Wind shear assessment using wind LiDAR profiler and Sonic 3D anemometer for wind energy applications-preliminary results

Abstract

This chapter presents an assessment of wind shear up to 400 m at a coastal location. The vertical structure, temporal variations and influence of atmospheric stability were investigated. The results show four important findings using light detection and ranging (LiDAR) and dimensionless shear analysis. First, the top of surface layer can be considered around 200 m. Second, the wind speed decreases with height above 240 m from 11:00 to 16:00 local time. Third, the atmosphere can be considered to be stable from 10:00 to 14:00 and unstable from 19:00 to 01:00 according to the Monin-Obukhov similarity theory (MOST) theory. Fourth, the wind speed remains almost constant, with a height of up to 300 m in the first part of the night when the dimensionless shear is low. In addition, measurements taken with a sonic 3D anemometer confirmed the excellent correlation between the turbulent fluxes and the dimensionless shear. For strong winds, when the friction velocity is high, dimensionless shear varies almost linearly and at low friction velocity, it varies exponentially.