齐齐哈尔两次暴雨天气过程对比分析

Comparative Analysis of Two Rainstorm Weather Processes in Qiqihar

利用多种资料对发生在齐齐哈尔的两次暴雨进行对比分析。结果表明:(1)这两次暴雨都发生在副热带高压位置最北期间,都是副热带高压、高空冷涡和地面低压大尺度环流造成的;“8.3”暴雨比“8.6”暴雨副热带高压位置更偏西,地面低压中心值更低。(2)“8.6”暴雨过程齐齐哈尔地区水汽输送量更大、辐合更强、低层上升运动更明显、造成暴雨范围更大。(3)“8.3”暴雨雷达回波强度更强,55 dBz以上强回波排列紧密,呈现带状;“8.6”暴雨雷达回波,甘南县境内存在“列车效应”,且径向速度场零速度线呈“S”型结构,有明显的暖平流。

Two rainstorm processes in Qiqihar are analyzed by using various data.The results indicate that:(1)The two rainstorm processes both occurred during the northernmost period of the subtropical high,and were caused by the large-scale circulation of the subtropical high,the upper cold vortex and the surface low;The“8.3”rainstorm is more westward than the“8.6”rainstorm subtropical high,and the center value of the ground low pressure is lower.(2)In the“8.6”rainstorm process,the water vapor transport in Qiqihar area is larger,the convergence is stronger,the low-level upward movement is more obvious,and the scope of the rainstorm is larger.(3)The echo intensity of"8.3"rainstorm radar is stronger,and the strong echoes above 55 dBz are closely arranged,showing banding;On the radar reflectivity factor map of“8.6”rainstorm,there is"train effect"in Gannan County,The zero velocity line of the radar radial velocity field presents an“S”shaped echo structure,with obvious warm advection.