doi:  10.3878/j.issn.1006-9895.1801.17220
一次具有对流合并现象的强飑线系统的闪电活动特征及其与动力场的关系

Lightning activity of a severe squall line with cell merging process and its relationships with dynamic field
摘要点击 1662  全文点击 238  投稿时间:2017-08-24  修订日期:2018-01-07
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基金:  国家重点基础研究规划项目、国家自然科学基金
中文关键词:  飑线,闪电,对流区,层云区,对流合并
英文关键词:  squall line, lightning, convection zone, stratiform zone, cell merge
                             
作者中文名作者英文名单位
徐 燕Xu Yan成都信息工程大学大气科学学院
孙竹玲孙竹玲中国科学院大气物理研究所中层大气与全球环境探测重点实验室
周筠珺Zhou Yunjun成都信息工程大学大气科学学院高原大气与环境四川省重点实验室
袁善锋中国科学院大气物理研究所中层大气与全球环境探测重点实验室
陈志雄中国科学院大气物理研究所中层大气与全球环境探测重点实验室
刘冬霞中国科学院大气物理研究所中层大气与全球环境探测重点实验室
王东方中国科学院大气物理研究所中层大气与全球环境探测重点实验室
田 野中国科学院大气物理研究所中层大气与全球环境探测重点实验室
徐文静北京城市气象研究所;北京城市气象研究所
郄秀书郄秀书中科院大气物理研究所
引用:徐 燕,孙竹玲,周筠珺,袁善锋,陈志雄,刘冬霞,王东方,田 野,徐文静,郄秀书.2018.一次具有对流合并现象的强飑线系统的闪电活动特征及其与动力场的关系[J].大气科学
Citation:Xu Yan,孙竹玲,Zhou Yunjun,郄秀书.2018.Lightning activity of a severe squall line with cell merging process and its relationships with dynamic field[J].Chinese Journal of Atmospheric Sciences (in Chinese)
中文摘要:
      摘要 受东北冷涡与副热带高压西北部暖湿气流影响,2015年7月27日北京地区爆发了一次具有明显对流单体合并特征的强飑线灾害性强对流天气过程。利用北京闪电定位网(BLNet)总闪定位、多普勒雷达和探空资料等,详细分析了此次飑线过程整个生命史期间不同对流区的总闪活动特征。结果表明,整个飑线过程以云闪为主,地闪活动以负地闪为主;对流单体合并时云闪数量激增,飑线过程后期正地闪比例跃增。85%的闪电主要分布在距对流线10km范围内,层云区闪电较少;层云区的闪电电荷来源主要是由对流区的电荷经过过渡区输送而来,正地闪更易发生在过渡区和层云区。对流合并过程中有大量的水汽集中,垂直积分液态含水量(VIL)峰值超前闪电峰值24 min。利用变分多普勒雷达分析系统(VDRAS)对这次过程的三维风场进了反演,据此对单体合并期间闪电增强的动力原因进行了研究。根据VDRAS反演的动力场来看,对流云单体合并主要发生在低层辐合区内,合并后上升运动加强,上升气流范围变大,闪电活动显著增强,并主要发生在具有较强垂直风切变的区域,少部分闪电发生在对流区后部开始出现下沉气流的区域。
Abstract:
      Influenced by the northeastern cold vortex and warm and humid airflow in the northwestern part of the subtropical high, a damaging squall line with cell merging process took place in Beijing area on July 27,2015. Based on the data from Beijing Lightning Network (BLNet), S-band Doppler radar data and raidosonde data, the total lightning activity characteristics of this severe squall line were analyzed. The results show that the lightning activities generated by squall line were mainly intra-cloud (IC) lightning flashes; the cloud-to-ground (CG) flashes were dominated by negative CG (NCG); and in the dissipation stage, the ratio of positive CG to CG (PCG/CG) increased sharply. About 85% of total lightning flashes were distributed within the 10 km range of the convection line, while flashes occurred in the stratiform region were relatively less. PCG was more likely to occur in the transition zone and stratiform region; the occurrence of lightning in stratiform region may result from the advection of charged particles from convective region through transition zone. There is a large amount of water vapor concentration during the convection merging, the peak of lightning was 24 min lagging behind the peak of vertical integral liquid water content (VIL). The Variational Doppler Radar Analysis System (VDRAS) was used to retrieve the three-dimensional wind field of the process, and the cause of the increase of lightning during the merging process was studied. According to the wind field retrieved from the VDRAS, The merging of convective clouds mainly occurs in the lower convergence zone; after convection merging, the extent and intensity of updraft all become intense, and lightning activity become more active. Lightning mainly concentrated in the region with strong vertical wind shear, meanwhile a small fraction of flashes occurred in the rear of the convection zone where the downdrafts were observed to appear.
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