Papers in Meteorology and Geophysics
Online ISSN : 1880-6643
Print ISSN : 0031-126X
ISSN-L : 0031-126X
Volume 26 , Issue 4
Showing 1-6 articles out of 6 articles from the selected issue
  • Naosuke Saito
    1975 Volume 26 Issue 4 Pages 121-147
    Published: 1975
    Released: December 11, 2012
    Analyses of the synoptic dat a during the AMTEX '74 revealed the spatial and time variations of the inversion layer over the AMTEX area. The quasi-stationary inversion formed between 700 mb and 850 mb and covered a considerable wide area from the Yellow Sea to the southwest Pacific.
    The formation of inversion was mainly attributed to free convection above the warm sea surface and isentropic sloping down at middle level during the period of cold air outbreak. As a result vertical transport of heat energy from the sea was stopped at the inversion.
    After the cold air outbreak, the southerly f low replaced the northerly flow. Even at this stage the inversion was recognizable between the southwest winds in the lower layer and the steady westerlies above 700 mb. The thermal stratification below the inversion, however, became more stable, and the height of the inversion base rose. When a synoptic disturbance was approaching to the area, moist and dry tongues were formed in the sub-inversion layer. The scales of the tongues were a few hundred kilometers. The formation of this sharp gradient of water vapour was related to the vertical circulation below the inversion rather than the horizontal advection of vapour. At this time a secondary low-level inversion was often formed.
    A few time s the inversion partly disappeared through large-scale upward motion of air, and an ensemble of cumulus convection developed.
    The cloud shield above the inversion was dependent on the moisture content of air coming from the China continent and the adjacent sea.
    The numerical analysis of static stability between 850 mb and 700 mb showed that: (1) Differential advection of potential temperature and vertical net transport of stability were equally important to the change in the stability when adiabatic condition was applicable. (2) During the period of cold air outbreak, diabatic heating in the lower layer played an important role in compensating the surplus contributions of the two terms.
    Download PDF (4264K)
  • Kozo Ninomiya
    1975 Volume 26 Issue 4 Pages 149-165
    Published: 1975
    Released: December 11, 2012
    A family of mesoscale distur b ances was observed in the vicinity of the cold vortex aloft which passed over the Japan Sea coastal region on January 16,1965. A detailed subjective mesoanalysis of them was made by MATSUMOTO et al. (1967 a).
    In the present paper, an objective surface analysis is made for one of the mesoscale disturbances in order to reexamine the results of the subjective analysis. The obtained mesoscale pressure and the wind fields in the present study coincide well with those of the subjective analysis. The phase difference between the pressure and the divergence fields suggests that the disturbance possesses the characteristics of a gravity wave. It is also shown from the evaluation of the divegence equation that (∂D/∂t+ V⋅∇D) is primarily balanced with 1/ρ∇2p.
    Download PDF (2289K)
  • Sadao Yoshizumi
    1975 Volume 26 Issue 4 Pages 167-180
    Published: 1975
    Released: December 11, 2012
    On July 7,1970 an instability line occurred in the vicinity of Kyushu in the southeast quadrant of a cut-off cold low over the Korean Penninsula. In this paper the development of the instability line on July 6 is investigated, which was not treated in detail by the previous investigators who studied its situation on July 7.
    It is shown that the insta b ility line formed on the morning of July 6in the northern East China Sea in the southwest quadrant of the cut-off low. Intensification of the warm advection upstream of the cold core after the complete formation of the cut-off low produced large-scale conditions favorable for the development of cumulus convections in the northern East China Sea. It is considered that the cumulus convections were organized into the instability line by a low-level jet stream which had occurred along the zone of concentrated temperature gradient in the lower troposphere due to the combined influence of the cut-off low and a lower cyclone resulting from a decayed typhoon before the development of convections.
    Download PDF (2882K)
  • Masako Momiyama-Sakamoto, Kunie Katayama
    1975 Volume 26 Issue 4 Pages 181-197
    Published: 1975
    Released: December 11, 2012
    In the preceding report on t h e seasonal variation of deaths from cerebrovascular diseases, the writers reported that mortality from cerebral thrombosis and embolism, more frequent than cerebral haemorrhage among the aged, picks up in summer in districts where temperature exceeds 24°C in the hot months. It is further studied in this report whether such a summer upcurve is seen only for this senile ailment or for others as well, such as heart disease, tuberculosis, pneumonia-bronchitis, and malignant neoplasm of stomach.
    1. The p h enomenon in which mortality declines along with the rise of temperature but turns upward in the summer season is witnessed for all these diseases but malignant neoplasm. Deaths from the last named cause occur differently.
    2. The s e asonal variations of deaths from cerebral thrombosis and embolism can roughly be classified in form according to regional climatic conditions. It is found, however, that mortality increases in summer for chronic rheumatism in those areas where no pickup is recorded in the hot months for cerebral thrombosis and embolism, and that the summer peak is much higher for tuberculosis than for this cerebral disease. That mortality resumes an upturn in summer is not a phenomenon confined to the senile disorder but one greatly dependent upon socio-economic conditions in some regions of the country.
    3. As for pneumonia- b ronchitis, this phenomenon appears more conspicuously for infants than for other age groups. On the other hand, the winter peak of mortality is now a little lower for infantry and old people, but it was formerly much higher and then has fallen off to the present level thanks probably to the improvement of room heating facilities in the cold months, indicative of the future possibility of deseasonalization at least for infant mortality.
    Download PDF (2535K)
  • Takeshi Uji
    1975 Volume 26 Issue 4 Pages 199-217
    Published: 1975
    Released: December 11, 2012
    Characteristics of waves in a typhoon area were estimated by our numerical ocean wave prediction model. Wave height distribution and two-dimensional wave spectra at various points in the area are obtained. Wave characteristics along the coast when a typhoon hits the land and wave characteristics when a typhoon moves along parabolic coursc are also obtained. Wave height distribution is somewhat different from that of IJIMA, et al. (1967) in areas where a swell is dominant. The highest wave height in a typhoon area and its variation with the forward speed of the typhoon agree considerably well with those of UNOKI (1957).
    Download PDF (2757K)
  • Hisafumi Muramatsu
    1975 Volume 26 Issue 4 Pages 219-264
    Published: 1975
    Released: December 11, 2012
    Photodissociation rates of ox y gen and ozone molecules in the stratosphere, mesosphere and lower thermosphere were examined to see the uncertainties in treatment of the predissociation of the Schumann-Runge bands, the solar flux and the transmission in the Schumann-Runge bands. The effect of these uncertainties on the calculated distribution of the ozone molecule was estimated.
    First were examined the previous studies about the predissociation of the Schumann-Runge bands. It is concluded that the vibrational levels of B3Σu state are predissociated to some extent between υ′=3 and υ′=17. This is confirmed by spectroscopic and photochemical evidences. But some questions remain about the crossing point of the potential curve of 3Πu state with that of B3Σu state, the contribution of the underlying continuum to the decomposition of the oxygen molecule, the quantum yield of the ozone formation from the decomposition of the excited oxygen molecule in the Schumann-Runge system and so on. The effect of the predissociation on the dissociation rates of the oxygen and ozone molecules was estimated.
    Next, we reviewed the estimations of solar ultraviolet radiation outside the atmosphere. Large variations are recognized in the reported solar radiation below 2500 Å. These variations come from several sources. The first of them is the absolute intensity calibration. The second problem is the variability of the sun. The third problem is difference in the detectors.
    We applied the band model to the calculations of transmission in the Schumann-Runge bands in order to reduce the labor involved in exact calculations of transmission in the bands. We examined the line broadening effects and adopted the Lorentz line shape for the predissociation line shape. From the line positions and the intensity distributions of the rotational lines, we came to the conclusion that the random model for the inverse first power or the exponential distribution of line intensities is most appropriate.
    The dissociation rate of the oxygen molecule excluding the predissociation was compared with that including the predissociation of the Schumann-Runge bands. The remarkable contribution of the predissociation appears above 45 km. The maximum contribution of the predissociation appears at 75 km for sec z=1.0, at 80 km for sec z=3.0 and at 85 km for sec z=6.0. The ratio of the dissociation rate including the predissociation to that excluding the predissociation falls in the range from 8 to 3for sec z=3.0.
    Taking account of the uncertainty in solar ultraviolet radiation due to the difference between the values obtained by photographic technique and those obtained by photoelectric technique, an uncertainty of factor 2to 4 appears in the dissociation rate of the oxygen molecule between 40and 100 km.
    The deviations of the dissociation rate of the oxygen molecule due to various causes originating from the band model in the Schumann-Runge bands were estimated. The deviation due to the distribution functions (inverse first power distribution and exponential distribution) is at most about 11% between 40 and 100 km. The deviations due to the band model parameters are: (1) 20% due to the mean line intensity (mean absorption coefficient), (2) 20% due to the mean line spacing, and (3) 5% due to the mean line half-width.
    The photodissociation rate of the ozone molecule is hardly affected by the predissociation or by the band model for the Schumann-Runge bands, but has the uncertainty of about 6% between 40 and 100 km due to the ambiguity of solar radiation.
    Download PDF (6800K)