2021年山东一次罕见区域性“雷打雪”天气成因分析  

Cause Analysis of a Rare Regional"Thunder Snow"Process in Shandong in 2021

作　　者：王宁 杨学斌 杨成芳 WANG Ning;YANG Xuebin;YANG Chengfang(Key Laboratory for Meteorological Disaster Prevention and Mitigation of Shandong,Jinan 250o31;Dezhou Meteorological Service,Shandong,Dezhou 253000;Shandong Meteorological Observatory,Jinan 250031)

机构地区：[1]山东省气象防灾减灾重点实验室,济南250031 [2]山东省德州市气象局,德州253000 [3]山东省气象台,济南250031

出　　处：《气象科技》2023年第4期562-572,共11页Meteorological Science and Technology

基　　金：山东省自然科学基金项目(ZR2022MD095);山东省气象局科研项目(SDYBY2021-09)共同资助。

摘　　要：利用气象观测资料、雷电定位资料、ERA5再分析资料和双偏振雷达资料,分析了2021年11月6—7日发生在山东西北部一次极端“雷打雪”天气过程。结果表明:(1)雷暴和降雪出现在冷锋后部150 km以外,属于冬季冷锋型高架对流。雷电维持时间和出现频数与降雪量有较好的对应关系。(2)环流形势具有下冷上暖的特点,低层为冷锋后的冷层,800 hPa附近为西南暖湿气流形成的暖层。西南低空急流和东北风超低空急流异常强盛,不仅提供了有利于对流产生的充足水汽,也使得深层垂直风切变达到6.7×10^(-3)s^(-1)。(3)“雷打雪”发生前,鲁西北地区上空大气具有对流不稳定,随着冷空气侵入,冷垫逐渐增厚,鲁西北上空锋面附近具有条件对称不稳定,800 hPa中尺度低涡在逆温层之上触发了对流,产生雷电。(4)通过双偏振雷达产品可以看到,雷打雪发生时,站点周围存在明显的2层回波,-10℃层高度(约为600 hPa)冰相粒子浓度较大,可能是雷电机制之一。Using conventional meteorological observation data,lightning location data,ERA5 reanalysis data and dualpolarization radar data,an extreme“thunder snow”process in Northwest Shandong Province from 6 to 7 November 2021 is analyzed.The results show:(1)Thunderstorm and snowfall occurred 150 km behind the cold front,which belonged to the cold front type elevated convection in winter.The duration and frequency of lightning had a good corresponding relationship with the snowfall.(2)The circulation pattern was characterized by“cold at the bottom and warm at the top”.The lower layer was the“cold layer”behind the cold front,and the“warm layer”formed by the southwest warm and humid airflow near 800 hPa.The southwest lowlevel jet and the northeast wind ultralowlevel jet were exceptionally strong,which not only provided sufficient water vapour for the convective generation but also made the deep vertical wind shear reach 6.7×10^(-3)s^(-1),which was conducive to increasing the stratification instability.(3)Before the occurrence of“thunder snow”,the atmosphere over Northwest Shandong was convective instability.The cold surface gradually thickened with the invasion of cold air,and there was conditional symmetric instability near the cold front over Northwest Shandong.The mesoscale vortex at 800 hPa triggered convection above the inversion layer and generated lightning.(4)It could be seen from the dualpolarization radar products that there were obvious twolayer echoes around the station when thunder snow occurred,and the concentration of ice phase particles at-10℃layer height(about 600 hPa)was relatively large,which might be one of the lightning mechanism.

关 键 词：雷打雪 高架雷暴 条件对称不稳定 双偏振雷达 

分 类 号：P446[天文地球—大气科学及气象学]