The pressure deviation from undisturbed ambient value within a barometer room due to high winds is tested in the wind tunnel using two room models, viz., a rectangular parallelepiped box and a circular cylindrical one, both with several perforations on the walls simulating the actual observation state. It is found that it is hardly possible to correct the pressure deviations in an ordinary barometer room, because they show so great variety.
Distribution diagrams of swell in a tropical cyclone, constructed under a simple geometric consideration, agreed satisfactorily with what had been shown by Cline, Tannehill, Ootani, Arakawa and others, and the variety of the distribution according to the speed and track of the storm was discussed quantitatively. Particularly, when the speed of the storm exceeds that of swell, it is noticeable that we can find the swell with almost an opposite direction from the wind in the left rear quadrant of the storm and the swell with a direction deviating from the wind to the left, contrary to Tannehill's consideration, in the right rear quadrant. Based upon a report on the typhoon reconnaissance by aircrafts, the variation of the state of the sea and swell with the development of the storm was investigated. It was also shown that in the case of typhoon associated with a frontal system the confused sea or the swell with an unusual direction is likely to be raised in the adjacent seas of the front. The facts that the sea in the eye of the storm is less confused when the storm moves slowly, very confused when it moves with almost the same speed as that of the wave and somewhat confused when it moves very rapidly were found and were explained theoretically. Moreover, a discussion was made with respect to the being of other regions in the storm than the eye, where the confused sea is raised.
Individual raindrops were sampled at four stations in mountain area of Hokkaido in the summer of 1954 and 1955 and the size distribution of giant non-hygroscopic particles in the raindrops was studied. The results of observations are as follows. (1) The form of size distribution curve is independent of raindrop size and is expressed by a formula dN/dγ=const•γ-β, where γ is the radius of the particles. The value of β are between 1.7 and 3.2. (2) Particle content of raindrops is approximately the same at various stations and is invariable with time. (3) Particle content is roughly proportional to the cross-sectional area of raindrops except for the small raindrops of diameters less than 0.3mm.
A computing formula of the intensity of insolation which reaches the horizontal area on the earth's surface is presented, where the shielding effect of cloud, the absorbing and scattering effect of water vapour and air molecules, and the variation of the sun's zenith distance are considered. In order to calculate the contribution of cloud coverage, two layer model of cloud is used, and 0.44 and 0.36 are adopted as mean albedos of the lower and the upper cloud layers, respectively. For the determination of the transmission coefficient due to water vapour and air molecules, Kimball's graph is used. As the result, it is proved that the introduction of this effect improves the result considerably.
Several examples of the Microbarographic Depression-Type or the V-shaped variation of pressure with a duration of half an hour or so and with magnitude of pressure deviation of 0.5-7.0mmHg are examined and the general characteristics are drawn.
The formation of the severe typhoon over the tropical ocean is studied synoptically. It is confirmed that the formation of such a severe typhoon is due to the formation of the secondary typhoon. The mechanism of the formation of the secondary typhoon is ascertained through the investigation of typical examples of the severe typhoon.
Kinetic energy exchange between a mean flow and a superposed disturbance in a two dimensional non-divergent fluid is investigated for a special example. It is found that, at initial moment, kinetic energy is transferred from the disturbance to the mean flow, if the mean flow has a scale which is smaller than the scale of the disdisturbance. Kinetic energy is transferred in the opposite direction if the opposite situation occurs. The mean flow kinetic energy reaches an extremum value after time Θ, which is a characteristic quantity, determined by the initial field of the fluid system. After then, the change of the mean flow energy occurs in opposite sense. Earth's rotation has a stabilizing effect in the sense that, it has a tendency to keep the state of the mean flow in the original one.
As the experiment of cloud seeding with silver iodide has been made by the Chubu Electric Power Company at the top of Mt. Fuji from November 1955, in concert with this the observation of the number of ice crystal nuclei by the cold box (its schematic diagram is shown in Fig. 2) was made at Nakano Branch of Meteorological Research Institute (Tokyo) in order to detect the increase of the number of ice crystal nuclei in the air near the ground at Tokyo due to the cloud seeding and to make a datum to determine whether the cloud seeding might be effective or not to the rainfall observed at Tokyo. It is necessary to know the number of ice crystal nuclei in the air near the ground and its variation under various weather conditions on unseeded days for the detection of the increase of its number, therefore the observation has been continued over about a month (in actual 20 days) from February to March 1956. (Observations were made for two 5 minutes at each observation time of 11 h, 14 h and 16 h 30 m every day. But on the seeded days the number of observation has been especially increased). However, since the number of ice crystal nuclei in the atmosphere is few and the detection by the method of small sampling as usually used can not be used for this observation, the continuously sucking air method was adopted. (Distributions of temperature and liquid water content in the cold box for the actual observation are shown in Figs. 3, 4, and 6, respectively). The results obtained from these observations are as follows: For the number of ice crystal nuclei in the air near the ground at Tokyo (with the exception of seeded days), (i) Its number increased with wind velocity as shown in Fig. 7 and (ii) Their maximum and mean values were 0.8 and about 0.25, respectively, per litre of air as shown in Fig. 10 and (iii) Its number did not depend upon wind direction and weather conditions throughout this observation. (that is, it could not be found for its number to decrease on rainy days). (cf. Figs. 8, 9 and 7) For the effect of the cloud seeding with silver iodide at the top of Mt. Fuji. (throughout this observation only 4 seeding experiments were made on Mar. 2, 3, 9 and 16) (iv) On Mar. 2 and 16, on which silver iodide smoke might be considered to direct towards the district of Tokyo from its path estimated from the direction of cloud motion and the weather map, the increase of the number of ice crystal nuclei was obviously found as shown in Figs. 11-(i), and 14-(i), (cf. Figs. 11-(iii), 14-(ii) and and -(iii). At about 12 h on Mar. 2, 1956, the estimated trajectory of the smoke has directed to ESE as shown in Fig. 11-(ii), but the wind direction has changed from NNW to WSW since about 14 h 30 m when the front would be supposed to pass through the Kanto district, and this will be also confirmed from Figs. 11-(i), -(iii) and -(iv).) and on other days, that is, Mar. 3 and 9 no increase could be found because of the deviation of the path of the smoke from the district of Tokyo as shown in Figs. 12-(ii), -(iii), 13-(ii), and -(iii), (v) Their maximum values amounted to about 3 or 4 times as large as that of unseeded usual days as shown in Figs. 11-(i) and 14-(i).