The simplified system of dynamic equation is solved by use of the first and the third kind of elliptic functions, to study the non-linear feed-back mechanism in the barotropic atmosphere. These solutions show that there is n o shorter period than 5 days in the barotropic variations, unless due to linear effect, that the influences of small-scale disturbances upon the large-scale ones are not so large with respect to the period of variation, that the magnitude of exchange of kinetic energy among disturbances of close scales is larger than the other couple, and that accordingly the contributions of smaller-scale disturbances to the time change of the zonal flow decreases rapidly with the increasing wave number. It may further be concluded that the per i o d of variation becomes longer the nearer the representative scale approaches the middle scale, and is in inverse proportion to the total kinetic energy. It has been suggested from the above that the domain of wave number less than m=12, nm=15 is enough for long-range prediction and time intervals Δt=12 hours used for integration of equation may be permitted.
The method to integrate the vorticity equation with the use of surface spherical harmonics has several advantages over the conventional method that uses the grid points. Namely,1) no relaxation is required to solve the poisson equation,2) we are not worried by the troubles accompanying the boundaries,3) it has no such malignant truncation error as can be seen in the grid point method, which was already pointed out by Phillips,4) square velocity and square vorticity are conserved. So, several points are explained here for preparations for the actual integration of barotropic equation. First, selection rules of interaction coefficients to determine the combinations of disturbances which contribute to the variation of a certain disturbance and the method to calculate them are investigated. And the method how to expand the meteorological elements into the series of surface spherical harmonics, the individual points necessary for the actual integration are also presented, with one example.
Observations on ice-forming nuclei in the atmosphere were made at the Meteorological Research Institute, Tokyo, at the ground surface, from November 1959 through February 1961, including special minute observations in summer (June through September) and winter (November through February). For those two seasons, for most of the days with high concentrations of ice nuclei, corresponding major meteor streams were recognized, and the concentration reached some dozens of times as high as usual twenty-eight days after the maxima of major meteor showers were observed. The durations of the high concentrations were around several hours, seldom more than ten hours. These results lead to the important suggestions that there would be some relation between the meteoritic dust and ice nucleus, and that some of the natural ice nuclei might have an extraterrestrial origin. On the other hand, a statistical inq u iry was made into whether the yearly major meteor shower has any influence upon the annual daily precipitation amount, from the records for about sixty years at twenty weather stations in Japan. From the results, the increment of precipitation amount caused by the meteor shower is recognized to a high degree of confidence, the increment being 15% on an average, and BOWEN's hypothesis is supported. An examination of the physical process by which the meteoritic dusts are carried to the earth's surface was also made.
A newly designed apparatus for measuring the mobility spectrum of atmospheric ions was constructed in 1959, on the basis of the method previously developed by the author. After the examination of the air flow pattern through the aspiration cylinder, measurements of the mobility spectrum have been resumed since 1960. Two ion probes were used in the present studies with different diameters and with the same length to scan the mobility ranges of 3-0.1 and 0.1-0.005 cm2/volt sec, respectively. Dedails on the experimental set-up, procedures of experiments and practical treatments of data analysis are described in this paper.
Experiments for obtaining the mobility spectrum of atmospheric ions in the mobility region between 3.0 and 0.2 cm2/ volt. sec. were carried out in 1960 under the conditions of the polluted air (Tokyo)and of the clean air (Karuizawa). Results of the diurnal series of observations made at both sites indicate some effects of pollution on the relation between the electrical conductivity and the mobility spectrum. In the polluted air, scores of percent of the conductivity should be attributed to the large or the intermediate ions, while the conductivity in the clean air is practically attributed to the small ions only, as is generally believed. The spectrum of the small ions does not shift on the m obility axis, maximum concentration lying in the interval 1.0∼1.7 cm2/volt. sec, and thus the average mobility of the small ions remains unchanged, regardless of the variations in the conductivity. On the contrary, the equivalent mobility, i. e. the ratio of the polar conductivity to the small ion concentration, changes with the variations of the conductivity in the intensely polluted air. In addition, some comments are put forward on the ordinary method for obtaining the small ion concentration with a constant applied voltage. When there is a considerable amount of pollution, the values obtained by the ordinary method are generally overestimated, because the ion-probe collects not only the small ions but a considerable amount of larger ions.
A new automatic continuous recording system was set for a trial in order to measure the natural radioactive dust in the atmosphere. This recording system can measure not only the alpha-ray, but also the beta-ray at the same time. Sampling time can be arbitrarily adjusted to the half-life of radioactive elements. As the aluminum tape reaches the d etector in five seconds after the collection of dust on it, so the apparatus can measure radioactive elements having such a short half-life as 84Po218. The time function of the Radon daught e r collected on the aluminum tape is considered. It is possible to estimate the Radon amount from the value of 84Po218, provided that there exists an equilibrium between Radon and 84Po218. The radioactive equilibrium between 84Po218and its daughter products does not hold in the atmosphere owing to precipitation, diffusion and deposition. This non-equilibrium can be estimated from the decay curve of the alpha-ray. High efficiency against submicron particles is required of collectors, because daughter products are attached to submicron particles. The electrostatic method can well trap particles of small sizes. A field observation is done from May 16,1961, t o May 20 and from June 19 to June 24 at Tokyo, and from July 8,1961, to July 12at Karuizawa. Meteorological elements are measured and the dust monitor is used in these observations at the same time. The results show that vertical diffusion is predominant over the diurnal variation of the radioactivity. Air temperature and humidity are not direct causes of that variation. Dusts, particularly dusts larger than a micron in diameter, do not exert any influence on the radioactivity.
An analysis is made of the formation and the feature of stationary rainbands observed in western and eastern Kanto District. It is shown that the generation of a small elementary cell depends on the atmospheric condition and the topography of the peninsulas, and that the principal factors governing the formation of astationary rainband are the vertical wind profile and the depth of the moist layer. Furthermore, in order to examine the effect of trigger action due to topography, the distribution of updraft by topographies is calculated.
The concentrations of the tropospheric ozone and nitrogen dioxide were observed at the side (elevation 1,450 m) and the top (elevation 2,770 m) of Mt. Norikura, Nagano Pref., in the early fall,1959 and 1960. The results of the ozone measurement showed that the day-to- d a y variation in the concentration during the daytime was parallel to those of the ambient atmospheric pressure. The average daytime values of the ozone obtained in 1959 were 58 and 35 μgO3/m3, respectively, at the top and the side of the mountain, showing that the ozone increased approximately in proportion to the altitude of the observing stations. The values in 1960 were essentially lower than those in 1959. The results of NO2 determination revealed that at the mountain side the concentration showed a marked diurnal variation with two maxima, i. e. at 07: 00 h-09: 00 h and 18: 00 h-20: 00 h, while no such a variation was observed at the mountain top. The average day and night values at the mountain side were nearly the same, namely,2.8and 3.1μgNO2/m3 in 1959 and 3.7 and 3.1μgNO2/m3 in 1960. The same is also observed at the mountain top, though the concentration is lower, the respective values in 1960 were 2.3 and 2.5 ugNO2/m3.