Zhang et al. (2026) K-means clustering analysis of autumn rainfall patterns over West China and their underlying mechanisms

Identification

• Journal: Atmospheric Research
• Year: 2026
• Date: 2026-01-04
• Authors: Han Zhang, Ke Fan
• DOI: 10.1016/j.atmosres.2026.108745

Research Groups

• School of Atmospheric Sciences, Sun Yat-sen University
• Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai)

Short Summary

This study identified three dominant anomalous patterns of autumn rainfall over West China using k-means clustering and investigated their underlying atmospheric and oceanic teleconnection mechanisms, primarily linking them to tropical Pacific and North Atlantic sea surface temperature anomalies.

Objective

• To identify three dominant anomalous patterns of autumn rainfall over West China using k-means clustering analysis.
• To investigate the underlying atmospheric circulation and oceanic teleconnection mechanisms driving these rainfall patterns.

Study Configuration

• Spatial Scale: West China (25°–37°N, 100°–111°E)
• Temporal Scale: Autumn rainfall, interannual and decadal variability

Methodology and Data

• Models used: K-means clustering analysis, Linear Baroclinic Model, ECHAM5 model
• Data sources: Sea surface temperature (SST) anomalies (tropical central-eastern Pacific, eastern North Atlantic), snow cover over the Tibetan Plateau

Main Results

• Three dominant anomalous patterns of autumn rainfall over West China were identified:
  1. A region-wide positive precipitation anomaly.
  2. A south-positive–north-negative dipole pattern.
  3. A west-positive–east-negative dipole pattern.
• The first two patterns account for most of the explained variance annually.
• The first pattern is primarily influenced by a strengthened and westward-extended western Pacific subtropical high and an intensified East Asian subtropical jet, mainly driven by negative tropical central-eastern Pacific SST anomalies. Reduced Tibetan Plateau snow cover plays a moderating role.
• The second pattern is associated with an anomalous anticyclone over the South China Sea and a weakened, southward-shifted East Asian subtropical jet, linked to El Niño-like tropical central-eastern Pacific SST anomalies and cold eastern North Atlantic SST anomalies.

Contributions

• Systematically identified and characterized the dominant anomalous patterns of autumn rainfall over West China using k-means clustering.
• Elucidated the distinct atmospheric circulation and oceanic teleconnection mechanisms for each identified pattern, linking them to specific SST anomalies and atmospheric systems.
• Verified the proposed mechanisms using numerical models (Linear Baroclinic Model and ECHAM5).

Funding

• Not specified in the provided text.

Citation

@article{Zhang2026Kmeans,
  author = {Zhang, Han and Fan, Ke},
  title = {K-means clustering analysis of autumn rainfall patterns over West China and their underlying mechanisms},
  journal = {Atmospheric Research},
  year = {2026},
  doi = {10.1016/j.atmosres.2026.108745},
  url = {https://doi.org/10.1016/j.atmosres.2026.108745}
}