PNNL

Abstract

The most common profiling techniques for the atmospheric boundary layer based on a monostatic Doppler wind lidar rely on the assumption of horizontal homogeneity of the flow at constant heights. This assumption breaks down in presence of either natural or manmade obstructions that can generate significant flow distortions. The necessity to deploy ground-based lidars in proximity of operating wind turbines for the AWAKEN campaign, spurred a search for novel profiling techniques that could mitigate the influence of the flow modifications caused by the wind farms. With this goal in mind, three well-established profiling scanning strategies have been retrofitted to allow to scan in a "tilted" fashion, enabling to steer the beams away from the inhomogeneous region of the flow. Results from a field test show that accuracy of the mean flow reconstruction is insensitive to the tilt of the scan, although higher-order wind statistics are severely deteriorated for extreme tilts. Numerical simulations of the AWAKEN domain are also leveraged to asses the relevance of titled profiling for the specific campaign.