摘要
利用多普勒天气雷达、常规探空和地面观测数据、1 min降水量和5 min间隔加密自动气象站观测数据,对比分析了2017年6月2日和8月6日山东两次强下击暴流风暴(简称6·2超级单体和8·6强单体)雷达特征及地面致灾大风的成因。研究表明:两次致灾大风过程在强天气尺度和有利中尺度环境下分别形成超级单体和强单体风暴并触发系列下击暴流,最强下击暴流发生时垂直积分液态水含量先跃增后骤降,6·2超级单体伴随中气旋顶和底高度的剧烈下沉。两次强下击暴流触地前均出现强反射率因子核的快速下降、底层高径向速度和强辐散、中层径向辐合和高空强辐散特征。6·2超级单体旋转特性强、中气旋深厚,低层伴随弧形入流缺口和勾状回波。8·6强单体中低层辐合特征显著,风暴前端低层伴有由雷暴出流和前侧入流形成的辐合带。两次强下击暴流引起地面致灾大风的过程中负浮力效应基本相当,6·2超级单体冷池密度流效应更明显,8·6强单体动量下传效应更显著。潍坊南孙站位于风暴移动方向正前侧,前侧辐散气流与同向快速移动的风暴叠加,是导致37 m·s^(-1)极端大风的重要原因。
Multi-source observations are used to comprehensively analyze the Doppler weather radar characteristics of strong storms and the formation mechanisms of surface damaging wind induced by two strong downbursts,occurred in Shandong on 2 June 2017 and 6 August 2017.It’s found that two damaging wind events occurs under strong synoptic scale weather system forcing and favorable meso-scale environmental conditions,the relatively isolated supercell storm on 2 June(6·2 supercell)and strong single storm on 6 August(8·6 strong single storm)fiercely develop into series of downbursts,which leads to the occurrence of large-scale damaging winds.As two strong downbursts induced by 6·2 supercell storm and 8·6 strong single storm evolves,the vertically integrated liquid water content radar parameter first rises and then quickly plunges down.During 6·2 supercell storm,a powerful downburst descends sharply,causing the mesocyclone’s top and bottom to shoal and its thickness to decrease.The occurrence of two strong downbursts are accompanied by obvious radar characteristics including reflective factor core rapid decline,high value area of radial velocity at low elevation,strong divergence at bottom,remarkable mid altitude radial convergence and severe divergence at upper-level.6·2 supercell storm is characterized by intense rotation.Its mesocyclone lasts for a long time and extends deeply both upwards and downwards.Additionally,there are arc-shaped inflow notches and hook echoes at low levels of 6·2 supercell storm.8·6 strong single storm is characterized by significant low-level convergence.Besides,there is a convergence zone at or near the surface formed by the outflow of the strong downburst and the inflow in front of 8·6 strong single storm.Among all the formation mechanisms of two damaging winds induced by two strong downbursts,the negative buoyancy effect of two storms is basically equivalent,but the cold pool outflow effect is more evident for 6·2 supercell storm,and the downward transport momentum effect is more significant for 8·6 strong single storm.The Nansun Station of Weifang locating right ahead of 8·6 strong single storm’s approaching direction,therefore the front divergence flow from the strong downbursts is preferable superimposed on the fast moving homodromous storm,indicating the speed of the front divergence flow better superimposes on the speed of the storm itself,which is crucial for the occurrence of 37.0 m·s^(-1) extreme wind.
作者
郭飞燕
丁锋
褚颖佳
郎嘉河
李晓东
栾在茂
Guo Feiyan;Ding Feng;Chu Yingjia;Lang Jiahe;Li Xiaodong;Luan Zaimao(Qingdao Meteorological Bureau,Qingdao 266003;Jinan Meteorological Bureau of Shandong,Jinan 250031)
出处
《应用气象学报》
CSCD
北大核心
2024年第5期590-605,共16页
Journal of Applied Meteorological Science
基金
山东省自然科学基金项目(ZR2021QD028)
青岛市气象局项目(2023qdqxz01,2023qdqxq01)
山东省气象局项目(2023SDBD05,2023sdqxz08)。
关键词
致灾大风
下击暴流
强下沉气流
动量下传
冷池密度流
damaging wind
downburst
strong downdraft
downward momentum transport
cold pool high-density flow
