贵阳地区暴雨和冰雹湿位涡对比诊断分析

应用湿位涡理论,对1997~2004年贵阳地区的6次冰雹天气和2004年贵阳地区的6次暴雨过程分别合成,进行诊断分析.结果表明:在θe陡立密集区,θe面陡立导致湿斜压涡度发展,密集区内冰雹和暴雨容易发生;MPV1<0和MPV2>0的配置,易产生暴雨,且MPV1数值比MPV2数值大一个量级,说明暴雨发生时正压过程起着主导的作用,而湿斜压项的高值区与暴雨的落区相一致.冰雹发生时,降雹区的低层为对流层不稳定层结下(MPV1<0),有MPV2>0,使湿斜压不稳定增强,倾斜涡度得以发展,冰雹易出现在高值中心偏南一侧,(即MPV1<0与MPV2高值中心交界处),冰雹出现后,高值中心强度减弱.

Comparative analysis of moist potential vorticity characteristics between heavy rainfall and hail in guiyang

Based on the moist vorticity theory,six hail events from1997 to 2004 and six heavy rain processes in 2004 in Guiyang are synthesized and diagnosed.The results show that heavy rain and hail often occur in the stiff and dense section of moist isentropes because the stiff moist isentropes can lead to the development of slantwise vorticity.It is favourable for causing a heavy rain when MPV1<0 and MPV2>0,and MPV1 is an order bigger than MPV2,which means barotropic process is dominant factor when a heavy rain occurs.The maximum region of moist baroclinic term is consistent with the location of the heavy rain.The lower level of hail falling is convective instable(MPV1<0 and MPV2>0 which strengthen the moist baroclinic instability,foster the development of the slantwise vorticity.The hail falls always in the southward region of the maximum center(the interface between MPV1<0 and MPV2>0,and the intensity of the maximum center weakened after the hail fell.