能量位涡在雷雨大风天气诊断分析中的应用

从大气基本运动方程及大气总能量概念出发,提出将大气动力学与能量天气学相结合的物理量——干能量位涡与湿能量位涡,并确定其守恒性.通过分析发现,以静力温度表达的能量位涡数学计算更方便,物理意义更明确.以2007年湖北的一次典型雷雨大风天气为例,对雷雨大风天气用能量位涡进行诊断分析.结果表明:本文提出的干能量位涡与湿能量位涡可以较好地预示雷雨大风天气,高空干能量位涡的增强与向下发展使对流层中下层不稳定能量增大,有利于雷雨大风天气发生;低层湿能量位涡的不稳定能量高值区与斜压系统耦合时预示该区域将有雷雨大风发生.

Application of energy potential vorticity to diagnosis of thunder wind

The conservative physical quantities,dry energy potential vorticity(DEPV) and wet energy vorticity(WEPV),which combine the energy synoptic meteorology with dynamics of the atmosphere,are derived from the basic atmospheric motion equation and the concept of total atmospheric energy.It is found that the energy potential vorticity(EPV) expressed by the static temperature is easier in mathematical computation with clearer physical meaning.DEPV and WEPV are applied to diagnose a typical thunder wind case in Hubei in 2007.It shows that both DEPV and WEPV could forebode the thunder wind weather.The enhancing and descending of DEPV in the upper troposphere increase unstable energy in the middle and lower troposphere,which promotes the thunder wind.It indicates that the thunder wind will occur in the superposition between the high WEPV region in the lower troposphere and the baroclinic system.