WINDS ON THE RIDGE, VALLEY SLOPE AND VALLEY BOTTOM (2)

Abstract

This paper is a continuation of a previous one appearing in the Geo-graphical Review of Japan Vol. 27 (1954). There the results of the first series of the main observation were discussed. Here the second and third series of the same obserbation are examined. In brief, conclusions reached in the present part of the study are; I) At the four stations situated on the ridge, upper and lower parts of the valley slope, and the valley bottom in the middle course of the river; A) Concerning the intensity of the inter-mediate scale turbulence, 1, a remarkable difference was observed.between two stations, such as the one on the ridge and that in the valley bottom, 2, there was no significant relationship to the wind velocity, and 3, relatively great deviations were shown between several observation times, while the maximum value of intensity reached more than 1.00. B) Distribution of the mean wind velocity, was quite different under diverse conditions of the prevailing wind direction. C) Fluctuation angle of the wind direction decreased with decent from the ridge to the adjacent valley bottom, but had no clear relation to the wind velocity. II) According to the results obserbed at seven stations in the valley bottom and four stations on the ridge, good representative values were seen at those stations on simple topography, for example, at the ridge station of the middle cource of the river, and at the valley bottom station near the pass at the head of the valley. As one important conclusion, it can be pointed out that the influences of topography on surface wind characteristics in a small valley must be considered not only from the view point of the valley's geometrical form, but also from the effects of the highly localized micro-circulation of the wind. Owing to the different direction of the prevailing wind, these micro-circulations were developed in distinct ways so that there were diverse conditions at the different stations. Complete results. of both the present paper and the one previously published are to be include in a paper that the author is now preparing in English concerning, “Local Characteristics of Surface Winds in Small valley”.