风廓线雷达和多普勒天气雷达在一次强对流天气过程中的分析应用

Application of wind profile radar and Doppler weather radar in a severe convective weather process

2018年3月18—19日,贵州省中部发生了一次由地面热低压引起的典型强对流天气过程,该文运用常规观测站资料、风廓线雷达资料和多普勒天气雷达资料对过程前后的雷达回波和风场特征做了诊断分析,得到如下结论:①在多普勒天气雷达的静锥区内,风廓线雷达的产品是很好的补充,两者点面结合可分析出锋面、急流和冷暖平流的变化情况;②在地面热地压和高空槽的引导下,对流单体不断生成并增强,测站上空观测到有近地面低空切变线稳定维持,低空急流出现的时间提前于降水开始的时间,低空急流范围扩大和位置下移时表明对流系统持续发展增强,配合多普勒天气雷达产品能更好的追踪大范围内单体的移动路径,降水结束后低空急流也逐渐减弱消失;③降水开始前,垂直层上垂直速度正负差别越大表明不同层热交换强烈,对流活动越强,当降水开始时垂直速度正值迅速加大,由于存在很大的脉动性,因此这个指数仅作为参考指标。

Based on the conventional observation,wind profile radar data and Doppler radar data,a diagnostic analysis was made of the meteorological radar and the wind field characteristics on the severe convective weather process that was caused by a surface thermal low on 18 Mar.2018 in central Guizhou.The results show that ①when it is in the radar static cone region,the wind profile radar data is important supplementary information to analyze the variation of the low-level jet,wind shear and advection;②influenced by upper trough and thermal low,the convective cell generates and enhances continually,with low-wind shears keeping stable over the wind profile radar.The time of low-level jet appearance is earlier than the onset of rainfall,and the low-level jet decreases and disappears eventually after the rainfall.The enlargement of the low-level jet and the height change is closely associated with the evolution of the severe system.③Before the rainfall,the bigger differences in the positive and negative vertical velocity mean the more intensely the heat exchanges between different levels.The vertical velocity accelerates as the rainfall starts.The index can only serve as a reference since it is characterized by pulsation.