Doppler Lidar Provide New Insights into the Wind Resource over Forests

The atmospheric boundary layer above forest canopies is difficult to measure in practice, and our understanding of its flow physics, including the potential wind resource, is limited in part by observational constraints. Most available datasets come from tower point measurements, which do not generally reach into heights encountered by a turbine rotor, or from remote sensing measurements, which are usually located outside of the forest in a clearing and thus do not accurately represent flow conditions above the canopy. Here, we present a field campaign that deployed four Doppler lidars in a U.S. Appalachian Forest including installment on top of a 30 m tall tower. These lidars allow for wind measurements across tall turbine rotor heights to be made directly above forested regions. Nearby wind turbines in the wooded Appalachians have hub-heights approaching 90 m and rotor diameters of 127 m, with maximum and minimum blade heights of 152 m and 25 m, respectively. We describe the experimental set-up, lidar strategies, adjoining radiosonde and UAS IOPs, and novel use of AI to drive optimal lidar scans. These data are being collected as part of the DOE “Addressing Challenges in Wind Forecasting for Tall Turbines Across Regions with Terrain and Land Surface Heterogeneity” project and will be used for analysis of forest-atmosphere interactions and numerical model validation.