摘要
多普勒天气雷达在强风速天气条件下经常出现的速度模糊误差,严重限制了风场信息的广泛应用,如反演VAD廓线等。本文将最优插值客观分析质量控制技术(OIQC),应用于雷达反演VAD廓线资料中速度模糊的质量控制。对用于反演VAD风廓线的那些格点圈层上的资料,以简化的多变量统计插值技术(Cressman插值),为被检查的资料提供一个对比分析的参考值,从而确定折叠次数,修正模糊速度。根据多普勒雷达径向速度资料的特点,水平方向采用非各向同性的单变量背景场误差协方差函数,垂直方向协方差函数取为高斯型。修正模糊速度后运用VAD技术得到水平风的垂直廓线。对强龙卷天气过程的数值试验结果表明,OIQC技术应用于雷达资料质量控制,无需引入外界风场,有能力修正模糊速度。结合VAD方法,可以从存在严重折叠的雷达资料中反演出较为准确的风廓线。
Doppler radar has the ability to scan large volumes of the atmosphere at high spatial and temporal resolutions, but ambiguities limit its data using widely. The application of the Optimal Interpolation Quality Control （OIQC） method to the Radar velocity-azimuth display（VAD） data quality control which is presented in this paper. This is based on the ECMWF optimal interpolation quality control technique. Here the simple statistical interpolation method just the Cressman interpolation is adopted. The single variable background error covariance is used because of the characters of the Doppler Radar radial velocity data. And the homogeneous but anisotropic covariance function is adopted in the horizontal orientation according to radial velocity characters. The covariance function in the vertical orientation is Gauss style. For the tested data on the circle and tilt which is formed the VAD wind profile, the Cressman interpolation is used to provide a reference value at every data gate. Comparison the reference velocity with observation data the Nyquist is decided. After the dealiasing, the horizontal wind velocity get by the classical VAD technique at different altitude and the vertical wind profile is obtained. Application this method into WSR-88D data collected during 3 May 1999 tornado outbreak, compares the wind profile with it obtained by wind profiler, Tabary＇s slope method, Bayes method, Yamada＇s continuity method. The aliased radial velocity and dealiasing radial velocity images also be presented. All these result show that this method has the ability of unfolding the ambiguity velocity, and it combined VAD method can obtain accurate wind profile from fold data.
出处
《高原气象》
CSCD
北大核心
2006年第5期862-869,共8页
Plateau Meteorology
基金
国家气象中心自筹经费课题(ZK2003A-09-02)
"十五"国家科技攻关计划课题"奥运气象保障技术研究"(2002BA904B05)共同资助
