From the same point of view with that for the Kew Standard nine-inch-cup anemometer expressed in the second report of this subject, we examined experimental data on the Robinson anemometer No.1259 of the Casella & Co., and obtained fair results. Errors in the values for true air speed calculated by our emperical formula do not exceed the limits of about ±0.3%.
Following the mathematical treatment of the flow of air over a mountain by Pockels and others, the present authors intended here to discuss the effect of topography with a periodic surface profile on the direction and velocity of winds. Here a conclusion is drawn that, at the bottom of the valley, the maximum frequency of winds is found in the direction parallel to the general trend of valley and the minimum one is found in the direction transverse to it. The existense of such a tendency can be verified with numerous data.
The mathematical treatment of the flow of air over a mountain was first attempted by Pockels with simple assumptions as to the conditions of flow together with the assumption of a periodic surface profile. Recently Mr. Arakawa studied the effects of topography on the direction and velocity of wind for the case of a mountain of semi-circular cylindrical shape lying on a flat plain. It is a well known fact that in the valley of a river the winds from the direction of the valley are frequent. At a station lying near the coast of a sea the winds having the direction perpendicular to the coastal line are most frequently observed. But, if the mountain ranges run parallel to the coastal line, near the coast, the winds of the direction parallel to the coastal line are most frequent on the coast. In this paper I studied a similar problem on the effect of mountain ranges for the case of a mountain of semi-elliptic cylindrical shape.
The atmosphere is always in a state of turbulence, and the effect of it is to produce a flow of heat downwards in a stable atmosphere, and upwards in an unstable atmosphere. In other words, turbulence continually strives to set up adiabatic equilibrium. But is it also the case with the transfer of momentum due to turbulence?. Here I tried to explain qualitatively the sense of the migration of momentum in mean motion and at the same time observed the air motion along the isobar in the atmosphere from the stand-point of the stability of laminar motion, which makes me think that turbulent motion has the tendency to be regulated by the relative motion between the atmosphere and the earth.
Three elements of Bai-u, the amount of precipitation, the number of rainy days, and the center of mass of rainy days were treated graphically for five stations in Japan. 33 years or 22 years periods were found in the secular variation of these elements. The phase of the secular change of the amount of precipitation seems to marchi E-wards or W-wards across Japan for several years. This phenomena seems to suggest the direct cause of the secular variation.
This earthquake was precisely investigated by Mr. Isikawa in the last year. (this journal Vol. 10, No.4.) This report is a supplementary one to it, especially on the point of the focal depth and reflected waves, taking advantage of the travel time table calculated by the author and others.
The deviation δ of monthly mean temperature at Tokyo from the normal annual mean is tabulated in Table I. From this the after effect of the monthly mean temperature on that of the next month is calculated. Next the author defines the dispersions Δm andΔy such that and the magnitude of dispersions are discussed from continuity of the weather, climatic elements, crop of rice and variations of Wolf's sun spot numbers.
Green's theorem on the laws of waves in a Canal of gradually varying section, freed from the restriction to the special form of section, is as follows: If the transverse dimeneions of the canal vary only by a small fraction of themselves within the limits of a wave-lengh, the amplitude of wave varies inversely as the square root of the breadth and inversely as the fourth root of the depth. The present author makes a further approximation and obtains a law of the variation of amplitude including Green's theorem as a special case. He also explains that the slower the slope of bottom, the larger become the amplitude. This holds good for the variation of the amplitudes of “Tunami” or destuctive sea-waves.