Introduction Representation in WAsP

Displacement height and roughness length8.0%8.0%7.0%7.0%RMS error on mean wind speed6.0%5.0%4.0%3.0%2.0%1.0%R 2 = 0.70R 2 = 0.86R 2 = 0.53all pairs,s=1:15all pairs,s=1:50goodpairs,s=1:15RMS error on mean wind speed6.0%5.0%4.0%3.0%2.0%1.0%R 2 = 0.002R 2 = 0.05z 0independent of hR 2 = 0.30all pairs,s=1:15all pairs,s=1:50goodpairs,s=1:150.0%0.6 0.8 1 1.2d/h0.0%0.2 0.4 0.6 0.8 1 1.2z0 (m) for tree height = 12.5 mConclusionsParameterDisplacementheightdDisplacementheight decay ratesRoughness lengthz 0Best canopymodel in thisstudyOptimal for ”good” sitesmast not too low relative to treesgood info on distance to forestHigh, 0.9 to 1.0 hWeak trendSweet spot around1:15Low, 0.4 to 0.5 m or 0.03 to 0.04 hWeak trendSlight advantage when z 0proportional to h ?ESDU with s=1:15d = h – 4.3 z 0(1-λ) ≈ 0.93 hz 0= 0.033 h = 0.41 m (12.5 m trees)RMS error on MWS: 1.5%Optimal for”bad”/mixed/unknown sitesHigh, 0.9 to 1.0 hStrong trendThe slower the better1:50No trend to speak ofCurrent GH with s=1:50d = 1.00 hz 0= 0.50 mRMS error on MWS: 3.2%