一次强对流天气的触发机制与演变过程分析——基于多源观测数据的个例研究

Analysis of the Trigger Mechanism and Evolution Process of a Severe Convective Weather Event—A Case Study Based on Multi-Source Observation Data

摘要: 采用地面气象观测站网、区域自动气象站、风云系列气象卫星、新一代天气雷达及MICAPS业务系统等多源观测资料，对2021年5月2日至3日仁寿县区域性强降雨天气过程开展综合诊断分析。研究结果表明：该过程具有显著的暖区降水与系统性降水复合特征。初期在高温高湿背景下，大气不稳定能量积聚触发分散性强对流天气；后期受冷暖空气交汇影响，大气层结不稳定性加剧，引发区域性持续强降水。关键影响因子包括：低空西南急流持续输送充沛水汽、强垂直风切变促进对流发展、中低层明显辐合抬升运动。这些要素的时空耦合作用共同构成了此次极端降水天气的物理机制。预报偏差主要来源于对冷空气南下引发的降水增幅效应估计不足以及对不稳定能量二次释放产生的降水强度研判不够充分。

Abstract: Using multi-source observational data from ground meteorological stations, regional automatic weather stations, Fengyun series meteorological satellites, new-generation weather radars, and the MICAPS operational system, this study conducts a comprehensive diagnostic analysis of the regional heavy rainfall event in Renshou County from May 2 to 3, 2021. The results indicate that this event exhibited distinct characteristics of warm-area precipitation combined with systematic precipitation. Initially, under conditions of high temperature and humidity, accumulated atmospheric instability triggered scattered severe convective weather. Later, influenced by the convergence of cold and warm air masses, atmospheric stratospheric instability intensified, leading to sustained regional heavy rainfall. Key influencing factors included: sustained transport of abundant moisture by the low-level southwest jet stream, strong vertical wind shear promoting convective development, and pronounced convergence-lifting motions in the middle and lower troposphere. The spatiotemporal coupling of these elements collectively formed the physical mechanism behind this extreme precipitation event. Forecast errors primarily stemmed from underestimating the precipitation amplification effect triggered by the southward movement of cold air and insufficient assessment of precipitation intensity resulting from secondary releases of instability energy.