Kim et al. (2026) Non-stationary atmospheric pathways limit seasonal predictability of Eurasian autumn snow impacts on East Asian winter temperature

Identification

• Journal: npj Climate and Atmospheric Science
• Year: 2026
• Date: 2026-08-31
• Authors: OkYeon Kim, Suyeon Moon
• DOI: 10.1038/s41612-026-01529-y

Research Groups

• Climate Services and Research Department, APEC Climate Center, Busan, South Korea.

Short Summary

This study examines the non-stationary atmospheric pathways that limit seasonal predictability of Eurasian autumn snow impacts on East Asian winter temperature. The results show that the endpoint relationship between October Eurasian snow and EA winter temperature remains comparatively robust across periods, while the intermediate pathway links are substantially less stable.

Objective

• Investigate the reorganization of dynamical pathways linking autumn snow to winter climate variability.
• Evaluate the process-level reproducibility of these pathways in a seasonal forecast model (ECMWF SEAS5).

Study Configuration

• Spatial Scale: Eurasian and East Asian regions, with a focus on mid-latitudes.
• Temporal Scale: Autumn (October) to winter (December, January, February), with a 21-year moving window analysis.

Methodology and Data

• Models used: ECMWF SEAS5 hindcasts.
• Data sources: Satellite-based snow products (NOAA, ESA, ERA5), atmospheric reanalysis fields (ERA5), and observational temperature data.

Main Results

• The coupled October Eurasian snow predictor is more closely linked to EA winter temperature than the basin-mean total snow index.
• The intermediate pathway links show substantial non-stationarity: tropospheric circulation adjustment weakens, and the snow-WAFz and WAFz-AO10 relationships are weak, vertically and seasonally dependent, and not consistently significant across periods.
• AO10-related circulation anomalies remain evident, but their regional projection over East Asia is spatially reorganized.

Contributions

• This study provides a process-based interpretation of why Eurasian autumn snow remains a meaningful but non-stationary source of EA winter predictability.
• The results highlight the importance of considering pathway-stage redistribution rather than simple loss of snow forcing or stratospheric causality.

Funding

• APEC Climate Center (APCC) research project.

Citation

@article{Kim2026Nonstationary,
  author = {Kim, OkYeon and Moon, Suyeon},
  title = {Non-stationary atmospheric pathways limit seasonal predictability of Eurasian autumn snow impacts on East Asian winter temperature},
  journal = {npj Climate and Atmospheric Science},
  year = {2026},
  doi = {10.1038/s41612-026-01529-y},
  url = {https://doi.org/10.1038/s41612-026-01529-y}
}