为研究暴雨过程中尺度低压系统的演变,推导出非守恒条件下的位涡方程并简化得出中尺度扰动位涡倾向方程,以广西一次特大暴雨过程为例,验证方程在分析中尺度系统发展演变中的有效性和可操作性,并分析了暴雨过程中两类中低压的不同演变因子。结果表明：（1）中尺度扰动位涡大值中心的演变对中尺度低压系统的发展演变具有较好的指示意义;（2）推导出的包含非绝热加热作用项的中尺度扰动位涡倾向方程,可用来揭示凝结加热潜热对中尺度低压系统发展演变的作用;（3）利用中尺度扰动位涡倾向方程定量分析凝结加热的贡献,是区分引发降水的中尺度系统和降水过程中凝结加热强迫出的中尺度系统的方法,对研究凝结加热和不同类型中尺度系统之间的相互作用具有重要意义。%Potential Vorticity Equation (PVE) is derived and simplified to get mesoscale Potential Vorticity Disturbance Tendency Equation (PVDTE) in order to investigate the evolution of mesoscale lows associated with torrential rain. The availability and operability of PVDTE to analyze the evolution of mesoscale lows is verified and the different evolution factors are analyzed with the torrential rain case in Guangxi province. The result shows the following. (1) The evolution of the high-value center of mesoscale disturbance potential vorticity can directly indicate the development and evolution of mesoscale lows. (2) The derived PVDTE containing the diabafic heating action term could be used to reveal the effect of latent heat of condensation heating on the evolution of mesoscale lows. (3) The quantitative analysis of the contribution of condensation heating by PVDTE is an effective method to differentiate the mesoscale lows causing precipitation from the mesoscale lows pro- duced forcibly by condensation heating during the precipitation. The equation has a great significance to research the interaction between con- densation heating and different types of mesoseale lows.
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