一次西南涡暴雨的等熵位涡特征分析

应用常规资料和0.5°×0.5°的GFS再分析资料，对2010年7月19日发生在河北山东的一次西南涡暴雨过程产生的条件及其等熵位涡演变特征进行了分析。结果表明：西南涡、高、低空急流、地面低压是这次暴雨过程的主要影响系统；等熵位涡的演变和形态对冷空气活动有很好的示踪作用；等熵位涡中心两侧气流辐合，利于地面低压发展；高位涡下传，导致了大暴雨产生；等熵位涡大值区及移动方向与降水落区有很好的对应关系。

Analysis of isentropic potential vorticity for a heavy rain caused by a southwestern low vortex

Based on the conventionally meteorological data and GFS reanalysis data with 0.5°×0.5° resolution, a heavy rainstorm on June 19, 2010 caused by a southwest low vortex in Hebei procince and Shandong province were analyzed, including its forming conditions and evolution of isentropic potential vorticity. The results show that the southwestern low vortex, high jet, low jet and surface low pressure are the main weather systems of this process．The evolution and forming of isentropic potential vorticity are indicative to activity status of cold air. Convergence of airflow on both south and north sides of the isentropic potential vorticity center is favorable to development of surface low pressure. High potential vorticity moves downward, which leads to the heavy rain. Precipitation area has a better corresponding relationship with area of large isentropic potential vorticity values and its moving direction.