

214

232

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Context. It is well known that the tilt angles of active regions increase with their latitude (Joy's law). It has never been checked before, however, whether the average tilt angles change from one cycle to the next. Flux transport models show the importance of tilt angles for the reversal and build up of magnetic flux at the poles, which is in turn correlated to the strength of the next cycle. Aims. Here we analyse time series of tilt angle measurements and look for a possible relationship of the tilt angles with other solar cycle parameters, in order to glean information on the solar dynamo and to estimate their potential for predicting solar activity. Methods. We employed tilt angle data from Mount Wilson and Kodaikanal observatories covering solar cycles 15 to 21. We analyse the latitudinal distribution of the tilt angles (Joy's law), their variation from cycle to cycle, and their relationship to other solar cycle parameters, such as the strength (or total area covered by sunspots in a cycle), amplitude, and length. Results. The two main results of our analysis follow. 1. We find an anti-correlation between the mean normalised tilt angle of a given cycle and the strength (or amplitude) of that cycle, with a correlation coefficient of r c = −0.95 (99.9% confidence level) and r c = −0.93 (99.76% confidence level) for Mount Wilson and Kodaikanal data, respectively. 2. The product of the cycle's averaged tilt angle and the strength of the same cycle displays a significant correlation with the strength of the next cycle (r c = 0.65 at 89% confidence level and r c = 0.70 at 92% confidence level for Mount Wilson and Kodaikanal data, respectively). An even better correlation is obtained between the source term of the poloidal flux in Babcock-Leighton-type dynamos (which contains the tilt angle) and the amplitude of the next cycle. Further we confirm the linear relationship (Joy's law) between the tilt angle and latitude with slopes of 0.26 and 0.28 for Mount Wilson and Kodaikanal data, respectively. In addition, we obtain good positive correlations between the normalised-areaweighted tilt angle and the length of the following cycle, whereas the strength or the amplitude of the next cycle does not appear to be correlated to the tilt angles of the current cycle alone. Conclusions. The results of this study indicate that, in combination with the cycle strength, the active region tilt angles play an important role in building up the polar fields at cycle minimum.

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“…They are Choudhuri et al (2007) and Jiang et al (2007), see also Chatterjee et al (2004). The turbulent diffusivity is in order of 10 12 cm 2 s −1 .…”

Section: Turbulent Diffusivity Dominated Classmentioning

confidence: 99%

“…The left panel of Figure 6 gives the relation between the directly observed maximum polar field of cycle n and the subsequent cycle n + 1 strength. Cycle 24 is included in using the predicted strength by Jiang et al(2007). These 4 points distribute closely along the straight line which hints the good correlation between the polar field and the cycle strength.…”

Section: Solar Polar Field Precursormentioning

confidence: 99%

Solar-cycle precursors and predictions

Jiang

2012

Proc. IAU

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Abstract. 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 field and the geomagnetic index are two precursors which are received the most attention. The geomagnetic variations during the solar minima are potentially caused by the solar polar field by the connection of the solar open flux. The robust prediction skill of the polar field indicates that the memory of the dynamo process is less than 11 yrs based on the frame of the Babcock-Leighton flux transport dynamo. One possible reason to get the short magnetic memory is the high magnetic diffusivity in the convective zone. Our recent studies show that the radial downward pumping is another possible reason. Based upon the mechanism, we well simulate the cycle irregularities during RGO time period. This opens the possibility to set up a standard dynamo based model to predict the solar cycle. In the end, the no correlation between the polar field and the preceding cycle strength due to two nonlinearities involved in the sunspot emergence will be stressed.

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Solar activity forecast with a dynamo model

Cited by 197 publications

References 62 publications

Empirical evidences for a planetary modulation of total solar irradiance and the TSI signature of the 1.09-year Earth-Jupiter conjunction cycle

Empirical evidences for a planetary modulation of total solar irradiance and the TSI signature of the 1.09-year Earth-Jupiter conjunction cycle

Sunspot group tilt angles and the strength of the solar cycle

Solar-cycle precursors and predictions

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