Papers in Meteorology and Geophysics
Online ISSN : 1880-6643
Print ISSN : 0031-126X
ISSN-L : 0031-126X
Volume 30, Issue 3-4
Displaying 1-5 of 5 articles from this issue
  • Zenji Yanagisawa
    1979 Volume 30 Issue 3-4 Pages 111-121
    Published: November 15, 1979
    Released on J-STAGE: December 11, 2012
    Radar echoes in the clear atmosphere have been observed by vertically pointing 8.6mm cloud detection radar. Number and intensity of the angel echoes were analysed with data taken continuously over several days. The data were obtained from altitudes 200to 1,500 m. The pulsed angel echoes are strongly coherent and the values of duration are distributed from 1 to 3 sec. The duration was found to be directly proportional to the beamwidth of the radar and to the wind speed of the generating level.
    The occurrence starts with gradual increase in number at a few h o urs after sunrise and then the height of the generating level increases at a rate of 3-5 m/min. On the basis of a comparison of the radar data with the simultaneous captive balloon observations, it is suggested that the initial formation of angel echoes is related to the destruction of the surface inversion. The occurrence of angel echoes is concentrated in the daytime and was related to the amount of insolation and to the surface temperature.
    The radar backscattering cross-section reduced from the intensity of t h e angel echoes is distributed from 10-4 to 1cm2. By using a 3-cm doppler radar with a vertical beam, it was found that the vertical velocity of angel echoes is about ±1m/sec or less.
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  • Nobuhisa Yasuda
    1979 Volume 30 Issue 3-4 Pages 123-132
    Published: November 15, 1979
    Released on J-STAGE: December 11, 2012
    With the radiosonde data obtained over the ocean in AMTEX, the parameters C and D of the Rossby similarity law in the planetary boundary layer are evaluated. The height of the planetary boundary layer, h, is assumed to be 0.3 u*/ |f| and concerning the profiles of temperature and humidity the laminar sub-layer above the sea surface is taken into account. The parameter C evaluated takes a large value in plus and minus signs for the unstable and the stable conditions, respectively, near the neutral conditions. This result seems to disagree with the previous results in which the value of C changes gradually in the near-neutral conditions. However, if examined in detail it is understood that our result is quite reasonable and does not contradict them. The values of sensible heat and vapor fluxes calculated by the Rossby similarity law with the empirical equations obtained in the present work are very well consistent with those by the bulk method.
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  • Toshie Kitagawa-Kitade, Haruhisa Maruyama
    1979 Volume 30 Issue 3-4 Pages 133-139
    Published: November 15, 1979
    Released on J-STAGE: December 11, 2012
    The observations of ice nucleus concentration with the mixing type cold chamber have been continuously carried out at the Meteorological Research Institute for a long time. In an attempt to compare the data of ice nucleus concentration obtained from the present observation with those of the past, a study was made on the variations over a two-year period between April,1968 and March,1970. This period was selected in view of the continuity of observations during that time.
    The seasonal variation of the mean valu e of -20°C nuclei measured at 10 minute intervals reached a high of 66.2 nuclei per liter in winter, and a low of 7.6 nuclei per liter in summer. Measurements both in spring and autumn showed a value of a little over 20 nuclei per liter. Monthly speaking, January, February and December marked high values, whereas those of June, July and August were low. Especially, the lowest of the year appeared in August with 3.8 nuclei per liter. Thus, considerable monthly variation was recognized.
    As for the diurnal variation of ice nucleus concentration for each season, it was clearly observed that its curve tended to have more fluctuations in winter than in summer, and that in winter, the concentration was distinctly low at night and high in the daytime.
    The examination of the dispersion of the distribution of ice nucleus concen t r ation indicated that, despite fewer fluctuations in the diurnal variation curve for summer and more fluctuations for winter, the value of standard deviations of ice nucleus concentration was smallest for winter and largest for summer.
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  • A Proposal of the Mechanism
    Kyo Sekihara
    1979 Volume 30 Issue 3-4 Pages 141-151
    Published: November 15, 1979
    Released on J-STAGE: December 11, 2012
    Solar corpuscular radiation which en t ers the earth's atmosphere in high latitudes, such as auroral particles of Key energy or solar cosmic rays of Mev energy, are supposed to influence wintertime tropospheric meteorology in the form of the trough development at 300 mb level or the increase of pressure height difference between middle and high latitudes.
    In this article a detailed analysis of the ionizing effect and the subsequent ionchemistry of high energy particles on the atmosphere was given, focusing on the behaviour of carbon dioxide. The conclusion was that there was a strong possibility of CO2decomposition because of its fast reaction rate with O+-ions and its instability of the ionized states of higher levels
    The radiational effec t of this stratospheric CO2 decomposition was discussed and it has turned out to have a profound meaning as influencing temperature change at tropopause levels. The reason is that the 15 um absorption band of the stratospheric carbon dioxide overlaps with the absorption bands of tropospheric water vapour and exerts an infrared blanketing effect on the troposphere and the removal of stratospheric CO2 gives rise to the enhancement of cooling-to-space effect at the tropopause level.
    The dynamical aspect of this cooling effect at the tropopause level over high latitudes was briefly discussed. This will cause the destabilization of air masses in high latitudes in the form of the trough development that was pointed out by Roberts et al. (1973). And at the same time it will enhance the meridional circulation of the so-called 3-cell pattern, resulting in an increase of pressure height difference between high and middle latitudes and also an increase of westerlies in middle latitude that was pointed out by Stolov et al. (1974) and Sekihara et al. (1976).
    Thus a comprehensive explanation h as been given to the solar-corpuscular-weather relationship that has so long remained unsolved.
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  • Shizuo Kashiwabara, Nobuo Hamada, Masahiro Yamamoto
    1979 Volume 30 Issue 3-4 Pages 153-165
    Published: November 15, 1979
    Released on J-STAGE: December 11, 2012
    The free oscillation of the earth excited by the Earthquake of Sumbawa Island, Indonesia, August 19,1977 with magnitude 7.9 (Ms) was investigated using the records of the silica tube extensometer at Matsushiro, and borehole type strainmeters at Mikkabi and Irako.
    The main results of this study are summarized as follows.
    (1) Eigenperiods of 53 spheroidal modes and 23 torsional modes which were determined in this study are in agrement with the results obtained by Anderson and H art (1976)within about ± 0.5%.
    (2) Phase velocities of Rayleigh waves with periods 200-900 sec and of Love waves with periods 280-900 sec were determined using the periods of free oscillation. The phase velocities of Rayleigh waves with periods le s s than 300 sec seem slightly higher than calculated values by Anderson and Hart (1976). This disc r epancy may be interpreted as the differences of tectonic condition along the p a ths.
    (3) The degree number m is determined by a comparison between the vanishing points in the specific spherical surface harmonics and the missing peaks in the obs e r ved spectral for the spheroidal modes at Matsushiro. It can be considered that oscillations of 0 or 2 degree number are generated.
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