【摘要】 利用0.25°×0.25°NCEP/NCAR再分析资料、常规观测资料和多普勒雷达资料等,对2018年6月13日发生在河南省北部地区的一次风雹天气过程进行诊断分析,结果表明:(1)此次强风雹天气发生在华北冷涡后部西北气流中,强天气发生前大气整层较为干燥,冷涡后部横槽南下,自上而下带来干冷空气,低层水汽辐合与午后地面高温共同作用,形成上干冷下暖湿的不稳定层结;(2)地面辐合线和弱冷锋是此次风雹天气的触发机制;(3)对流单体在干侵入的一侧首先发展加强,随后在地面辐合线附近不断产生小的对流单体,对流单体合并后进一步加强,逐渐形成弓形回波带,大风出现在回波带前地面辐合线附近,冰雹出现在中气旋左侧区域;(4)对流单体的移动方向与地面辐合线一致,地面辐合线稳定有利于对流系统的增强,地面辐合线断裂后对流系统迅速减弱、消亡。更多还原

【Abstract】 By using NCEP reanalysis data(0.25 °×0.25 °,4-times-a-day),conventional observation data,and Doppler radar data,a hail weather process in the northern part of Henan province on 13 June2018 was diagnostic analyzed.The results showed that:(1) The strong hailstorm occurred in the northwest airflow behind the northern China cold vortex.Before the occurrence of strong weather,the whole layer of the atmosphere was relatively dry,and the transverse groove behind the cold vortex moved southward,bringing in dry air from above.The convergence of water vapor occoured in the lower layer and the high surface temperature in the afternoon,formed the upper dry and cold under the warm and wet unstable stratification.(2) Ground convergence line and weak cold front were the trigger mechanisms of the hailstorm.(3)Convection cells first developed and strengthened on the dry invasion side.Subsequently,small convective cells were continuously generated near the surface convergence line.The convective cells were further strengthened after merger and gradually formed an arch echo band.The wind appeared near the ground convergence line on the front side of the echo zone and the hail appeared in the left side of the mesocyclone.(4) The movement direction of the convective cells was consistent with the ground convergence line.The stable and less moving of the surface convergence line were beneficial to the enhancement of the convective system.The fracture of the surface convergence line causes the weakening and extinction of the convective system.These conclusions provide a reference for the prediction and early warning of short imminent strong hailstorms.更多还原