The purpose of this study is to investigate the structure of natural wind in the urban area and its effects or influences on buildings from the standpoint of environmental engineering. In this investigation, the authors deal with the following themes. 1. The properties of the natural wind over the urban, viz., the vertical distribution of mean wind velocity, the effect to the atmospheric stability and the velocity fluctuation over the center of Tokyo, which is chosen as the typical urban area. (These are described in Report No.1 and 2) 2. The behaviour of the velocity and the pressure fluctuation of the air flow around the two or six storied building in Tokyo or the outskerts. (These are reported in No.3, 4, 5 and 6. In these reports, some behaviours on turbulent compornents in the velocity or wall pressure are discussed.) 3. The relation with the convectional heat transmission and the air flow around the outside surfaces of the building. (These are reported in No.7 and 8.) 4. The characteristics of the air pollusion generated in the urban area and its effect around the building or the influence in the inside of building. (These are reported in No.9.) The authors report the results on the above mentioned problems, as a series from report No.1 to No.9. In this report No.1, the authors discussed on the base of the meteorological data obserbed at Tokyo Tower (Sibakoen, Minatoku, Tokyo.) It is find that, when the vertical distribution of mean wind velocity is represented by the power law, the power index, n, depends on the state of the atmosphern (stable or unstable), the value of the n is smaller in day time, 14h, than that in nights, 2h. Next, the relation between the vertical distribution and the atmospheric stability is discussed using the stability ratio, S.R., the distribution is affected remarkably by the stability of the atmosphere in the layer over the urban area.
