The diffusion properties are strongly affected by thermal stratification in atmosphere. A lot of field observations about the relationship between diffusion properties and thermal stratification in the boundary layer have been conducted. In addition, many researchers have developed diffusion models based on the result of above observations. However the results of the field observations may include significant uncertainty. Therefore, highly accurate experiments in the laboratory are required. The authors have conducted wind tunnel test of heat and momentum flux properties under various thermal stratification conditions by LDV (Laser Doppler Velocimeter).In this study, 4 experimental patterns were conducted. Roughness height is 15mm and vertical profile measurement distance is 10mm pitch from 10mm to 400mm. The temperature profiles, the wind velocity profiles, the heat and momentum flux profiles have been observed.The result of the wind tunnel experiments showed that the profiles were variously changed depending on temperature conditions of the floor and the wind flow.
