Wind speed measurements at up to 500m altitude using Doppler sodars and effects of terrain roughness on wind speed profiles

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Wind speed measurements using two or three sets of Doppler sodars were conducted with different combinations at various sites : Minami-Machida (a suburban residential area), Hiratsuka City (a low-rise urban area), Takahamadai (a sea shore), Odaiba (a bay area), Etchujima (an urban area), Minamisenju (a high density residential area) and Atsugi (a middle-rise urban area). Methods of measuring mean wind speed profiles and turbulence intensities, height correction methods and noise effect evaluations were examined in detail to improve measurement accuracy.Various important results were obtained on atmospheric boundary layer winds developed over ground with different terrain roughnesses at up to 500m altitude.Physical model studies were also conducted using two different wind tunnels. Two ground roughness models were made that geometrically simulated buildings in the range of 8km between Takahamadai and Hiratsuka City, and 12km between Odaiba , Etchujima and Minamisenju. Development of the model scale atmospheric boundary layers for fetches simulated in the wind tunnels were examined and compared with full-scale results.Numerical simulations using the k-ε model coded by Maruyama were also conducted using the digital database of buildings on the ground between Takahamadai and Hiratsuka City, and between Odaiba, Etchujima and Minamisenju. The spatial distributions of the mean wind speed and turbulence intensities were calculated and compared with the wind tunnel experiments and full-scale data.Three years of comprehensive studies of atmospheric boundary layer winds using Doppler sodars at seven different sites of up to 500m altitude, wind tunnel studies and numerical simulations provided new knowledge and information that was useful for the accurate evaluation of the design wind speed for various terrain categories.