Presentations

Abstract

Estimation of turbulence intensity (TI) has become a major focus within the wind lidar industry in recent years. TI is a critical parameter in wind energy, as it directly influences fatigue loading and the selection of appropriate wind turbine classes in accordance with international design standards. In addition, TI contributes to uncertainty in annual energy production, with associated financial implications for wind energy projects. Despite its importance, accurately estimating TI remains challenging in pulsed Doppler lidars due to probe-volume averaging effects and cross-contamination. TI measurements from lidars are often subject to systematic underestimation when compared with reference instruments such as sonic anemometers. This study presents a correction framework that leverages knowledge of the turbulence energy dissipation rate to improve the accuracy of lidar-based TI measurements. Recent advances demonstrate that the energy dissipation rate can be inferred through model fitting to the second-order longitudinal structure function (Syed et al., 2025). The main hypothesis in this work is that incorporating information about energy dissipation rate may allow for compensating for the inherent underestimation of variance associated with probe-volume averaging in each individual line-of-sight. The compensation method assumes that the probe length is within the isotropic inertial subrange. This hypothesis is evaluated through a field experiment with BEAM 6x profiling lidar from Lumibird, located close to the Light Mast North at the Danish National Test Station for Large Wind Turbines in Østerild, Northern Jutland, Denmark. The findings of this study clarify the extent to which reconstructing wind-velocity variances from the six-beam method (Sathe et al., 2015) applied to corrected radial variances can yield more accurate TI assessments. References: Sathe, A., Mann, J., Vasiljevic, N., and Lea, G.: A six-beam method to measure turbulence statistics using ground-based wind lidars, Atmospheric Measurement Techniques, 8, 729–740, https://doi.org/10.5194/amt-8-729-2015, 2015. Syed, A. H., Mann, J., and Manami, M.: Measurement of turbulence energy dissipation rate by a standalone high-resolution Doppler lidar, EGUsphere, 2025, 1–18, https://doi.org/10.5194/egusphere-2025-5214, 2025.