对一次台风暴雨的位涡与湿位涡诊断分析  

A Diagnostic Analysis of PV and MPV on the Heavy Rain Caused by Typhoon Khanun

作　　者：黄亿[1,2] 寿绍文[1] 傅灵艳[1,2] 

机构地区：[1]南京信息工程大学江苏省气象灾害重点实验室,210044 [2]南京信息工程大学

出　　处：《气象》2009年第1期65-73,共9页Meteorological Monthly

基　　金：国家自然科学基金项目(40405009;4057022;40205008);江苏省气象局科技开发项目(200406);江苏省气象灾害重点实验室项目(KLME050201);国家重点基础研究发展规划项目(2004CB418301);江苏省自然科学基金项目(BK2005141)

摘　　要：利用中尺度模式WRF对台风卡努模拟所输出的高分辨率资料,借助等熵位涡及湿位涡的方法进行诊断分析,揭示台风暴雨过程中的中尺度系统演变特征以及探讨台风暴雨发展与维持的机制。结果表明:等熵面位涡图的分析清楚地揭示了台风低压及周边环境的位涡演变特征。暴雨区落在低层等熵面位涡高值中心的东北侧,或者在高层等熵面位涡高值中心右侧最大位涡梯度处;等位温面向正位涡异常中心收拢,高层的高位涡值下传,高位涡的干冷空气加强了低层的扰动,引起低层暖空气的抬升,这些条件促使对流不稳定能量与潜热能的释放,有利于暴雨增幅;条件性对称不稳定与对流不稳定是此次台风暴雨发展与维持的重要机制,暴雨区内中尺度系统的发展符合倾斜涡度发展理论。By using the high resolution output data from mesoscale model WRF successfully simulating typhoon ＂Khanun＂, with the diagnostic method of isentropic potential vorticity（IPV） and moist potential vorticity（MPV）, the evolvement characteristic of mesoscale system is analyzed in the course of rainstorm and the mechanism of typhoon rainstorm development and maintenance is discussed. The results show that the study of PV on isentropic surface reveals PV evolvement characteristic of typhoon low pressure and nearby, the rainstorm region lies in the northeast part of high PV center on the lower isentropic surface or lies in the right side of the maximum PV gradient on the upper isentropic surface. It also shows that high PV, including in dry and cold air, spreads downward from the upper layer to intensify the turbulence of lower layers along with the isentropic surface furling to the center of positive PV anomaly, which helps the release of potential instability energy and the amplification of rainstorm. Conditional symmetry instability and convective instability can be considered as significant mechanism of typhoon rainstorm development and maintenance. Meanwhile, the development of mesoscale system in the rainstorm region agrees with slantwise vorticity development theory.

关 键 词：台风暴雨 等熵位涡 湿位涡 条件性对称不稳定 

分 类 号：P444[天文地球—大气科学及气象学] P458.121.1