华北地区夏季一次致雹强风暴的分析

文章对2007年7月9日下午华北中部地区一次区域性强对流性天气过程中风暴单体的短时临近预报方法进行研究。对实际探测资料和数值模式产品的分析发现以下特点：高空槽将由后倾槽转为前倾槽、底层不稳定层结会明显加大,在地面冷锋东移冲击下在沿锋面伸展的露点锋区内可能将有强雷暴系统发展;全球谱模式T213、中尺度MM5模式的产品对区域性对流天气发生、影响的区域有3h以上的预报时效,具有一定的区域预报能力,但落点预报能力明显有限。对多普勒雷达产品的分析表明：多普勒雷达产品对灾害性天气的落点、影响区域具有30分钟以上的预测时效,通过基本反射率、相对风暴速度等产品的特征判断一个对流风暴具有类似强降水超级单体特征,可据此预报该雷暴中心经过区域可能有冰雹、大风等灾害性天气;风廓线产品在3-7km高度层内垂直风切变矢量具有顺时针旋转特点,有利于风暴发展成强风暴;风暴追踪信息基本能反映风暴移动路径的变化,其路径预报时效最长达1h,在雷暴初期预报准确率随雷暴数目增多、移动异向性明显而越低,在雷暴中后期则明显提高并对临近预报具有明显的指示性。

Analysis on a Severe Storm Caused Haily in North China Region

A local convective weather occurred in Hebei Province on 9 July 2007,we studied some ways of short-range prediction about a convective storm＇s path and incidence.Analysis of the exploration data and product of numerical Model showed the tilted trough became forward from backward,and stratification became more judder on bottom layer;Strong storm could create in a local area of dew-point line moist tongue extending along cold front.Based on some T213 Model and MM5 Model＇s products we forecasted the local of convective storm before 3hours,but had limited ability on short-range prediction about the idiographic place of severe weather.Based on the Doppler radar products,including Base Reflectivity and Storm Relative Vel Map,we distinguished the storm had some similar characters about HP supercell;VAD product emerged perpendicular wind shear spin round on clock-wise between 3—7km high level;Storm Tracking Information showed the change of storm＇s path,its forecast path had lower accuracy with more storms and different direction of movement during storms＇ earlier time,but had higher accuracy during storms＇ middle and later time,so it could provid helpfulness on short-range prediction.