Journal of the Meteorological Society of Japan. Ser. II
Online ISSN : 2186-9057
Print ISSN : 0026-1165
ISSN-L : 0026-1165
Volume 17 , Issue 7
Showing 1-8 articles out of 8 articles from the selected issue
  • K. Takahasi
    1939 Volume 17 Issue 7 Pages 261-267
    Published: July 05, 1939
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    In Kawantõ district when sõutherly wind blows, the overcasted weather and even sometimes drizzle is often experienced after the sunset, especially in morning, thought it is fine in day time. Some examples of such weather situation were investigated by synoptic atlas and it is found that they are explained by discontinuity between land and sea caused by nocturnal cooling of the land. The mode of the development of the discontinuity was mathematically treated under a simple assumption and the result was obtained which agrees well with the observation
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  • R. Kuraisi
    1939 Volume 17 Issue 7 Pages 267-270
    Published: July 05, 1939
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    The author constructed a newly designed hair hygrograph. Although this instrument is seemingly similar to the F. Richard's one, but has two cranks and one connecting bar in place of cams (see Fig. 1 and Fig. 2), and it can also record the relative humidity in uniform scale on a recording chart Excellence of this instrument is in the simplicity of the construction and in the smooth action due to small friction, therefore it may be made more easily than the old one.
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  • S. Kitazawa
    1939 Volume 17 Issue 7 Pages 270-281
    Published: July 05, 1939
    Released: February 05, 2009
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    In the present paper it is shown that the standard deviation of the monthly mean air temperature T of August and the frequency of unusual lowness of the five-day-mean of air temperature t in August are abnormally large on the Pacific side of Tohoku district especially at Miyako. The relation between the lowness of temperature and the total failure of the yield of rice crops in Tohoku district is very close.
    It was found from the observations during 37 years from 1900 to 1936 that there is a close relationship between the unusual lowness of T or t in July and August at Miyako and the position of the north pole of the earth's axis in the summer or the former winter.
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  • S. Katada, T. Kameda, H. Tamaki
    1939 Volume 17 Issue 7 Pages 282-294
    Published: July 05, 1939
    Released: February 05, 2009
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    In Part I, the correlations between the wind velocity at Tateno and the temperature in summer, especially in August, were studied. A good negative correlation was found between the upper wind in summer and the temperature in that season. But the correlations between the temperature in July and August and the wind velocity in months before it, were found not to be good enough for the practical purpose of forecasting the temperature in that season, and hence of estimating the rice crop in this district.
    Part II contains the studies on the correlations between the temperature in August in Tohoku and that of the surface water of the western part of the northern Pacific. Two zones of sea surface having different types of correlation were found; the one lies the south presenting a positive correlation, and the other in the north presenting a negative one, and the influence of the former increases as time goes on from winter to spring and summer. Several good positive correlations were found between the temperature in August in Tõhoku and that of the surface water from April to June, which will be useful for the seasonal weather forecasting.
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  • S. Sakuraba
    1939 Volume 17 Issue 7 Pages 295-296
    Published: July 05, 1939
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    According to the recent investigation by H. Solberg and C. L. Godske the “Scherungswirkung” due to the difference of velocity across the discontinuous surface is considered to be the only factor inducing the instability of wave motion. Therefore this factor is very important in the wave theory of cyclone. The present paper aims at the modification of the above conclusion by the presence of intermediate layer. Consider the three layers of different velocity distribution, the upper and the lower stratum having the uniform velocity U2 and U1 respectively, both of infinite extent, and the transient layer of the width b' varying linearly from U1 to U2 in velocity.
    The period equation is derivable as, on the assumption of no density difference, The discriminant of this equation is given by which, in case of b'→O, reduces to the usual characteristic equation of Helmholtzian wave: Here β is the frequency, Δ=(U2-U1)/b' and α=2π/L, L being the wave length. It is readily seen that the instability occurs in the following domain: 4.9 b'<L, while in the domain: 4.9 b'>L, the wave motion is stable. The above result is very interesting in the light of usual theory on the Helmholtzian wave in which the wave motion of any wave length is unstable when the distribution of density is uniform.
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  • S. Sakuraba
    1939 Volume 17 Issue 7 Pages 296-298
    Published: July 05, 1939
    Released: February 05, 2009
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    Take the x-and y-axis east-and northwards respectively, and let the general westerly wind be U(y), then Here u and υ denote the velocity components associated with wave motion. The equation of continuity is then the instability of wave motion sets in only when β is complex.
    The vorticity of the steady motion is 1/2 dU/dy If throughout any layer the vorticity is constant, d2U/dy2 vanishes and wherever β+αU does not also vanish. When there are several layers in each of which the steady vorticity is constant the various solution of the form (4) are to be fitted together, the arbitrary constants being so chosen as to satisfy certain boundary conditions. The first of these conditions is evidently The second may be obtained from the continuity of pressure across the boundary. Thus when U(y) is continuous across the boundary. At a fixed wall, of course Under these circumstances the examinations of stability coincides with Lord Rayleigh's investigation on the stability of certain fluid motions. Thus it may be concluded that in the isolated system of west wind zone the wave motion of any wave length is stable and has no chance of transforming into vortical motion, but on coupling with the east wind zone such as the equatorial trade wind zone or the polar east wind zone, the wave motion becomes unstable and transforms into vortical motion when the wave length is large compared with the breadth of the wind zone. The critical wave length is estimated to be about 10, 000km, which is too large compared with the cyclone wave of wave length 1000km. This discordance may be ascribed to the much simplified assumptions adopted here.
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  • H. Arakawa
    1939 Volume 17 Issue 7 Pages 298-300
    Published: July 05, 1939
    Released: February 05, 2009
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    Die Klimatologie bestand früher wesentlich aus statistischen Tabellen der meteorologischen Elemente. Die Klimatologie betrachtet im Gegensxtz zu der Meteorologie nicht die Einzelscheinungen in der Atmosphäre, sondern sie untersucht und beschreibt deren durchschnittliche oder mittlere Zustände. Z. B. haven die Dampfdruck in einem bestimmten Augenblick alle verschiedene Werten, und aus diesen kann man ebenfalls das arithmitische Mittel è bilden. Es ist aber nicht notwendig, den mittlere Dampfdruck gerade durch è darzustellen. Vielmehr kann das geschehen durch _??_•E (_??_), wo _??_ die mittlere relative Feuchtichkeit, E der Sättigungsdruck des Wasserdampfes bei mittleren Temperatur _??_ ist. Man sieht, das è und _??_•E (_??_) nahe zu gleich ist auf solche Falle, bei denen die Temperatur sowie die relative Feuchtigkeit nur unwesentlich von dem Mittelwert _??_ und _??_ abweichen.
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  • T. Sakurai
    1939 Volume 17 Issue 7 Pages 300-303
    Published: July 05, 1939
    Released: February 05, 2009
    JOURNALS FREE ACCESS
    At the Kakioka magnetic observatory induction current in a single turned horizontal circuit caused by changes of the vertical magnetic field of the earth is recorded continuously. The area of the circuit is 1×103 square meters, and in it a galvanometer is connected in series. Traces, which were considered to be due to some kind of electric discharges in the atmosphere, were often recorded on the sensitised paper. In this note the statistical investigation of those records was made. The main results are as follows:
    (1) Three kinds of groups are distinguished; (a) non-periodic, (b) quasi-periodic, (c) periodic variation. The first group has the largest number of occurrence and the second follows it, the third being smallest. The group b is accompanied with cyclones and thunderstorms attacking near the observatory and frequently observed between 20h and 4h in local time, while group c appears only when the main part of thunderstorm passes near the observatory.
    (2) The mean diurnal variation of the number of discharges, having a maximum in the night, is quite similar to that of atmospherics. But considering the similar type of b and the result (1), it is likely that electric discharge of this type originates not so far from the observatory.
    (3) There is no distinct relation between discharge and line of discontinuity as well as rainfall, but marked discharges increase with the former, and decrease with the latter to some extent.
    (4) The distance and direction of the cyclone from the observatory seem to bear close relation to the sign of discharges. The negative discharge (decrease of the earth's vertical magnetic field) is more numerous when a cyclone is found in the southwest direction of the observing station, and the positive in the north-east direction, while both signs appear when the cyclone is in the south-east and north-west direction.
    (5) In most cases discharges precede rainfall about 7 or 8 hours, though there are many cases of discharge without rainfall or the latter without the former.
    (6) It seems that discharges are rarely accompanied with Typhoons, while they are observed for almost all cyclones.
    (7) In the case of ash-fall accompanied with volcanic eruption, none of discharge is recorded.
    (8) Discharges are observed five or six hours before thunders are beared. As the thunder approaches to the observatory, amplitudes of discharges become larger, and frequency of them are greatly increased. When it comes so near that _??_2s are observed, c type discharges begin, and amplitudes of them become very large, while the frequency of occurrence of discharge decreases extremely.
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