A Dynamo-based Forecast of Solar Cycle 25
Abstract
We present a data-driven version of the solar cycle model of Lemerle and Charbonneau (Astrophys. J.834, 133; 2017), which we use to forecast properties of the upcoming sunspot Cycle 25. The two free parameters of the model are fixed by requiring the model to reproduce Cycle 24 upon being driven by active region data for Cycle 23. Our forecasting model incorporates self-consistently the expected fluctuations associated with stochastic variations in properties of emerging active regions, most notably the scatter in the tilt angle of the line segment joining the opposite polarity focii of bipolar magnetic regions, as embodied in Joy's law. By carrying out ensemble forecasts with statistically independent realizations of active region parameters, we can produce error bars that capture the impact of this physical source of fluctuations. We forecast a smoothed monthly international sunspot number (version 2.0) peaking at 89−14+29 in year 2025.3−1.05+0.89, with a 6 month onset delay in the northern hemisphere, but a peak amplitude 20% higher than in the southern hemisphere.
- Publication:
-
Solar Physics
- Pub Date:
- June 2019
- DOI:
- 10.1007/s11207-019-1480-0
- Bibcode:
- 2019SoPh..294...82L
- Keywords:
-
- Solar cycle;
- models;
- observations;
- Magnetic fields;
- photosphere