The frequency distribution of rainfall of different intensities in different parts of the country is studied. The distribution is found to be hyperbolic in all the cases. The equation y=a/(x+c)+b, where x is the rainfall per day, y dx is the frequency of rainfall and a, b and c are constants, is very satisfactorily found to fit into the data. A, theoretical method is developed to evaluate the constants a, b and c from the rainfall amount and the number of rainy days. The equation is also applied to daily rainfall data of individual stations and the fit is found to be correct by more than 90% accuracy and it is finally suggested that the equation may be applicable for rainfall in any part of the globe.
An analysis of cloud distribution on 4th September, 1961, is presented, which is based on the photograph of Tiros III with a view to interpret the structure of precipitating clouds and the formation mechanism of widespread cloud sheets in relation to air stream, and horizontal convergence and divergence. Simultaneous observations by the network of all-sky camera in Japan are used for better rectification of Tiros III's picture. It is presented that the orientation of detached clouds, such as cirrus and altocumulus clouds, closely relates to air streams and wind shears at the cloud level, and that the cloud distribution seems to be strongly affected by the orographic influence, hence the air stream is inevitably important to deform cloud appearance. It is also postulated that the widespread cirrus clouds are formed in the layer beneath horizontal divergence area. A model of precipitating cloud is outlined, in which ice crystals fall through thick medium cloud layers into the lower water cloud layer. The computed vertical distribution of horizontal convergence and divergence seems to explain the existence of the interstices between lower and upper layers of precipitating stratiform clouds.
Thirty B2 type circulations (a blocking type pattern characterized by clear stationary troughs were proposed in the previous paper (Tsuchiya, 1963)) are selected at a certain criterion from the data of thirteen winter seasons for December 1944-February 1957. Then their climatic features are examined using daily meteorological data at nearly 100 stations of the middle latitudes in Northern Hemisphere. And we found out that there are clear temperature and precipitation anomalies over the eastern North America, the western Europe and the vicinity of Japan. This anomaly pattern resembles the continental glacier distribution during Pleistocene period. Milankovitch presented a theory that seasonal and latitudinal secular variation of insolation computed from the earth's orbital movement as a planet explains the glacial growth. In connection with it, this paper describes the fact that the variation of insolation is favourable for causing the B2 type pattern in general circulation in winter. It is considered that Milankovitch's hypothesis is reasonable in the light of the modern theory and the observed fact on general circulation of the atmosphere. Finally, as an example of the process of the B2 type circulation, discussion is made on the abnormal worldwide cold wave observed in the winter of 1962/63.
Chemical composition of spray drops from aqueous solutions of seasalt was experimentally determined as a function of the drop radius. The purpose of the experiment is to examine the primary fractionation hypothesis which has been suggested for the explanation of the difference between a chemical composition of giant condensation nuclei in unstable maritime airmasses and that of the seawater. Mother solutions used in this experiment were aqueous solutions of NaCI-MgC12, NaCICaCl2, NaCI-SrC12 and NaCI-BaC12, each of which contains Na of concentration equal to that in the seawater. Spray drops of 0.4 micron in radius was found to have a different composition from that of their mother solution. Mg/Na in the spray drops was 1.37 times of that of the mother liquid, Ca/Na 1.87, Sr/Na 2.04 and Ba/Na 1.40 times respectively. Composition of drops larger than 0.4 micron in radius showed no difference from that of the mother liquid.
The winter weather in 1963 was unusually severe over the Far East, and many observation stations in Japan reported new records of the amount of snow fall. This case may be a suitable situation to study about the water-vapor supply from the Japan Sea and the snow fall over the Japan Islands. Water-substance budget over these areas were analysed using the data of ten days from January 16th to 26th, during which special observations were carried out under the Heavy Snow Storm Project. It is concluded that the amount of evaporation from the Japan Sea was about 5mm day-1, and that the transport of water-substance in the form of liquid or solid water is very important to explain the large amount of snow fall over the Japan Islands. The liquid or solid water content in the active connective cloud over the coastal area of the Japan Sea was estimated, by the budget analysis, to be about 0.4 gr kg-1(i. e. about 0.4 gr m-3). It is also found, that the amount of snow fall over the Japan Islands was especially large in front of a cold vortex.
Life times of water drops before breaking suspended freely in a vertical air stream have been empirically determined as a function of drop diameter. It has been found that breaking probability of a drop increases with increasing drop diameter. Average life times are 273 sec at 5.5mm, 63.4 sec at 6.5mm and 10.1 sec at 7.5mm. An empirical formula obtained (average life τ sec at D cm in diameter) is τ=3.40x106e-17.0D. The number of droplets produced by breaking of a drop increases with diameter of the drop. Empirical formula is obtained for the size distribution of the droplets. No marked difference is found between the results of the experiment at a room temperature and those at 0°C.