Estimator for the Standard Deviation of Wind Direction Based on Moments of the Cartesian Components

Abstract

Mean and variance of horizontal wind direction are defined in a minimal variance sense. Starting from a theoretical model, termed anisotropic Gaussian model, of the probability density functions of the Cartesian wind components, the standard deviation of wind direction is calculated. This angular standard deviation is expressed as a function of the means and variances of the Cartesian wind components alone. These latter moments can be obtained by single-pass methods from measured data. Additionally, a parameterization of the angular standard deviation as a function of persistence of wind direction is given. A comparison with other estimation methods is made and some applications to experimental data are given.