多普勒测风激光雷达三波束反演方法与实验

为研究激光测风技术中五波束和三波束风廓线反演方法的异同,采用波长1.5μm的相干多普勒测风激光雷达在中国海洋大学崂山校区进行风场测量。利用三波束风廓线反演法对13 d的多普勒激光雷达观测数据进行计算,设定信噪比和数据获取率门限阈值,对数据质量进行控制,将计算结果与五波束风廓线反演法的计算结果进行比对分析。与五波束风廓线反演法相比,三波束风廓线反演法仅用三个方向的径向数据反演风廓线,可缩短观测时间跨度,从而提高数据刷新率,在气流不稳定的情况下可获取更多的风场特征参数。比对结果表明,两种风廓线反演法的计算结果在不同高度上均表现出良好的一致性。90 m测量高度处的风速决定系数为0.9825,风向决定系数为0.9769;随着湍流强度增大,两种风廓线反演法之间的差异呈增大趋势。

Three-Beam Methodology and Observations of Wind Profiling with Doppler Lidar

To study the similarities and differences between five-beam and three-beam algorithm in the detection of atmosphere wind profile,a Doppler wind lidar with the wavelength of 1.5μm was used to measure the wind field at Laoshan campus of Ocean University of China.The wind profile observed for 13 days was retrieved with the three-beam algorithm after data quality control with a threshold on signal-to-noise ratio and acquisition rate.Compared with five-beam algorithm,three-beam algorithm could reduce the average time,improve the data update rate and capture more wind filed structures under unsteady flow field since it extracts the wind profile with three independent beam observations instead of with five beams.The results of these two algorithms show good agreements at different heights.The comparisons show that the coefficient of determination of wind speed at 90 m height is 0.9825,and the coefficient of determination of wind direction is 0.9769.The differences between the results of these two algorithms increase with greater turbulence intensity.