An assessment of the performance of a 1.5 μm Doppler lidar for operational vertical wind profiling based on a 1-year trial

摘要

We present the results of a 1-year quasi-operational testing of the 1.5 μm StreamLine Doppler lidar developed by Halo Photonics from2 October 2012 to 2 October 2013. The system was configured to continuouslyperform a velocity-azimuth display scan pattern using 24 azimuthaldirections with a constant beam elevation angle of 75°. Radial wind estimates wereselected using a rather conservative signal-to-noise ratio basedthreshold of ?18.2 dB (0.015). A 30 min average profile of the wind vector was calculatedbased on the assumption of a horizontally homogeneous wind field through aMoore–Penrose pseudoinverse of the overdetermined linear system.A strategy for the quality control of the retrieved wind vector components is outlined for ensuring consistencybetween the Doppler lidar wind products and the inherent assumptions employed in the wind vector retrieval.Quality-controlled lidar measurements were compared with independent reference data from acollocated operational 482 MHz radar wind profiler running in a four-beam Doppler beam swinging mode andwinds from operational radiosonde measurements. The intercomparison results reveal a particularly good agreementbetween the Doppler lidar and the radar wind profiler, with root mean square errors ranging between 0.5 and 0.7 m s?1for wind speed and between 5 and 10° for wind direction. The median of the half-hourly averaged wind speed forthe intercomparison data set is 8.2 m s?1, with a lower quartile of 5.4 m s?1 and an upper quartile of 11.6 m s?1.