Gust Structure in the Neutral Surface Boundary Layer

Abstract

Measured characteristics of gust amplitudes and times in the neutral surface boundary layer are presented. The probability of gust amplitudes exceeding a prescribed level is shown to decrease exponentially with amplitude, provided the amplitude is scaled with the root-mean-square turbulent speed. The 25 and 75 percentile conditional probabilities of gust duration obey power laws in the scaled amplitudes if the durations are normalized by N0, the frequency of occurrence of all gusts. These relationships are nearly independent of mean wind speed and measurement height. The effects of digital filtering of the data also are discussed.