7.20—7.24川西南连续暴雨天气小时强降水时空分布特征

Spatiotemporal Distribution of Hourly Heavy Rainfall during the Continuous Rainstorm in Southwestern Sichuan from July 20 to 24

  • 摘要: 利用2024年7月19日20时—24日20时川西南逐小时降水和地形资料,分析了小时强降水(Hourly Heavy Rainfall,HHR)的时空分布及不同历时强降水事件(Heavy Rainfall Event,HRE)的统计特性。结果表明:(1)此次暴雨过程具有持续时间长、影响范围广、累计雨量大、降水频次多且短时强降水显著的特点;(2)HHR受地形影响显著,高值区主要分布在龙门山沿山、青衣江流域和峨眉山等地,双台风和地形效应有利于其增幅与持续;(3)HHR共出现4次峰值,第4次最强,受高原切变影响最大,最大降雨量达178.3 mm;(4)长历时HRE占比最高,降水量多超200 mm,短、中历时HRE降水量多在20, 50) mm和50, 100) mm区间,最大降水量随历时增加而增加;(5)空间上,长历时HRE的降水量和频次高于短、中历时,雅安中部和峨眉山为高值区。

     

    Abstract: Based on hourly precipitation and topographical data in southwestern Sichuan, the spatiotemporal distribution of hourly heavy rainfall (HHR) and the statistical characteristics of heavy rainfall events (HRE) with different durations were analyzed. The results show that: (1)This heavy rainfall event was characterized by its prolonged duration, extensive impact area, large cumulative precipitation, high frequency of rainfall events, and significant short-duration intense precipitation. (2) HHR was influenced by topography, with high-value areas primarily distributed along the Longmen Mountains, the Qingyi River Basin, and Mount Emei. The dual typhoon effect and topographic forcing contributed to the intensification and persistence of the rainfall. (3) HHR experienced four peaks, with the fourth peak being the strongest and most active under the influence of the plateau shear line, reaching a maximum rainfall of 178.3 mm. (4) Long-duration HREs had the highest proportion, with precipitation mostly exceeding 200 mm. The precipitation amounts of short- and medium-duration HREs were mostly in the ranges of 20, 50) and 50, 100) mm, respectively, and the maximum precipitation increased with the duration. (5) Spatially, long-duration HREs had higher precipitation and frequency than short- and medium-duration HREs, with high-value areas located in the central part of Ya’an and Mount Emei.

     

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