黄淮气旋引发山东两次暴雨过程的对比分析

利用常规天气图资料和NCEP再分析资料,对2002年5月14日和2013年5月26日发生在山东的两次气旋暴雨过程进行对比分析。结果表明:两次过程均是在高空低槽、西南涡及地面气旋共同作用下形成的,但气旋形成方式、高低空急流及空气不稳定层结有明显的差异。前者为倒槽锋生型,空气层结呈对流性稳定,冷暖空气在近地层交汇使得等熵面陡立触发垂直涡度增长和湿对称不稳定能量释放造成暴雨,后者为静止锋上冷暖平流加强形成气旋波,冷空气团叠加在暖湿气流之上通过降低低层稳定度强迫暖空气抬升触发对流不稳定能量释放造成暴雨;前者高空急流偏南,后者高低空急流配合较好激发出次级环流从而使上升运动增强;两次过程暴雨落区均在850hPa高能轴顶端冷暖空气交汇处。

Comparative Analysis of Two Heavy Rain Events Induced by Huanghe Cyclone in Shandong

Based on the conventional weather chart data and NCEP reanalysis data, two cyclone induced rainstorm events on 14 May 2002 and 26 May 2013 in Shandong are analyzed. The results show that: the two processes were affected by the upper level trough, southwest vortex, and surface cyclone, but there were significant differences in the path of cold air, upper and lower level jets and air instability stratification. During the rain process of the former, the invasion of cold air was from bottom to top, and the atmospheric stratification was convective stability; the vertical isentropic surface triggered the growth of vertical vorticity and the energy release of moist symmetrical instability. The latter was cyclone waves resulted from the enhancement of cold/warm advection above a stationary front, in which the convective instability energy released through reducing the lower level stability forces warm air to lift, which was superimposed by the cold air mass above the warm moist air flow.