新疆地区一次对流性降水的三维中尺度风场研究  

Study on Three-dimensional Wind Fields of Mesoscale Convective Systems in Xinjiang

作　　者：庄薇[1] 刘黎平[1] 王楠[2] 

机构地区：[1]中国气象科学研究院灾害天气国家重点实验室,北京100081 [2]陕西省气象台,西安710015

出　　处：《应用气象学报》2006年第4期444-451,共8页Journal of Applied Meteorological Science

基　　金：国家自然科学基金项目(40375008)资助

摘　　要：利用2004年外场试验获得的乌鲁木齐和五家渠C波段双多普勒雷达资料,分析了双多普勒雷达风场反演方法和资料的可靠性,研究了2004年8月8日发生在乌鲁木齐和五家渠的一次强对流性降水的回波和风场中尺度结构及演变过程。结果表明:这两部雷达观测的回波强度相关很好,雷达基线上的径向速度基本一致,资料可靠,适合进行双多普勒雷达观测;Cressman插值的影响半径的变化对风场的中尺度结构基本没有影响,径向速度误差引起的风场反演误差与该点所处的位置有关,1 m/s径向速度误差也不会改变风场的中尺度结构。该过程为对流单体发展为对流带状回波的过程,在对流单体的左侧生成新的对流单体,逐步发展为长度约90 km范围的带状对流系统,该系统恰与较强的东北风和较弱的西风形成的辐合相对应,上升气流与强对流回波相对应,不同对流单体有各自相独立的风场结构。用双多普勒雷达观测得到对流系统的内部风场有利于了解对流系统的内部动力过程,从而探讨降水的形成和演变机理。The dual Doppler radar system constructed by two C-band Doppler radars in Urumqi and Wujiaqu is used to detect convective systems in Xinjiang Uighur Autonomous Region in 2004, it is supported by the project of National Natural Science Foundation of China （NSFC） ＂Study on Meso-scale Kinetic and Thermodynamic Feature of Precipitation System with Dual Doppler Radar in Xinjiang＂. It focuses on the three-dimensional wind field retrieved with dual Doppler radar technique in the strong mesoscale convective systems that produces relatively heavy rainfall within the observational network from 22：30（BT） 7 August to 02：30 8 August 2004, and the three-dimensional wind structure of these systems as well as their evolution processes are analyzed. Moreover, the radar data quality and reliability of the wind retrieval algorithm with dual Doppler radar are also examined. The positions and structures of radar echoes captured by the two radars are well matched, the radial velocities observed by the radars above the radar baseline are mostly the same, the dual Doppler radar technique is reliable and suitable for the observations of mesoscale convective systems. The sensitivity analysis of the interpolation algorithm on wind retrieval framework demonstrates that the influence radius of Cressman interpolation does not play a significant role in determining the wind structures of mesoscale convections. Even though the wind retrieval errors resulted from the radial velocity measurement errors are associated with their relative positions to the radars, however, such type of errors within 1 m/s on redial velocity would not change the major shapes of the mesoscale wind structures. According to the evolutions of these mesoscale systems, the several convective cells develop into convective precipitation band. Some new cells are generated along the left side of the old ones, whose reflectivity vary from 50 to 55 dBz with the maximum 8 km top height, and finally develop as a band-shaped convective cluster （with 90 km length

关 键 词：双多普勒雷达 风场结构 中尺度对流系统 

分 类 号：P458.121[天文地球—大气科学及气象学]