2022年7月博州一次暴雨过程分析及预报评估

Analysis and Forecast Evaluation of a Heavy Rainfall Event in Bozhou in July 2022

摘要: 2022年7月5日博州出现暴雨，落区集中在温泉东部至博乐北部，最大日降水量39.5毫米，具有强度大、持续时间长且有三个降水峰值的特征。本文分析得出：此次暴雨由冷锋锋面降水叠加对流性降水形成，大尺度环流背景中，200 hPa南亚高压强盛提供背景场，500 hPa副高北上与北部冷涡形成冷暖对峙，极锋急流与副热带急流合并增强水汽输送，低层切变线、地面锢囚锋及天山地形共同强化抬升动力。物理量场显示湿层深厚、水汽辐合显著，存在对流不稳定，雷达回波显示低质心回波，降水效率高。对比ECMWF、CMA_GFS、CMA_MESO和NCEP模式降水预报偏弱，日常工作中需要加强对天气形势的研判能力，结合多家模式极端值综合预报。

Abstract: A heavy rainfall event occurred in Bozhou on July 5, 2022, with the rainfall area concentrated from eastern Wenquan to northern Bole. The maximum daily precipitation reached 39.5 mm, characterized by high intensity, long duration, and three precipitation peaks. The analysis shows that this heavy rainfall was formed by the superposition of cold-front precipitation and convective precipitation. In the large-scale circulation background, the strong South Asian High at 200 hPa provided the background field; the northward movement of the subtropical high at 500 hPa formed a cold-warm confrontation with the northern cold vortex; the merger of the polar front jet and the subtropical jet enhanced water vapor transport; and the low-level shear line, surface occluded front, and Tianshan terrain jointly strengthened the lifting dynamics. The physical quantity field indicates a deep wet layer, significant water vapor convergence, and convective instability. Radar echoes show low-centroid echoes with high precipitation efficiency. Compared with observations, the precipitation forecasts of ECMWF, CMA_GFS, CMA_MESO, and NCEP models were weaker. In daily work, it is necessary to strengthen the ability to judge weather situations and integrate the extreme values of multiple models for comprehensive forecasting.