Cross correlation coefficients between the 500 mb contour height at about 50°N 140°E and those at the twenty five points in its vicinity, were calculated from the data of the Januaries 1948-1952 and the features of the correlation fields were investigated. The contour heights at the several points having the relatively stable correlation were selected as predictors and the 24-hour predictions of the 500 mb contour height at about 50°N 140°E were performed by the method of linear regression. When time lag τ is relatively large, the correlation coefficients at above twenty five points become small and unstable, and so cross correlation coefficients of lag 1-10 days between the 500 mb contour height at about 50°N 140°E and those at many points over the northern hemisphere, were calculated and the behaviours of the distributions of correlation coefficients were discussed. At the same time, the theoretical correlation field was obtained from the linearized vorticity equation and compared with the actual correlation fields, and the features of the correlation field were discussed by the method of spectrum analysis. Some considerations on the nonlinear system were also made.
Some glass-like ice-drops, considered to be frozen rain drops or cloud particles (in this paper, these drops will be seen ice pellet)have been found in falling snow-flakes during the observation on radiation from the snow surface at Maruike, Shiga Plateau, on February 25,1957. The author made some observations on the shape, size-distribution, and collision coefficient of the ice pellets from their plastic replicas, and found that MARSHALL-PALMER'S equation holds well for the sizedistribution of the ice pellet, and that combination among the similarsized ice pellets occurs more frequently than expected.
It was found that thunders were apt to break out in succession towards the leeward along the path of the drifting silver iodide smoke in cloud seeding experiments and some explanation was tried about it in the light of recent knowledge of thunderstorms. The height and temperature of the level at which the top of the smoke reached cumulo-nimbus clouds and the process of the outbreak of thunders after the arrival of the smoke in the clouds were discussed.
Using a photomultiplier tube and filters, the intensities of ultraviolet sky radiation from various directions were measured at Mt. Norikura in summer 1957. The measurement was done in two different wave-length ranges, i. e.3200Å and 3300Å or so respectively, with the aim of finding the effect of the ozone layer in the upper atmosphere. The measurement of the intensities of U. V. sky radiation was done in three directions in the principal meridian plane, that is, in the zenith distance of 15°towards the sun, just in the zenith and in that of 15° backward of the sun. Also each measurement was carried out at every four or five minutes during the time when the sun's altitude was from 0° to 30°. The relative values were computed at each instant taking the values in the zenith as a unit. Then their time variation was examined especially in view of its difference between the two wave lengths. Investigating the results of observation a rapid increase of the difference was pointed out when the sun's altitude was lower than two or three degrees. These phenomena were theoretically analyzed, computing the primary scattered intensities in the atmosphere with a typical absorption layer and also without it. And the above-mentioned feature was proved to be the effect of an ozone absorption layer. Thus a new method of determining the vertical distribution of the atmospheric ozone was suggested.
The disturbance of the atmospheric electric field caused by the smoke-cloud of the Volcano Asama-yama was observed at Karuisawa Weather Station (about 9 km from the crater), Maebashi Weather Station (about 50 km from the crater) and several other temporary stations around Maebashi. At Karuisawa the disturbance of the electric field is composed, earlier, of a small positive and, later, of a large negative one, but at Maebashi the disturbance is mainly in a negative field. In the smoke-cloud the screening of ash grains with respect to height is performed by the action of gravity. Smaller ash granules have a positive electric charge and exist in the upper part of the smoke-cloud and larger ash grains have a negative electric charge and exist in the lower part of the cloud. Laboratory experiments on the electrification of volcanic ashes were made and it was confirmed that larger ash grains obtain a negative electric charge and smaller ash granules obtain a positive charge after mutual collision. Two hypotheses were proposed to explain the fact that near the crater the effect of both positive and negative charges is observed but far from it only the effect of the negative charge is observable.
The cold water region in the offing of Enshfmada is generated by the overflow of the intermediate water upwelling in the sea off the coast of Tôkaidô. And when the Kuroshio is strong, the overflowing of the intermediate water is stopped and the cold water region is pushed away and disappear. From the mean values of actual sounding, no cold water region can be seen when the maximum velocity of the Kuroshio is larger than 2.5 knots.