Erst im Jahre 1904 A. Defant, weiter H. Köhler (1925) und E. Niederdorfer (1932) auch fanden eine Gesetzmässigkeit in Regentropfen, dass Häufigkeitsmaxima sich bei der Tropfengewichten hervorstellen, die sich wie 1:2:4:8:…verhielten In der “Absorptionsmethode”, die gänzlichvon der oben erwähnten Autoren angewandt worden ist, muss man jeden Fleckdurchmesser abmessen, um diesem entsprechenden Tropfengewicht nach Eichtabelle zu berechnen. Aus meiner einigen dieselber Verfahren, bin ich aber der Ansicht, dass bei Köhler- und Niederdorferschen Messungen der Fleckgrösse “Psychologische Wahl von zehnteiliger Skalasfraktion des Massstabs” wahrscheinlich vorhanden ist. Z. B. die von Niederdorfer bekommten Häufigkeitsverteilungder Fleckgrösse zeigt klar, dass Häufigkeitsmaxima sich bei 1.0, 1.5, 2.0, 2.5, 3.0mm usw. hervorstellen. Daher, selbst wenn eine Häufigkeitsverteilung von Regentropfen mit derAbsorptionsmethode bekommt worden ist, ist es sehr zweifelhaft, ob diese tatsächlich so gewesen ist, oder scheinbar wegen der “Wahl von zehnteiliger Skalasfraktion”
The relation between the gradient wind velocity and surface wind velocity has first been studied by Guldberg and Mohn as early as 1876. Since then, G. I. Taylor obtained, by introducing the eddy viscosity of the atmosphere, the equation based on the assumption that the directions of the stress components just agree with those of the wind components. Recently Y. Ishimaru and others touched upon the same problem with different conditions and obtained the resulting relation in the form where _??_ is a constant being determined from the nature of the eddy motion. In this paper, the author discussed the same problem using the surface conditions where r, s are slipping coefficients, η the coefficient of eddy viscosity, and obtained the following relation The results represented by theory were found to agree fairly with those obtained by direct observation at Croydon, Lympne, Calshot, Holyhead, Lindenberg, Naba and Tateno.
A popular formula of evaporation suggested by Trabert is of the form in which Q is the depth of the evaporated water expressed in mm., E the maximum vapour tension at the air temperature, e the actual tension, W the wind velocity in metre per second, P the observed pressure, T the temperature in absolute unit and the suffix represents the standard value. We examined the variation of the coefficient C with the data during 6 months in 1921, obtained at the Central Meteorological Observatory in Tôkyô, and the remarkable parallelism, the positive under free exposure and the negative in shade, was found between the monthly me_??_n of C and the monthly mean air temperature (t). Of which, a linear relation C=C' (1-kt), k: constant, was satisfactorily assumed, especially in the case of evaporation in shade. As to the evaporation under free exposure, however, this relation could not be found in the rainy season, May and June. But generally these
D. Nisimura found the conspicuous orographic effect on the distribution of the amount of rainfall due to cyclones in Japan. Since his result is very important for the practical weatherforcasting, we have studied after the suggestion of Prof. S. Fujiwhara, the same problem with the recent data in the district around Hirosima which is one of the anomalous districts, pointed out by Nisimura and extended it into surrounding districts, Tyûgoku and Sikoku. We have studied all cases up to the end of 1932 of rainfalls more than 50mm. that lasted over one or several days due to cyclones. The same general results as Nisimura's were obtained with some supplement. The most remarkable conclusion is as follows; the cyclones passing from west to east over the Japan Sea or the Inland Sea of Japan and lines of discontinuity trending east to west over the neighbourhood of Hirosima caused anomalously heavy rainfalls in this district. But we have never experienced any similar phenomena of cyclones passing over the Pacific Ocean nor in a case of typhoon passing the Japan Sea.