Diabatic wind speed profiles in coastal regions: Comparison of an internal boundary layer (IBL) model with observations

A model is presented to transform wind speed observations at a single height over sea or near the coast to any possible location and height in a topographic flat coastal region (up to distances of about 5 km from the coast and up to heights of 100 m). Only moderate and strong winds from the sea are considered, which are particularly important for wind energy applications. The model, called diabatic coast model, which is based on the well known internal boundary layer (IBL) concept and Monin-Obukhov similarity theory, describes the effects of the roughness transition from sea to land as well as the effect of stability on the shape of the profiles and the IBL growth. The predicted IBL heights are compared with published data.In the second part of this paper, the model is compared with measurements taken at the Maasvlakte location near the Dutch coast. It is shown that a neutral formulation of the IBL height is sufficient to model the overall mean wind speed with height, but that stability corrections are needed to describe the diurnal variations in wind speed properly. Finally, an application is given, where a single routine wind speed observation at the coast, combined with air-water temperature differences is used to predict the wind speed at 500m from the coast at heights of 10 and 53 m. The results are in good agreement with the measurements.