Correlation of Real and Model Wind Speeds in Different Terrains

Abstract

Wind speeds over a 6-month period from 21 surface stations, 3 upper-wind stations, and 2 different models are compared. Similar data are used for three different topographic regions of New Zealand broadly classed as having low, moderate, and high terrain. Mesoscale model winds are obtained in the three regions over 300 km by 300 km squares. The dataset is at 40-km grid spacing but some 20-km winds are also used. Correlation coefficients among the surface wind speeds decrease more quickly with separation the more mountainous the terrain. Correlation coefficients of observed surface speeds are lower than for model winds but composites of the observed station winds in each region have similar spatial variations to the model winds. An extrapolation technique for estimating the quality of model wind speed fields is inferred.