Journal of the Meteorological Society of Japan. Ser. II
Online ISSN : 2186-9057
Print ISSN : 0026-1165
ISSN-L : 0026-1165
Volume 63 , Issue 2
Showing 1-23 articles out of 23 articles from the selected issue
  • Tomonori Matsuura, Toshio Yamagata
    1985 Volume 63 Issue 2 Pages 151-167
    Published: 1985
    Released: October 19, 2007
    JOURNALS FREE ACCESS
    Numerical solutions of a homogeneous, incompressible and viscous flow past a circular cylinder on an ƒ-plane are presented. A direct comparison is made between published experimental results and the numerical results and shown to be in good agreement. As observed experimentally by Boyer (1970) and Boyer and Davies (1982), the presence of the Ekman friction delays the boundary layer separation. This is because the Ekman friction alleviates the adverse pressure gradient at the surface of the cylinder. It is shown that the eddies initially formed behind the cylinder finally spin-down. The core of these eddies, in contrast to a non-rotating case, becomes almost stagnant in a final state. The drag coefficient Cd is dependent on both Re and α where α is the ratio of the square root of the Ekman number to the Rossby number. It decreases as Re increases at least for 20≤Re≤200 when α is fixed. If Re is kept constant, Cd increases with increasing α. The Stokes's drag law adapted for a rotating fluid is found to be in good agreement with the present numerical result at a small Reynolds number. It is also found that a nonlinear effect (O(R20)) associated with the Ekman suction can generate a noticeable asymmetry (which was observed in the experiments) in the wake when separation occurs.
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  • Katsumi Tamaki, Kazuo Ukaji
    1985 Volume 63 Issue 2 Pages 168-179
    Published: 1985
    Released: October 19, 2007
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    Thermal properties of amplitude vacillation are studied experimentally. Use is made of a fluid annulus with the properly selected geometry to produce unmodulated baroclinic waves and a small number of temperature sensing probes so as to reduce the disturbing influences of probes on the flow field. Experiments, though conducted with only one value of imposed temperature difference, show that strong amplitude vacillation takes place virtually without the long wave (wavenumber=l) and the sidebands of the dominant wave. This exhibits a striking contrast to other experimental results (e. g. Hide et al., 1977; Pfeffer et al., 1980) obtained by using a large number of probes. The rate of radial heat transport and the azimuthally averaged temperature field vary with time with the same period as that of the amplitude vacillation. Further, nonlinear interaction between the azimuthally averaged temperature field and the deviations from it due to the waves (the dominant wave and its harmonics) is observed when the fluid is undergoing amplitude vacillation. These results indicate that amplitude vacillation is caused by baroclinic interactions between the waves and the azimuthally averaged flow field; although this simple mechanism was suggested in an earlier paper by Pfeffer and Chiang (1967), it has been somewhat confused by the subsequently observed sidebands.
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  • Hiroshi Tanaka
    1985 Volume 63 Issue 2 Pages 180-200
    Published: 1985
    Released: October 19, 2007
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    A diagnostic energetics scheme is developed in order to investigate the energy flows among three-dimensional normal modes (Hough modes in horizontal) in the atmosphere. This scheme is applied to the GFDL version of the FGGE level IIIb data during the winter from December 1978 to February 1979.
    The resultant energy flow is summarized as follows: available potential energy generated at zonal baroclinic modes (especially at the vertical mode m=4) is directly converted into kinetic energy of the planetary scale barotropic mode. Kinetic energy of the cyclone scale baroclinic mode is transformed into zonal and eddy kinetic energies of the barotropic mode. Parameterizing the horizontal scale of waves by their eigenfrequencies, we find for vertically trapped modes, the kinetic energy spectrum follows approximately the 3 power of the frequency. However, for the propagative Rossby modes, the spectrum obeys the -5/3 power law and merges continuously with the spectrum of the gravity modes. It is concluded from the results that the energy spectrum depends on the vertical propagation properties; the energy spectrum of the propagative Rossby waves is similar to that of gravity waves in the frequency domain. The trapped and the critical modes gain their energy through the interactions mentioned above, whereas we find the propagative modes lose a part of energy through nonlinear mode-mode interactions.
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  • Geoff Love, Geoff Love
    1985 Volume 63 Issue 2 Pages 201-209
    Published: 1985
    Released: October 19, 2007
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    Approximately sixty seven months (January 1978 through September 1983) of monthly anomaly data for the fields of sea surface temperature, mean sea level pressure and high cloud amount over the Northwest Pacific have been used to investigate the linear relationships between these parameters. Linear relationships were sought using the empirical orthogonal function technique on the data fields stratified into summer and winter data sets. The first winter eigenvector/amplitude coefficient pair resembled an El Nino/Southern Oscillation event. No other statistically significant eigenvector/amplitude coefficient pairs were obtained. Generally the relationships between the three pairs of variables were statistically insignificant.
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  • Masahito Ishihara
    1985 Volume 63 Issue 2 Pages 210-225
    Published: 1985
    Released: October 19, 2007
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    This paper presents results of the statistical analysis of cumulus-scale to mesoscale radar echoes observed over the 1.3×105km2 area in the equatorial western Pacific for the period of 20 days in May and June 1979 during MONEX. In this period easterly flows in the middle and lower troposphere began to be enhanced over the experimental area. The experimental area was located to the north of the ITCZ in the Southern Hemisphere during May and between the ITCZ's in the Northern and Southern Hemispheres during June. The mean echo area and the echo height averaged during the entire period were 125km2 and 2.9km, respectively. In average, 5.0% of the experimental area was covered by radar echoes. We could express the relationship between echo area and the number of echoes by a simple empirical formula. The number of mesoscale echoes larger than 103km2 in area was only 1.6%, but the total area of these echoes amounted to 47% of the total echo area.
    The analyses of the radar echo population and the position of the ITCZ showed that the convective activity around the experimental area was enhanced in June more than in May. The number of radar echoes fluctuated with period of 3.5 to 4 days. Upper air data showed that large-scale westward propagating waves existed in the easterly flows at the middle and lower troposphere over the experimental area in June. The number of mesoscale echoes increased ahead of the 500mb trough (behind the 500mb ridge) in the waves. The radar echoes whose area were smaller than 103km2 tended to appear in the daytime rather than at night.
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  • Fumiaki Fujibe
    1985 Volume 63 Issue 2 Pages 226-237
    Published: 1985
    Released: October 19, 2007
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    A statistical study is made on the air pollution in the surface layer associated with a front-like phenomenon which propagates eastward in the central part of the Kanto plain at the transition from the sea breeze to the land breeze. It is shown that on winter days with westerly land breeze the passage of the front is followed by maxima of concentration of pollutants which are the constituents of vehicle exhaust. On the other hand, pollution is found to be less remarkable on winter days with northerly land breeze and on summer days. On the basis of statistical analysis and conjecture, it is considered that the pollution intensity is related to stability of the surface layer and emission rate in the land breeze layer, and that advection by the land breeze contributes to the transport of pollutant. Relations between these controlling factors and local meteorological conditions are examined.
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  • Gaishi Onishi, Nobuo Obara
    1985 Volume 63 Issue 2 Pages 238-248
    Published: 1985
    Released: October 19, 2007
    JOURNALS FREE ACCESS
    The explanation of winter land and sea breezes, which blow sometimes in the Sagami Plain is attempted. In the upper layer, the temperature is not affected by the surface temperature, and the pressure gradient is from the land to the sea. While, at night, the air is in contact with the cooled land surface and becomes denser than the air on the sea. lIn the lower layer, the pressure gradient develops from the sea to the land. This is seemed to be the cause of the winter land and sea breezes.
    The quantitative explanation of this idea is undertaken based on a two-dimensional numerical model which simulates a circulation in a vertical plain perpendicular to the coast-line. It is shown that the diurnal variation of eddy temperature conductivity and eddy viscosity have a possibility to produce winter land and sea breezes.
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  • Yoshio Sasyo, Takayo Matsuo
    1985 Volume 63 Issue 2 Pages 249-261
    Published: 1985
    Released: October 19, 2007
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    A new kernel of a stochastie equation for snowflake aggregation with the effects of variations of falling velocities is determined by observed data of falling snowflakes (Sasyo and Matsuo, 1980).
    Based on a stochastic equation with a new kernel, the snowflake aggregations in cloud with uniform elemental snow crystals are simulated without assuming an initial size distribution of snowflakes.
    The following results are obtained.
    i) The new kernel for the combination of colliding snowflakes is not symmetrical function with respect to the difference between their falling velocities. This suggests that j-snowflake whose mass is less than that of i-snowflake can collide with the latter at its rear. These results are different from those for the order collision in which the kernel is a symmetrical function.
    ii) The variation of falling velocity reduces considerably the time required to get a specified snowfall intensity compared with the case of the order collision but is not effective for increasing snowfall intensity.
    iii) The snowfall intensity is mainly determined by the initial number concentration of elemental snow crystals in a cloud.
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  • Tsutomu Takahashi
    1985 Volume 63 Issue 2 Pages 262-266
    Published: 1985
    Released: October 19, 2007
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    A positive electric charge separates on ice irrespective of the chemical impurities found in liquid water when the liquid water is removed from the ice surface at temperatures warmer than -10°C. This mechanism can be explained in relation to the formation of an electric charge double-layer at the boundary between water and ice. This phenomenon helps to explain the positive electrification of rime when it collides with ice crystals in clouds with warm temperatures and large cloud water contents.
    A special electric current is measured when liquid water moves over an ice surface. This phenomenon could affect the charge separation in thundercloud when large, supercooled drops collide with hail.
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  • M. P. McCormick, Patrick Hamill, U. O. Farrukh
    1985 Volume 63 Issue 2 Pages 267-276
    Published: 1985
    Released: October 19, 2007
    JOURNALS FREE ACCESS
    The discovery of polar stratospheric clouds (PSC's) in the Arctic and Antarctic stratosphere during winter is described, and the directly observed and implied properties of these clouds are discussed. It is proposed that the more familiar "mother-of-pearl" or "nacreous" clouds are a special subset of PSC's. The size, location, prevalence and temperature dependence of the clouds as measured by the SAM II and SAGE satellite systems are outlined. Airborne lidar measurements have recently demonstrated that the PSC phenomenon is most probably associated with an extended stratospheric cloud bank existing within the cold polar vortex region during the winter period with the PSC's bounded by a 188 K temperature isotherm. The PSC's probably exist at a 50 percent frequency within the 193 K isotherm. Using the observed information on the cloud extinction and change in location with time we consider possible formation mechanisms, the size of the cloud particles, and show the descending motion of the cloud during wintertime.
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  • Masumi Takagi, Yasuhiro Morita, Akira Iwata, Yutaka Kondo
    1985 Volume 63 Issue 2 Pages 277-282
    Published: 1985
    Released: October 19, 2007
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  • Yasunobu Iwasaka
    1985 Volume 63 Issue 2 Pages 283-287
    Published: 1985
    Released: October 19, 2007
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    The measurements on polar stratospheric aerosol particles using lidar and meteorological sonde at Syowa Station (69.00°S, 39.35°E), Antarctica revealed that the content of stratospheric aerosols noticeably increased in winter when atmospheric temperature frequently fell down to about -80°C in the lower atmosphere.
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  • Osamu Uchino
    1985 Volume 63 Issue 2 Pages 288-293
    Published: 1985
    Released: October 19, 2007
    JOURNALS FREE ACCESS
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  • Motokazu Hirono, Noboru Fujiwara, Motowo Fujiwara, Takashi Shibata
    1985 Volume 63 Issue 2 Pages 294-302
    Published: 1985
    Released: October 19, 2007
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  • Motokazu Hirono, Takashi Shibata, Motowo Fujiwara
    1985 Volume 63 Issue 2 Pages 303-310
    Published: 1985
    Released: October 19, 2007
    JOURNALS FREE ACCESS
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  • Ronald M. Nagatani, M. P. McCormick, L. R. McMaster
    1985 Volume 63 Issue 2 Pages 311-319
    Published: 1985
    Released: October 19, 2007
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    The fine scale vertical structure of SAGE I ozone and aerosol data during a stratospheric warming is investigated using meteorological and SBUV ozone data. By stratifying the ozone and aerosol data for a limited time period, we are able to compare the structure of profiles under different meteorological conditions. For example, the cold air region shows more laminated structures than the other regions. In addition, vertical motions calculated at the same locations as the SAGE profiles show that they are consistent with variances found in the ozone and aerosol data.
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  • David G. Murcray, Frank H. Murcray, Frank J. Murcray, George Vanasse
    1985 Volume 63 Issue 2 Pages 320-324
    Published: 1985
    Released: October 19, 2007
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    A liquid N2 cooled infrared interferometer system was flown on a balloon and used to obtain atmospheric emission spectra at high spectral resolution at various altitudes. The instrument was also used to view the earth from 28km. Samples of the spectra obtained during this balloon flight are presented.
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  • N. Iwagami, T. Ogawa, K. Shibasaki
    1985 Volume 63 Issue 2 Pages 325-327
    Published: 1985
    Released: October 19, 2007
    JOURNALS FREE ACCESS
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  • A. Matsuzaki, T. Itoh, Y. Nakamura
    1985 Volume 63 Issue 2 Pages 328-333
    Published: 1985
    Released: October 19, 2007
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    For the global investigation on H2O, CO2, CH4, O3, N2O, and aerosol in the middle atmosphere, the limb-atmospheric infrared spectrometer (LAS) on board the satellite "Ohzora" has been launched from Kagoshima Space Center, Japan, on Feburuary 14, 1984. This letter discusses the characteristics of the LAS observation.
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  • T. Ogawa, K. Suzuki, M. Takano, M. Nakamura
    1985 Volume 63 Issue 2 Pages 334-339
    Published: 1985
    Released: October 19, 2007
    JOURNALS FREE ACCESS
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  • Takayo Matsuo, Hitoshi Sakakibara, Jiro Aoyagi, Kazuo Matsuura
    1985 Volume 63 Issue 2 Pages 340-346
    Published: 1985
    Released: October 19, 2007
    JOURNALS FREE ACCESS
    To examine the process of atmospheric cooling due to melting, nine cases of a melting layer in continuous rain were observed by means of a Doppler radar and rawinsondes between 1981 and 1982 in the Tsukuba District, Japan. Six cases displayed the existence of cold air around the melting layer but three cases did not. The cold air existed in cloud regions with relative humilities greater than 90%, and it was related to the amount of precipitation on the ground. The results indicate that the cold air is associated with the melting of snowflakes. A nearly isothermal layer existed below the 0°C level and also stretched upward above the 0°C level. Below the isothermal layer, a layer with large lapse rate, i. e. an unstable layer, was observed. The stretch of the isothermal layer above the 0°C level suggests that some vertical mixing of air takes place around the melting layer.
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  • Naomi Kuba, Takao Takeda
    1985 Volume 63 Issue 2 Pages 347-353
    Published: 1985
    Released: October 19, 2007
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  • Tosio Takeuti, Zen-Ichiro Kawasaki, Kazuki Funaki, Nobuichiro Kitagawa ...
    1985 Volume 63 Issue 2 Pages 354-358
    Published: 1985
    Released: October 19, 2007
    JOURNALS FREE ACCESS
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