Journal of the Meteorological Society of Japan. Ser. II
Online ISSN : 2186-9057
Print ISSN : 0026-1165
ISSN-L : 0026-1165
Volume 28 , Issue 1
Showing 1-4 articles out of 4 articles from the selected issue
  • Part 1, Theooretical Consideration
    G. Yamamoto
    1950 Volume 28 Issue 1 Pages 1-11
    Published: 1950
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    The equation for the radiative transfer was solved on earth's atmosphere to calculate the incoming radiation at the ground level. Different formulae were obtained for the incoming radiations due to absorption of water vapour both in the intermediate region where the change of absorption coefficient with wave-length is smooth and in the absorption bands where the absorption coefficient fluctuates rapidly with wave-length. The formula which is available for mixed gas of H2O and CO2 (or O3) was derived too.
    Using the values of the absorption coefficient of water vapour calculated by Yamamoto-Onishi and by Elsasser, and those of Co2 and O3 properly assumed, the incoming radiations were calculated for several weather conditions appropriate to clear skies. The comparison of calculations with observations shows that the calculated values based on Yamamoto-Onishi's absorption coefficient agree fairly well with observations, and that those based on Elsasser's absorption coefficient are generally smaller than the observed values.
    By formulating the calculated values the following formula was obtained: where G (O) is the incoming radiation and W is the amount of water vapour in the air column in cm unit of precipitable water. When the vapour pressure at the ground level, ε0 in mb, is taken as abscissa, the empirical formula of Brunt's type agree with many observations as a whole.
    The possibility of deriving these formulae was discussed also.
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  • Part II, Numerical Calculation
    G. Yamamoto
    1950 Volume 28 Issue 1 Pages 11-20
    Published: 1950
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    The equation for the radiative transfer was solved on earth's atmosphere to calculate the incoming radiation at the ground level. Different formulae were obtained for the incoming radiations due to absorption of water vapour both in the intermediate region where the change of absorption coefficient with wave-length is smooth and in the absorption bands where the absorption coefficient fluctuates rapidly with wave-length. The formula which is available for mixed gas of H2O and C02 (or O3) was derived too.
    Using the values of the absorption coefficient of water vapour calculated by Yamamoto-Onishi and by Elsasser, and those of Co2 and O3 properly assumed, the incoming radiations were calculated for several weather conditions appropriate to clear skies. The comparison of calculations with observations shows that the calculated values based on Yamamoto-Onishi's absorption coefficient agree fairly well with observations, and that those based on Elsasser's absorption coefficient are generally smaller than the observed values.
    By formulating the calculated values the following formula was obtained:
    where G (O) is the incoming radiation and W is the amount of water vapour in the air column in cm unit of precipitable water. When the vapour pressure at the ground level, ε0 in mb, is taken as abscissa, the empirical formula of Brunt's type
    agree with many observations as a whole.
    The possibility of deriving these formulae was discussed also.
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  • M. Abe
    1950 Volume 28 Issue 1 Pages 21-24
    Published: 1950
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    As cameras for photographing the clouds we have the theodolite kinematograph and other various sorts of cameras. But when we use the lenses of the ordinary focal length, only 50° of the sky can be rendered and so the photography is limited to some extent. Moreover, if we intend to render 150° or so, the photographic plate must have the diameter of 3 feet, and for 180°, infinitely large plate is needed. This is a matter of impossibility. The improved camera, to photograph the clouds of the whole sky in one plate by using a special lens, devised to converge the incident ray to about 90° before it comes into the lens, is the whole-sky camera of Mr. Robin Hill. When we use this camera, all the objects in the whole sky, which can be regarded as a semisphere, can be photographed in a plate of 3.1×4.1 inches (8×10.5cm). The study of the clouds using this has been carried out by many persons, but 1 devised the connection of the whole-sky lens with the kinematograph to see the states of the ever changing whole sky clouds in a roll of moving picture. The focal length must be prolonged to catch the image of the whole sky on the standard film. For this purpose 1 set two concave lenses in the midway and fitted them adequately, and succeeded, in making a practical whole-sky kinematograph. After the accomplishment of this camera, we took photographs of the change of the clouds of the whole sky at the time of the solar eclipse of May 9' 1948, at Wakkanai in Hokkaido and at Tateno in Ibaragi Prefecture. The investigation of the change of the clouds then photographed is shown in another report, so that 1 will only refer to the structure and method of measuring with regard to this camera.
    In Fig. 1, the whole-sky lens, the concave lenses, the lens of the camera and the photographic plate are the main parts. And when we take photographs directing the lens axis to the zenith, we can get the image of the clouds of the whole sky. The sunlight may give rise to halation on fine days, so to prevent it the sunshade as shown in Fig, 5 is used, and an automatic apparatus is attached to turn the shade following the sun. Besides, as an automatic apparatus to know the movement and the change of the clouds, by means of exposures at every five seconds, the sprocket-type electrical automatic apparatus, shown in Fig. 5, is used. For the measurement of the direction and velocity of clouds, a scale as shown in Fig. 7 is set on the screen, and adjusting the scale as the clouds should trace the curve, one end of the curve shows the azimuth of the aloud direction.
    Suppose that the cloud-point which was at the intersection P1 on the curve at time t1 came to the intersection p2 at time t2, then the average velocity of cloud can be obtained by the formula H(tan θ2±tan θ1)/t2-t1, where H is the height of the cloud, and must be obtained by another method; θ1 and θ2 are the angles from the zenith at p1 and p2 respectively. The scale used is the curve obtained by photographing a grating, which consists of lines that intersect at right angles at each 10° in the sky, by the whole-sky camera.
    To obtain the cloud-amount, the scale as shown in Fig. 8 is used. This scale consists of concentric circles spread from the centre to the circumference, and each round bands have the same areas, and is separated in eight directions. The sum of the cloud-amount is obtained, when we measure the amount in each section. The whole-sky camera of Mr. Robin Hill was equidistant, and had the form φ/tan θ=const. In our camera, however, sin φ/tan θ=const, because the concave lenses are not specially designed. φ is the angle of incidence and θ is that of refraction.
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  • T. Okano, S. Homma
    1950 Volume 28 Issue 1 Pages 25-34
    Published: 1950
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    Recently, M. Hayakawa discussed on the time variation of the velocity of seismic wave in connection with the internal stress in the earth's crust. (not yet published.) In the present paper, we examined this problem with a somewhat different method which is simpler than that of Hayakawa's. The travel time of the first impulse to a station from two foci of different shocks, which are nearly the same point, are compared. The difference of the two seems to be closely connected with the mechanism of another larger shock occurred during the period of the two shocks under consideration; if the most part of the path of the first impulse lies across the compression (dilation) area of the intermediate shock, the travel time of the first impulse of the earlier shock is usually less (greater) than that of the later one, concording with Hayakawa's conclusion. In part 1, we show the examples of Tajima-earthquake (Fukushima Prefecture) in Au ust 1943, and Tottori-earthquake in March-October 1943.
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