Spatial and Stability-driven variability of the TKE Dissipation Rate in the Marine Atmospheric Surface Layer: A LiDAR Experiment*

The dissipation rate of turbulent kinetic energy, ε, is a critical parameter for turbulence characterization as it encompasses fundamental processes related to scalar, momentum, and energy transport. Dissipation rate can significantly affect accuracy in turbulence predictions for many applications, such as wildfire development, air traffic control, pollutant dispersion, and wind energy production. In the marine atmospheric boundary layer at coastal region, the shore-normal variability due to the presence of the coastline and air-sea interaction induces complex modulations in ε, which are difficult to predict with classical turbulence models. The main goal of this work is to characterize and model ε variability with the atmospheric stability, height, and sea/wave conditions. In this study, ε is estimated from streamwise velocity measurements collected with a scanning Doppler LiDAR deployed in coastal region. The turbulent dissipation rate is calculated using methods involving the second-order structure function or the power spectral density of the streamwise velocity. Special attention is paid to the identification of the inertial subrange from the LiDAR turbulence measurements. Findings indicate that colder offshore winds, which are typically associated with unstable atmospheric conditions, generate higher ε compared to milder onshore winds associated with stable atmospheric conditions. Clear trends of ε are also identified as a function of the wave age and the reference wind velocity.