Multi-scale simulations of wind farm impacts on nighttime near-surface temperature in complex terrain

Abstract. Various studies have shown that wind turbine wakes can induce meteorological variations, investigating these effects near the ground is particularly important for assessing their potential impact on vegetation and human activities. In this study, the multi-scale Meso-NH/SURFEX/EOL modelling framework, which includes coupled atmosphere-soil-vegetation and actuator models, is used to investigate turbine-atmosphere interactions at the Ensemble Éolien Catalan wind farm during a stable nocturnal radiative cooling event associated with frost risk in nearby vineyards. The simulations are performed using nested domains to dynamically downscale the atmospheric conditions from the operational weather forecast AROME-1.3km to a horizontal resolution of 5 m, allowing explicit representation of turbine wakes through rotative actuator disk representation. Turbine-induced meteorological variations are quantified by comparing simulations performed with and without actuator model. The results reveal that near-surface meteorological responses arise from the combined influence of individual turbine wakes and the large-scale impact of the wind farm, which modifies the flow dynamic and temperature field. In the immediate vicinity of the farm, a mean near-surface warming of approximately 0.4 °C is found, with localized temperature increases reaching up to 1.6 °C in the near wake of individual turbines. The strongest perturbations occur for turbines located within valleys, where strong temperature inversions enhance turbine-induced thermal variation. In addition, the wind farm shifts the position of a convergence zone associated with a katabatic flow by about 100–400 m, producing warming anomalies of up to 2 °C along the displaced meteorological front.