Evaluation of empirical and statistical methods for predicting offshore wind speeds

Modification of the wind field moving offshore is examined here with particular emphasis on the relationship between off- to on-shore wind speed ratios and other meteorological variables in near-neutral atmospheric conditions and with varying stability. These relationships are affected by the height of the measured wind speeds; the influence of the initial roughness decreases with height while the influence of wind speed and stability increases. Thus the performance of prediction methods also varies with height. Statistical or empirical methods predict wind speed ratios adequately for a near-neutral data set but predictive capabilites are reduced under different stability conditions.