Applications Of Fourier Phase Analysis Technique To The Computation Of Radar Cloud Echo Motion Vectors

An algorithm of motion vectors, tracking and nowcasting of clouds based on Fast Fourier Transform (FFT)technique is presented for the radar volume-scan data. The basic principle is that firstly, the FFT is separatelyused on two successive volume-scan radar echo data whose time interval is small, and a phasic differencebetween the two radar echoes can be gotten; secondly, using the phasic difference, the direction and speed ofradar echo motion can be obtained. On the base of the algorithm, the software is programmed in Visual Netsoftware, using Visual C++ programming technology, Visual C++ interface programming, Windows ShellProgramming, and other programming technology based on the multithreaded program design thinking that is aWindows-based radar data processing for the interactive system. The system is simple and intuitive to operator,interactive, and user-friendly operation of the application, with its friendly Windows-style interface,This algorithm is systemically validated with the data of a Doppler polarimetric meteorological radar belongedto the Institute of Atmospheric Physics, Chinese Academy of Sciences. The retrieved results showed that using bythe new algorithm, a more precise construction of echo motion vectors is caught, and some typical dynamiccharacteristics of meso- and microscale weather systems are also depicted. The technique also has a goodperformance of tracking and nowcasting radar echo movement. It is also found that there is obviousnon-uniformity in movements of strong echoes in a squall line.