傅立叶相位技术在雷达回波移动矢量特征分析中的应用

应用傅立叶相位分析技术，建立了一种新的基于雷达体扫资料的回波移动矢量、移动路径计算和临近预报算法。其基本思路是：对两个相邻时刻的雷达体扫回波资料分别进行快速傅立叶变换，得到两个雷达回波的相位差，再计算出回波的移动方向及移动速度。利用X波段多普勒多偏振雷达在吉林省获得的雷达资料对本算法进行检验，结果表明，此方法可以给出雷达回波内更加精细的回波移动矢量结构，能够较准确地反映出不同类型回波的中小尺度系统移动特征，对雷达回波移动路径有较好的追踪和临近预报能力。对一次飑线过程的计算结果显示，飑线上的强回波区移速移向存在明显的不均匀性。

Applications of Fourier Phase Analysis Technique to Computation of Radar Cloud Echo Motion Vectors

An algorithm of motion vectors, tracking and nowcasting of echoes based on Fast Fourier Transform（FFT） technique is developed for the radar volume-scan data. The basic principle is that firstly, the FFT is separately used to two successive volume-scan radar echo data whose time interval is small, yielding a phasic difference between the two radar echoes;secondly, using the phasic difference, the direction and speed of radar echo motion can be obtained. This algorithm is validated with the data of a Doppler polarimetric meteorological radar from the Institute of Atmospheric Physics, Chinese Academy of Sciences. The retrieved results show that using the new algorithm, a more precise structure of echo motion vectors is captured, and some typical dynamic characteristics of meso- and micro-scale weather systems are also depicted. The technique also has a good performance of tracking and nowcasting radar echo movement. It is also found that there was obvious non-uniformity in movements of strong echoes in a squall line on 12th July 2006.