一次雷暴大风天气的触发机制及物理量诊断分析  

The Trigger Mechanism and Physical Diagnostic Analysis of a Thunderstorm Gale Weather

作　　者：周航 唐舟 徐恩 邵禹晨 程昕 王锦杰 庞礴 张莹 ZHOU Hang(Suqian Meteorological Bureau,Suqian,Jiangsu 223800)

机构地区：[1]宿迁市气象局,江苏宿迁223800

出　　处：《农业灾害研究》2021年第1期15-19,共5页Journal of Agricultural Catastrophology

摘　　要：利用FNL0.25°×0.25°再分析资料,分析2017年7月15日发生在宿迁地区雷暴大风过程的天气形势、环境条件、触发机制和物理量特征。发现:(1)此次雷暴大风天气的主要影响系统是高空冷涡,低空切变线、西南急流和地面冷锋;700 hPa和850 hPa干线、中尺度切变线和地面辐合线是其触发机制。(2)此次强对流过程的水汽通道主要是副高西北侧南到西南风急流的水汽输送,水汽来源于南海和印度洋,且水汽强辐合中心位于宿迁西部上空;假相当位温高值区由西南向东北延伸至宿迁南部地区,宿迁位于能量梯度锋区内;雷暴发生时,对流层低层有强辐散,中层为强辐合区,对应中低层为强下沉气流,是导致下击暴流和地面强阵风的主要因素之一;雷暴发生前,宿迁地区0~6 km和0~3 km垂直风切变出现一致增大,中层增幅较低层明显,表明此次雷暴大风发生在较强的垂直风切变环境下。Based on the reanalysis data of FNL,the synoptic situation,environmental conditions,trigger mechanism and physical characteristics of the thunderstorm process in Suqian area on 15 July 2017 are analyzed.The results show that the main Impact systems of the thunderstorm are high-altitude cold vortex,low-altitude shear line,southwest jet and surface cold front.The trigger mechanisms of the above thunderstorm include 700 hPa and 850 hPa drylines,the mesoscale shear line and the surface cold front.The water vapor channel of the above thunderstorm mainly is the water vapor transportation from south to southwest jet on northwest side of subtropical high,Besides,its water vapor comes from the South China Sea and the Indian Ocean,and the strong convergence center of water vapor is located over the western Suqian city.High pseudo-equivalent potential temperature range extends from southwest to northeast to southern Suqian,and Suqian is located in the energy gradient front area.When the thunderstorm occurs,there is a strong divergence center in the lower troposphere,while there is a strong convergence center in the middle troposphere,corresponding to a strong downdraft in the middle and lower layer,which is one of the main factors leading to downbursts and extreme wind on the ground,Before the thunderstorm occurs,the 0~3 km and 0~6 km wind vertical shear increase consistently in Suqian,and the increase amplitude in the middle layer is more significant than the lower layer.The conclusion indicates that the thunderstorm occurred in a strong vertical wind shear environment.

关 键 词：雷暴大风 触发机制 物理量特征 

分 类 号：P4[天文地球—大气科学及气象学]