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
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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。93%的闪电主要分布在距对流线10 km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24min。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。
Influenced by the Northeast China cold vortex and warm and moist airflow in the northwestern part of the subtropical high, a damaging squall line with cell merging process took place in Beijing area on 27 July 2015. Based on data from Beijing Lightning Network(BLNet), S-band Doppler radar observations, and radiosonde data, the characteristics of total lightning activity associated with this severe squall line are analyzed. The results show that the lightning activities generated by the squall line were mainly IC(intra-cloud) lightning flashes; CG(cloud-to-ground flashes) were dominated by NCG(negative CG); in the dissipation stage, the ratio of PCG/CG(positive CG to CG) increased sharply. About 93% of total lightning flashes were distributed within 10 km distance of the convection line, while flashes occurring in the stratiform region were relatively fewer. PCG was more likely to occur in the transition zone and stratiform region; the occurrence of lightning in the stratiform region might result from the advection of charged particles from convective region through transition zone. There existed a large amount of water vapor concentration during the convection merging, and the peak of lightning lagged 24 minutes behind the peak of vertically integrated liquid water content(VIL). The Variational Doppler Radar Analysis System(VDRAS) is used to retrieve the three-dimensional wind field during the squall line process, and the reasons for the increase in lightning during the merging process are studied. According to the wind field retrieved from the VDRAS, the merging of convective clouds mainly occurred in the lower convergence zone; after the convection merging, the extent and intensity of the updraft both became intense, and the lightning activity became more active. Lightning was mainly concentrated in the region with strong vertical wind shear, while a small fraction of flashes occurred in the rear of the convection zone where downdrafts were observed to appear.
Influenced by the Northeast China cold vortex and warm and moist airflow in the northwestern part of the subtropical high, a damaging squall line with cell merging process took place in Beijing area on 27 July 2015. Based on data from Beijing Lightning Network(BLNet), S-band Doppler radar observations, and radiosonde data, the characteristics of total lightning activity associated with this severe squall line are analyzed. The results show that the lightning activities generated by the squall line were mainly IC(intra-cloud) lightning flashes; CG(cloud-to-ground flashes) were dominated by NCG(negative CG); in the dissipation stage, the ratio of PCG/CG(positive CG to CG) increased sharply. About 93% of total lightning flashes were distributed within 10 km distance of the convection line, while flashes occurring in the stratiform region were relatively fewer. PCG was more likely to occur in the transition zone and stratiform region; the occurrence of lightning in the stratiform region might result from the advection of charged particles from convective region through transition zone. There existed a large amount of water vapor concentration during the convection merging, and the peak of lightning lagged 24 minutes behind the peak of vertically integrated liquid water content(VIL). The Variational Doppler Radar Analysis System(VDRAS) is used to retrieve the three-dimensional wind field during the squall line process, and the reasons for the increase in lightning during the merging process are studied. According to the wind field retrieved from the VDRAS, the merging of convective clouds mainly occurred in the lower convergence zone; after the convection merging, the extent and intensity of the updraft both became intense, and the lightning activity became more active. Lightning was mainly concentrated in the region with strong vertical wind shear, while a small fraction of flashes occurred in the rear of the convection zone where downdrafts were observed to appear.
引文
Bruning E C,MacGorman D R.2013.Theory and observations of controls on lightning flash size spectra[J].J.Atmos.Sci.,70(12):4012-4029,doi:10.1175/JAS-D-12-0289.1.
Carey L D,Murphy M J,McCormick T L,et al.2005.Lightning location relative to storm structure in a leading-line,trailing-stratiform mesoscale convective system[J].J.Geophys.Res.,110(D3):D03105,doi:10.1029/2003JD004371.
陈明轩,王迎春,肖现,等.2012.基于雷达资料四维变分同化和三维云模式对一次超级单体风暴发展维持热动力机制的模拟分析[J].大气科学,36(5):929-944.Chen Mingxuan,Wang Yingchun,Xiao Xian,et al.2012.A case simulation analysis on thermodynamical mechanism of supercell storm development using 3-D cloud model and 4-D variational assimilation on radar data[J].Chinese Journal of Atmospheric Sciences(in Chinese),36(5):929-944,doi:10.3878/j.issn.1006-9895.2012.11132.
陈明轩,肖现,高峰,等.2016.基于雷达四维变分分析系统的强对流高分辨率模拟个例分析和批量检验[J].气象学报,74(3):421-441.Chen Mingxuan,Xiao Xian,Gao Feng,et al.2016.A case study and batch verification on high resolution numerical simulations of severe convective events using an analysis system based on rapid-refresh 4-Dvariational radar data assimilation[J].Acta Meteor.Sin.(in Chinese),74(3):421-441,doi:10.11676/qxxb2016.031.
付丹红,郭学良.2007.积云并合在强对流系统形成中的作用[J].大气科学,31(4):635-644.Fu Danhong,Guo Xueliang.2007.The role of cumulus merger in a severe mesoscale convective system[J].Chinese Journal of Atmospheric Sciences(in Chinese),31(4):635-644,doi:10.3878/j.issn.1006-9895.2007.04.08.
Gauthier M L,Petersen W A,Carey L D.2010.Cell mergers and their impact on cloud-to-ground lightning over the Houston area[J].Atmospheric Research,96(4):626-632,doi:10.1016/j.atmosres.2010.02.010.
黄勇,覃丹宇,邱学兴.2012.暴雨过程中对流云合并现象的观测与分析[J].大气科学,36(6):1135-1149.Huang Yong,Qin Danyu,Qiu Xuexing.2012.Study of convective cloud merger in heavy rain using multi-observation data[J].Chinese Journal of Atmospheric Sciences(in Chinese),36(6):1135-1149,doi:10.3878/j.issn.1006-9895.2012.11191.
黄勇,王雪芹,苏爱芳,等.2013.江淮夏季强天气过程中对流云合并现象的卫星观测[J].遥感学报,17(2):350-360.Huang Yong,Wang Xueqin,Su Aifang,et al.2013.Satellite infrared imagery characteristics of convective cloud merger in summer severe weather in Huaihe and Yangtze River basin[J].Journal of Remote Sensing(in Chinese),17(2):350-360,doi:10.11834/jrs.20132008.
黄勇,冯妍,翟菁.2016.对流云合并的国内外研究进展[J].暴雨灾害,35(1):91-96.Huang Yong,Feng Yan,Zhai Jing.2016.A review of convective cloud merger studies[J].Torrential Rain and Disasters(in Chinese),35(1):91-96,doi:10.3969/j.issn.1004-9045.2016.01.013.
赖悦,张其林,陈洪滨,等.2015.深圳一次强飑线过程的闪电频数与天气雷达回波关系分析[J].热带气象学报,31(4):549-558.Lai Yue,Zhang Qilin,Chen Hongbin,et al.2015.Analysis of the relationship between cloud-to-ground flash frequency and radar echo during a severe squall line in Shenzhen[J].Journal of Tropical Meteorology(in Chinese),31(4):549-558,doi:10.16032/j.issn.1004-4965.2015.04.012.
Lang T J,Rutledge S A.2008.Kinematic,microphysical,and electrical aspects of an asymmetric bow-echo mesoscale convective system observed during STEPS 2000[J].J.Geophys.Res.,113(D8):D08213,doi:10.1029/2006JD007709.
Lee B D,Jewett B F,Wilhelmson R B.2006.The 19 April 1996 Illinois tornado outbreak.Part II:Cell mergers and associated tornado incidence[J].Wea.Forecasting,21(4):449-464,doi:10.1175/WAF943.1.
Liu D X,Qie X S,Xiong Y J,et al.2011.Evolution of the total lightning activity in a leading-line and trailing stratiform mesoscale convective system over Beijing[J].Adv.Atmos.Sci.,28(4):866-878,doi:10.1007/s00376-010-0001-8.
Liu D X,Qie X S,Pan L X,et al.2013.Some characteristics of lightning activity and radiation source distribution in a squall line over North China[J].Atmospheric Research,132-133:423-433,doi:10.1016/j.atmosres.2013.06.010.
刘冬霞,郄秀书,王志超,等.2013.飑线系统中的闪电辐射源分布特征及云内电荷结构讨论[J].物理学报,62(21):219201.Liu Dongxia,Qie Xiushu,Wang Zhichao,et al.2013.Characteristics of lightning radiation source distribution and charge structure of squall line[J].Acta Physica Sinica(in Chinese),62(21):219201,doi:10.7498/aps.62.219201.
Mac Gorman D R,Rust W D,Krehbiel P,et al.2005.The electrical structure of two supercell storms during STEPS[J].Mon.Wea.Rev.,133(9):2583-2607,doi:10.1175/MWR2994.1.
Petersen,W.A.,Rutledge S.A.,Orville R.E.1996.Cloud-to-ground lightning observations from TOGA COARE:Selected results and lightning location algorithms[J].Mon.Weather Rev.,124,602-620.
Peterson M,Liu C T.2011.Global statistics of lightning in anvil and stratiform regions over the tropics and subtropics observed by the tropical rainfall measuring mission[J].J.Geophys.Res,116(D23):D23201,doi:10.1029/2011JD015908.
Srivastava A,Tian Y,Qie X S,et al.2017.Performance assessment of Beijing Lightning Network(BLNET)and comparison with other lightning location networks across Beijing[J].Atmospheric Research,197:76-83,doi:10.1016/j.atmosres.2017.06.026.
Sun J Z,Chen M X,Wang Y C.2011.A frequent-updating analysis system based on radar,surface,and mesoscale model data for the Beijing 2008forecast demonstration project[J].Wea.Forecasting,25(6):1715-17354248,doi:10.1175/2010WAF2222336.1.
Tessendorf S A,Rutledge S A.2007.Radar and lightning observations of normal and inverted polarity multicellular storms from STEPS[J].Mon.Wea.Rev.,135(11):3682-3706,doi:10.1175/2007MWR1954.1.
Wang C X,Zheng D,Zhang Y J,et al.2017.Relationship between lightning activity and vertical airflow characteristics in thunderstorms[J].Atmospheric Research,191:12-19,doi:10.1016/j.atmosres.2017.03.003.
王宇,郄秀书,王东方,等.2015.北京闪电综合探测网(BLNET):网络构成与初步定位结果[J].大气科学,39(3):571-582.Wang Yu,Qie Xiushu,Wang Dongfang,et al.2015.Beijing Lightning Network(BLNET):Configuration and preliminary results of lightning location[J].Chinese Journal of Atmospheric Sciences(in Chinese),39(3):571-582,doi:10.3878/j.issn.1006-9895.1407.14138.
Wang Y,Qie X S,Wang D F,et al.2016a.Beijing Lightning Network(BLNET)and the observation on preliminary breakdown processes[J].Atmospheric Research,171:121-132,doi:10.1016/j.atmosres.2015.12.012.
Wang F,Zhang Y J,Liu H Y,et al.2016b.Characteristics of cloud-toground lightning strikes in the stratiform regions of mesoscale convective systems[J].Atmospheric Research,178-179:207-216,doi:10.1016/j.atmosres.2016.03.021.
肖现,陈明轩,高峰,等.2015.弱天气系统强迫下北京地区对流下山演变的热动力机制[J].大气科学,39(1):100-124.Xiao Xian,Chen Mingxuan,Gao Feng,et al.2015.A thermodynamic mechanism analysis on enhancement or dissipation of convective systems from the mountains under weak synoptic forcing[J].Chinese Journal of Atmospheric Sciences(in Chinese),39(1):100-124,doi:10.3878/j.issn.1006-9895.1403.13318.
易笑园,孙晓磊,张义军,等.2017.雷暴单体合并进行中雷达回波参数演变及闪电活动的特征分析[J].气象学报,75(6):981-995.Yi Xiaoyuan,Sun Xiaolei,Zhang Yijun,et al.2017.Analysis on the“dump”phenomenon and lightning activity in cells merging based on radar parameters[J].Acta Meteor.Sin.(in Chinese),75(6):981-995,doi:10.11676/qxxb2017.073.
Zajac B A,Rutledge S A.2001.Cloud-to-ground lightning activity in the contiguous united states from 1995 to 1999[J].Mon.Wea.Rev.,129(5):999-1019,doi:10.1175/1520-0493(2001)129<0999:CTGLAI>2.0.CO;2.
Zheng D,Mac Gorman D R.2016.Characteristics of flash initiations in a supercell cluster with tornadoes[J].Atmospheric Research,167:249-264,doi:10.1016/j.atmosres.2015.08.015.
朱乾根,林锦瑞,寿绍文,等.2007.天气学原理和方法[M].4版.北京:气象出版社.Zhu Qiangen,Lin Jinrui,Shou Shaowen,et al.2007.Principles and Methods of Synoptic Meteorology(in Chinese)[M].4th ed.Beijing:China Meteorology Press.
Carey L D,Murphy M J,McCormick T L,et al.2005.Lightning location relative to storm structure in a leading-line,trailing-stratiform mesoscale convective system[J].J.Geophys.Res.,110(D3):D03105,doi:10.1029/2003JD004371.
陈明轩,王迎春,肖现,等.2012.基于雷达资料四维变分同化和三维云模式对一次超级单体风暴发展维持热动力机制的模拟分析[J].大气科学,36(5):929-944.Chen Mingxuan,Wang Yingchun,Xiao Xian,et al.2012.A case simulation analysis on thermodynamical mechanism of supercell storm development using 3-D cloud model and 4-D variational assimilation on radar data[J].Chinese Journal of Atmospheric Sciences(in Chinese),36(5):929-944,doi:10.3878/j.issn.1006-9895.2012.11132.
陈明轩,肖现,高峰,等.2016.基于雷达四维变分分析系统的强对流高分辨率模拟个例分析和批量检验[J].气象学报,74(3):421-441.Chen Mingxuan,Xiao Xian,Gao Feng,et al.2016.A case study and batch verification on high resolution numerical simulations of severe convective events using an analysis system based on rapid-refresh 4-Dvariational radar data assimilation[J].Acta Meteor.Sin.(in Chinese),74(3):421-441,doi:10.11676/qxxb2016.031.
付丹红,郭学良.2007.积云并合在强对流系统形成中的作用[J].大气科学,31(4):635-644.Fu Danhong,Guo Xueliang.2007.The role of cumulus merger in a severe mesoscale convective system[J].Chinese Journal of Atmospheric Sciences(in Chinese),31(4):635-644,doi:10.3878/j.issn.1006-9895.2007.04.08.
Gauthier M L,Petersen W A,Carey L D.2010.Cell mergers and their impact on cloud-to-ground lightning over the Houston area[J].Atmospheric Research,96(4):626-632,doi:10.1016/j.atmosres.2010.02.010.
黄勇,覃丹宇,邱学兴.2012.暴雨过程中对流云合并现象的观测与分析[J].大气科学,36(6):1135-1149.Huang Yong,Qin Danyu,Qiu Xuexing.2012.Study of convective cloud merger in heavy rain using multi-observation data[J].Chinese Journal of Atmospheric Sciences(in Chinese),36(6):1135-1149,doi:10.3878/j.issn.1006-9895.2012.11191.
黄勇,王雪芹,苏爱芳,等.2013.江淮夏季强天气过程中对流云合并现象的卫星观测[J].遥感学报,17(2):350-360.Huang Yong,Wang Xueqin,Su Aifang,et al.2013.Satellite infrared imagery characteristics of convective cloud merger in summer severe weather in Huaihe and Yangtze River basin[J].Journal of Remote Sensing(in Chinese),17(2):350-360,doi:10.11834/jrs.20132008.
黄勇,冯妍,翟菁.2016.对流云合并的国内外研究进展[J].暴雨灾害,35(1):91-96.Huang Yong,Feng Yan,Zhai Jing.2016.A review of convective cloud merger studies[J].Torrential Rain and Disasters(in Chinese),35(1):91-96,doi:10.3969/j.issn.1004-9045.2016.01.013.
赖悦,张其林,陈洪滨,等.2015.深圳一次强飑线过程的闪电频数与天气雷达回波关系分析[J].热带气象学报,31(4):549-558.Lai Yue,Zhang Qilin,Chen Hongbin,et al.2015.Analysis of the relationship between cloud-to-ground flash frequency and radar echo during a severe squall line in Shenzhen[J].Journal of Tropical Meteorology(in Chinese),31(4):549-558,doi:10.16032/j.issn.1004-4965.2015.04.012.
Lang T J,Rutledge S A.2008.Kinematic,microphysical,and electrical aspects of an asymmetric bow-echo mesoscale convective system observed during STEPS 2000[J].J.Geophys.Res.,113(D8):D08213,doi:10.1029/2006JD007709.
Lee B D,Jewett B F,Wilhelmson R B.2006.The 19 April 1996 Illinois tornado outbreak.Part II:Cell mergers and associated tornado incidence[J].Wea.Forecasting,21(4):449-464,doi:10.1175/WAF943.1.
Liu D X,Qie X S,Xiong Y J,et al.2011.Evolution of the total lightning activity in a leading-line and trailing stratiform mesoscale convective system over Beijing[J].Adv.Atmos.Sci.,28(4):866-878,doi:10.1007/s00376-010-0001-8.
Liu D X,Qie X S,Pan L X,et al.2013.Some characteristics of lightning activity and radiation source distribution in a squall line over North China[J].Atmospheric Research,132-133:423-433,doi:10.1016/j.atmosres.2013.06.010.
刘冬霞,郄秀书,王志超,等.2013.飑线系统中的闪电辐射源分布特征及云内电荷结构讨论[J].物理学报,62(21):219201.Liu Dongxia,Qie Xiushu,Wang Zhichao,et al.2013.Characteristics of lightning radiation source distribution and charge structure of squall line[J].Acta Physica Sinica(in Chinese),62(21):219201,doi:10.7498/aps.62.219201.
Mac Gorman D R,Rust W D,Krehbiel P,et al.2005.The electrical structure of two supercell storms during STEPS[J].Mon.Wea.Rev.,133(9):2583-2607,doi:10.1175/MWR2994.1.
Petersen,W.A.,Rutledge S.A.,Orville R.E.1996.Cloud-to-ground lightning observations from TOGA COARE:Selected results and lightning location algorithms[J].Mon.Weather Rev.,124,602-620.
Peterson M,Liu C T.2011.Global statistics of lightning in anvil and stratiform regions over the tropics and subtropics observed by the tropical rainfall measuring mission[J].J.Geophys.Res,116(D23):D23201,doi:10.1029/2011JD015908.
Srivastava A,Tian Y,Qie X S,et al.2017.Performance assessment of Beijing Lightning Network(BLNET)and comparison with other lightning location networks across Beijing[J].Atmospheric Research,197:76-83,doi:10.1016/j.atmosres.2017.06.026.
Sun J Z,Chen M X,Wang Y C.2011.A frequent-updating analysis system based on radar,surface,and mesoscale model data for the Beijing 2008forecast demonstration project[J].Wea.Forecasting,25(6):1715-17354248,doi:10.1175/2010WAF2222336.1.
Tessendorf S A,Rutledge S A.2007.Radar and lightning observations of normal and inverted polarity multicellular storms from STEPS[J].Mon.Wea.Rev.,135(11):3682-3706,doi:10.1175/2007MWR1954.1.
Wang C X,Zheng D,Zhang Y J,et al.2017.Relationship between lightning activity and vertical airflow characteristics in thunderstorms[J].Atmospheric Research,191:12-19,doi:10.1016/j.atmosres.2017.03.003.
王宇,郄秀书,王东方,等.2015.北京闪电综合探测网(BLNET):网络构成与初步定位结果[J].大气科学,39(3):571-582.Wang Yu,Qie Xiushu,Wang Dongfang,et al.2015.Beijing Lightning Network(BLNET):Configuration and preliminary results of lightning location[J].Chinese Journal of Atmospheric Sciences(in Chinese),39(3):571-582,doi:10.3878/j.issn.1006-9895.1407.14138.
Wang Y,Qie X S,Wang D F,et al.2016a.Beijing Lightning Network(BLNET)and the observation on preliminary breakdown processes[J].Atmospheric Research,171:121-132,doi:10.1016/j.atmosres.2015.12.012.
Wang F,Zhang Y J,Liu H Y,et al.2016b.Characteristics of cloud-toground lightning strikes in the stratiform regions of mesoscale convective systems[J].Atmospheric Research,178-179:207-216,doi:10.1016/j.atmosres.2016.03.021.
肖现,陈明轩,高峰,等.2015.弱天气系统强迫下北京地区对流下山演变的热动力机制[J].大气科学,39(1):100-124.Xiao Xian,Chen Mingxuan,Gao Feng,et al.2015.A thermodynamic mechanism analysis on enhancement or dissipation of convective systems from the mountains under weak synoptic forcing[J].Chinese Journal of Atmospheric Sciences(in Chinese),39(1):100-124,doi:10.3878/j.issn.1006-9895.1403.13318.
易笑园,孙晓磊,张义军,等.2017.雷暴单体合并进行中雷达回波参数演变及闪电活动的特征分析[J].气象学报,75(6):981-995.Yi Xiaoyuan,Sun Xiaolei,Zhang Yijun,et al.2017.Analysis on the“dump”phenomenon and lightning activity in cells merging based on radar parameters[J].Acta Meteor.Sin.(in Chinese),75(6):981-995,doi:10.11676/qxxb2017.073.
Zajac B A,Rutledge S A.2001.Cloud-to-ground lightning activity in the contiguous united states from 1995 to 1999[J].Mon.Wea.Rev.,129(5):999-1019,doi:10.1175/1520-0493(2001)129<0999:CTGLAI>2.0.CO;2.
Zheng D,Mac Gorman D R.2016.Characteristics of flash initiations in a supercell cluster with tornadoes[J].Atmospheric Research,167:249-264,doi:10.1016/j.atmosres.2015.08.015.
朱乾根,林锦瑞,寿绍文,等.2007.天气学原理和方法[M].4版.北京:气象出版社.Zhu Qiangen,Lin Jinrui,Shou Shaowen,et al.2007.Principles and Methods of Synoptic Meteorology(in Chinese)[M].4th ed.Beijing:China Meteorology Press.