A new approach for the determination of horizontal wind direction fluctuations

Abstract

A new method to determine horizontal wind direction fluctuations σθ is presented based on the hypothesis of a Gaussian distribution of wind direction that gradually moves to a circular, uniform distribution under near-calm conditions. A theoretical formulation for σθ, the persistence of wind and the total horizontal standard derivation σ is provided and supported by experimental observations, both in a complex terrain valley site and in an open grassland spot in Spain. Comparisons of the proposed model with observations yielded a fairly good agreement, making the theoretical functions a straightforward procedure for use in atmospheric dispersion calculations. -from Author