doi:  10.3878/j.issn.1006-9895.1701.16246
2015年7月中旬京津冀持续性夜间雷雨天气成因初步分析

An Analysis on Night Thunderstorm Weather over Beijing-Tianjin-Hebei Area during Mid-July 2015
摘要点击 225  全文点击 160  投稿时间:2016-10-14  
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基金:  国家重点基础研究发展计划(973计划)项目2014CB441402,国家自然科学基金项目41475054、41661144024、41275065、41475097
中文关键词:  京津冀地区  雷雨天气  水汽  辐合辐散
英文关键词:  Beijing-Tianjin-Hebei region  Thunderstorm  Water vapor  Convergence and divergence
           
作者中文名作者英文名单位
王小晴WANG Xiaoqing南京信息工程大学地理与遥感学院, 南京 210044
周玉淑ZHOU Yushu中国科学院大气物理研究所云降水物理与强风暴院重点实验室(LACS), 北京 100029;中国科学院大学地球科学学院, 北京 100049
平凡PING Fan中国科学院大气物理研究所云降水物理与强风暴院重点实验室(LACS), 北京 100029
蔡军CAI Jun北京应用气象研究所, 北京 100029
引用:王小晴,周玉淑,平凡,蔡军.2017.2015年7月中旬京津冀持续性夜间雷雨天气成因初步分析[J].大气科学,41(6):1284-1299,doi:10.3878/j.issn.1006-9895.1701.16246.
Citation:WANG Xiaoqing,ZHOU Yushu,PING Fan,CAI Jun.2017.An Analysis on Night Thunderstorm Weather over Beijing-Tianjin-Hebei Area during Mid-July 2015[J].Chinese Journal of Atmospheric Sciences (in Chinese),41(6):1284-1299,doi:10.3878/j.issn.1006-9895.1701.16246.
中文摘要:
      2015年7月15日00:00至20日00:00(协调世界时,下同)期间,京津冀地区每天傍晚均有明显雷阵雨天气过程发生,持续约一周时间。天气形势分析发现:虽然都是傍晚到夜间出现雷雨天气,但15~17日的雷雨过程,500 hPa主要表现为两槽一脊天气形势,京津冀地区处于低槽前部的不稳定区。18~19日两天,京津冀地区西部为低槽,东部为副热带高压(副高),主要表现为西低东高的天气形势,是华北地区典型的暴雨天气型之一。15~17日与18~19日的水汽输送路径也有明显区别,15~17日以西南暖湿气流直接向东北方向输送以及台风外围偏东风气流向京津冀输送水汽为主,18~19日则为西南暖湿气流向东北方向直接输送到东海以东洋面后转为偏东风向京津冀输送为主,但是,水汽辐合中心均出现在京津冀附近,且水汽通量及辐合总是在12:00大于00:00,意味着傍晚的水汽条件好于白天。动力条件方面,整个降水期间,京津冀区域的对流层高层均处于南亚高压外围辐散区,低层辐合层次主要集中在700 hPa以下,近地面层12:00的辐合更为剧烈,中层均有干冷偏西气流下沉后与低层暖湿偏东气流辐合抬升,12:00的干冷气流下沉层次更低,与偏东风的辐合更强。温度层结方面,京津冀区域平均的气温垂直温差在800 hPa以下总是12:00高于00:00。降水期间,上升速度在中高层均表现为00:00大于12:00,但是低层的上升速度都是12:00强于00:00,傍晚的动力和水汽条件都更利于降水发生。
Abstract:
      Thundershowers occurred every evening from 0000 UTC 15 July to 0000 UTC 19 July in Beijing-Tianjin-Hebei region. Results showed that the weather situation was different though the heavy rainstorm always occurred from evening to night. There was a "trough-ridge-trough" weather pattern at 500 hPa and Beijing-Tianjin-Hebei region was located in the unstable area in front of a trough from 15 July to 17 July. From 18 July to 19 July, the western part of Beijing-Tianjin-Hebei region was under the control of the trough while the eastern part was controlled by the subtropical high, which was a typical rainstorm pattern in North China. The water vapor transportation was also significantly different. From 15 July to 17 July, the warm wet southwesterly winds and the easterly winds along the periphery of a typhoon provided the main water vapor supply for thunderstorms in Beijing-Tianjin-Hebei region. From 18 July to 19 July, the major moisture supply was provided by warm wet southwesterly winds, which reached East China Sea first and then turned eastward, transporting moisture to Beijing-Tianjin-Hebei region. During the whole week, the center of water vapor convergence appeared near the Beijing-Tianjin-Hebei area, and the water vapor flux and convergence occurred at 1200 UTC were always greater than that at 0000 UTC, which suggested that the water vapor condition in the evening was better than in the daytime. As for the dynamic condition, Beijing-Tianjin-Hebei area was located in the peripheral divergence region of South Asia high, while convergence mainly occurred beneath 700 hPa and was stronger at 1200 UTC. The dry cold downdraft originated from the middle troposphere merged with the moist warm air originated from low levels. The dry cold downdraft descended to lower levels and the convergence was stronger at 1200 UTC. At the same time, vertical temperature difference beneath 800 hPa was stronger at 1200 UTC, which indicated the atmospheric instability was stronger at 1200 UTC. Though the vertical velocity at the upper level at 0000 UTC was stronger than that at 1200 UTC, the vertical velocity at low levels was always stronger at 1200 UTC. In summary, the thermodynamic and moisture conditions were more conducive to thunderstorm occurrence from evening to night.
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