Wei Yingzhi, Tang Dazhang, Xu Jianmin, et al. The asymmetric wind structure of Typhoon Aere detected by Doppler radar. J Appl Meteor Sci, 2007, 18(3): 285-294.
Citation: Wei Yingzhi, Tang Dazhang, Xu Jianmin, et al. The asymmetric wind structure of Typhoon Aere detected by Doppler radar. J Appl Meteor Sci, 2007, 18(3): 285-294.

The Asymmetric Wind Structure of Typhoon Aere Detected by Doppler Radar

  • Received Date: 2005-12-12
  • Rev Recd Date: 2007-01-18
  • Publish Date: 2007-06-30
  • On August 25, 2004, after typhoon Aere approaches the ocean regions northeast of Taiwan, China, its track path turns left twice consecutively, i.e., it turns firstly from northwest to west, and then from west to southwest, which differs from the normal cases and seldom occurs in history. According to the observations of Aere both by single Doppler radar and double Doppler radars, the maximum wind speed always appears in the front right side of Aere forward direction, which means the wind speed in the northwest quadrant is the maximum among all the quadrants. Furthermore, the above results further prove that the wind distributions of Aere follow the one wave number asymmetry. And it is also confirmed by other dataset analyses, i.e., the radar data from two radars situated in Changle of Fuzhou and Xiamen which are distributed in different quadrants, regular data with both ground-based observation and radiosonde observation, and NCEP reanalysis data. Among these dataset, it is revealed by the detected results with Doppler radars in both Changle of Fuzhou and Xiamen that the fundamental causes for the phenomenon that the variation of extreme radial velocity accompanies with that of the relative positions of radar and typhoon, are the unsymmetrical structure of typhoon wind. And because of that, the wind speed in the northwest quadrant is the maximum compared with the others. When the relative position of radar to that of typhoon center changes, different extreme radial velocity in different quadrants can be detected by radar. This research indicates that when Aere locates to the southeast of the continent high, there exists an environmental guide-airflow around it with velocity of about 7 m/s. Therefore, the unsymmetrical distribution with the largest maximum wind speed occurring in the northwest quadrant may be caused by both the environmental wind and Aere itself, and such asymmetry is in favor of maintaining the southw estward movement of Aere. In the coastal regions of the southeast of China, the maximum wind speed of typhoon in the northwest, northeast and southwest quadrants can not be detected simultaneously by single Doppler radar, it can be done by the double Doppler radars and the multiple Doppler radars. Therefore, when forecasting the turning tendency of typhoon track path based on the possible unsym metrical distributions of maximum wind speed, the significance for the enhancements of capability in monitoring and forecasting typhoon is great by using the double Doppler radars or multiple Doppler radars. At the same time, methods of calculating unsym metrical Rankine wind speed with the observations of Doppler radar are discussed. The calculated results show that the variation characteristics of the direction and distance of Aere unsymmetrical wind speed are very clear, and they are identical to the observations of Doppler radars. Additionally, the calculation process is simple, and to some extent, it can work as a reference to the operational forecast. The final aim is that with the detected wind velocity structure of typhoon by Doppler radars, especially the unsymmetrical structure, the possible mechanism for the sudden turn of typhoon track path can be presented, and the beneficial clues can be the further supplied for its forecast.
  • Fig. 1  Velocity image of typhoon Aere detected by radar in Changle of Fuzhou on August 25 2004(elevation:1.5°, range:150km)

    Fig. 2  Time evolution of extreme radial velocity by Doppler radar

    Fig. 3  Surface real-time wind velocity and pressure near the typhoon center on Aug 25, 2004

    Fig. 4  Extreme velocity images in the same region detected by radars in both Xiamen (a, 09:53) and Changle (b, 09:54)

    the parts in down-left and upright indicate the red points in the images

    Fig. 5  Wind velocites in upper air (a) and surface (b) near the typhoon center(unit:m/s)

    Fig. 6  Illustration of typhoon radial velocity detected by radars in the southeast coastal regions (a) the single Doppler radar to detect a typhoon, (b) the double Doppler radars to detect a typhoon moving along parallel to the coast, (c) the double Doppler radars to detect a typhoon moving from east to west, (d) the double Doppler radars to a typhoon moving along vertical to the coast

    Fig. 7  Unsymmetrical Rankine wind structure detected by Doppler radar

    Fig. 8  Typhoon Aere wind structure obtained by NCEP reanalysis data on August 25, 2004

    Table  1  500 hPa steering current for continent high around the typhoon (unit:m/s)

    Table  2  Asymmetry of extreme radial velocity detected by a single radar

  • [1]
    陈联寿. 热带气旋运动研究和业务预报的现状和发展∥台风会议文集. 北京: 气象出版社, 1985: 6-30.
    [2]
    陈联寿, 孟智勇.我国热带气旋研究十年进展.大气科学, 2001, 25(3):420-432. http://www.cnki.com.cn/Article/CJFDTOTAL-DQXK200103012.htm
    [3]
    陈联寿, 董克勤, 金汉良, 等译.热带气旋全球观.北京:气象出版社, 1994:40-52.
    [4]
    林元弼, 汤明敏, 陆森娥, 等.天气学.南京:南京大学出版社, 1988:225-228.
    [5]
    陈联寿, 罗哲贤, 李英.登陆热带气旋研究进展.气象学报, 2004, 62(5):541-549. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXB200405003.htm
    [6]
    Donaldson R J. A proposed technique for diagnosis by radar for hurricane structure. Appl Meteor, 1991, 30(12):1636-1645. doi:  10.1175/1520-0450(1991)030<1636:APTFDB>2.0.CO;2
    [7]
    Wood V T. A technique for detecting a tropical cyclone center using a Doppler radar. J Atmos Ocean Technol, 1994, 11(5): 1207-1216. doi:  10.1175/1520-0426(1994)011<1207:ATFDAT>2.0.CO;2
    [8]
    Roux F, Marks F D. Extended velocity track display (EVTD):An improved processing method for Doppler radar observations of tropical cyclones. J Atmos Ocean Technol, 1996, 13(4):875-899. doi:  10.1175/1520-0426(1996)013<0875:EVTDAI>2.0.CO;2
    [9]
    Harasti P R. The Hurricane Volume Velocity Processing Method. 31th International Conference on Radar Meteorology. Seattle, WA: Amer Meteor Soc, 2003:1008-1011.
    [10]
    Lee W C, Jou B J, Chang P L, et al. Tropical cyclone kinematic structure retrieved from single-Doppler radar observations.Part Ⅰ:Interpolation of Doppler velocity patterns and the GBVTD technique. Mon Wea Rev, 1999, 127(10):2419-2439. doi:  10.1175/1520-0493(1999)127<2419:TCKSRF>2.0.CO;2
    [11]
    Lee W C, Marks F D. Tropical cyclone kinematic structure retrieved from single-Doppler radar observations.Part Ⅱ:The GBVTD-simplex center finding algorithm. Mon Wea Rev, 2000, 128(6):1925-1936. doi:  10.1175/1520-0493(2000)128<1925:TCKSRF>2.0.CO;2
    [12]
    Harasti P R, McAdie C J, Dodge P P, et al. Real-time implementation of single-Doppler radar analysis methods for tropical cyclones:Algorithm improvements and use with WSR-88D display data. Wea Forecasting, 2004, 19(2):219-239. doi:  10.1175/1520-0434(2004)019<0219:RIOSRA>2.0.CO;2
    [13]
    张沛源, 周海光, 胡绍萍.双多普勒天气雷达风场探测的可靠性研究.应用气象学报, 2002, 13(4):485-496. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20020464&flag=1
    [14]
    张光智, 徐祥德, 王继志, 等.采用外场观测试验资料对登陆台风"黄蜂"的风场及湍流特征的观测研究.应用气象学报, 2004, 15(增刊):111-115. http://www.cnki.com.cn/Article/CJFDTOTAL-YYQX2004S1015.htm
    [15]
    朱龙彪, 郑铮, 何彩芬.0414号台风"云娜"多普勒雷达探测.应用气象学报, 2005, 16(4):500-508. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20050463&flag=1
    [16]
    李伟, 汤达章, 苏卫东.单多普勒雷达对台风的自动定位方法.南京气象学院学报, 1999, 22(2):232-237. http://www.cnki.com.cn/Article/CJFDTOTAL-NJQX199902013.htm
    [17]
    陈春忠, 姚林塔, 武锦霖.台风"飞燕"登陆前后的运动特征.气象, 2002, 28(7):38-41. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXX200207009.htm
    [18]
    陈联寿, 徐祥德, 罗哲贤, 等.热带气旋动力学引论.北京:气象出版社, 2002:92-146.
    [19]
    胡明宝, 高太长, 汤达章.多普勒天气雷达资料分析与应用.北京:解放军出版社, 2000:119-140.
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    • Received : 2005-12-12
    • Accepted : 2007-01-18
    • Published : 2007-06-30

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