【摘要】 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 d Bz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。更多还原

【Abstract】 From the weather background, and taking into consideration the Doppler radar data, the authors analyzed the weather situation on May 6, 2015. The results showed that:(1) the process was mainly thenortheast cold vortex type, with a lower shear dry wet unstable stratification, which caused the convectiveclouds from the northwest to develop over Shanxi and Henan Province and ultimately formed the squall linestorm;(2) atmospheric stratification instability in the index K, CAPE value, index(SI), strong vertical windshear, near surface inversion layer exhibited significantly, 0℃ and-20℃ layer height were also beneficial tohail formation, at the same time, the vertical structure of the cold and warm advection made the atmospheremore unstable;(3) >60 d Bz strong echo center successively evolved from bow echo-squall to line-cross to the"people"-shaped echo-squall line, the convection development in the top position of"people"was the mostexuberant;(4) the process was a storm group with squall line, along the radar direction there was a very obvious"V"type gap and three body scattering, which sustained about 2 hours, the echo characteristic was the strongecho hang in low layer weak echo area;(5) the echo top height was 11 km and had a wide range, the processwas a number of storm group composed of super monomer storms, which had big intensity, wide area, long duration, and it was rare in history.更多还原