Predictions of Solar Cycle 24

Pesnell, W. D.

doi:10.1007/s11207-008-9252-2

Cited by 180 publications

(164 citation statements)

References 36 publications

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“…Lanza [2009] and others at this meeting show that stars like the Sun have similar dynamo-driven cycles with similar variations in characteristics, but observational limitations make it difficult to be certain of the details. Even solar dynamo models have given very divergent predictions for the magnitude of the upcoming cycle [Pesnell, 2008]. Improved measurements of meridional and other flows in the photospheric and below should help resolve the solar uncertainties.…”

Section: Discussionmentioning

confidence: 99%

“…The Earth, never more than 7 degrees from the equator, encounters the interplanetary extension of the neutral line, the heliospheric current sheet (HCS), every rotation. At higher latitude during long intervals near minimum the polarity of the heliospheric field does not reverse [McComas et al, 2000]. The HCS becomes increasingly distorted during the rise of the cycle as active regions make the photospheric field more complex.…”

Section: The Effect Of the Polar Field On The Corona And Heliospherementioning

confidence: 97%

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Evolution of the large-scale magnetic field over three solar cycles

Hoeksema

2009

Proc. IAU

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Abstract.Observations of the large-scale magnetic field show that the current extended solar cycle minimum is different from the three previous well-observed minima. The weaker polar fields increase the relative influence of middle and low-latitude flux patterns on the configuration of the corona and heliosphere. A much larger portion of the open flux originates in equatorial coronal holes. Even though the mean magnetic field of the Sun as a star is the weakest since measurements began, the sector structure of the interplanetary field, though smaller in magnitude, reached fairly high latitude until 2009. The emergence of active regions through the cycle and transport of flux from low to high latitudes also show quite different patterns, providing insight into the dynamo that drives the cycle. Long records of synoptic observations provide a rich source of information about solar activity that must be maintained.

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Section: Discussionmentioning

confidence: 99%

Section: The Effect Of the Polar Field On The Corona And Heliospherementioning

confidence: 97%

Evolution of the large-scale magnetic field over three solar cycles

Hoeksema

2009

Proc. IAU

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“…Pesnell (2008) carried out a comprehensive review of 54 different predictions obtained by applying techniques based on climatology (past behaviour), dynamo models, spectral analysis, neural networks, geomagnetic and solar precursor methods. As a reference, in Table 1 we report all the prediction models considered by Pesnell, grouped by category (and within each category ordered by reference date) to provide a scenario of the refinement evolution in this field.…”

Section: The Solar Dynamomentioning

confidence: 99%

“…An average solar cycle peaks at 114 and therefore the next cycle will be neither extreme nor average. Hiremath (2008) Autoregressive, linear prediction see Pesnell (2008) Combined empirical mode decomposition and autoregression Xu et al (2008) Neural Network Spectral analysis and neurofuzzy modelling Gholipour et al (2005) Neural network forecast Maris and Oncica (2006) Geomagnetic precursor Disturbed days Thompson (1993) Disturbed days analysis Chopra and Dabas (2006) Howe et al (2009) examined the evolution of the zonal flow pattern in the upper solar convection zone during the current extended solar minimum, and compared it with that during the previous minimum. Interestingly, the torsional oscillation progress seems to predict the solar cycle onset and it could have predicted the delayed onset of Cycle 24.…”

Section: The Solar Dynamomentioning

confidence: 99%

“…As stressed in Sect. 3.3, the analysis by Pesnell (2008) points out that the existing dynamo-based models do not have predictive capabilities yet and precursorbased ones result in significant discrepancies, leading to the need to consider solar and geomagnetic precursor as separate categories. Finally, whereas the prediction of solar activity climatology is to some extent successful, the prediction of exceptional activity events is still a challenge.…”

Section: Prediction Models For the Emergence Of Magnetic Flux And Actmentioning

confidence: 99%

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Solar Weather Event Modelling and Prediction

et al. 2009

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Key drivers of solar weather and mid-term solar weather are reviewed by considering a selection of relevant physics-and statistics-based scientific models as well as a selection of related prediction models, in order to provide an updated operational scenario for space weather applications. The characteristics and outcomes of the considered scientific and prediction models indicate that they only partially cope with the complex nature of solar activity for the lack of a detailed knowledge of the underlying physics. This is indicated by the fact that, on one hand, scientific models based on chaos theory and non-linear dynamics reproduce better the observed features, and, on the other hand, that prediction models based on statistics and artificial neural networks perform better. To date, the solar weather prediction success at most time and spatial scales is far from being satisfactory, but the forthcoming ground-and space-based high-resolution observations can add fundamental tiles to the modelling and predicting frameworks as well as the application of advanced mathematical approaches in the analysis of diachronic solar observations, that are a must to provide comprehensive and homogeneous data sets.

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Is a sudden increase of irregularity of sunspot numbers a precursor of a return to low solar activity?

et al. 2014

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We have recently introduced an irregularity index λ for daily sunspot numbers International Sunspot Number (ISSN), derived from the well-known Lyapunov exponent, that attempts to reflect irregularities in the chaotic process of solar activity. Like the Lyapunov exponent, the irregularity index is computed from the data for different embedding dimensions m (2-32). When m = 2, λ maxima match ISSN maxima of the Schwabe cycle, whereas when m = 3, λ maxima occur at ISSN minima. The patterns of λ as a function of time remain similar from m = 4 to 16: the dynamics of λ change between 1915 and 1935, separating two regimes, one from 1850 to 1915 and the other from 1935 to 2005, in which λ retains a similar structure. A sharp peak occurs at the time of the ISSN minimum between cycles 23 and 24, possibly a precursor of unusual cycle 24 and maybe a new regime change; λ is significantly smaller during the ascending and descending phases of solar cycles. Differences in values of the irregularity index observed for different cycles reflect differences in correlations in sunspot series at a scale much less than the 4 year sliding window used in computing them; the lifetime of sunspots provides a source of correlation at that time scale. The burst of short-term irregularity evidenced by the strong λ peak at the minimum of cycles 23 and 24 would reflect a decrease in correlation at the time scale of several days rather than a change in the shape of the cycle.

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Predictions of Solar Cycle 24

Cited by 180 publications

References 36 publications

Evolution of the large-scale magnetic field over three solar cycles

Evolution of the large-scale magnetic field over three solar cycles

Solar Weather Event Modelling and Prediction

Is a sudden increase of irregularity of sunspot numbers a precursor of a return to low solar activity?

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