山东半岛北部090717特大暴雨分析

对2009年7月17日夜间山东半岛北部的特大暴雨过程进行了总结分析。环流形势分析表明:副高边缘暖湿气流、冷空气和低涡切变线的共同影响,是造成此次半岛北部特大暴雨的主要原因,暴雨区与588线和切变线位置密切相关;17日夜间副高长时间稳定少动是造成此次强降水非常重要的原因之一;不稳定的大气层结、K≥36℃对夏季大尺度系统背景下局地强对流的预报具有指示意义。雷达资料分析表明,此次特大暴雨是混合性降水,从渤海不断有平行的条状强降水回波带生成发展东移,回波带中有对流单体不断加强,强降水回波持续时间较长,导致特大暴雨的产生;对于局地强降水,数值预报产品预报的降水量远远小于实况,实际工作中要综合分析,不可偏信。

Analysis of 090717 Heavy Rain in Northern Area of Shandong Peninsula

A heavy rain at the northern part of Shandong Peninsula during night on 17 July,2009 was analyzed.Circulation situation analysis showed that: the combined effect of vice-high edge warm air,cold air and low vortex shear line is the main reason that caused the heavy rain.Rainfall area is closely related to 588 lines and the shear line position.Subtropical moved slowly is another main reason for the heavy rain.Unstable atmospheric stratification and K≥36℃ are indicative significance for such strong convective.Radar data analysis showed that this heavy rain is mixed precipitation.From the Bohai Sea,there have been parallel to generate strip development with a strong eastward shift of precipitation echoes.Echo with the convective cells has been strengthened,strong precipitation echo last long time,which lead to the production of heavy rain.For local heavy rainfall,numerical prediction of precipitation forecast products is far less than live,the actual work should not be biased.