宝鸡市陇县冰雹气候特征和新型预警指标研究

利用1980—2016年陇县的冰雹资料,采用数理统计方法,分析近37年来陇县冰雹时空特征;利用多普勒雷达资料对风暴发展特征进行统计分析,探讨上游风暴对陇县风暴的指标性和大小冰雹的回波特征、区别。结果表明,陇县冰雹频次5.2次/a,其中直径2 cm的大冰雹频次为1.1次/a,冰雹主要集中在6、7、8月,最多发生于14∶00—17∶00;陇县冰雹主要在北部,上游交界的乡镇形成东西向带状多雹区;陇县冰雹均自上游组合反射率因子(CR)≥45 dBz风暴移入陇县发展,自西北路华亭移来占主体,单体移入陇县时间为18~100 min;风暴CR≥60 dBz、出现旁瓣回波和三体散射对应有大冰雹,风暴CR≥55 dBz、出现旁瓣回波对应有小冰雹;关注上游CR≥45 dBz风暴动向,可提前预警陇县冰雹。雷达冰雹指数(HI)、风暴追踪信息(STI)产品可参考发布预警。

Study on Climatic Characteristics and New Early Warning Index of Hail in Longxian County of Baoji City

Using the hail data of Longxian in 1980-2016,the mathematical characteristics of hail in Longxian County were analyzed by mathematical statistics.Using the Doppler radar data to analyze the characteristics of storm development,and discuss the characteristics of upstream storm on the indicators of Longxian storm and the echo characteristics of hail.The results showed that the hail frequency was 5.2 times/a in Longxian County,and the hail frequency was 1.1 times/a with a diameter greater than 2 cm.The hail was mainly concentrated in June,July,August and occurred at 14:00-17:00.The hail of Longxian County was mainly in the north,towns upstream junction formed the east-west banded hail area.The hail of Longxian County from the upstream CR ≥ 45 dBz storm into the development of Longxian County,since the northwest Huating moved to the main body,monomer moved to Longxian County for 18-100 min.Side echo was related to small hail while thunderstorm C R≥ 55 dBz,and further three body scattering means large hail while thunderstorm CR≥ 60dBz.Therefore,the motion of upstream hail (CR≥ 45 dBz) could indicate the hail produced in Longxian County.Hail index(HI) and storm tracking information(STI) from radar can be considered as a reference for releasing warning of hail.