In this paper we report the seasonal change of the transmission coefficient of ultraviolet solar radiation observed at Misima over the period from September 1932 to November 1933. The instrument we used is the so-called “vital ray meter” made by the Tokyo Electric Company, consisting principally of cadmium photo-cell and aluminium leaf electroscope. Since the light we dealt with is not homogeneous, but covers the wavelengths ranginging from 0.29μ, to 0.32μ, the transmission coefficient has a meaning only in a sense of some mean. We define it as _??_ in the formula: where Isecz is the intensity observed, z being the zenith-distance of the sun, and I0 the intensity outside the earth's atmosphere. We determined I0 from the data of simultaneous observations made by Prof. R. Sekiguti on the summit of Mt. Fuji in June 1933 with our instrument and the standard cadmium cell, which had been in use there. The method of calculation is the one which was also suggested by him and is as follows. We calculate I0/Isecz by numerical integration for the value of ozone-depth, which is determined from the observation with the standard photo-cell, and then multiplying I0/Isecz by the value of Isecz, observed with our instrument, I0 is obtained. The transmission coefficient was found to be markedly dependent upon sec z, so, in order to investigate the seasonal variation, we constructed isopleth diagram with season as abscissa and sec z as ordinate. We see from this diagram that the transmission coefficient becomes maximum in November, December and January and minimum in June and July. This may be attributed to the corresponding variation of ozone and dust content in the upper atmosphere.
The influence of topography on the wave-length and the amplitude of Helmholtz wave has not, so far as I know, been discussed, so I intend here to study such a problem. H. Arakawa(2) has already studied the influence of topography on the barometric oscillation, comparing the record of micro barograph taken at Huzisan Meteorological Observatory with that of Tokyo. Following the result introduced by H. Arakawa the present author treated mathematically the effect of topography. Here a conclusion is drawn that, if the difference of the velocity and the temperature between the upper medium and the lower medium are constants, on the top of mountain range the wave length must be considerably longer, and the amplitude must be smaller than that of far distance free from the effect of topography for the stable wave, and there are some places, at which even if the wave length becomes shorter and the amplitude becomes larger than that of the places free from topographic effect the Helmholtz wave is stable, at a little a way off the summit, and the lower the surface of discontinuity is in comparison to the height of mountain range, the more remarkable such a effect becomes. In other words, the above conclusion tells us, on the top of mountain range the Helmholtz wave is difficult to appear but at some places at a distance from the summit, it is frequent to occure.
In this paper the author made some discussions chiefly on the anomaly of depth of bays. In Part I, he showed the result of application of the method of procedure explained in the previous papers to an actual case i.e. to the Bay of Mano (Hutami) in Sado Island, the depth of which seems to have been affected by tidal and oceanic currents, etc. as well as by wind. In Part II he discussed the method of investigation of the anomaly of depth, and proposed the following two tentative methods of detecting it, viz. (1) the method with “Anomaly-curve” Ψ(s), (2) the method with k-Diagram. In Part III he applied the above methods to some actual cases. A more detailed discussion will appear in a future number of the “Geophysical Magazine.”
On the basis of the records obtained by the simultaneous oceanographical surveys carried out during a certain period covering the 5 th in June 1932, the 5th in August 1933 and the 5th in October 1933, the distributions of air temperature were plotted in Fig. 1, 2, and 3 respectively. Some remarks on the sea-fogs appeared in the cold current-area in June and August were given. Also the distributions of air temperature were compared with the distributions of surface water temperature.
In this second report on the study of observations of direct solar radiation made by means of silver-disk pyrheliometers, the author discussed annual and diurnal change of solar radiation as well as the variation of atmospheric turbidity at eleven meteorological stations during the interval between August 1932 and July 1933. The principal results of the present investigations are as follows: i) The coefficients of turbidity (Feussner u. Dubois, 1930) calculated from monthly mean values of solar radiation show that the values, in general, were in minima at about December, and then began to increase until May, when the values were generally at their maxima. This seems to be in agreement with the results obtained at several European and American observatories. ii) It is interesting to note that there is the tendency to give greater values of coefficient of turbidity observed at 12h than that of 9h, or 15h. The tendency above noted seems to be in connection with the formation of invisible condensation products of water vapour in the daily ascending air current and increase of dust in the lower part of air. iii) Assuming the coefficient of turbidity actually calculated from observations, the diurnal variation of the intensity of solar radiation were calculated for four seasons at five selccted stations respectively, and then by means of graphical integration, calculated total amount of solar radiation were determined.