Pan et al. (2025) Intraseasonal Variations in Spring East Asian Subtropical Jet: Role of Mid–High Latitude Wave Trains and Influence on Rainfall Anomalies in China

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Identification

• Journal: Journal of Climate
• Year: 2025
• Date: 2025-08-12
• Authors: Wenqi Pan, Jianqi Sun, Haixu Hong, Jiehua Ma
• DOI: 10.1175/jcli-d-25-0075.1

Research Groups

Not specified in the provided text.

Short Summary

This study identifies eight phases of the spring East Asian subtropical westerly jet (EAWJ) intraseasonal variability and demonstrates that its northward shift significantly increases precipitation and extreme weather events in the Yangtze–Huai River valley.

Objective

• To analyze the intraseasonal variability of the spring EAWJ and determine its influence on precipitation intensity, extreme precipitation events, and regional consecutive cloudy-rainy events (RCCREs) in the Yangtze–Huai River valley (YHRV).

Study Configuration

• Spatial Scale: Regional to Continental (East Asia, specifically the Yangtze–Huai River valley, Mongolia, Northeast China, and the Eurasian wave train from the Ural Mountains to East Asia).
• Temporal Scale: Spring season, focusing on intraseasonal periodicity of 10–30 days.

Methodology and Data

• Models used: Empirical Orthogonal Function (EOF) analysis, power spectrum analysis, and lead–lag correlation analysis.
• Data sources: 200-hPa zonal wind anomalies.

Main Results

• Identified eight phases of EAWJ intraseasonal variability (EAWJ_ISV) based on the first two dominant EOF modes (PC1 and PC2).
• Phases 1–4: Characterized by a northward EAWJ shift and positive zonal wind anomalies over Mongolia–Northeast China; this enhances moisture convergence and ascending motion over the YHRV, accounting for 71.2% of rainy days.
• Phases 5–8: Characterized by weakened water vapor transport and upward motion over the YHRV, accounting for 71.3% of dry days.
• Driver: The EAWJ_ISV is modulated by an intraseasonal wave train propagating southeastward from the Ural Mountains to East Asia.

Contributions

• Provides a mechanistic understanding of how the intraseasonal variability of the EAWJ modulates secondary atmospheric circulation to drive precipitation extremes in the Yangtze–Huai River valley.
• Links regional precipitation patterns in China to remote atmospheric forcing via the Eurasian mid–high latitude wave train.

Funding

Not specified in the provided text.

Citation

@article{Pan2025Intraseasonal,
  author = {Pan, Wenqi and Sun, Jianqi and Hong, Haixu and Ma, Jiehua},
  title = {Intraseasonal Variations in Spring East Asian Subtropical Jet: Role of Mid–High Latitude Wave Trains and Influence on Rainfall Anomalies in China},
  journal = {Journal of Climate},
  year = {2025},
  doi = {10.1175/jcli-d-25-0075.1},
  url = {https://doi.org/10.1175/jcli-d-25-0075.1}
}