北京城区热动力条件对雷暴下山后强度的影响
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摘要
2014年6月15-17日,在弱天气尺度环流系统影响下,多个γ中尺度雷暴单体经过门头沟、延庆和怀柔进入北京城区,其中一部分雷暴单体下山后强度维持不变或增强,并造成了两次短时强降水天气,但另一部分却减弱消亡。雷暴下山后强度变化的不同为预报带来了一定的困难。为此,本文利用北京地面自动站、探空、风廓线和雷达数据,着重对城区上空热动力条件进行了分析。分析结果表明,对于多个先后下山的雷暴,最先下山的雷暴会消耗城区的热动力能量,并产生中尺度的冷池和下沉气流,进而对之后经过城区的下山雷暴的强度变化产生间接影响;雷暴自身强弱是其下山后强度可否增强的另外一个主要因素,特别是有些雷暴在下山前或下山过程中强度有所增强,也有利于雷暴的顺利下山和之后的强度维持或增强。因此,追踪城区热动力条件和雷暴下山前强度的变化,是成功预报雷暴下山后强度变化的关键因素。
There are some γ-scale thunder storms moving from either the west or north mountain areas to the city of Beijing under the weak circulation systems of synoptic scale within 15-17 June 2014. It is interesting that the strength of each down-to-hill thunder storm is changing differently. For example,the first and the last moving storms become stronger while closing to the city of Beijing,but the others become weaker,which increases the difficulties in the prediction for the local forecasters. In order to find the clues to understand the various changing,several observation data,such as surface auto weather station data,sounding data,wind profiles and Doppler Radar data,are used to analysis these cases. According to the study,except for the strength of moving storms themselves is an obvious factor to influence the changes after leaving the hills,an important reason been found is that the thermal and dynamic energy would be consumed,the cold pool and the downward floware created by the moving of the thunder storms from mountain to the plain at first,so there is not enough energy and advantages available for the next thunder storms' to development. Then with the temperature of the plain increasing because of the sunshine and south wind,the thermal and dynamical condition become advantageous available again to maintain and strengthen the convective cell. M oreover,it should be noted that if the thunder storms' strength can be intensified in the mountain area,then the strength will maintain and even become stronger easily when leaving away from the hill. In conclusion,it is necessary to observe the change of the thermal and dynamic conditions in city areas,which is key to successfully forecast the strength change of down-to-hill thunder storms.
There are some γ-scale thunder storms moving from either the west or north mountain areas to the city of Beijing under the weak circulation systems of synoptic scale within 15-17 June 2014. It is interesting that the strength of each down-to-hill thunder storm is changing differently. For example,the first and the last moving storms become stronger while closing to the city of Beijing,but the others become weaker,which increases the difficulties in the prediction for the local forecasters. In order to find the clues to understand the various changing,several observation data,such as surface auto weather station data,sounding data,wind profiles and Doppler Radar data,are used to analysis these cases. According to the study,except for the strength of moving storms themselves is an obvious factor to influence the changes after leaving the hills,an important reason been found is that the thermal and dynamic energy would be consumed,the cold pool and the downward floware created by the moving of the thunder storms from mountain to the plain at first,so there is not enough energy and advantages available for the next thunder storms' to development. Then with the temperature of the plain increasing because of the sunshine and south wind,the thermal and dynamical condition become advantageous available again to maintain and strengthen the convective cell. M oreover,it should be noted that if the thunder storms' strength can be intensified in the mountain area,then the strength will maintain and even become stronger easily when leaving away from the hill. In conclusion,it is necessary to observe the change of the thermal and dynamic conditions in city areas,which is key to successfully forecast the strength change of down-to-hill thunder storms.
引文
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Wilson J W,Chen M X,Wang Y C.2007.Now casting thunderstorms for the 2008 summer Olympics[C]//The 33rdInternational Conference on Radar M eteorology.Cairns:Australia,Amer M eteor Soc,12.
Wilson J W,Crook N A,M ueller C K.1998.Now casting thunderstorms:A status report[J].Bull Amer M eteor Soc,79(10):2079-2099.
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Wilson J W,M egenhardt D L.1997.Thunderstorm initiation,organization and lifetime associated w ith Florida boundary layer convergence lines[J].M on Wea Rev,125(7):1507-1525.
曹云昌,方宗义,李成才,等.2005.利用GPS和云图资料监测北京地区中尺度降水的研究[J].高原气象,24(1):91-96.Cao Yunchang,Fang Zongyi,Li Chengcai,et al.2005.Test on monitoring meso-and micro-scale precipitation in Beijing using GPSdata and satellite image[J].Plateau M eteor,24(1):91-96.
陈明轩,高峰,孔荣等.2010.自动临近预报系统及其在北京奥运期间的应用[J].应用气象学报,21(4):395-404.Chen Mingxuan,Gao Feng,Kong Rong,et al.2010.Introduction of auto-nowcasting system for convective storm and its performance in Beijing Olympics meteorological service[J].J Appl M eteor Sci,21(4):395-404.
陈明轩,王迎春,肖现,等.2013.北京“7·21”暴雨雨团的发生和传播机理[J].气象学报,71(4):569-592.Chen Mingxuan,Wang Yingchun,Xiao Xian,et al.2013.Initiation and propagation mechanism for the Beijing extreme heavy rainstorm clusters on21 July 2012[J].Acta M eteor Sinica,71(4):569-592.
陈双,王迎春,张文龙,等.2011.复杂地写下雷暴增强过程的个例研究[J].气象,37(7):802-813.Chen Shuang,Wang Yingchun,Zhang Wenlong,et al.2011.Intensifying mechanism of the convective storm moving from the mountain to the plain over Beijing area[J].M eteor M on,37(7):802-813.
黄荣,王迎春,张文龙.2012a.复杂地形下北京一次局地雷暴新生和增强机制初探[J].暴雨灾害,31(3):232-241.Huang Rong,Wang Yingchun,Zhang Wenlong.2012a.Initiating and intensifying mechanism of a local hunderstorm over complex terrain of Beijing[J].Torrential Rain and Disasters,31(3):232-241.
黄荣,王迎春.2012b.北京地区雷暴下山增强的特征分析及个例研究[D].北京:中国气象科学研究院.Huang Rong,Wang Yingchun.2012b.Features of Intensifying thunderstorms moving dow n from the mountains and case study in Beijing[D].Beijing:Chinese Academy of M eteorological Sciences.
李娜,冉令坤,周玉淑,等.2013.北京“7·21”暴雨过程中变形场引起的锋生与倾斜涡度发展诊断分析[J].气象学报,71(4):593-605.Li Na,Ran Lingkun,Zhou Yushu,et al.2013.Diagnosis of the frontogenesis and slantw ise vorticity development caused by the deformation in the Beijing“7·21”torrential rainfall event[J].Acta Meteor Sinica,71(4):593-605.
李青春,苗世光,郑祚芳,等.2011.北京局地暴雨过程中近地面辐合线的形成与作用[J].高原气象,30(5):1232-1242.Li Qingchun,M iao Shiguang,Zheng Zuofang,et al.2011.Formation and effect of surface convergence line in local rainstorm process of Beijing[J].Plateau M eteor,30(5):1232-1242.
李书严,陈洪滨,李伟.2008.城市化对北京地区气候的影响[J].高原气象,27(5):1102-1110.Li Shuyan,Chen Hongbin,Li Wei.2008.The impact of urbanization on city climate of Beijing region[J].Plateau Meteor,27(5):1102-1110.
廖晓农,倪允琪,何娜,等.2013.导致“7·21”特大暴雨过程水汽异常充沛的天气尺度动力过程分析研究[J].气象学报,71(6):997-1011.Liao Xiaonong,Ni Yunqi,He Na,et al.2013.Analysis of the synoptic-scale dynamic process causing the extreme moisture environment in the“7·21”heavy rain case[J].Acta M eteoro,71(6):997-1011.
廖晓农,俞小鼎,王迎春.2008.北京地区一次罕见的雷暴大风过程特征分析[J].高原气象,27(6):1350-1362.Liao Xiaonong,Yu Xiaoding,Wang Yingchun.2008.Analysis on an exceptionally strong w ind gust event in Beijing[J].Plateau M eteor,27(6):1350-1362.
孙继松,杨波.2008.地形与城市环流共同作用下的β中尺度暴雨[J].大气科学,32(6):1352-1364.Sun Jisong,Yang Bo.2008.M eso-βscale torrential rain affected by topography and the urban circulation[J].Chinese J Atmos Sci,32(6):1352-1364.
孙继松,舒文军.2007.北京城市热岛效应对冬夏季降水的影响研究[J].大气科学,31(2):311-320.Sun Jisong,Shu Wenjun.2007.The Effect of urban heat island on w inter and summer precipitation in Beijing region[J].Chinese J Atmos Sci,31(2):311-320.
孙继松,王华,王令,等.2006.城市边界层过程在北京2004年7月10日局地暴雨过程中的作用[J].大气科学,30(2):221-234.Sun Jisong,Wang Hua,Wang Ling,et al.2006.The role of urban boundary layer in local convective torrential rain happening in Beijing on 10 July 2004[J].Chinese J Atmos Sci,30(2):221-234.
孙建华,赵思雄,傅慎明,等.2013.2012年7月21日北京特大暴雨的多尺度特征[J].大气科学,37(3):705-718.Sun Jianhua,Zhao Sixiong,Fu Shenming,et al.2013.M ulti-scale characteristics of record heavy rainfall over Beijing area on July 21,2012[J].Chinese J Atmos Sci,37(3):705-718.
孙靖,王建捷.2010.北京地区一次引发强降水的中尺度对流系统的组织发展特征及成因探讨[J].气象,36(12):19-27.Sun Jing,Wang Jianjie.2010.Investigation on systematic development of mesoscale convective systems in a torrential rain event over Beijing[J].Meteor Mon,36(12):19-27.
王建捷,李泽椿.2002.1998年一次梅雨锋暴雨中尺度对流系统的模拟与诊断分析[J].气象学报,60(2):146-156.Wang Jianjie,Li Zechun.2002.Numerical simulation and diagnostic analysis on mesoscale convective systems of a torrential rain case in M eiyu period of 1998[J].Acta M eteor Sinica,60(2):146-156.
王秀明,俞小鼎,周小刚.2014.雷暴潜势预报中几个基本问题的讨论[J].气象,40(4):389-399.Wang Xiuming,Yu Xiaoding,Zhou Xiaogang.2014.Discussion on basical issues of thunderstorm potential forecasting[J].M eteor M on,40(4):389-399.
王秀荣,王维国,刘还珠,等.2008.北京降水特征与西太副高关系的若干统计[J].高原气象,27(4):822-829.Wang Xiurong,Wang Weiguo,Liu Huanzhu,et al.2008.Beijing region precipitation feature and some statistics of relationship betw een it and SH-WP[J].Plateau M eteor,27(4):822-829.
肖现,王迎春,陈明轩,等.2013.基于雷达资料四维变分同化技术对北京地区一次下山突发性增强风暴热动力机制的模拟分析[J].气象学报,71(5):797-816.Xiao Xian,Wang Yingchun,Chen M ingxuan,et al.2013.A mechanism analysis of the thermodynamical field of a suddenly intensifying storm from mountains in the Beijing area w ith the radar data 4DVar[J].Acta M eteor Sinica,71(5):797-816.
俞小鼎,周小刚,王秀明.2012.雷暴与强对流临近天气预报技术进展[J].气象学报,70(3):311-337.Yu Xiaoding,Zhou Xiaogang,Wang Xiuming.2012.The advances in the now casting techniques on thunderstorms and severe convection[J].Acta M eteor Sinica,70(3):311-337.
Wilson J W,Chen M X,Wang Y C.2007.Now casting thunderstorms for the 2008 summer Olympics[C]//The 33rdInternational Conference on Radar M eteorology.Cairns:Australia,Amer M eteor Soc,12.
Wilson J W,Crook N A,M ueller C K.1998.Now casting thunderstorms:A status report[J].Bull Amer M eteor Soc,79(10):2079-2099.
Wilson J W,Feng Y,Chen M,et al.2010.Now casting challenges during the Beijing Olympics:Successes,failures,and implications for future now casting systems[J].Wea Forecasting,25(6):1691-1714.
Wilson J W,M egenhardt D L.1997.Thunderstorm initiation,organization and lifetime associated w ith Florida boundary layer convergence lines[J].M on Wea Rev,125(7):1507-1525.
曹云昌,方宗义,李成才,等.2005.利用GPS和云图资料监测北京地区中尺度降水的研究[J].高原气象,24(1):91-96.Cao Yunchang,Fang Zongyi,Li Chengcai,et al.2005.Test on monitoring meso-and micro-scale precipitation in Beijing using GPSdata and satellite image[J].Plateau M eteor,24(1):91-96.
陈明轩,高峰,孔荣等.2010.自动临近预报系统及其在北京奥运期间的应用[J].应用气象学报,21(4):395-404.Chen Mingxuan,Gao Feng,Kong Rong,et al.2010.Introduction of auto-nowcasting system for convective storm and its performance in Beijing Olympics meteorological service[J].J Appl M eteor Sci,21(4):395-404.
陈明轩,王迎春,肖现,等.2013.北京“7·21”暴雨雨团的发生和传播机理[J].气象学报,71(4):569-592.Chen Mingxuan,Wang Yingchun,Xiao Xian,et al.2013.Initiation and propagation mechanism for the Beijing extreme heavy rainstorm clusters on21 July 2012[J].Acta M eteor Sinica,71(4):569-592.
陈双,王迎春,张文龙,等.2011.复杂地写下雷暴增强过程的个例研究[J].气象,37(7):802-813.Chen Shuang,Wang Yingchun,Zhang Wenlong,et al.2011.Intensifying mechanism of the convective storm moving from the mountain to the plain over Beijing area[J].M eteor M on,37(7):802-813.
黄荣,王迎春,张文龙.2012a.复杂地形下北京一次局地雷暴新生和增强机制初探[J].暴雨灾害,31(3):232-241.Huang Rong,Wang Yingchun,Zhang Wenlong.2012a.Initiating and intensifying mechanism of a local hunderstorm over complex terrain of Beijing[J].Torrential Rain and Disasters,31(3):232-241.
黄荣,王迎春.2012b.北京地区雷暴下山增强的特征分析及个例研究[D].北京:中国气象科学研究院.Huang Rong,Wang Yingchun.2012b.Features of Intensifying thunderstorms moving dow n from the mountains and case study in Beijing[D].Beijing:Chinese Academy of M eteorological Sciences.
李娜,冉令坤,周玉淑,等.2013.北京“7·21”暴雨过程中变形场引起的锋生与倾斜涡度发展诊断分析[J].气象学报,71(4):593-605.Li Na,Ran Lingkun,Zhou Yushu,et al.2013.Diagnosis of the frontogenesis and slantw ise vorticity development caused by the deformation in the Beijing“7·21”torrential rainfall event[J].Acta Meteor Sinica,71(4):593-605.
李青春,苗世光,郑祚芳,等.2011.北京局地暴雨过程中近地面辐合线的形成与作用[J].高原气象,30(5):1232-1242.Li Qingchun,M iao Shiguang,Zheng Zuofang,et al.2011.Formation and effect of surface convergence line in local rainstorm process of Beijing[J].Plateau M eteor,30(5):1232-1242.
李书严,陈洪滨,李伟.2008.城市化对北京地区气候的影响[J].高原气象,27(5):1102-1110.Li Shuyan,Chen Hongbin,Li Wei.2008.The impact of urbanization on city climate of Beijing region[J].Plateau Meteor,27(5):1102-1110.
廖晓农,倪允琪,何娜,等.2013.导致“7·21”特大暴雨过程水汽异常充沛的天气尺度动力过程分析研究[J].气象学报,71(6):997-1011.Liao Xiaonong,Ni Yunqi,He Na,et al.2013.Analysis of the synoptic-scale dynamic process causing the extreme moisture environment in the“7·21”heavy rain case[J].Acta M eteoro,71(6):997-1011.
廖晓农,俞小鼎,王迎春.2008.北京地区一次罕见的雷暴大风过程特征分析[J].高原气象,27(6):1350-1362.Liao Xiaonong,Yu Xiaoding,Wang Yingchun.2008.Analysis on an exceptionally strong w ind gust event in Beijing[J].Plateau M eteor,27(6):1350-1362.
孙继松,杨波.2008.地形与城市环流共同作用下的β中尺度暴雨[J].大气科学,32(6):1352-1364.Sun Jisong,Yang Bo.2008.M eso-βscale torrential rain affected by topography and the urban circulation[J].Chinese J Atmos Sci,32(6):1352-1364.
孙继松,舒文军.2007.北京城市热岛效应对冬夏季降水的影响研究[J].大气科学,31(2):311-320.Sun Jisong,Shu Wenjun.2007.The Effect of urban heat island on w inter and summer precipitation in Beijing region[J].Chinese J Atmos Sci,31(2):311-320.
孙继松,王华,王令,等.2006.城市边界层过程在北京2004年7月10日局地暴雨过程中的作用[J].大气科学,30(2):221-234.Sun Jisong,Wang Hua,Wang Ling,et al.2006.The role of urban boundary layer in local convective torrential rain happening in Beijing on 10 July 2004[J].Chinese J Atmos Sci,30(2):221-234.
孙建华,赵思雄,傅慎明,等.2013.2012年7月21日北京特大暴雨的多尺度特征[J].大气科学,37(3):705-718.Sun Jianhua,Zhao Sixiong,Fu Shenming,et al.2013.M ulti-scale characteristics of record heavy rainfall over Beijing area on July 21,2012[J].Chinese J Atmos Sci,37(3):705-718.
孙靖,王建捷.2010.北京地区一次引发强降水的中尺度对流系统的组织发展特征及成因探讨[J].气象,36(12):19-27.Sun Jing,Wang Jianjie.2010.Investigation on systematic development of mesoscale convective systems in a torrential rain event over Beijing[J].Meteor Mon,36(12):19-27.
王建捷,李泽椿.2002.1998年一次梅雨锋暴雨中尺度对流系统的模拟与诊断分析[J].气象学报,60(2):146-156.Wang Jianjie,Li Zechun.2002.Numerical simulation and diagnostic analysis on mesoscale convective systems of a torrential rain case in M eiyu period of 1998[J].Acta M eteor Sinica,60(2):146-156.
王秀明,俞小鼎,周小刚.2014.雷暴潜势预报中几个基本问题的讨论[J].气象,40(4):389-399.Wang Xiuming,Yu Xiaoding,Zhou Xiaogang.2014.Discussion on basical issues of thunderstorm potential forecasting[J].M eteor M on,40(4):389-399.
王秀荣,王维国,刘还珠,等.2008.北京降水特征与西太副高关系的若干统计[J].高原气象,27(4):822-829.Wang Xiurong,Wang Weiguo,Liu Huanzhu,et al.2008.Beijing region precipitation feature and some statistics of relationship betw een it and SH-WP[J].Plateau M eteor,27(4):822-829.
肖现,王迎春,陈明轩,等.2013.基于雷达资料四维变分同化技术对北京地区一次下山突发性增强风暴热动力机制的模拟分析[J].气象学报,71(5):797-816.Xiao Xian,Wang Yingchun,Chen M ingxuan,et al.2013.A mechanism analysis of the thermodynamical field of a suddenly intensifying storm from mountains in the Beijing area w ith the radar data 4DVar[J].Acta M eteor Sinica,71(5):797-816.
俞小鼎,周小刚,王秀明.2012.雷暴与强对流临近天气预报技术进展[J].气象学报,70(3):311-337.Yu Xiaoding,Zhou Xiaogang,Wang Xiuming.2012.The advances in the now casting techniques on thunderstorms and severe convection[J].Acta M eteor Sinica,70(3):311-337.