Sensitivity of Nocturnal Low‐Level Jet Representation to Model Resolution and Boundary Layer Schemes: Implications for Wind Energy Assessment Over Saudi Arabia

Abstract Sensitivity tests on low‐level wind speeds and stability associated with the diurnal cycle of convective boundary layer (CBL) are performed using five Weather Research and Forecasting (WRF) Model simulations over the Riyadh, Saudi Arabia region. Multiscale WRF domain configurations with domain grid‐spacings ranging from 12,150–450 m are coupled with different planetary boundary layer schemes with one simulation having two inner‐domains of 150 and 50 m using a large‐eddy simulation (LES) turbulence model. Low‐level wind speed and stability from these simulations indicate a deep, well‐mixed daytime CBL extending to 3 km, with winds that are nearly uniform with height. Following sunset, the surface layer rapidly stabilizes, and a nocturnal low‐level jet (NLLJ) forms between 100 and 800 m altitude, with a core near 500 m and wind speeds of 7.5–12.5 m s −1 . Model PBL scheme choice and changes in horizontal and vertical resolution affect the stability and wind speed output little in this study. Additionally, low‐level winds in this region are important for wind energy production. Sensitivity of wind energy production to WRF model configuration, wind turbine height, and model resolution indicates that wind energy output is highest during nighttime, associated with the NLLJ and predicted best by the WRF simulation employing the MYNN scheme in this study. Higher hub heights produce greater wind output while the greatest sensitivity to model resolution for wind energy occurs at the transition from daytime to nighttime with the subsequent CBL evolution and NLLJ formation.