Journal of the Meteorological Society of Japan. Ser. II
Online ISSN : 2186-9057
Print ISSN : 0026-1165
ISSN-L : 0026-1165
Volume 18 , Issue 10
Showing 1-5 articles out of 5 articles from the selected issue
  • U. Nakays, T. Magono
    1940 Volume 18 Issue 10 Pages 313-321
    Published: 1940
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    The mode of freezing of soil was examined by digging in the frozen ground at eight spots. in Hokkaido. where the climatic condition and the soil nature are qui_??_e different from each other. The excavation was one always on railway tracks.
    The frozen ballast was found to consist of gravels stuck together with hoar crystals; that is crystaline frost. Many beautiful hoar crystals in various forms were found on the bottom surface of gravels. showing that the ventilation of water vapour is quite well through the frozen ballast From the stan lpoint of m croscopic view. the thermal conduc_??_ivity of a ballast layer must be very large. as the latent heat of evaporation and condensation of ice conveys a considerable amount of heat by convection from the depth of the ballast ot the upper layer.
    The freezing of soil, especially of the one mixed with clay is characterlsed by many ice layers, the ice being separated from the moistened soil by freezing. Two sors of ice layers w_??_re found. The ones are thick and few in number, two or three of them being usu_??_ly observel in a section of the ground. The others are very thin and an innumerable number of them are observed in the section of one frozen laryr. The ice in the former case s of the same nature as the frost pillar that is a common product in winter in some districts of our conntry. The ice in the latter case originates in the cracks in soil which are produced by contraction of soil. The frost heaving is found to be chiefly due to these ice layers separated from the soil by freezing.
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  • Z. Yosida
    1940 Volume 18 Issue 10 Pages 321-328
    Published: 1940
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    It is well known that a dry snow layer differs remarkably in m_??_hanical character from a wet one. The wetness of a snow layer is evidently due to the presence of thaw water in it. The present paper describes a method for determining the content of the thaw water in a snow layer. When a mass of snow weighing M gr. contains m gr. of thaw water. heat quantity required to melt the mass should b_??_ equal to 79.60 (M-m) cal., where 79.60 cal. is the latent heat of fusion of ice. If this heat quantity is determined by calorimetry, the thaw water content m/M can be obtained. Ca'orimetry was carried out by means of an ordinary water ca orimeter, upon which so ne improvements were made in order to raise the accuracy of measurement and to make the outdoor manipulation easy. The error was estimated by applying this method to a block of ice at 0°C, which can be consi lered as a special form of snow without thaw water. The value of m/M was fo _??_nd to be acc_??_ra e to the first position above the decimal point, when m/M was expressed in %. Examples of the measurements _??_n the actual snow layer are shown in diagrams, which represent the distribution of the thaw water content along the height of a cross section of the snow layer.
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  • Y. Kawabata, T. Ayuda
    1940 Volume 18 Issue 10 Pages 329-333
    Published: 1940
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    The intensity of the ultra-violet radiation between the wave lengths 2700Å-3150Å (Fig. 1) was measur_??_d with a proper combination of the vacuum Chrom-photo-cell and the glass filter which is transparent enough for shorter wave lengths (Fig. 2). The results of the measurements are as follows:-
    (1) The intensity of the U. V. radiation is strongest in the direction towards the sun, and becomes weak with the distance from the sun (Fig. 3 and 4). The U. V. radiation from the area with the radius of 30° around the sun exceeds oneha f of the total U. V. radiation from the whole sky.
    (2) The daily variation is very remarkable (Fig. 5). The range of it is larger than that of the direct or scattered sky radiation which includes the whole wave lengths. The effect of the scattering for shorter wave lengths is very remarkable wh_??_n the altitude of the sun is low, as is expected by the theory of Rayleigh. (Fig. 6.)
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  • Y. Daigo
    1940 Volume 18 Issue 10 Pages 333-338
    Published: 1940
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    The coefficients of correlation between the yield of rapes and the weather factors (month'y mean temperature, month'y amount of rainfall and monthly total hours of sunshine) have been calculated by the method previously reported in this journal, for each prefecture in Japan, for each month during the cultivating period. The correlation coefficients ca'culated are shown in tables 1, 2, 3 and the following relations are recognized.
    1. The correlation between the yield and the weather factors in the months during the cultivating period is generally not so conspicuous and does not indicate a certain tendency.
    2. The correlation between the yield and the temperature from autumn to spring is positive in the north-eastern provinces, and negative in the other districts. It is noteworthy that the correlation between the yield and the temperature from ripening time to harvest time is negative against expectation.
    3. The correlation of the yield with the rainfall indicates that the rainless weather from ripening time to flowering time is favourable for the rapes culture.
    4. The correlation of the yield with the sunshine is closer than with other weather factors, and the sunshine from flowering time to harvest time has the largest influence on the yield.
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  • S. Akai
    1940 Volume 18 Issue 10 Pages 338-345
    Published: 1940
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    The author of the present paper studied the variation of the temperature in a hollow sphere when the temperature of the outer side of the sphere varies periodically and the temperature at any point depends merely on the distance from the center, and he showed an example of the numerical calculation.
    The temperature in the shell of the hollow sphere u1, and that of the air in the sphere u2 are obtained by solving the following equations:
    ∂(ru_??_)/∂t=K1 2∂_??_(ru_??_)/∂r2, [0<r<b]
    ∂(ru2)/∂t=K_??_ 22ru)/∂r2, [0<r<a]
    provided that
    (u1)r_??_b= A cos pt,
    {∂u1/∂r-h(u1-u2)}r=a=0,
    (k1 ∂u1/∂r)r=a=(k2 ∂u2/∂r)r=a, where a denotes the inner radius, b the outer radius, k1 and k2 thermal conductivities of the shell and of the air respectively, h an experimental constant depending upon the surface conductivity of the sphere.
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