Journal of the Meteorological Society of Japan. Ser. II
Online ISSN : 2186-9057
Print ISSN : 0026-1165
ISSN-L : 0026-1165
Volume 17 , Issue 2
Showing 1-6 articles out of 6 articles from the selected issue
  • T. Ootani, K. Takahasi
    1939 Volume 17 Issue 2 Pages 45-50
    Published: February 05, 1939
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    A nomogram was made which is useful for the estimation of the atmospheric pressure in high altitude from the surface observation, and it is found that the estimation can be made within the error of 0.5mm compared with the calculated value. Next, a scale was made which is used for the estimation of wind velceity from isobar, assuming the gradient wind. And these two were applied for the forecast of upper winds and the satisfactory results were obtained.
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  • K. Fukuda
    1939 Volume 17 Issue 2 Pages 50-56
    Published: February 05, 1939
    Released: February 05, 2009
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    (a) The valley breeze at the foot of Mt. Tukuba begins from 8h-9h, a. m. and it reaches the maximum at 11h a. m.; from 4h p. m. the mountain breeze blows and the maximum occurs at 6h p. m. From midnight to morning it is calm. The valley breeze blows off fog near the top of the mountain. The frequency of fog is large at 9h a. m. and has minimum at noon and again at 3h-4h p. m. shows maximum. This is the time of the beginning of the mountain breeze.
    (b) When it is fair the diurnal variation of the wind-vector at the foot of the mountain describes an ellipse. Its major axis and the hangdirection of mountain are perpendicular to each other. This coincides with the law which has been found by T. Okada and T. Yamada as to the effect of topography on the diurnal variation of wind direction.
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  • K. Sone
    1939 Volume 17 Issue 2 Pages 56-61
    Published: February 05, 1939
    Released: February 05, 2009
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    This short note is a preliminary one, which contains the observational results obtained during last summer in Tokyo by means of a simple recorder of Simpson's type (Pron. Roy. Soc. A 161 309-352, 1937). The antenna used is about 70m long, one end being about 30m high, the other 69m. Three near thunderstorms were investigated which were weak and originated without exception in the vicinity of Tokyo and had almost negative atmospheric potential gradients on the ground. Three other remote thunderstorms were also recorded, potential gradients being more often negative than positive. So far as the present results are concerned. the electric fields under thunderclouds are completely explained by Simpson's model. It is also noteworthy that several hours before the attack of a typhoon in Tõkyõ, a negative electric field was recorded. It was already noticed among Japanese forecasters that a typhoon was often preceeded by thunderstorms. The above record is thus interesting in connection with this fact together with Arakawa's hypothesis of typhoon rainfall, which, after him, must be accomplished by some instability mechanism.
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  • R. Yamasita
    1939 Volume 17 Issue 2 Pages 61-68
    Published: February 05, 1939
    Released: February 05, 2009
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    In the theory of the “land and sea breezes, ” the earth's deflecting force should not be neglected, for the terms etc. are of the same order as the terms 2 ω sin ρ etc. In the present paper, the author took them into account but negleeted the inertial terms as in usual ways, and solved the equation of motlon for the air under the condition suitable for the land and sea breezes. And he found that the breezes deflected a little to the right in the northern hemisphere as shown in the diagram, and that the maximum of the surface sea breeze occurs about three hours before that of the surface air temperature, probably because the convection is greatest at that time.
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  • S. Todyo
    1939 Volume 17 Issue 2 Pages 69-73
    Published: February 05, 1939
    Released: February 05, 2009
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    Consider a discontinuous surface given by the equation where x, y, z denote the cartesian coordinatcs and t the time. The free atmosphere is divided into two strata by the above discontinuous surface, the upper stratum of the atmosphere being expressed by the suffix u and the lower stratum by the suffix d.
    The fundamental equations of motion and continuity are, in customary notation, λ being the coriolian parameter. Here the approximation as is adopted, which gives rise to no serious error in the present problem. By the relations the equations of motion may be transformed as ollo ws: in the upper stratum, and in the lower stratum.
    Denoting the jump of physical quantity along the discontinuous surface by Δο={ρ_??_(H)-ρu(H)}, Δ(ρ_??_), etc. the following relations are readily derivable: The above three equations determine the motion of the discontinuous surface.
    Let the x-axis make an angle ϑ with Δ(ρ_??_) and an angle θ with Grad H, then Put and we get the result: Generally speaking the variation of ψ is so small that we may safely put as ψ=const.
    In this case From the above equations the following relations are noticeable: The present result is also essentially the same as Ertel's equation derived from his theory of singular advection. Take ξ-axis along the direction of Grad H, then The above equation, with the initial condition of (H=-tanδ•ξat t=0), may be integrated as follows: which means the motion of the discontinuous surface with the velocity g/2λsin 2ψ•tanδ, the inclination of the surface being invariable. The above result, in a special case of ψ=π/2, reduces to the stationary discontinuous surface by M. Margules. In the last part ot the paper some numerical examples are given.
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  • Y. Yokouti
    1939 Volume 17 Issue 2 Pages 73-75
    Published: February 05, 1939
    Released: February 05, 2009
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    Point-discharge in the electric field of the earth is an important factor for the maintenance of the earth's negative charge. The observation of point-discharge at the Kakioka Magnetic Observatory has been begun from June, 1937 and the results of these observations are reported in this paper during a year, from June, 1937 to May, 1938. Point-discharge-currents have been continuously recorded with a galvanometer and photographical recording apparatus.
    For a year, the quantity of discharge q1, positive electricity flows into the earth through the point, is 530 millicoulombs and the quantity of discharge q2, positive electricity flows out of the earth through the point, is 108.89 millicoulombs.
    Thus the difference (q2-q1) and the ratio q2/q1 is 55.80 millicoulombs and 2.1 respectively for a year.
    The number of discharge in which q1<q2 is markedly numerous than that in which q1q2. It is shown, by these results, that the earth is charged negatively as a whole by point-discharge now concerned. The greatest discharge occurs in July in the annual variation and in the period 16h_??_18h in the diurnal variation.
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