干侵入在皖北暴雨天气过程中的特征分析

通过对2005年8月13日发生在淮北地区的大暴雨天气过程的分析,探讨此次暴雨天气形成过程中干侵入的主要特征。结果表明,在此次暴雨过程中以相对湿度≤60%,位涡值0.50.8 PVU作为干冷空气入侵暖湿气流的特征值;在此次暴雨过程中,高纬度对流层顶附近的高位涡空气具有沿着等位温线密集区下滑的特征,且此次过程还具有层结不稳定结构;CAPE与暴雨中心相对应,CAPE的变化反映了暴雨天气过程的演变。干侵入是此次暴雨天气发生的催化剂,应在天气预报中引起足够的重视。

Dry Intrusion Features of Heavy Rainstorm in North Anhut

Through analyzing the heavy rainstorm process in North Anhui Province on August 1-3,2005,the main dry intrusion features were discussed.As indicated by the results,with the relative humidity ≤60% and PV value of 0.5-0.8 PVU as the eigenvalue of this dry intrusion,the high PV air near the high-altitude troposphere glided along the intensive area of potential temperature lines,the stratification was unstable;CAPE corresponded with the rainstorm center,its change reflected the evolution of rainstorm process.Dry intrusion catalyzed this rainstorm,which thus should be paid enough attention to.