Since sampling time of actu a l analysis or recording period of observation is of finite length, statistical values obtained are sample means, sample variances and so on, and not ones computed with the use of data over allmembers of the ensemble. Taking this fact i nto consideration, the received fields in transhorizon propagation of microwaves are found to present, for a short sampling time, apparent coherency, which explains the results of Waterman's rapid beam-swinging experiments. Furthermore, a method is presented to determine whether or not only radio scattering due to atmospheric eddies is dominant in transhorizon propagation. Actual analyses seem to show that, in most cases, not only scatterings due to eddies but reflections due to wavy layers are dominant in over-sea transhorizon propagation of 3,000 MC/S and 1,300 MC/S, apart from other possible mechanisms which may be relevant to the propagations. In a few cases obtained in a well-mixed atmosphere, the most dominant seemed to be eddy scatterings. It may also be suggested that the sort of analyses made here would be useful in affording some measure of weather situation on the so-called meso-scale.
The Fiji region in the southwest Pacific Ocean is the most active source of deep earthquakes. U. S. C. G. S. registered 141 deep earthquakes of more than 300 km in depth in the Fiji region in a period from July,1959 to March,1961, and a short period vertical seismograph at the Matsushiro Seismological Observatory, which is about 70 degrees away from the region, surprisingly well recorded these earthquakes, namely,112 out of 141. Predominant period, spectral structure, dependence of period on magnitude, appearance of seismogram of the initial part of P wave, and frequency of occurrence of these earthquakes are investigated in comparison with the shallow earthquakes in the adjacent regions. The nature of deep earthquakes is likely to be different from that of shallow earthquakes. The results of the present investigation are itemized in section 5, “ Conclusion ”.
The wokers of the Meteorological Research Institute and the Osaka District Observation make their effort to establish the critical value which discriminates between shower and thunderstorm. One of the methods which determine this value, is published in the Soviet meteorological journals by N. F. KoTOV. His method is seemed to be convenient in order to make the discriminative study of shower and thunderstorm from the material which observed the height of radar echoes. The critical values of shower and thunder s t orm are determined by the materials obtained by radars of the Meteorological Research Institute and the Osaka District Observatory. The value of the former is published by author and Ichimura in 1961, and the latter is defined in this paper. By the use of the material of radar echoes obtained in the region of Osaka in 1955, the critical value in the case of a covered uniformly air mass is equal to 15.0°C in temperature, the value of Osaka approximate to the value which is estimated by the use of the materials of radar observation in 1956 and 1958 at the Meteorological Research Institute, that is, -15.6°C. In the case o f the thunderstorms which are accompanied by the fronts, the critical value has the temperature 9.8°C and obtains higher value by about 5°C than the above-mentioned cases. In our territory, when the tops of radar ech o es pass the level of the isothermal layer -15°C--16°C, the convective clouds in agreement with radar echoes are determined as thunderstorms, but the thunderstorms in the frontal zone occur at lower layer.
The deuterium content in w a ter in the primitive ocean was estimated under the assumption of gradual accumulation of oceanic waters at a constant rate which is a difference of supply from the earth's interior and loss of water through photo-dissociation followed by escape of hydrogen into the outer space. The result of calculation showed that the deuterium content in the primitive ocean was 3-4% less than that in the present surface water. As to the distribution of deuterium in the ocean, no significant correlation was found between deuterium content, salinity and depth, except for those in sea areas where the rate of evaporation exceeds considerably that of precipitation or the sea water is mixed with a greater amount of melt water. Concerning d euterium content of meteoric water, fractionation between both vapor-liquid and vapor-ice systems were calculated and it was pointed out that the latter is more important in considering the deuterium content in rain water. It is also to be noted that fractionation factor of deuterium and protium in vapor-ice system reaches its maximum at about 5°C (at 0°C for vapor-liquid system) and vapor pressure of HDO ice is higher than that of H2O ice for temperatures below 25°C. A balance sheet of deuterium on the earth was made together with the transfer rates among different reservoirs of water. As a result, it was concluded that concentration of deuterium in oceanic rain water (-6.9 %) is 2 % higher than that in continental rain (-8.9%) and 55% of water in rain on land is derived from the vapor coming from the oceans.