Progress in Solar Cycle Predictions: Sunspot Cycles 24-25 in Perspective

Abstract

The dynamic activity of the Sun -- sustained by a magnetohydrodynamic dynamo mechanism working in its interior -- modulates the electromagnetic, particulate and radiative environment in space. While solar activity variations on short timescale create space weather, slow long-term modulation forms the basis of space climate. Space weather impacts diverse space-reliant technologies while space climate influences planetary atmospheres and climate. Having prior knowledge of the Sun's activity is important in these contexts. However, forecasting solar-stellar magnetic activity has remained an outstanding challenge. In this review, predictions for sunspot cycle 24 and the upcoming cycle 25 are summarized, and critically assessed. The analysis demonstrates that while predictions based on diverse techniques disagree across solar cycles 24--25, physics-based predictions for solar cycle 25 have converged and indicates a weak sunspot cycle 25. It is argued that this convergence in physics-based predictions is indicative of progress in the fundamental understanding of solar cycle predictability. Based on this understanding, resolutions to several outstanding questions related to solar cycle predictions are discussed.

Review draft soliciting community feedback. Currently under refereeing. Request comments if any to corresponding author within 15 September 2020

References in corpus (26)

• Understanding space weather to shield society: A global road map for 2015-2025 commissioned by COSPAR and ILWS
• Predicting solar cycle 24 with a solar dynamo model
• Exploring the Physical Basis of Solar Cycle Predictions: Flux Transport Dynamics and Persistence of Memory in Advection versus Diffusion Dominated Solar Convection Zones
• Prediction of the strength and timing of sunspot cycle 25 reveal decadal-scale space environmental conditions
• The crucial role of surface magnetic fields for the solar dynamo
• Magnetic Flux Transport at the Solar Surface
• The unusual minimum of sunspot cycle 23 a consequence of Sun's meridional plasma flow variations
• Calibrating 100 Years of Polar Faculae Measurements: Implications for the Evolution of the Heliospheric Magnetic Field
• On Predicting the Solar Cycle using Mean-Field Models
• Overlapping Magnetic Activity Cycles and the Sunspot Number: Forecasting Sunspot Cycle 25 Amplitude
• The Effect of "Rogue" Active Regions on the Solar Cycle
• Prediction of Sunspot Cycles by Data Assimilation Method
• The Solar-Stellar Connection
• A Double-Ring Algorithm for Modeling Solar Active Regions: Unifying Kinematic Dynamo Models and Surface Flux-Transport Simulations
• Turbulent Pumping of Magnetic Flux Reduces Solar Cycle Memory and thus Impacts Predictability of the Sun's Activity
• North-south asymmetry in solar activity: predicting the amplitude of the next solar cycle
• Helioseismic data inclusion in solar dynamo models
• Improvement of solar cycle prediction: Plateau of solar axial dipole moment
• Long-term variations in the north-south asymmetry of solar activity and solar cycle prediction, III: prediction for the amplitude of solar cycle 25
• A proposed paradigm for solar cycle dynamics mediated via turbulent pumping of magnetic flux in Babcock-Leighton type solar dynamos
• Observations and modelling of North-South asymmetries using a Flux Transport Dynamo
• A 3D kinematic Babcock Leighton solar dynamo model sustained by dynamic magnetic buoyancy and flux transport processes
• Timing Terminators: Forecasting Sunspot Cycle 25 Onset
• Application of Synoptic Magnetograms to Global Solar Activity Forecast
• Modeling star-planet interactions in far-out planetary and exoplanetary systems
• Does the mean-field alpha effect have any impact on the memory of the solar cycle?

Cited by in corpus (28)

• Physical Models for Solar Cycle Predictions
• Mean field models of flux transport dynamo and meridional circulation in the Sun and stars
• The 10 October 2024 geomagnetic storm may have caused the premature reentry of a Starlink satellite
• a dynamo-based prediction of solar cycle 25
• Physical link of the polar field build-up with the Waldmeier effect broadens the scope of early solar cycle prediction: Cycle 25 is likely to be slightly stronger than Cycle 24
• Comparison of physics-based prediction models of solar cycle 25
• Long-term Variations in Solar Activity: Predictions for Amplitude and North--South Asymmetry of Solar Cycle 25
• Role of observable nonlinearities in solar cycle modulation
• What do halo CMEs tell us about solar cycle 25?
• A magnetic cloud prediction model for forecasting space weather relevant properties of Earth-directed coronal mass ejections
• Impact of Anomalous Active Regions on the Large-scale Magnetic Field of the Sun
• Dynamo Model for North-South Asymmetry of Solar Activity
• Discovery of a relation between the decay rate of the Sun's magnetic dipole and the growth rate of the following sunspot cycle: a new precursor for solar cycle prediction
• Solar Activity and Space Weather
• Long-term forcing of Sun's coronal field, open flux and cosmic ray modulation potential during grand minima, maxima and regular activity phases by the solar dynamo mechanism
• Evolution of solar wind sources and coronal rotation driven by the cyclic variation of the Sun's large-scale magnetic field
• Solar Energetic Particle Ground-Level Enhancements and the Solar Cycle
• Algebraic Quantification of the Contribution of Active Regions to the Sun's Dipole Moment: Applications to Century-scale Polar Field Estimates and Solar Cycle Forecasting
• Zonal harmonics of solar magnetic field for solar cycle forecast
• On the Strength and Duration of Solar Cycle 25: A Novel Quantile-based Superposed Epoch Analysis
• A Time-Efficient, Data Driven Modelling Approach For Predicting The Geomagnetic Impact of Coronal Mass Ejections
• Forecasting the solar cycle using variational data assimilation: validation on cycles 22 to 25
• Hemispheric analysis of the magnetic flux in regular and irregular solar active regions
• Solar cycle 25 prediction using length-to-amplitude relations
• Effects of Observational Data Shortage on Accuracy of Global Solar Activity Forecast
• Solar Cycles: Can They Be Predicted?
• A Comparative Analysis of Machine-learning Models for Solar Flare Forecasting: Identifying High-performing Active Region Flare Indicators
• Solar Cycle Prediction: Challenges, Progress, and Future Perspectives