2024年7月5日山东龙卷爆发事件雷达观测特征  

Radar observation characteristics of tornado outbreak events in Shandong on 5 July 2024

作　　者：刁秀广 孟宪贵[1,2] 朱晓清 韩永清[1,2] DIAO Xiuguang;MENG Xiangui;ZHU Xiaoqing;HAN Yongqing(Key Laboratory for Meteorological Disaster Prevention and Mitigation of Shandong,Jinan 250031,China;Shandong Meteorological Observatory,Jinan 250031,China)

机构地区：[1]山东省气象防灾减灾重点实验室,山东济南250031 [2]山东省气象台,山东济南250031

出　　处：《海洋气象学报》2025年第2期14-27,共14页Journal of Marine Meteorology

基　　金：山东省自然科学基金项目(ZR2022MD035,ZR2022MD088)。

摘　　要：基于新一代天气雷达探测资料,结合探空、地面实况资料、灾情调查报告及ERA5资料,对2024年7月5日山东爆发性龙卷天气的环境物理量、风暴演变、龙卷风暴低层小尺度涡旋及双偏振特征进行分析。结果表明:温带气旋形势下,爆发性龙卷都出现在地面低压中心的东或东北方,低空急流较强,大的低空垂直风切变、风暴相对螺旋度和能量螺旋度指数是龙卷爆发的关键环境因子。6个龙卷产生在地面强的3 h负变压区内偏东风气流附近。准线性对流系统内的超级单体或弓形回波,或者线性对流系统前侧暖区新生发展起来的强风暴是爆发性龙卷的直接缔造者,强涡旋中心的快速下降或低层局部径向风的迅速增大,是小尺度龙卷涡旋产生的前兆。8个中气旋龙卷风暴低层中气旋旋转速度在20 m·s^(-1)以上,1个非中气旋龙卷由弓形回波诱发,其后部入流为42~45 m·s^(-1)。东明龙卷破坏性最强,母体风暴上升气流最强,低层龙卷碎片宽度约为2 km,顶部高度达9 km左右,呈分散状态,最大宽度约为4 km。Using CINRAD data,sounding data,data of automatic meteorological observing stations,disaster investigation reports and ERA5 data,the environmental physical quantities,storm evolution,low-level small-scale vortex and dual-polarization characteristics of the outbreak tornado events in Shandong on 5 July 2024 are analyzed.The results show that under the extratropical cyclone situation,outbreak tornadoes are generated east or northeast of the ground low-pressure center,and the low-level jet is strong.Strong vertical wind shear at low altitudes,storm relative helicity and large energy helicity index are the key environmental factors for tornado outbreak.Six tornadoes are generated near the strong 3-h negative pressure change zone with the easterly airflow on the ground.The supercells/bow echoes within quasi-linear convective systems or the newly developed supercell storms in the warm zone in front of linear convective systems are efficient in producing tornadoes.The rapid decrease of the strong vortex center or the rapid increase of the partial radial velocity in the low level is a precursor to the generation of small-scale tornadic vortices.Eight mesocyclone tornadoes are characterized by strong mesocyclones with the rotation speed exceeding 20 m·s^(-1)in the low level,and one non-mesocyclone tornado is induced by bow echo with rear inflow jet of 42-45 m·s^(-1).The tornado in Dongming County is the most damaging and lethal tornado,whose parent storm has the strongest updrafts.The width of the low-level tornadic debris signature(TDS)is about 2 km,and the top of the TDS reaches about 9 km,showing a dispersed state with the maximum width of about 4 km.

关 键 词：龙卷爆发 小尺度涡旋 龙卷碎片特征 

分 类 号：P445.1[天文地球—大气科学及气象学] P458.3