Solar Cycle Observations
Abstract
We describe the defining observations of the solar cycle that provide constraints for the dynamo processes operating within the Sun. Specifically, we report on the following topics: historical sunspot numbers and revisions; active region (AR) flux ranges and lifetimes; bipolar magnetic region tilt angles; Hale and Joy's law; the impact of rogue ARs on cycle progression and the amplitude of the following cycle; the spatio-temporal emergence of ARs that creates the butterfly diagram; polar fields; large-scale flows including zonal, meridional, and AR in-flows; short-term cycle variability; and helioseismic results including mode parameter changes.
Cite
@article{arxiv.2305.19803,
title = {Solar Cycle Observations},
author = {Aimee Norton and Rachel Howe and Lisa Upton and Ilya Usoskin},
journal= {arXiv preprint arXiv:2305.19803},
year = {2023}
}
Comments
39 pages, 11 figures, ISSI workshop on Solar and Stellar Dynamos (June 2022). Submitted to Space Science Reviews, May 2023. This is the revised version accepted September 2023