State-resolved multimodal contributions to stratospheric polar vortex predictability
Abstract
The dynamical basis of stratospheric polar vortex (SPV) predictability remains unclear, particularly the relative roles of persistence, structural variability, and cross-level coupling. Here we combine eigen microstate theory with mesoscopic Granger-causality analysis of ERA5 geopotential height fields to quantify the predictive contributions of eigen microstates. We show that short-term predictability is dominated by the persistence of the leading stratospheric state, whereas higher-order stratospheric structures and tropospheric variability provide additional predictive information at subseasonal leads. Including these additional states increases the all-winter 30-day prediction correlation from 0.24 to 0.33 and reduces forecast error. These contributions exhibit strong lead-time dependence and vary between winters with and without sudden stratospheric warmings. Part of this predictive information overlaps with that contained in preceding 100 hPa eddy heat flux, linking state-resolved predictability to wave-related circulation variability. Our results unify SPV predictability within a multimodal, state-resolved framework and provide a physically interpretable pathway.
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BibTeX
@misc{yang2026stateresolved,
title = {{State-resolved multimodal contributions to stratospheric polar vortex predictability}},
author = {Shuo Yang and Dan Zhao and Tingting Xue and Chunhua Zeng and Yongwen Zhang and Xiaosong Chen},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2605.13417},
eprint = {2605.13417},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.13417},
}
RIS
TY - UNPB
TI - State-resolved multimodal contributions to stratospheric polar vortex predictability
AU - Shuo Yang
AU - Dan Zhao
AU - Tingting Xue
AU - Chunhua Zeng
AU - Yongwen Zhang
AU - Xiaosong Chen
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2605.13417
UR - https://arxiv.org/abs/2605.13417
AB - The dynamical basis of stratospheric polar vortex (SPV) predictability remains unclear, particularly the relative roles of persistence, structural variability, and cross-level coupling. Here we combine eigen microstate theory with mesoscopic Granger-causality analysis of ERA5 geopotential height fields to quantify the predictive contributions of eigen microstates. We show that short-term predictability is dominated by the persistence of the leading stratospheric state, whereas higher-order stratospheric structures and tropospheric variability provide additional predictive information at subseasonal leads. Including these additional states increases the all-winter 30-day prediction correlation from 0.24 to 0.33 and reduces forecast error. These contributions exhibit strong lead-time dependence and vary between winters with and without sudden stratospheric warmings. Part of this predictive information overlaps with that contained in preceding 100 hPa eddy heat flux, linking state-resolved predictability to wave-related circulation variability. Our results unify SPV predictability within a multimodal, state-resolved framework and provide a physically interpretable pathway.
ER -