Answer Happy

Estimate the roughness that is relevant for the wind profile at the mast location. Is the roughness length larger than 0.4m? Is the roughness length between 0.01 and 0.1m? Is the roughness length smaller than 0.002m? 2. Which statement describes the friction velocity (U+)? The friction velocity (us) is larger during the night than during the day The friction velocity (us) is smaller during the night than during the day The friction velocity (ux) is about the same size during day and night 3. Using the wind speed measurements at 60mwhich option describes the behavior of Ø ? There is no systematic diurnal variation. U is positive during the night an negative during the day. It is negative during the night and positive during the day. 4. Which of the following statements is correct? The estimated roughness is found to be nearly constant throughout the diurnal cycle and therefore stability has little effect on the determination of the roughness from wind profiles. The issue of roughness is not important - whether it is 0.001or lm has little effect on the wind profile anyway. The estimated roughness, when derived from the wind profiles, varies a lot during the diurnal cycle and therefore it is not permissible to neglect the stability correction.