To discern the appropriate U for power curves, 10 min power **data** P norm are plotted as a function of (a) nacelle cup anemometer 80 m U, (b) nacelle cup anemometer 'true-flux' equivalent U, (c) SODAR 80 m U, and (d) SODAR 'true-flux' equivalent U for a typical summer day in figure 3. The uncertainty induced by a non-co-located SODAR wind speed in the power curves can be seen in figures 3(c) and (d). When compared with the manufacturer's power curve, the SODAR-based power curves have lower Pearson's coefficient (r) values (r = 0.88-0.89) than the nacelle-based (r = 0.94-0.95). Furthermore, a small improvement (in terms of a higher r value and lower standard deviation of residuals) is evident from using the nacelle-adjusted 'true-flux' equivalent wind speed instead of the nacelle hub-height U ( figure 3(b)). Though small, these differences suggest that the nacelle-adjusted 'true-flux' equivalent wind speed generates the most accurate power curves at this site.