Wind Profile: Estimation of Displacement Height and Aerodynamic Roughness
ABSTRACT KEY parameters for describing the wind velocity profile are displacement height, D, and aerodynamic roughness, Z^. Both D and Z^ appear to be independent of wind velocity but dependent on surface characteristics. A procedure was developed to predict D and Zo from the geometry and fraction of cover of rigid surface roughness elements. The procedure was verified with three independent data sets. One data set obtained from several sources in the literature was used to estimate an unknown coefficient in the developed equations. An R^ of 0.92 and a significance level of a = 0.001 was obtained. The other two data sets fit the developed equations without further calibration and gave very high R^ and significance levels. Roughness elements ranged in size from sand grains to trees 20 m in height. Because of the excellent fit with independent data sets and the wide range in roughness height, the prediction procedure appears to be general.