Role of sunspot latitude versus tilt in determining the polar field and amplitude of the next cycle: Cause of the weak Solar Cycle 20
arXiv:2509.17146 · doi:10.3847/1538-4357/ae0ccb
Abstract
One prominent feature of solar cycle is its irregular variation in its cycle strength, making it challenging to predict the amplitude of the next cycle. Studies show that fluctuations and nonlinearity in generating poloidal field throughout the decay and dispersal of tilted sunspots produce variation in the solar cycle. The flux, latitudinal position, and tilt angle of sunspots are the primary parameters that determine the polar field and, thus, the next solar cycle strength. By analysing the observed sunspots and polar field proxy, we show that the nonlinearity in the poloidal field generation becomes important for strong cycles. Except for strong cycles, we can reasonably predict the polar field at the end of the cycle (and thus the next cycle strength) using the total sunspot area alone. Combining the mean tilt angle and latitude positions with the sunspot area, we can predict the polar field of Cycles 15 -- 24 (or the amplitude of sunspot Cycles 16-25) with reasonable accuracy except for Cycle 23 for which the average tilt angle cannot predict the polar field. For Cycles 15--22, we show that the average tilt angle variation dominates over the latitude variation in determining the polar field of a cycle. In particular, the reduction of tilt in Cycle 19 was the primary cause of the following weak cycle (Cycle 20). Thus, we conclude that tilt quenching is essential in regulating the solar cycle strength in the solar dynamo.
Accepted for publication in ApJ. Comments are welcome
References in corpus (26)
- Predicting solar cycle 24 with a solar dynamo model
- The crucial role of surface magnetic fields for the solar dynamo
- Solar Cycle Propagation, Memory, and Prediction: Insights from a Century of Magnetic Proxies
- The unusual minimum of sunspot cycle 23 a consequence of Sun's meridional plasma flow variations
- Effects of the scatter in sunspot group tilt angles on the large-scale magnetic field at the solar surface
- Solar cyclic activity over the last millennium reconstructed from annual 14C data
- Importance of Meridional Circulation in Flux Transport Dynamo: The Possibility of a Maunder-like Grand Minimum
- Solar Cycle Variability Induced by Tilt Angle Scatter in a Babcock--Leighton Solar Dynamo Model
- The Effect of "Rogue" Active Regions on the Solar Cycle
- Sunspot area catalogue revisited: Daily cross-calibrated areas since 1874
- Models for the long-term variations of solar activity
- Long-term modulation of solar cycles
- Nonlinear mechanisms that regulate the solar cycle amplitude
- The polar precursor method for solar cycle prediction: comparison of predictors and their temporal range
- Dynamo saturation through the latitudinal variation of bipolar magnetic regions in the Sun
- Sunspot tilt angles revisited: Dependence on the solar cycle strength
- Latitude Distribution of Sunspots: Analysis Using Sunspot Data and A Dynamo Model
- 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
- Role of observable nonlinearities in solar cycle modulation
- Impact of Anomalous Active Regions on the Large-scale Magnetic Field of the Sun
- Analysis of BMR tilt from AutoTAB catalog: Hinting towards the thin flux tube model?
- Toroidal flux loss due to flux emergence explains why solar cycles rise differently but decay in a similar way
- Dynamo modelling for cycle variability and occurrence of grand minima in Sun-like stars: Rotation rate dependence
- AutoTAB: Automatic Tracking Algorithm for Bipolar Magnetic Regions
- Supercriticality of the dynamo limits the memory of the polar field to one cycle
- Extreme Fluctuations in the Sun's Activity over the Modern Maximum: Understanding the Enigmatic Solar Cycles 19-20