Guo Hu, Duan Li, Yang Bo, et al. Mesoscale and microscale analysis on a local torrential rain event in Fragrant Hills area of Beijing on July 9, 2006. J Appl Meteor Sci, 2008, 19(3): 265-275.
Citation: Guo Hu, Duan Li, Yang Bo, et al. Mesoscale and microscale analysis on a local torrential rain event in Fragrant Hills area of Beijing on July 9, 2006. J Appl Meteor Sci, 2008, 19(3): 265-275.

Mesoscale and Microscale Analysis on a Local Torrential Rain Event in Fragrant Hills Area of Beijing on July 9, 2006

  • Received Date: 2007-09-17
  • Rev Recd Date: 2008-01-03
  • Publish Date: 2008-06-30
  • The local rainstorm in fragrant hills area of western Beijing at night on July 9, 2006 is an intense rainfall event, which covers only around 10 to 20 kilometers, and the severe rain lasts only 2 hours. Considering the temporal and spatial scale and the distribution of the rainfall, it is difficult to analyze and describe by regular meteorological data and synoptic-dynamic diagnosis methods even mesoscale dynamic models. Therefore, it is studied by intensified observation data including Doppler weather radar products, wind profile data, wind element of surface automatic weather stations and detection data of atmospheric water vapor by GPS, etc. It is found that development of the meso-γ scale heavy rain, even the disturbance in surface and boundary layer around the rainfall area, can be captured by the above mentioned data. Moreover, meso-scale convective system of the local heavy rain event and dynamic mechanism forming severe rain can also be explained by these data exactly.Fine research on the local heavy rain event by these observation data shows that topographic convergence line is proved to be the major system that causes the local torrential rainfall, and the formation and development of mesocyclone in the echo belt by topographic convergence line is the main factor causing the heavy rain. Convergence in atmospheric surface layer is very important in the local heavy rain event. Besides, the studies show that topographic convergence disturbance in surface layer in front of the mountain spreads upward giving rise to boundary layer disturbance which is the main dynamic factor of the heavy rain in fragrant hills zone. Sufficient water vapor and energy for the heavy rainstorm are provided by warm-moist advection of atmospheric surface layer from southeast.From the above analysis, it is concluded: Against the large scale background of warm-moist airflow ahead of long-wave trough in middle troposphere about 500 hPa in the daytime in summer and weak anti-cyclone wind in low layer in Beijing, topographic convergence echo belts can be formed by formation and development of southeast wind in surface layer at dusk on the plain. Meso-γ scale echoes with features of mesocyclone in the echo belts move and develop from southwest to northeast along southwest airflow ahead of 500 hPa long-wave trough. It is the major cause that brings the local rainstorm in fragrant hills area of Beijing at night on July 9, 2006. Convergence in atmospheric surface layer plays an important role in the local heavy rain event. There are three types of convergence simultaneously during the severe rain period of two hours: Wind shear convergence between the southeast wind from the plain and the north wind from the mountains, convergence and lifting of the southeast wind from the plain by mountains, and cyclonic convergence of meso-γ scale system in the center of rainfall region. Fine research on wind profile data around heavy rainfall region shows that there are disturbance in surface layer and it spreads upward, then boundary layer disturbance appears twice during the severe rain period during the two hours. Each propagation is about one hour and twenty minutes. It is one of the main dynamic mechanisms that cause the local heavy rain to occur. According to GPS water vapor data and Doppler radar velocity products, there warm-moist airflow in atmospheric surface layer from southeast to the core of the heavy rainstorm before and during the torrential rain.
  • Fig. 1  Total precipitation and precipitation hourly during severe rain period of the local rainstorm in Xiangshan zone (unit: mm)

    (a) 21:00 Jul 9—04:00 Jul 10, 2006, (b) 21:00 Jul 9—01:00 Jul 10, 2006, (c) 21:00Jul 9—22:00 Jul 9, 2006, (d) 22:00 Jul 9—23:00 Jul 9, 2006, (e) 23:00 Jul 9—00:00 Jul 10, 2006, (f) 00:00 Jul 10—01:00 Jul 10, 2006

    Fig. 2  Radar composite reflectivity factor by Doppler weather radar in south Beijing, wind element from surface automatic weather stations and terrain of Beijing (a) radar composite reflectivity factor intensity at 21:01 on Jul 9, 2006, (b) Beijing topographic map, (c) radar composite reflectivity factor intensity at 21:20 on Jul 9, 2006, (d) wind element of surface automatic weather stations at 21:00 on Jul 9, 2006 (the red curve shows the wind convergence line)

    Fig. 3  Trace pictures of radar reflectivity factor (elevation:2.4°) by Doppler weather radar in south Beijing during severe rain period in heavy rainfall region

    (a) 21:20 Jul 9, 2006, (b) 21:32 Jul 9, 2006, (c) 21:50 Jul 9, 2006, (d) 22:08 Jul 9, 2006, (e) 22:30 Jul 9, 2006(the pink elliptical circle shows the heavy rainfall region, the white elliptical circle is echo No.1, the black one is echo No.2, the red one is echo No.3)

    Fig. 4  Mesocyclone analysis on the local rainstorm from comprehensive products of Doppler weather radar in south Beijing on Jul 9, 2006 (a) Doppler radar echo reflectivity velocity picture at 21:32 (elevation:2.4°), (b) Doppler radar echo reflectivity velocity picture at 21:38 (elevation:2.4°), (c) Doppler radar echo reflectivity velocity picture at 21:44 (elevation:2.4°), (d) vertical integrated liquid content at 21:32, (e) height of maximum echo tops at 21:32 (the yellow elliptical circle shows the heavy rainfall region, the white one is position of mesocyclone echo)

    Fig. 5  Surface wind element from automatic weather stations and trace of composite reflectivity factor of Doppler weather radar in south Beijing on Jul 9—10, 2006 (a)—(d) surface wind element from automatic weather stations

    Fig. 6  Wind profilers at Haidian (a) and Guanxiangtai (b) stations every 6 minutes from 19:30 Jul 9 to 00:30 Jul 10, 2006

    (the green elliptical circle shows the increasing period of surface south-east wind at Haidian station; the pink one shows the period of surface disturbance; the blue rectangle shows the wind convergence period between the north wind after surface disturbance at Haidian station and surface east wind at Guanxiangtai; the yellow elliptical circle is the period when surface disturbance spread to boundary layer at Haidian station)

    Fig. 7  Topographic influence on distribution of surface vertical wind profilers in heavy rainfall region

    Fig. 8  Radar reflectivity velocity picture and water vapor picture by GPS before and during the heavy rain at night on Jul 9, 2006

  • [1]
    毕宝贵.中尺度地形对陕南暴雨的影响研究.南京:南京信息工程大学, 2004.
    [2]
    陶诗言.中国之暴雨.北京:科学出版社, 1980.
    [3]
    孙淑清, 马廷标, 孙纪改.低空急流与暴雨相互关系的对比分析.气象学报, 1979, 37(4): 36-44. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXB197904004.htm
    [4]
    孙淑清, 翟国庆.低空急流的不稳定性及其对暴雨的触发作用.大气科学, 1980, 4(4): 327-337. http://www.cnki.com.cn/Article/CJFDTOTAL-DQXK198004005.htm
    [5]
    Ninomiya K, Akiyama T, Ikawa M. Evolution and fine structure of a long-lived meso-α scale convective system in Baiu front zone. Part Ⅰ: Evolution and meso-β-scale characteristics. J Meteor Soc Japan, 1988, 66: 331-350. http://cat.inist.fr/?aModele=afficheN&cpsidt=6980599
    [6]
    Ninomiya K, Akiyama T, Ikawa M. Evolution and fine structure of a long-lived meso-α scale convective system in Baiu front zone. Part Ⅱ: Evolution and meso-γ-scale characteristics of precipitation. J Meteor Soc Japan, 1988, 66: 351-371.
    [7]
    Shibagaki Y, Yabanaka M D, Shimizu S, et al. Meso-β to meso-γ-scale wind circulations associated with precipitating clouds near Beiu front observed by the MU and meteorological radars. J Meteor Soc Japan, 2000, 78: 69-91.
    [8]
    周海光, 王玉彬.2003年6月30日梅雨锋大暴雨βγ中尺度结构的双多普勒雷达反演.气象学报, 2005, 63(3): 301-312. http://kns.cnki.net/KCMS/detail/detail.aspx?dbcode=CJFQ&dbname=CJFD2005&filename=QXXB200503005&v=MDA1ODBGckNVUkwyZlpPUnRGeXZnVWI3UE5EWFRiTEc0SHRUTXJJOUZZWVI4ZVgxTHV4WVM3RGgxVDNxVHJXTTE=
    [9]
    倪允琪, 周秀骥.中国长江流域中下游梅雨锋暴雨形成机理及监测与预测理论和方法研究.气象学报, 2005, 63(3): 647-661. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXB200405011.htm
    [10]
    冯伍虎.强暴雨中尺度系统发展结构和机理的非静力数值模式模拟研究.兰州:兰州大学, 2006.
    [11]
    王令, 康玉霞, 焦热光, 等.北京地区强对流天气雷达回波特征.气象, 2004, 30(7): 31-36. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXX200407006.htm
    [12]
    俞小鼎, 郑媛媛, 张爱民, 等.安徽一次强烈龙卷的多普勒天气雷达分析.高原气象, 2006, 25(5): 914-924. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX200605019.htm
    [13]
    刘黎平, 阮征, 覃丹宇.长江流域梅雨锋暴雨过程的中尺度结构个例分析.中国科学 (D辑), 2004, 34(12): 1193-1201. http://www.cnki.com.cn/Article/CJFDTOTAL-JDXK20041200C.htm
    [14]
    刘淑媛, 郑永光, 陶祖钰.利用风廓线雷达资料分析低空急流的脉动与暴雨关系.热带气象学报, 2003, 19(3): 285-290. http://cpfd.cnki.com.cn/Article/CPFDTOTAL-BJQX200811001013.htm
    [15]
    王欣, 卞林根, 彭浩, 等.风廓线仪系统探测试验与应用.应用气象学报, 2005, 16(5) : 693-698. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20050590&flag=1
    [16]
    俞小鼎, 姚秀萍, 熊廷南, 等.多普勒天气雷达原理与业务应用.北京:气象出版社, 2006.
    [17]
    朱乾根, 林锦瑞, 寿绍文, 等.天气学原理和方法.北京:气象出版社, 1981.
  • 加载中
  • -->

Catalog

    Figures(8)

    Article views (7908) PDF downloads(4838) Cited by()
    • Received : 2007-09-17
    • Accepted : 2008-01-03
    • Published : 2008-06-30

    /

    DownLoad:  Full-Size Img  PowerPoint