Analysis of wind data gathered by three sonic anemometers on a mast in urban area

One year of continuous wind and turbulence measurements at three levels (5, 9 and 25 m) on a mast located in the suburb of Turin were collected. The area is characterised by the presence of small houses, sheds and trees close to the mast and by medium size buildings in a range of 200-300 metres. Data were subdivided in one hour series. Those recorded during April 2007 were firstly analysed and their main characteristics will be presented and discussed. Analysis includes, for the three levels, mean, standard deviation, Skewness, Kurtosis for the 3D wind components and sonic temperature. The integral time scales for the 3D wind components were also computed and friction velocity and Obukhov length were determined as well. In particular, the wind standard deviation profiles as a function of stability were compared to the literature predictions for flat undisturbed terrain, finding that while the vertical components agree reasonably well, the horizontal components deviate from the prescribed values, as expected due to the buildings and other obstacles effects and to the high percentage of low wind situations. Also the integral time scales, estimated by the autocorrelation functions, were compared to the literature predictions, finding significant differences, also attributed to the low wind speed occurrence.