The moving velocity of the center of a circular vortex is computed by applying the kinematical method on the solution of barotropic vorticity equation derived by Thompson (1954). The steering velocity is expressed in a form of weighted mean of averaged geostrophic wind. This method is also applicable for the baroclinic field both of general current and of typhoon. The baroclinic structure of typhoon has rather small effect on its movement.
The author shows dynamically that a cyclone can be maintained by the latent heat of condensation and calculates the values of the elements, i.e. the wind velocities, the temperature deviation and that of the pressure, when the intensity of precipitation is given. The results do not contradict so much to the observational common knowledge and several characteristic properties of actual cyclones are well understood at least in his own opinion, though he has treated an ideal case on the assumption that the elements are expressed by one cylindrical function with respect to γ. In the next he gets the graphs of the whirlwind and the pressure which correspond considerably to ordinary records of tropical cyclones by a simple theory. The discussion of cyclones owing to surface heating in the 2nd paragraph is only intended for the convenience of comparison with the subject problem. -Typhoons may be originated from them?
It is the purpose of this paper to make clear the effect of topography upon the jet stream. As the numerical example, the strong jet stream over the Far East is discussed quantitatively in connection with the Himalays. The fundamental concept we used is that the stationary pattern is obtained if η+αh (η: absolute vorticity, α; constant, h: height of the topography) coincides with the stream function. The difference of roles of topographical effect upon the stationary pattern between the Himalayas and the Rocky mountains is also discussed.
High tropospheric conditions of wind and temperature fields of 3 November 1952 are analysed in detail. Observed winds show the two branches of jet stream, i.e. subtropical and polar-front jet; the former at 200mb near 37°N, the latter at 260mb near 45°N. Three main tropopauses (i.e. tropical, polar-front, and polar tropopauses) are distinguished, and subtropical upper frontal zone is situated under the subtropical jet in its well-developed form.
The decay rate of the ice-forming properties of silver iodide smoke has been studied under the condition of ultraviolet light irradiation. The smoke from its generator was, at room temperature, introduced into a smoke-chamber (52×30×28cm3) and exposed, through a sheet of polyvinyl chloride making one of the walls of the chamber, to an ultraviolet light source (mercury lamp); measured, small amounts of the smoke were withdrawn, at frequent intervals, from the chamber by means of a syringe, and discharged into supercooled cloud in a ice-box (-12°C); the number of ice-crystals thereby produced and immediately, falling was counted by the naked eye; the same procedure was taken as well with the smoke previously mixed with water vapor, ammonia or hydrogen sulfide and subsequently subjected to the irradiation of ultraviolet light. The particle-size distribution of the smoke was estimated from the electron microscope photograph taken with shadow-casted sample to be ranging from 0.01μto 0.4μin diameter, the maximum frequency of the distribution in size appearing at about 0.07μ; the initial concentration of the smoke in the chamber was controlled to yield about 103 ice-particles per cm3 through all the runs of experiment. The results obtained are shown in condensed form as follows: Water vapor, ammonia and hydrogen sulfide are all effective in keeping the nucleation agency of silver iodide smoke from the deactivating action of ultraviolet light. The effectiveness of water vapor as protective agent increases rapidly with its concentration and lasts almost the highest value at relative humidities of about 60% or more, and this tendency is found to be more remarkable with ammonia; the ability of hydrogen sulfide falls between them. The above results were analyzed by making use of a decay-rate equation derived by taking into consideration of (1) the reduction in nucleating activity of smoke due to ultraviolet light irradiation, (2) the sedimentation as well as adhesion of particles to stirrer and walls of smoke chamber and (3) the coagulation of particles owing to collision between them, and the specific rate of photolytic deactivation (kp) was estimated by applyingg the equation to experimental data. With the intention of inquiring into the mechanism of the protective action of water vapor, the studies were carried out, next, on the adsorption of water vapor on finely divided silver iodide powder at room temperature by gravimetric method. It was found through the runs that the adsorption of water vapor is negligibly small in the range of relative humidities less than 60% or thereabouts, and increases sharply as the relative humidity goes over 70%, this circumstance being in striking contrast to the interrelation between the decrease of kp and the water vapor content of smoke. It appears, moreover, from the results of the adsorption experiment that the particles of silver iodide smoke would be covered, in an atmosphere of relative humidities of 70% and upwards with an adsorption layer of water of several decades of molecules thick. The results of the present experiments on adsorption of water as well as photolysis lead to the conclusion that the adsorption layer might turn down the transmission of ultraviolet light and prevent iodine, produced by photolysis, from being scattered and lost into surroundings, and these processes might stand for the protective action of water vapor. The effect of ammonia is supposed to be due to the chemisorption on silver iodide or, more probably, to the formation of complex-compounds of the type AgI•nNH3 (n=1/2, 1, 3/2, 2, •••); the same would happen to hydrogen sulfide.
In the winter season of 1955, the electric charge of snow flakes was individually measured simultaneously with the atmospheric field intensity and the size of snow flakes, using a vacuum tube electrometer, Wulf's electrometer and filter papers respectively. The shape of snow flakes was also observed by the microphotographic method. The following results were obtained. i) When the field gradient was steep, the sign of charge on snow flakes was generally the opposite of that of the prevailing field. Under the weak field, the sign was changeable. ii) The steeper the field gradient and the larger the size of snow flakes was, the larger the charge on them was. iii) The charge was extremely large while the field gradient was rapidly changing, in other words, when the string which showed the gradient was vibrating. The vibrating phenomenon of the string may perhaps represent the existence of a strong turbulence. iv) No special relations were observed between the sign of electric charges and the crystal form. Considering those results, it is supposed that the snow flakes carry electric charges mainly as a result of the selective ion capture under an atmospheric field similar to what happens in the case of raindrops, and on that mechanism are superposed the other effects, that is to say, the friction or disruption of snow flakes.