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<p>Strong near-surface winds pose risks to infrastructure, agriculture, and wind energy systems in Southwest China, yet their long-term variability and drivers in complex terrain remain uncertain. Using a reconstructed hourly 10-m wind dataset from 365 stations (1959–2021), we quantify the climatology, trends, and large scale controls of strong-wind days (SWD). We map spatiotemporal patterns and station-level trends, and apply EOF analysis to the spring SWD series, relating the leading modes to 500&#xa0;hPa geopotential height and the East Atlantic/West Russia (EA/WR) teleconnection. SWD exhibit a robust basin-plateau dipole, with multiyear means ranging from 10.1 d/yr in the northeastern Sichuan Basin to 44.7 d/yr along the southwestern Yunnan-Guizhou plateau. Significant trends occur at 103 stations, with 93(25.5%) decreasing and 10 (2.7%) increasing; the fastest changes reach − 2.8 and + 2.4 d/decade. Spring shows the highest frequency and variability, and the first three spring EOF modes explain 52.5% of the variance. The basin–plateau dipolar mode (EOF2) is linked to an EA/WR-like 500&#xa0;hPa height tripole pattern and its PC2 correlates with the spring EA/WR index (<i>r</i> = 0.44). Mechanistically, during the EA/WR positive phase the upper-level jet shifts poleward and the East Asian trough weakens and shifts westward, thereby reducing meridional height gradients, baroclinicity, and frontal passages, whereas orographic channeling and downslope flow sustain or locally increase SWD in the west. The negative phase produces opposite anomalies and enhanced SWD, especially in the east. These results identify and quantify a dipolar SWD pattern and support a teleconnection–topography coupling mechanism. These hotspots imply elevated exposure of transport corridors, power transmission infrastructure, and mountain–basin agro-ecosystems to damaging gusts, underscoring the need for targeted early warning and region-specific risk management.&#xa0;</p> Graphical Abstract <p></p> <p><b>Graphical abstract descriptions</b></p> <p>This graphical abstract summarizes a station-based assessment of spring SWD across Southwest China (1960–2021). The study area includes the Sichuan Basin, the Hengduan Mountains, and the Yunnan–Guizhou Plateau. This circulation–orography setting provides the physical context for variability associated with the midlatitude jet and the East Asian trough. Spatial maps reveal higher SWD over the Hengduan–Yunnan–Guizhou highlands and fewer events in the Sichuan Basin, with significant trends at many stations. Empirical orthogonal function analysis isolates a coherent spring mode (PC2), its correlation with 500 hPa geopotential height exhibits the canonical EA/WR positive-phase tripole over Eurasia. The right panel sketches the dynamics: during EA/WR positive, the upper level jet shifts poleward and the East Asian trough weakens and shifts westward, lowering the 30–40° N meridional height gradient, baroclinicity, and frontal passages. Near-surface winds and SWD decrease in the eastern basin, whereas orographic channeling and downslope flow maintain exceedances in western plateaus and valleys. During EA/WR negative, the jet shifts equatorward and the trough deepens/eastward-extends, strengthening baroclinicity and fronts and producing increased SWD, with a stronger response in the east.</p>

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Dipolar Spatiotemporal Variation of Strong-Wind Days across Southwest China Under Circulation–Topography Coupling

  • 期刊论文

  • 发表日期：

    2026年1月20日

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  • Zhang Jiyong,
  • Wang Hao,
  • Zhao Chunhui,
  • Yu Gao,
  • Liu Donghui,
  • Gao Yiwen

摘要

Strong near-surface winds pose risks to infrastructure, agriculture, and wind energy systems in Southwest China, yet their long-term variability and drivers in complex terrain remain uncertain. Using a reconstructed hourly 10-m wind dataset from 365 stations (1959–2021), we quantify the climatology, trends, and large scale controls of strong-wind days (SWD). We map spatiotemporal patterns and station-level trends, and apply EOF analysis to the spring SWD series, relating the leading modes to 500 hPa geopotential height and the East Atlantic/West Russia (EA/WR) teleconnection. SWD exhibit a robust basin-plateau dipole, with multiyear means ranging from 10.1 d/yr in the northeastern Sichuan Basin to 44.7 d/yr along the southwestern Yunnan-Guizhou plateau. Significant trends occur at 103 stations, with 93(25.5%) decreasing and 10 (2.7%) increasing; the fastest changes reach − 2.8 and + 2.4 d/decade. Spring shows the highest frequency and variability, and the first three spring EOF modes explain 52.5% of the variance. The basin–plateau dipolar mode (EOF2) is linked to an EA/WR-like 500 hPa height tripole pattern and its PC2 correlates with the spring EA/WR index (r = 0.44). Mechanistically, during the EA/WR positive phase the upper-level jet shifts poleward and the East Asian trough weakens and shifts westward, thereby reducing meridional height gradients, baroclinicity, and frontal passages, whereas orographic channeling and downslope flow sustain or locally increase SWD in the west. The negative phase produces opposite anomalies and enhanced SWD, especially in the east. These results identify and quantify a dipolar SWD pattern and support a teleconnection–topography coupling mechanism. These hotspots imply elevated exposure of transport corridors, power transmission infrastructure, and mountain–basin agro-ecosystems to damaging gusts, underscoring the need for targeted early warning and region-specific risk management. 

Graphical Abstract

Graphical abstract descriptions

This graphical abstract summarizes a station-based assessment of spring SWD across Southwest China (1960–2021). The study area includes the Sichuan Basin, the Hengduan Mountains, and the Yunnan–Guizhou Plateau. This circulation–orography setting provides the physical context for variability associated with the midlatitude jet and the East Asian trough. Spatial maps reveal higher SWD over the Hengduan–Yunnan–Guizhou highlands and fewer events in the Sichuan Basin, with significant trends at many stations. Empirical orthogonal function analysis isolates a coherent spring mode (PC2), its correlation with 500 hPa geopotential height exhibits the canonical EA/WR positive-phase tripole over Eurasia. The right panel sketches the dynamics: during EA/WR positive, the upper level jet shifts poleward and the East Asian trough weakens and shifts westward, lowering the 30–40° N meridional height gradient, baroclinicity, and frontal passages. Near-surface winds and SWD decrease in the eastern basin, whereas orographic channeling and downslope flow maintain exceedances in western plateaus and valleys. During EA/WR negative, the jet shifts equatorward and the trough deepens/eastward-extends, strengthening baroclinicity and fronts and producing increased SWD, with a stronger response in the east.