湿位涡诊断分析在河南台风远距离降水中的应用

Application of Diagnostic Analysis of Moist Potential Vorticity for the Typhoon Remote Precipitation in Henan

应用湿位涡理论,分析了两个发生在河南的台风远距离降水个例,讨论了湿位涡与台风远距离降水形成的关系。结果表明:两个个例中,河南具有有利于强降水发生的湿位涡特征;异常暴雨的发展与湿位涡的变化有很好的对应关系:湿位涡的异常区域对应着最强的降水,对流层高层ζMPV1(湿位涡的垂直分量)正值区与低层ζMPV2负值区相互作用,即高层下滑的干冷空气与中低层由东南急流输送的高温高湿空气交汇,容易储存和释放湿对流不稳定能量,有利于强降水产生。湿位涡理论在河南台风远距离降水诊断中有很好的应用前景。

By using moist potential vorticity theory, the article analyzed two cases of typhoon remote precipitation that happened in Henan and discussed the formative relationship between moist potential vorticity and typhoon remote precipitation. The results show that the moist potential vorticity characteristics were in favor of severe precipitation in Henan. There was good relationship between abnormal rainstorm＇ s development and moist potential vorticity＇ s change. The abnormal area of moist potential vorticity was corresponding to the severest precipitation. The positive value area of ζMPV1 in upper troposphere （the vertical component of moist potential vorticity） had interaction with the negative value area of ζMPV2· Dry and cool air gliding from upper level joined with the high temperature and high moisture air that conveyed from south-east jet. That was easy to store up and release moist convective instability energy. That could also be in favor of severe precipitation. The moist potential vorticity theory has better prospect for diagnostic analysis of typhoon remote precipitation in Henan.