Measurement of turbulence energy dissipation rate by a standalone high-resolution Doppler lidar

A second-order structure-function model for lidar line-of-sight (LOS) velocities is proposed. This structure-function model corrects for turbulence filtering caused by probe volume averaging using a Gaussian weighting function. The structure function model corrects for both spatial and temporal averaging effects. It takes advantage of the high range gate resolution of the BEAM 6x pulsed lidar used in this study, i.e., 3 m, to effectively resolve the inertial subrange. The structure function model is then used to obtain the turbulence energy dissipation rate ( ε ) by fitting it to lidar measurements in the inertial subrange. Unlike previously presented structure-function methods for evaluating ε in the literature, this method has a weaker dependence on the turbulence length scale. The estimated ε values from the lidar are compared with those from ultrasonic anemometers at three heights: 103, 175, and 241 m. The comparison results show an excellent correlation between the two sets, with a Pearson correlation coefficient ( ρ ) exceeding 0.9 across all three heights. The observed bias was also very small: more than 50 % of all lidar-measured ε values were within ±20 % of the sonic-measured values. This method relies on accurate detection of the inertial subrange; hence, under very stable atmospheric conditions, the model fit to the measurements produced relatively large errors due to the difficulty of detecting the inertial subrange. Applications of this method include, but are not limited to, quantifying turbulence in the wake of aircraft, understanding pollutant dispersion in urban environments, and assessing wind resources and turbulence in areas or at heights where erecting a meteorological mast is not possible.