宁波机场附近一次孤立强雷暴大风事件分析

利用区域自动气象站资料、天气雷达资料、宁波机场AWOS(automated weather observation system)资料和NCEP再分析资料等对2017年7月22日发生在宁波机场附近的一次孤立强雷暴大风环境条件和雷达回波特征进行分析。结果表明：1)雷暴大风发生在较强的对流有效位能、弱的垂直风切变和上层干燥近地面暖湿的大气层结配置下，海风锋是主要触发系统。2)雷暴大风发生时，地面出现明显冷池和中尺度雷暴高压。3)强反射率因子顶部高度快速下降，中层径向辐合达到18 m·s-1，低层速度辐散超过25 m·s-1等指标，对雷暴大风预警具有较好的指示意义。

Analysis on an isolated strong thunderstorm gale near Ningbo Airport

Based on automatic weather station data, weather radar data, AWOS (Automated Weather Observation System) data collected at Ningbo Airport, and NCEP reanalysis data, the physical parameter field and radar echo characteristics of an isolated strong thunderstorm gale that occurred near Ningbo Airport on 22 July 2017 are analyzed. The results show the thunderstorm gale is mainly triggered by sea breeze front. The upper dry air, as well as warm and moist air near the surface, generates unstable atmospheric stratification of strong convective available potential energy and weak vertical wind shear. Cold pool and mesoscale thunderstorm high appear on the surface when the thunderstorm gale occurred. Rapid decline of top height of strong reflectivity, radial convergence at middle layer reaching 18 m·s-1,and velocity divergence at lower layer exceeding 25 m·s-1 are good indicators for thunderstorm gale warning.