A New Planetary Boundary Layer Scheme Based on LES: Application to the XPIA Campaign

Abstract

AbstractWe present a new planetary boundary layer scheme based on large‐eddy simulations for different atmospheric stability classes. Large‐eddy simulations results are compared with the wind speed measurements from the meteorological mast at the Test Centre for Large Wind Turbines at Høvsøre, Denmark. A generic formulation for the determination of mixing length scale is proposed and incorporated with the updated closure coefficients derived under realizability constraints by Temel et al. (2018, https://doi.org/10.1016/j.jweia.2018.01.002). The new planetary boundary layer scheme is implemented into the Weather Research and Forecasting model to perform mesoscale simulations for the Høvsøre test site as an idealized case as well as for a real‐data case at the eXperimental Planetary boundary layer Instrumentation Assessment campaign. Results of the idealized case reveal that the proposed scheme, VKI01, well represents the potential temperature and wind speed characteristics. It decreases mean absolute errors for most of the stability levels despite a slight overestimation for near‐neutral stable and very stable conditions. Regarding the real‐data case, a significant improvement has been achieved by the VKI01 for both turbulence kinetic energy and its dissipation rate in comparison to sonic anemometer measurements for a 2‐day period during the eXperimental Planetary boundary layer Instrumentation Assessment campaign.