An asymptotic closed form solution for the distribution of combined wind speed and wind direction extremes

Abstract

This paper presents an asymptotic expression for the joint distribution of the largest combined wind speed- and wind direction excursion, during a large but otherwise arbitrary recurrence period, based on a "mother" distribution that reflects the Exponential-like distribution behaviour of large wind speed excursions. The derived asymptotic joint distribution is shown to equal a joint Gumbel EV1 type distribution, and the associated distribution parameter is expressed as simple functions of basic parameters characterizing the stochastic longitudinal- and transversal wind speed processes in the atmospheric boundary layer and the recurrence time. Finally, predictions of the derived model are compared to results derived from full-scale measurements of wind speeds in the atmospheric boundary layer. © 2007 IOP Publishing Ltd.