风廓线雷达基于均匀风场假定条件计算水平风,在不考虑雷达系统测量误差的情况下,探测波束内风的不均匀性是影响雷达数据质量的主要因素。通过5波束风廓线雷达计算出两组独立的水平风分量Ue、Uw和Vn、Vs,利用旋转坐标系方法将风的水平速度不均匀分布和垂直速度水平不均匀分布对雷达测风的影响进行分离,对北京延庆CFL08风廓线雷达2012年全年数据进行时间一致性平均质控处理,针对一小时分辨率数据分析了两种不均匀对测风数据质量的影响程度。结果表明:(1)雷达波束空间内的水平不均匀和垂直不均匀对水平风测风数据的质量均有影响,影响程度与风速大小有关;(2)晴空条件下垂直速度较小,水平不均匀是影响测风质量的主要因子,水平不均匀与垂直不均匀对测风质量影响比约为2∶1;(3)降水期间水平不均匀和垂直不均匀程度均大于晴空,二者对测风质量影响比约为1∶1。分别分析了晴空和降水情况下风的空间不均匀分布对测风质量影响的可能原因,是改进水平风数据质量算法的预研究。
Horizontal wind measurement by wind profile radar (WPR) is based on the assumption of uniform wind. However, this assumption cannot be completely met in the atmosphere, leading to radar measurement error. Five-beam WPR can independently measure two groups of horizontal wind components Ue , Uw and Vn , Vs, using the motion difference to evaluate the influence of the inhomogeneity of the atmospheric motion on wind measurement. The influence on wind measurement can be divided into inhomogeneous distribution of horizontal motion and vertical motion. Based on the basic data of WPR and meteorological background information, a new means of coordinate rotation will separate the two kinds of inhomogeneous factor and then we can discuss their impact on different weather background. Combined with PB-type II troposphere WPR detection data from Yanqing Meteorological Observatory of Beijing, the feature of WPR data is analyzed by processing all continuous observation data of 2012, except for some missing measurements. Results show that the inhomogeneity of horizontal motion is nearly the same in the u and v direction, and the inhomogeneity of horizontal and vertical motion influences wind measurement. Both of the influences are associated with the change of wind speed. In clear air, the inhomogeneity of horizontal motion is the main influence for wind measurement because of small vertical velocity. The two influences on wind measurement are larger in precipitation than in clear air. Two kinds of radar measurement error are analyzed. This study is a pre-study for proposing reasonable algorithms to reduce the error of horizontal wind.