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Table 2 A selection of early forecasts for Cycle 25

From: Solar cycle prediction

Category Minimum Maximum Peak amplitude References
Internal precursors 2019.9 2023.8 175 (154–202) Li et al. (2015)
External precursor
 Polar precursor    \(117\pm 15\) Table 1 here
 Polar precursor    \(136\pm 48\) Pesnell and Schatten (2018)
 Helicity    117 Hawkes and Berger (2018)
 SoDA   \(2025.2\pm 1.5\) \(120\pm 39\) Based on Pesnell and Schatten (2018)
 Rush-to-the-poles 2019.4 2024.8 130 Petrovay et al. (2018)
Model-based: SFT
 SFT    \(124\pm 31\) Jiang et al. (2018)
 AFT 2020.9   110 Upton and Hathaway (2018)
Model-based: dynamo
 \(2{\times }2\)D \(2020.5\pm 0.12\) \(2027.2\pm 1.0\) \(89^{+29}_{-14}\) Labonville et al. (2019)
 Truncated 2019–2020 \(2024\pm 1\) \(90\pm 15\) Kitiashvili (2016)
Spectral
 Wavelet decomposition tree   2023.4 132 Rigozo et al. (2011)
Attractor analysis
 Simplex projection analysis   \(2024.0\pm 0.6\) \(103\pm 25\) Singh and Bhargawa (2017)
 Simplex proj./time-delay   \(2023.2\pm 1.1\) \(154\pm 12\) Sarp et al. (2018)
Neural networks
 Neuro-fuzzy   2022 \(90.7\pm 8\) Attia et al. (2013)
 Spatiotemporal   2022–2023 \(57\pm 17\) Covas et al. (2019)
Cycle 24 (comparison) 2008.9 2014.3 116  
  1. In the case of SFT models, forecasts were obtained by multiplying the amplitude of Cycle 24 with the predicted % increase in polar field strength between the two minima. Errors resulting from a natural scatter in the polar field–cycle ampliude relation are therefore not included in the error range given