Improvement of wind vector retrieval method for increasing data acquisition rate of the wind profiler and the wind lidar

Representative meteorological instruments that utilize the Doppler effect include Doppler radar, wind profiler, and wind lidar. The latter two instruments produce a vertical profile of winds in high spatio-temporal resolution, in the atmospheric boundary layer. Wind lidar observes with a vertical resolution of 50 m or less and a temporal resolution in minutes, so it fills the observation gap in the lower layer where the wind profiler misses meteorological data. The wind lidar makes the wind vector using DBS (Doppler Beam Swinging) and VAD (Velocity Azimuth Display) methods. It is known that the wind by the VAD method is more accurate than the wind by the DBS method. The DBS method has the advantage of obtaining a wind profile with a fast scan time. On the other hand, there is a restriction that requires at least two beams including vertical beams (one of the east and west beams, and one of the south and north beams), which causes a decrease in the data acquisition rate. The VAD method was improved to produce more wind vector of the wind profiler as well as the wind lidar, which generally uses 5 beams. First, the Fourier series was estimated with the radial velocity by the DBS method. Next, the wind vector was determined by setting the azimuth interval and applying the radial velocity by the Fourier series to the VAD method. The wind vectors were retrieved at the altitude where the wind was not calculated by the DBS method, and the results of the two methods were consistent at the altitude where the wind was calculated by the DBS and the improved VAD method. In this study, we propose a method to increase the data acquisition rate even if the vertical beam or one of the inclined beams is insufficient.