Investigation of exposure correction models for wind speed measurements

Abstract

Considerable errors may be introduced in storm intensity estimations and their subsequent applications if raw surface wind speed records are not corrected to properly account for exposure effects. This study investigates the calculation of exposure correction factors (ECFs) by different theoretical and code-based models. Estimation of the roughness length z 0 based on the suitable gustiness model is provided, as this metric is involved in calculating ECFs. The sensitivity of the z 0 estimation to the input parameters is analysed. A comprehensive evaluation of ECF models is made, which includes the World Meteorological Organization (WMO) model with various blending heights z b , Biétry model, the power-law model, the Engineering Sciences Data Unit model, the models in Chinese, Japanese, Eurocode and the International Organization for Standardization codes, as well as the combination of the WMO formula with two gustiness models (He model and Ashcroft model) respectively. It is found that the most appropriate model in practice for calculating ECFs is provided by the combined application of the He gustiness model and WMO ECF formula with a blending height, z b , of 80m.