In order to make the study of the mountain air current, I have carried out an experiment using a model of mountain exposed in an air current, and a specially constructed small wind vane has been used. The vane can be shifted horizontally over the model mountain. The author has studied the stream-lines of the current. To study the motion of the vane, I have devised an optical system to take a photograph of the atitude of the vane at every position as it takes.
The long period change of weather is atributed to the change of upper air current. From this stand point F. Baur succeeded in issuing long range weather forecast of Europe. The atmospheric pressure of upper layer can be calculated in good approximation at least for a height of 3000m from the pressure and air temperature observed at the earth surface. The relation between the long period change of weather and the estimated isobars in the upper layer in Japan is investigated, and the possibility of long range weather forecast is shown.
From the observations of the long-wave solar radiation made by means of a silver disc pyrheliometer with and without a red filter R. G. 2, during the period from Dec. 1939 to Dec. 1940, have been Linke's turbidity factors for total solar radiation τ, for long-wave τ, and for shortwave radiations τ' computed. The annual variation of the turbidity factors at Tokyo is shown in Fig. 2. We perceive some times lags between τ' and τ', i.e, maximum of τ' and τ' occurs in late spring and in early summer respectively. On the other hand, the amount of precipitable water W was calculated from the result of simultaneous radio-sounding W varies, as a whole, nearly lineary with the water vapour at the earth's surface, but in some cases there are found considerble deviations. Comparing the turbidity for long wave solar radiations τ' and the precipitable water W, we can find that τ' increases as W increases, but this correlation depends on the blueness of the sky in some extent. The turbidity τa due to the particles suspended in the atmosphere was also computed correcting for the influence of water vapour for τ' It was shown that this turbidity τa has a close connection with the type of the air masses in the neighbourhood of Japan.
In this paper, the author studied the atmospheric impurities in the City of Maebasi observed during July 19th-July 30th, 1941. As for the method of determination of the atmospheric impurities is referred to this Journal II 17 (1941), p. 367. The results obtained are as follows:- 1. The chloride content diminishes remarkably with increasing wind velocity. 2. There is a negative correlation between the chloride content and the humidity of the atmosphere, as in the case of W. C. Jacobs. 3. A trace of the sulphuric acid content is noticed. 4. There is a parallelism between the daily variation of the amount of ammonia and the temperature at the earth-surface. 5. The nitrite content in Maebasi is very small compared with that in Tokyo. 6. The nitrite decreases the transparency of the atmosphere.