Journal of the Meteorological Society of Japan. Ser. II
Online ISSN : 2186-9057
Print ISSN : 0026-1165
ISSN-L : 0026-1165
Volume 36, Issue 3
Displaying 1-6 of 6 articles from this issue
• Y. Sasaki
1958 Volume 36 Issue 3 Pages 77-88
Published: 1958
Released on J-STAGE: October 19, 2007
JOURNAL FREE ACCESS
Based on a simple principle, a method of obtaining an objective analysis is considered. Techniques of the calculus of variations are employed. Using this principle, two cases are studied. Case I is based on the assumption of quasi-geostrophic and thermal wind conditions. Case II is based on conditions defined by non-divergence and the “balance equation” which correspond to an equivalent barotropic flow. The method is demonstrated by three simple examples.
• T. Murakami
1958 Volume 36 Issue 3 Pages 89-96
Published: 1958
Released on J-STAGE: October 19, 2007
JOURNAL FREE ACCESS
In section 2, it is shown that we must consider the effect of friction in the numerical forecasting of the stream function in the lower atmosphere. The stream function, as well as the velocity potential, is easily obtained by use of the observed wind. By means of the so-called divergence equation we determined the frictional coefficient, assuming, for the sake of simplicity, that it is proportional to the wind speed. In our case, it is estimated about 4.2×10-5sec-1.
In section 3, we are interested in discussing the so-called ω-equation and the balance equation. The magnitude of the vertical velocity, obtained by the cu-equation, is about a half of that of the vertical velocity, obtained by using the observed wind. In the lower atmosphere, the stream function, which is obtained by the balance equation, is likely to overcompensate the sharpness of isobaric contour height. This fact leads to the result that near the ground surface the balance equation cannot safely be used as a first approximation of the divergence equation.
• K. Takahashi
1958 Volume 36 Issue 3 Pages 97-107
Published: 1958
Released on J-STAGE: October 19, 2007
JOURNAL FREE ACCESS
Tidal oscillations on the sun due to planets were calculated, and the following periods were obtained. Such periodicities were detected in the change of solar activity as well as in some meteorological elements on the earth. It must be noticed, however, that the phase angles of the periodicities change regularly due to the 11 years cycle of the sunspot number.
Such periodic changes in the meteorological elements were correlated with those in the solar activity and the effects of the change of solar activity to meteorological phenomena were confirmed though the physical process of the effects was not yet clear. Of course, the amplitudes of such oscillations are very small, being estimated to be of the order of 10-4 times the absolute values. Therefore, they are insignificant in daily change of meteorological phenomena but can not be neglected for changes of long periods.
Such oscillation on the earth is modified by the general circulation of the atmosphere. The periodicities produced by the coupling between the solar effects and the annual change of the general circulation were calculated for a simple model. Some of the periodicities obtained by such calculations were detected in certain meteorological elements.
• C. Magono, S. Koenuma
1958 Volume 36 Issue 3 Pages 108-111
Published: 1958
Released on J-STAGE: October 19, 2007
JOURNAL FREE ACCESS
The charge on water droplets produced by the breaking of drops under an electric field of strength 20v/cm was measured by a cathode ray oscillograph; the charge was found to be larger than that due to Lenard's effect. From both experimental and theoretical considerations, it was concluded that the charge on the droplets resulted from electrostatic induction in such a manner that the surface charge induced on the surface of the drop under the field was left on the droplets after they were disrupted.
• I. Sano, Y. Fujitani, K. Kawase
1958 Volume 36 Issue 3 Pages 112-117
Published: 1958
Released on J-STAGE: October 19, 2007
JOURNAL FREE ACCESS
A number of water-droplets, uniform in size at 1.0, 0.6, 0.3 or 0.2mm diameter, were prepared from water holding powder suspended as well as water having no addition, by electrical atomization, on a paraffin-covered glass-plate. This glass-plate was placed horizontally in a flat case tightly made of two brass-plates together with a rubber-frame between, and was cooled at various temperatures down to -30°C in a cryostat. Following this, the plate was quickly taken out from the case, and the droplets which had frozen were counted without delay in a low-temperature chamber, using a phase-contrast microscope and, on occasions, by the naked eye.
The powder-materials suspended were iodides of silver, mercury and lead, and further, oxides of copper, cadmium and zinc. As for lead iodide, it was the most soluble of the materials examined, so that an investigation into the influence of aging of the powder in suspended state upon the supercooling phenomenon was carried out in the following manner; the suspension of lead iodide was, after its production, allowed to stand in a closed vessel with frequent stirring for the periods of 0, 2 and 8 days at 5°C or thereabouts, and these three samplings dispersed each to droplets by the same method as with the other materials.
The results are roughly as follows:
1) The smaller the droplets, the more likely they are to exhibit supercooling, the finding being the same in both the absence and presence of solid particles in water, and there appears to exist a linear relation between the logarithm of droplet-diameter and the freezing-temperature.
2) Of the materials tested, silver iodide is most effective in solidifying water under supercooled condition, and its effectiveness goes up, though slightly, as the amount added to water is increased; lead iodide deteriolates considerably on account of its solubility, it being left to itself in suspended state.
3) The following equation
ln{x/(100-x)} =k•(θ-θ')
is presented as giving the fraction (x%) of droplets frozen at a supercooling (θ°C, expressed in terms of the lowering from 0°C), k being a constant depending on the conditions of experiment such as the droplet-size, the nature and amount of the powder suspended, etc. and θ'the supercooling at which x=50.