2015年5月晋豫强降雹过程的诊断分析

从天气背景入手，结合多普勒雷达资料，分析2015年5月6日天气形势。结果发现：（1）此次过程主要为东北冷涡型，低层切变配合上干下湿不稳定层结，导致从西北地区来的对流云团到晋豫两省境内上空不断加强发展，最终形成飑线型风暴。（2）大气层结的不稳定性在K指数、CAPE值、SI指数、强的垂直风切变、近地面逆温层等方面均表现明显，0和-20℃层高度也有利于冰雹的产生。同时冷暖平流的垂直结构使得大气层结变得更不稳定。（3）>60 dBz强回波中心先后以“弓状回波—飑线—横倒着的“人”字型回波—飑线”的形式演变，“人”字型的顶端位置对流发展最为旺盛。（4）此次过程为飑线型的风暴群。沿着雷达方向上有非常明显的“V”型缺口和三体散射，三体散射前后持续约2 h，回波特征为低层弱回波区上空的强回波悬垂。（5）回波顶高持续在11 km以上且范围大。此次过程是多个超级单体风暴组成的风暴群，强度大、面积广、持续时间长，在历史上实属罕见。

Diagnostic Analysis of a Hail Process in Shanxi and Henan

From the weather background, combined with Doppler radar data, the author analyzed the weather situation in May 6, 2015. The results showed that: (1) The process mainly for the northeast cold vortex type, with the lower shear dry wet unstable stratification, resulting in from the northwest to the convective clouds above Shanxi and Henan Province will continue to strengthen the development, and ultimately the formation of the squall line storm. (2) atmospheric stratification instability in the index K, Cape value, index (SI), strong vertical wind shear, near surface inversion layer exhibited significant, 0 and - 20 ℃ layer height also has benefit to hail. At the same time, the vertical structure of the cold and warm advection made the atmosphere more unstable. (3) >60 dBz strong echo center successively evolved in the form of “bow echo-squall line-cross the ‘people’-shaped echo-squall line”, the convection development in the top position of “people” was the most exuberant. (4) The process was storm group with squall line. Along the radar direction there was a very obvious “V” type gap and three body scattering, the three body scattering sustained about 2 hours, the echo characteristics was the strong echo hang in low layer weak echo area. (5) Echo top height was 11 km and had wide range. The process was a number of storm group composed by super monomer storms, which had big intensity, wide area, long duration, it was rare in history.