Prediction of the Solar Polar Fields in 2026: An Unusually Weak Level Across the Last Five Solar Cycles

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Wang, Ruihui, Jiang, Jie, Luo, Yukun
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866912986169344000
author Wang, Ruihui
Jiang, Jie
Luo, Yukun
author_facet Wang, Ruihui
Jiang, Jie
Luo, Yukun
contents Solar polar fields are essential for the solar cycle and the heliospheric magnetic field. Cycle 25 is now entering its declining phase, the critical period during which most of the cycle's polar fields are established. Therefore, reliable polar-field prediction is now especially important. Polar-field evolution is governed by the poleward transport of already-emerged active-region (AR) flux over a timescale of a few years. Thus, surface flux-transport models can reliably provide one-year predictions without requiring information about future AR emergence. Our prediction method is validated using simulations of the surface magnetic field from 2020-2025 and hindcasts of the 2023-2024 polar fields, employing a newly constrained profile of the meridional flow. Using the most recent HMI synoptic magnetogram as the initial condition, we predict the polar-field evolution from October 2025 to October 2026. The southern polar field is predicted to strengthen gradually, while the northern field is expected to decline sharply until March 2026 due to some ARs with abnormal polarity. By that time, the northern polar field becomes exceptionally weak, and the southern field remains relatively weak, raising concerns about the polar-field strength at the cycle 25/26 minimum and the amplitude of cycle 26.
format Preprint
id arxiv_https___arxiv_org_abs_2512_17359
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Prediction of the Solar Polar Fields in 2026: An Unusually Weak Level Across the Last Five Solar Cycles
Wang, Ruihui
Jiang, Jie
Luo, Yukun
Solar and Stellar Astrophysics
Solar polar fields are essential for the solar cycle and the heliospheric magnetic field. Cycle 25 is now entering its declining phase, the critical period during which most of the cycle's polar fields are established. Therefore, reliable polar-field prediction is now especially important. Polar-field evolution is governed by the poleward transport of already-emerged active-region (AR) flux over a timescale of a few years. Thus, surface flux-transport models can reliably provide one-year predictions without requiring information about future AR emergence. Our prediction method is validated using simulations of the surface magnetic field from 2020-2025 and hindcasts of the 2023-2024 polar fields, employing a newly constrained profile of the meridional flow. Using the most recent HMI synoptic magnetogram as the initial condition, we predict the polar-field evolution from October 2025 to October 2026. The southern polar field is predicted to strengthen gradually, while the northern field is expected to decline sharply until March 2026 due to some ARs with abnormal polarity. By that time, the northern polar field becomes exceptionally weak, and the southern field remains relatively weak, raising concerns about the polar-field strength at the cycle 25/26 minimum and the amplitude of cycle 26.
title Prediction of the Solar Polar Fields in 2026: An Unusually Weak Level Across the Last Five Solar Cycles
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2512.17359