Andrew飓风发展过程中的湿位涡诊断

根据PSU—NCAR中尺度模式(MM5)对1992年Andrew飓风数值试验的高分辨率输出资料，计算了湿位涡。针对湿位涡在飓风中的分布、湿位涡的分布随时间变化而表现出的特征等内容，进行了较为全面的分析。认为在飓风眼壁区，有很好的湿位涡分布与倾斜上升气流对应；指出在飓风眼壁区存在着激发并维持倾斜上升气流的一种可能机制——条件性对称不稳定CSI(Conditional Symmetrical Instability)，正是这种机制维持着整个旺盛阶段内飓风的发展演变。

D iagnosing the Hurr icane Andrew in theWho le Develop ing Course by MPV

Based on the high resolution output of the numerical simulation of the 1992 hurricane Andrew with a mesoscale model MM5 of PUS-MCAR, the paper caculates the Moist Potential Vorticity(MPV). The paper analyses the distribution of MPV in the hurricane and the characteristics of MPV variation with time in detail. The analyses show that, in the eyewall, the distribution of MPV coincides properly with the slantwise updraft and there is surely a kind of developing mechanism (CSI) which excites and maintains the updraft in the eyewall. During the whole developing phase of the hurricane Andrew, it is the mechanism (CSI) that maintains the growth of the hurricance Andrew.