Cloud observations were made over the Gulf of Siam, using a passenger flight airplane. Several ring-shaped cloud distributions were observed near the periphery of a convergence zone, and it was considered that they were not look like the usual Benard's cell type motion, but were produced by a several downward air motion near the periphery of the convergence zone. A Cb cloud and a characteristic towering cumulus cloud with cloud bands of starfish-like form were observed. An effective sucking area with about 60km diameter for the Cb or the towering cloud was estimated from the cloud band distribution.
Micro-meteorological data are analysed to determine the flux-gradient relationships for the tamsfer of momentum, sensible heat and water vapor in the atmospheric surface layer. The results obtained agree well with the universal relationships under the condition of (Ζ/L) varying from 0 to -1 for the unstable and from 0 to 0.25 for the stable. The universal relationships imply a relationship between eddy diffusivity and the stability parameter Ζ/L. The derivation shows that the gradient Richardson number Ri is not equal to the Ζ/L. Empirical evidence for the validity is obtained. A turbulent-scale, which is derived in this report, is related to the eddy diffusivities. The results show that the eddy diffusivities for momentum, sensible heat and water vapor are expressed respectively by KM=ε1/3Lυ4/3 KH=ε1/3Lu1/3•Lθ Kωε1/3Lυ1/3Lw Here, Li indicates the turbulent-scale in the vertical direction of wind, temperature and water vapor respectively with a subscript of υ, θ and ω. ε is the dissipation rate of turbulent energy.
Freezing experiments of freely falling water drops 100 to 800μ in diameter were carried out in an open field at about -20°C. About 4, 600 frozen drops nucleated at about -15°C, deformation and fragmentation of an individual drop were examined. Cracking of frozen drops was frequently observed and the probability became large in proportion to the size of frozen drops. Shattering of frozen drops was observed with less probability than that of cracking.
The Boussinesq equations are reduced to a two-dimensional form governing convection between two free surfaces maintained at a constant temperature difference. These equations are then transformed to a set of ordinary differential equations governing the time variations of the double-Fourier coefficients for the motion and temperature fields. The system is then highly truncated by taking into account only a very limited number of terms of the Fourier expansions. Numerical integrations of the system have been performed at supercritical conditions, initiating the motion by the introduction of various sets of initial conditions. In all cases investigated, the system achieves a steady state and only one mode is present at the steady state. The results show however that slightly different initial conditions give rise the motion of different modes for the same Rayleigh number. Once established, the motion of that selected mode is found to be very stable against the superposition of perturbations of other modes.
The growth equation of ice crystals was solved under assumption that the latent heat of sublimation is dispersed by conduction through the air and radiative cooling. Such condition can be expected for ice cystal growth in the polar atmosphere during the polar night or in cirrus clouds at night. The growth rate of ice crystals was computed under the condition of no temperature difference between ice crystal and the ambient air. The critical relative humidity was computed for dry air which is in vapor equilibrium with ice crystal cooled by radiation. It can be concluded that the radiative cooling of ice crystals results in an increase of thickness and area of air layer suitable for their growth.
Vertical heat transport by single row convection cells in silicone oil is studied experimentally. Lateral walls of the convection chamber are made transparent so that the number of convection cells is observable by means of alminium powder contaminated in the working fluid. Although various number of cells may develop for each Rayleigh number, the rate of upward heat transport remains the same. There is a definite tendency, however, for the most frequent number of cells to increase with the Rayleigh number. This is in a great contrast to other experimental results (Deardorff and Willis, 1965; Koschmieder, 1966), which remains to be explained.
The properties of the clouds with the shape of Kármán vortex street in the wake of Cheju Island, Korea are studied using satellite pictures which are taken approximately four hours apart. The results indicate that non-dimensional numbers and physical quantities obtained from the cloud vortex street satisfy theoretically as well as experimentally obtained criteria of Karman vortex street. The equation of the displacement of the cloud vortex street is derived through drag consideration. The displacement speed obtained from this equation agrees fairly well with the observed value. The speed is approximately 76% of the undisturbed flow when the ratio between the spacing of two rows and that of individual vortex is 0.332. It is foundd that such a cloud vortex street appears in the wake of Cheju Island from late autumn to early spring when steady northerly wind of more than moderate intensity (above 10 kts) prevails and a well defined inversion is found at around 1000 meters or at about half the height of the mountain located in the center of the Island.
After their extensive investigations into the seasonal variation of mortality in various countries in the world, the authoresses have found the concentration of deaths in winter in Japan and the West European countries, on the one hand, and, on the other, the steady moderaration of seasonal variation itself in the United States and the North European countries. In this paper, they attempt to study the latter phenomenon in the United States: namely, they study in detail seasonal variation types by climatic region (Renner), by temperature region based upon seasons (Parkins), and by climatic zone in January. In the 1960's, seasonal variation is conspicuous in the South (Climatic Region No. 1 and No. 2, see Fig. 2 a) but very slight in the North (No. 4 and No. 5 see Fig. 2 a). In the 1930's and 1910's, variation is bigger than in the 1960's, and the summer death peak is very high in some regions. Classified by temperature region (see Fig. 2 b), seasonal variation is generally small in the 1960's, particularly in the Pacific region (No. 1), but visibly large in the South, especially Temperature Region No. 5. In the 1930's and 1910's, variation is bigger in all the regions, and there is some upcurve in summer in some regions. A study by climatic zone in January (see Fig. 2 c) shows that seasonal variation is rather big in the South (Region No. 5 and No. 7) but very slight in the North (No. 8 and No. 9) in the 1960's. In the 1930's and 1910's, variation turns out to be bigger than in the 1960's, and a summer upcurve, together with the winter peak, exist in some regions. For all this, signs of seasonal variation moderation are seen in all the zones. An investigation into the eight geographic regions (see Fig. 5) reveals that the variation curve of total mortality in the 1960's is generally moderate, though there is an upcurve in winter, while on the other hand it is bimodal (one peak in summer and the other in winter) and less moderate generally in the preceding decades. Classified by color, the variation curve is bimodal for the Whites and the Nonwhites in the 1930's and 1910's, but in the 1960's no upcurve is seen in summer for the Whites but the summer upcurve is conspicuous for the Nonwhites in the southern regions. Infant mortality in the 1960's varies less visibly than total mortaiity in all the geographic regions except the South. Seasonal variation is marked for the Nonwhites in all the regions, especially Region No. 7 (see Fig. 5) where the coefficient of variation is three times larger for the Nonwhites than for the Whites. Thus, total and infant mortality now vary less tangibly than decades ago. But the moderation of infant mortality variation is more conspicuous and, moreover, differentials by color prove to be much bigger for infant mortality, particularly for the Nonwhites in the South. An regression analysis also accounts for the moderation of seasonal death variation. The coefficient of regression is smaller in the North than in the South, for infant mortality than for total mortality, and also for the Whites than for the Nonwhites. After all, the recent moderation December M. Momiyama (Sakamoto) and K. Katayama 467 of variation is most predominant for White infants. The summer upcurve gradually disappears decade after decade and the winter peak gets flatter the recent moderation of death seasonal variation, articularly for infants in the southern regions of the United States, bespeaking the influence of artificial climate on human mortality. It is also worth mentioning that seasonal variation is conspicuous in the South densely populated by the Nonwhites, especially for Nonwhite infants.