The electricity of the thunderstorm was observed by various facilities during the summers of 1940 to 1944, in the neighbourhood of Maebashi, Gumma Prefecture, where the top occurrence of thunderstorms in Japan is recorded. The report(1) of the observations in the summers of 1940 and 1941, was already published. In this paper the author intends to report the electric charge neutralized by the lightning discharge and the distance of the consecutive discharge in the thunder-cloud. In the observation in three summers from 1942 to 1944, we investigated twenty four thunderstorms. We took 171 simultaneous observations of sudden changes of the electric field at three places and 543 simultaneous observations at two places. The general tendency of the results of the analysis was nearly the same as in the summers of 1940 and 1941. The following results were obtained by the detailed analysis of the observation data. (1) The electric charge neutralized by a lightning discharge is large and generally more than 100 coulombs and seldom reaches 300-400 coulombs when the thunderstorm is developing. (2) The electric charge neutralized is small and generally less than 40-60 coulombs, and most numerous in the region less than 10 coulombs when the thunderstorm is decaying. (3) The electric charge neutralized is medium when the thundercloud is moving and stationary in the electrical activity. And it is also perceived that the electric charge neutralized is greater in the front-side of the thundercloud and smaller in the rear-side of it. (4) These facts may be due to the ending of the generation of electrified water drops and to the increase of the electrical conductivity of the air in the clouds. (5) The distance between the discharging spots is large in the developing stage of the thunderstorm and smaller in the decaying stage. And the distance becomes longer as the electric charge neutralized by a lightning discharge becomes greater. The distance is about 1km when the electric charge is 10-20coulombs, 2-3km when the charge is 100coulombs, and more than 4km when the charge is 300coulombs. (6) The rather large negative change of the electric field somewhat frequently occurs in eighteen thunderstorms out of twenty four storms examined. These negative changes occur in the decaying stage of the thunderstorm. This may perhaps be due to the horizontal lightning discharge.
The total solar radiation during the annular eclipse on May 9, 1948. was measured with actinomenters at Wakkanai. Hokkaido, Japan. The limb darkening of the solar disk was calculated from the observed data. The result shows that at the border region of the solar disk the brightness decreases more rapidly than the resulte of Julius.
Atmospheric turbulence was observed by using a hot-wire anemometer and an electromagnetic oscillograph at the Central Meteorological Observatory (Tokyo) in autumn, 1946. _??_e hot-wire anemometers were equipped. to a wireless tower at 60, 55, 45, 35 and 25 meters above the ground. From the records of velocity fluctuations for ten minutes, we Calculated the following quantities; mean velocity (_??_), energy of turbulence (1/2_??_2 ), intensity of turbulence (√_??_2/_??_), frequency distribution of u'-fluctuation and eddy viscosity. A linear relation was seen between the mean velocity and the logarithm of height. 1/2_??_2/_??_and √_??_2/_??_ were larger than those which were expected from the experiment in the wind tunnel. The vertical distributions did not show any regularity. The authors further discussed on the magnitudes and vertical distributions of eddy viscosity.
In the theory of the Electromagnetic wave, we know that an incident wave may be scattered by small particles having a small difference in that dielectric conatant with the surrounding medium, and its intensity is invensely proportional to the fourth power of the wave-length. In this paper we investigatod what phenomenon will be expected in the elastic problem. As a simple example, we took the special case in which a small spherical obstacle having a little difference in the elastic constant with the surrounding medium, was buried in the latter, and its radius was supposed to be very small compared with the wave-length of the incident wave. We consider here dilatational waves as shown in equation (1) for incident ones. Substituting (1), (2) and (3) in the boundary conditions (4), we obtain (8) as the coeficients of the seattering waves. Taking main terms of (8), we get the scettering wavs shown by (9). From the present calculation, we can derive the following results _??_ when elastic dilatitional waves propagete in a medium in which small spherical obstacles of radius a exist and if the elastic constants of both material from one antother, the amplitudes of scattered waves are proportional to (ha)3, so that their intensities should be proportional to (ha)6 at the most. It must be noticed that the amplitudes of the polarized component are not greater than the order of (ha)5. Thus it becomes evident from what above stated that a hsterogeneous construction supposed to exist in the vicinity of the earth's surface may not be the cause of such distinct phenomenon as “Blue sky” in the optical problem.
We frequently experience south wind at Utunomiya in the daytime in winter when the NW monsoon should blow. To investigate its mechanism simultaneous observation were made on Feb. 3rd, 1946, at about 30 stations in Totigi Profecture. As a result of the analysis of the data of observations, it was ascertained that the south wind occurrences are caused by the local front of diurnal change. And with the aid of statistical data, a clue, for the forecasting of the gale accompanied by the front was obtained and interpretation of the climate of Totigi Prefecture in winter was given.
This paper is the report of the Observation of sea fog performed at Kushiro in Hokkaido in summer of 1943. The size and the number of fog particles which fell on the deck glass were measured by a microscope and from these the number of particles in the air and the liquid water content were estimated.