Evidence of the resemblance of the Bènard cell with shearing flow to band echoes observed under abnormal weather conditions of very high winds is presented. A variety of band echoes can thus be explained as the effect of thermal instability combined with the shearing motion caused by high winds.

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The aspects of the cloud formation over the Japan Sea during the three day period from Feb.10 to Feb.12,1962 was analysed by using T. V. data and channel 2 radiation data of TIROS IV in the author's previous report.
In this report, the distrribution of the albedo over the Japan Sea and her neighbourhood during the period mentioned above is obtained by using channel 3 radiation data. The bright areas in channel 3, which indicate solid overcast, are very well correlated to low equivalent black body temperatures in channel 2. The estimations of cloud cover and cloud height over the Japan Sea are tried by coordinating the albedo and equivalent black body temperature. It is shown that, under the winter monsoon situation, cloud cover increases rapidly 2-300 km off the shore of the Japan Islands and that the cloud exists mainly under the inversion layer.

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A problem of the “ Turusi ”-cloud of a wing shape is discussed in this paper. The cloud was observed in the sky to the northeast of Mt. Fuji on the 26th of June in 1966. The deformation of this cloud was photographed by an 8 mm cinecamera.
As shown in picture 1, the limb of this cloud shows a violent turbulent feature. This suggests that various vortices with nearly vertical axes of rotation are arranged along the cloud limb.
When the cloud falls into decay, its apparen t area decreases progressively with time, and then an intermittent increase and a gradual decrease of the area take place alternately.

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This is the first part of a study dealing with various seismological, geophysical and geological characteristics such as time and space distributions, energy release and focal mechanisms of foreshocks. aftershocks and earthquake swarms. Seismological data of the Japan Meteorological Agency are chiefly made use of.
Before any investigation of foreshock, aftershock and earthquake swarms is undertaken, it is fundamentally important to give a clear definition of these seismic activities which are here tentatively called “ abnormal seismic activities ”. A definition of abnormal seismic activities based on a statistical method is proposed. This method is applied to distinguish abnormal seismic activities from the normal or background seismic activity in one of the seismically active regions in and near the Japanese islands.

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On the basis of solar radiation data of the Eppley 180°-pyranometer and the duration of sunshine of the Jordan: sunshine recorder on six sta-AiOns through a sevenvear period, we eXarnined the coefficients as -well as the correlation Coefficient of empirical regression lines of the form Q/Q₀=a+b n/N (where Q and Q₀ are the monthly mean vojues of daily total amount of solar energy falling on a horizontal surface, each with and without the atmosphere respectively, and n/N denotes the ratio of measured duration of sunshine to maxime 'possible values of respective month). Calculations were done from four points of view, that is monthly trend of each station, annual mean of each station, monthly trend of all the stations put together, and the total mean of the same.
According to the results of calcutation, the correlation coefficients of the respective stations turned out to be higher than those. of the monthly trend of all stations, contrary to DAVIES' result (1965) on West Africa.
Average and reduced atmospheric trasparency (t) as calculated by the equation t^m=a+b (where m denotes the mean optical air mass of respective latitude) turned out to be 0.79, which appears to be smaller than the value 0.83 of the previous paper of other authors. But when the difference of sensitivity between the two types of sunshine recorder i. e. of the Jordan type and the Campbell-Stokes type, is taken into, account and recalculated, it increased to 0.83, just the same value of previous papers. Thus it is pointed out that 'different sensitivity between different types of sunshine recorders may be important in this sort of calculation.
The mean values of a and b in Japan turned out to be 0.22 and 0.52respectively by the Jordan sunshine iecordei while they became 0.22and 0.57 after the correction corresponding to the Campbell-Stokes sunshine recorder.

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Four separate series of observations of surface NO₂ and ozone were made at inland (Sudagai) and seashore (Tomisaki) stations in the central part of Honshu, Japan.
The results of NO₂ determination showed a diurnal variation with two Maxima respectively at about one hour after sunrise and one to two hours after sunset. The NO₂ concentrations on the evenings of fine days were extraordinarily high when the snow around the inland station was gradually melting. On the other hand, the concentrations in maritime air in winter were very low, being 1.5, ugNO₂/m³ on the average when there was a strong wind with a prevailing SW or SSW-component. At the inland station, the winter and the summer average values were the same, being 3.6μgNO₂/m³, and the average values in early autumn and winter at the seashore station were respectively 3.7 and 7.3μgNO₂/m³.
At the inland station the average concentrations of ozon e during the daytime in winter and summer were respectively 23 and 26μgNO₂/m³. These values are lower than those in early autumn and winter at the seashore station, though the altitude of the former station is 701 meters above the sea level. This is explained by taking the topographic situation of the inland station into consideration.

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According to the authors' calculation, the total amount of invasion of oxygen from the air into the sea is less than the amount of consumption by oxidation of the organic debris in the deep layer until the time when the invasion and the consumption reach the equilibrium. The rate of consumption of oxygen decreases exponentially with the depth. On the other hand, the oxygen which is supplied from the air enters into the deep layer according to the law of diffusion, decreasing rapidly with the depth. The combination of the above two makes the minimum layer of oxygen at a certain depth at the steady state.
However, in the oceans, there are currents and eddy diffusion in horizontal and vertical directions, and the pattern of oxygen distribution is decided as the superposition of biogeochemical processes and the dynamical motion of water. Using the equation given by Sverdrup concerning the change with time of the amount of dissolved oxygen in the sea, the distribution of oxygen in the western North Pacific is discussed. The results showed that at the steady state, the effect of horizontal advection is much larger than those of horizontal diffusion and biological consumption and the former seem to be in balance with vertical diffusion.

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The radioactive decay rate of radio-carbon in the ocean (1.5x10^-11g/m², y) is much smaller than the rate of biological uptake and regeneration of inorganic radio-carbon from organic matters (1 x 10^-10 g/m², y)and the exchange rate at the air-sea interface (2 x 10^-10 g/m², y). Therefore, the radio-carbon age of sea water is controlled not only by the radioactive decay but also by the other factors mentioned above. This is the reason for the higher age of the surface water in polar areas.
The radio-carbon age of sea water in the deep layers of the oce a ns is determined by radioactive decay, the exchange of inorganic carbon between the surface and the deep layers and regeneration of the inorganic carbon through biological decomposition. Owing to the smaller concentration of the inorganic carbon at the surface layer than that in the deep layer, the specific activity of radio-carbon in the deep layer tends to decrease through mixing with surface water, which gives a higher radiocarbon age to the deep waters. Results of calculation show that when the residence time of the deep waters is 200 to 300 years and that of the surface water is 5 to 7 years, the apparent age is estimated to be about 1,300 years, which is in good accordance with the observation.

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