抄録
In the 3rd report of our study, we presented the statistics about the wind during cooling season. In this paper we deal with the wind during heating period in Tokyo and Osaka. The method used for statistical treatment of data and for preparing "windloses" are similar to those of our preceding paper. The essential points are: (1) The wind in winter is stronger in the early morning and weaker in the daytime than in summer. Daily mean wind velocity ranges 2.5m/s〜3.0m/s. (2) The main wind direction is proved different in the two cities. In Tokyo, it is NNW (in the daytime N prevails), and the frequency for other directions is nearly zero, while in Osaka it is in W December and January, becoming N in February. (3) For each wind direction, we calculated the mean wind velocities to compare them with the mean frequencies obtained. In Tokyo, maximum of both velocity and frequency does'nt agree with except at 2.00 p.m., when mean velocity is large in all directions (6m/s in the main direction, NNW). In Osaka, the coincidence of maximum velocity and frequency is fairly well. The velocity is largest at 2.00 p.m. (4.2m/s in the main direction, WSW). From these results, the design velocity and direction of wind in winter can be decided with corresponding probability.
