太原一次罕见的区域雷暴大风过程潜势预报分析

Prediction and Analysis on the Potential of a Rare Regional Thunderstorm Gale Process in Taiyuan

利用太原MICAPS高低空实况、探空、物理量场等资料对太原2011年6月7日一次罕见的较强区域雷暴大风过程进行潜势预报分析,为太原区域雷暴大风潜势预报提供参考依据。研究表明,此次过程具有范围大、强度强的特点,属于太原罕见的较强区域雷暴大风过程;500 hPa横槽转竖以及低空切变线,为此次过程提供了有利的动力抬升条件,影响系统从低层到高层接近于垂直,层结不稳定,有利于强对流天气的发生;近地层存在逆温,有利于不稳定能量的积累,"上干下湿"的层结结构,潜在不稳定,有利于强对流天气的产生;沙氏指数SI对此次雷暴大风天气有一定的指示意义,下沉对流有效位能DCAPE在此次雷暴大风过程中有较好的指示效果;500 hPa冷平流、850 hPa暖平流使层结更加趋于不稳定,潜势上更有利于雷暴大风等强对流天气的发生;冷锋在不断发展和南压过程中触发了此次区域雷暴大风过程。

Using the data of high and low air reality,sounding and physical quantity field of Taiyuan MICAPS,the potential prediction of a rare strong regional thunderstorm gales on June 7,2011 in Taiyuan was analyzed,so as to provide reference for the potential prediction of regional thunderstorm gales in Taiyuan.The study shows that this process has the characteristics of large scope and strong intensity,which belongs to the rare strong regional thunderstorm gale process in Taiyuan.The vertical rotation of the 500 hPa transverse groove and the low level shear line provide favorable dynamic lifting conditions for this process,which affect the system to be nearly vertical from the low level to the high level,and the stratification is unstable,which is conducive to the occurrence of strong convective weather.There is a temperature inversion near surface layer,which is conducive to the accumulation of unstable energy.The stratified structure with“upper dry and lower wet”is potentially unstable,which is conducive to the generation of strong convective weather.The Schaeffler index SI has a certain indicating significance for the thunderstorm gale weather,and the sinking convective effective potential energy DCAPE has a good indicating effect during the thunderstorm gale.500 hPa cold advection and 850 hPa warm advection make the stratification more unstable,the potential is more conducive to the occurrence of strong convective weather.The cold front triggered the regional thunderstorm gales during the development and southward pressure process.