三场暴雨中湿位涡的中尺度分析

MESOSCALE ANALYSIS OF MOISTURE POTENTIAL VORTICITY IN THE THREE HEAVY RAIN EVENTS

利用中尺度数值预报模式MM5v3.6,对发生在山东境内的三场不同影响系统的暴雨天气过程进行了数值模拟.并应用湿位涡理论,对这三场暴雨过程进行了诊断分析。结果表明:这三场暴雨都产生在θ_(se)陡峭密集区附近,θ_(se)面的陡立易导致湿斜压涡度的发展,有利于上升运动的显著增长;暴雨的发展与湿位涡有很好的联系,暴雨主要出现在850 hPa的MPV1负值区和MPV2正值区等值线密集区附近,降水中心位于MPV1负值中心前部对流不稳定区中。

By using the mesoscale numerical model MM5V3.6, the simulations were made for three different rainstorms in Shandong province. And using the theory of moisture potential vorticity（MPV）,the characteristics of MPV are analyzed in the process of three rainstorms. The results show that the three heavy rain events occurred in the very stiff and dense section of moist isentropes,which can lead to the development of moist slantwise vorticity and ascending movement. And the development of heavy rain is closely related to moisture potential vorticity. The heavy rain occurs in the isoline dense section of the neg- ative MPV1 and positive MPV2 ,and the rain center lies in the convective instable section in the front of the negative MPV1 center at 850 hPa.