Lu et al. (2026) The Impact of Urban Heat Island on Extreme Rainfall Events in Presummer Over the Pearl River Delta Metropolitan Region Under Different Synoptic Systems

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Identification

• Journal: International Journal of Climatology
• Year: 2026
• Date: 2026-08-31
• Authors: Xi Lu, Tiantong Yang, Hailai Duan, Yu Du
• DOI: 10.1002/joc.70570

Research Groups

• Guangdong Provincial Key Laboratory of Urbanization and Geo-Hazard Mitigation
• School of Atmospheric Sciences, Sun Yat-sen University
• State Key Laboratory of Hydrometeorological Prediction of Lancang-Mekong River Basin

Short Summary

This study examines the impact of urban heat island (UHI) effects on extreme rainfall events in the Pearl River Delta metropolitan region under different synoptic systems. The results show that UHI influences vary according to differing synoptic conditions.

Objective

• Investigate how UHI effects influence the spatial distribution and diurnal variation of presummer extreme rainfall events (EREs) in the PRD across three dominant synoptic categories: Warm-Sector (WS), Front/Shear Line (FS), and Cyclonic-Anomaly (CA) systems.

Study Configuration

• Spatial Scale: Metropolitan region of the Pearl River Delta, China.
• Temporal Scale: 2008-2021 period with a focus on presummer extreme rainfall events.

Methodology and Data

• Models used: K-means clustering algorithm for data analysis.
• Data sources: Rain gauge observations from 2008 to 2021.

Main Results

• The association between UHI and EREs varies according to differing synoptic conditions.
• WS EREs: Strong UHI is accompanied by a shift in peak rainfall intensity from the early morning to the afternoon, with intensified precipitation concentrated in the northern Pearl River Estuary during the afternoon.
• FS EREs: Strong UHI conditions are associated with a northward retreat of the front and intensified sea breezes in the afternoon, with precipitation primarily concentrated over inland urban and downwind areas within the PRD region.
• CA EREs: A reversed diurnal rainfall pattern under strong UHI conditions, with rainfall intensification occurring in coastal areas during the morning.

Contributions

This study provides observational evidence to enhance fine-scale predictions of urban extreme rainfall and offers practical insights for urban flood risk mitigation and regional meteorological disaster prevention.

Funding

• Guangdong Provincial Key Laboratory of Urbanization and Geo-Hazard Mitigation (Grant No. 2021GK102)
• National Natural Science Foundation of China (Grant No. 41975040)

Citation

@article{Lu2026Impact,
  author = {Lu, Xi and Peng, Wenxing and Yang, Tiantong and Duan, Hailai and Du, Yu},
  title = {The Impact of Urban Heat Island on Extreme Rainfall Events in Presummer Over the Pearl River Delta Metropolitan Region Under Different Synoptic Systems},
  journal = {International Journal of Climatology},
  year = {2026},
  doi = {10.1002/joc.70570},
  url = {https://doi.org/10.1002/joc.70570}
}