Some Aspects on the Distribution of the Surface Winds within a Small Area

Abstract

 Intensive observations of the distribution of the surface winds in the city area of Tokyo were made four times a week from September, 1943 to August, 1945. Using these Data, wind characteristics were studied from a microclimatological viewpoint and the results were summarized as follows; (1) The greater the prevailing wind velocity, the smaller the deviation of the surface wind direction at each station from the avereage direction within an area. (2) In the condition of high wind velocity more than 5 m/s, the differences of the wind direction distribution between inland, coastal, upland, and lowland area in Tokyo were not significant statistically. (3) When the prevailing wind velocity was weak, the distribution of the stations having deviated wind direction showed some localization. Especially this was obvious in the coastal area. (4) Convergence zone or conflict zone of two winds flowing in right angle was shown as a calm zone because of relatively low velocity of the prevailing general wind. The position of this zone and a discontinuous line between the prevailing northerly winds and sea breezes showed a close relation to the topography, and to the distribution of land, sea and rivers in the area.