台州夏季短时强降水日变化特征及其成因初探

Diurnal Variation and Causes of Summer Short-Duration Heavy Rainfall in Taizhou

摘要: 本文利用2014~2023年台州市98个气象站点的逐小时降水资料，统计分析了台州市夏季短时强降水的降水量PA、降水频率PF和降水强度PI的日变化特征及区域差异，并利用ERA5再分析资料对一次极端短时强降水过程进行了初步分析。研究结果表明，台州市夏季短时强降水的PA、PF日峰值的空间分布相似。PA和PF的日变化均呈现为午后单峰型，而PI呈双峰结构。PA日变化的日峰值受PF和PI共同影响，受PF的影响更为显著。L1类短时强降水对夏季短强总降水量的贡献更大，其中中部地区的贡献尤为显著；各子区域L1类短时强降水和L2类极端短时强降水的PA、PF的日变化呈现为单峰型分布，而西部地区短时强降水更为活跃。在动力抬升机制、不稳定能量、水汽条件、地形强迫等方面的良好配合下，易发生极端短时强降水。

Abstract: This study utilizes hourly precipitation data from 98 meteorological stations in Taizhou during 2014~2023 to statistically analyze the diurnal variation and regional differences of precipitation amount (PA), precipitation frequency (PF) and precipitation intensity (PI) for summer short-duration heavy rainfall events in Taizhou. Additionally, ERA5 reanalysis data were employed to conduct a preliminary analysis of one extreme short-duration heavy rainfall. Results indicate that the spatial distributions of peak values for PA and PF in Taizhou’s summer short-duration heavy rainfall are similar. Both PA and PF exhibit a single-peak diurnal pattern, while PI shows a double-peak structure. The peak of PA is influenced by both PF and PI, with PF exerting a more significant effect. Short-duration heavy rainfall L1 contributes more significantly to total summer short-duration heavy rainfall, with the central region exhibiting the highest contribution. Diurnal variations of PA and PF for L1 and extreme short-duration heavy rainfall L2 in each subregion follow a single-peak distribution, while western regions experience more active short-duration heavy rainfall. Extreme short-duration heavy rainfall is prone to occur under the synergistic interaction of dynamic lifting mechanisms, instability energy, moisture conditions, and topographic forcing.