Here it is pointed out that the vertical influence of a mountain range is comparatively greater than usually considered, and the horizontal influence particularly so; the current bending on both sides is deduced from the alternative change of signs of its horizontal divergence, namely the horizontal convergence proceeds the horizontal divergence on the weather side, and vice versa on the lee side. These two influences are suggestible to be applied to explain the formation of westerly waves and jet streams.
In the third chapter, we try the stochastic analysis and forecasting of the mean August temperature at Miyako in the Tohoku district. That is, the original data are so complicated that they are separated into six simple components: secular trend m(t), three harmonics with 7.4-year, 13-year and 11.4-year periods, V7.4(t), V13(t) and V11.4(t), and two fluctuations with two cyclic periodicities, U10(t) and U2(t). Each component is precisely analysed and composite values are forecasted with the precision expressed by probability. In the fourth chapter, the periodicities picked up in the second chapter are synoptically analysed. Namely, in view of synoptic climatology, we recognize the significant difference between the patterns of August temperature anomalies in the maximum years and in the minimum years of the V7.4(t) in which the V13(t) is under consideration. Such differences are found in the upper westerly currents at Tateno and in the paths of typhoons in August. Lastly, using the cross correlation coefficients, we investigate on the lag relation between Wolf's sun-spot numbers and the residual temperature series where two harmonics, V7.4(t) and V13(t), are eliminated.
The basic data for the tabulations and graphs in this study come from the “Aerological Data of Japan” published by the Central Meteorological Observatory, Tokyo. The values of precipitable water content were computed by the standard method as follows: Σ0.01 q _??_p, where _??_p is the pressure difference (in mb) between the standard levels or the siginificant levels of a sounding. Values of q, specific humidity, were computed by means of the slide rule devised by H. Arakwa. All computations of precipitable water at 11 stations in Japan were made from 1000 mb to 400 mb (about 7 kilometers). The other table shows the annual variation of a theoretical value of depth of precipitable water, also 1000mb to 400mb, tabulated for the purposes of comparison. It is also of interest to compare the mean station values in Japan with the monthly mean depths of precipitable water in the United States (U. S. Weather Bureau Technical Paper No.10). The monthly mean depths of precipitable water in Japan are 52.69mm at Shionomisaki (August) and 53.14mm at Tare (August), while the maximum monthly mean depths of precipitable water in the United States are 2.004 inches at Charleston (July) and 1.995 inches at Miami (August).