Brief communication: A simple axial induction modification to WRF’s Fitch wind farm parameterisation

Abstract. We propose a modification to the Fitch wind farm parameterisation implemented in the Weather Research and Forecasting (WRF) model. This modification, derived from the 1D momentum theory, employs a wind speed dependent induction factor to correct the local grid wind speed back to free stream, before computing the turbine’s power and thrust. While the original implementation underestimates power, the modified version shows a better agreement with the power curve. We strongly recommend the modification to be employed for all studies that model not more than one turbine per WRF grid cell.