Weight-number distribution of giant salt nuclei which fell to the ground in Kyoto was determined every night from Jan. 4 to Feb. 3, 1962. Similar observations were also made at the same time at several stations along a transversal cross-section of Japan in the direction of the winter monsoon, at a few nights in the above period. From analysis of the data, it was concluded that giant salt nuclei in the atmosphere are primarily produced from the sea surface through an air-sea boundary process, and carried over the land by wind, as predicted by Toba (1961) based on studies of a model system utilizing a wind flume. The weight-number distribution curve, however, varied day by day and it is suggested that the accumulation of data concerning sea-salt nuclei distribution may afford some clue for further understanding of the precipitation mechanism. Rate of the total dry fallout of sea-salt was also calculated from the above data. It was between 3.10-12-2.10-14gm cm-2 sec-1.
Meso-scale structure of a cold front is analyzed, using the data from radar and surface meteorographs. The principal results obtained from this analysis are as follows: 1. This cold front is accompanied by many line echoes having a definite orientation (ca. 35°-215°). 2. There are many generation areas of echo cell along the surface of cold front, where convective cells are generated successively. The generated cells remove to leeward (NE), increasing gradually. Thus many line echoes are formed, which extend from the cold front toward the definite direction. And so the line echoes become parallel to the vector difference between the moving velocity of cell and that of generation area. As the echo cells move with 600-700 mb wind and the generation areas move with 700-850 mb wind, the line echoes would be also parallel to the vertical wind shear between the two levels. 3. As a result, where the cold front runs from NNE to SSW, the line echo is situated on the warm air side of cold front and constitutes the so-called prefrontal squall line. While where the front runs from ENE to WSW, the line echoes are arranged on the cold air side and compose the mesoscale pattern of precipitation behind the cold front. 4. The mechanism of generation area is not studied in detail, however, a minor cyclone formed on the cold front is accompanied with several generation areas and considered as a large generation area as a whole. 5. In order to discriminate the cold front from prefrontal squall line, the analysis of pseudo-wet-bulb potential temperature is performed.
The problem of the deformation due to the movement of hurricanes, typhoons or circular vortices are investigated theoretically and numerically in the baroclinic case, by making use of the parametric representations. According to them, the baroclinic correction in evaluating the deformation seems to be not so large as to upset the conclusions on the deformation problem that are deduced only form the barotropic treatments. Rather, it seems that the importance of the role of the vorticity gradient around the center, that has been left untouched so far, must be stressed more both in the barotropic and baroclinic cases.
During the 1957-58 winter, island stations of a large arid area in the Equatorial Central Pacific Ocean experienced anomalous precipitation which exceeded normal values by factors of 5 to 20. Average meteorological and oceanographical features of the area are explained and compared to the features of the abnormal period. Historical records of precipitation at some stations in the area are discussed. Some mechanisms which could be a cause of the anomalous precipitation are suggested.