In the previous paper, the author introduced into meteorology Hamilton's canonical equations based on the variational principle. Using the canonical equations, we obtain an exact solution in a special case where the vortex is initially in the uniform flow, and we get the same result as Syono's that the meandering motion of vortex is due to the change of basic flow, and that the ageostrophic wind acts effectively on the change of basic flow in low latitudes.
Several examples of the Microbarographic Elevation-Type, i.e., pressure rise of 0.4-2.0mmHg during 15-60 minutes accompanied by no appreciable change of weather, are treated and its general characteristics are drawn out. The dispersive internal gravitational wave hypothesis is proposed for the origin of these types.
Typhoons Faye and Freda are examined as the examples of typhoon not accompanied by extratropical cyclone, namely Main Typhoon only. It is suggested that either non-existence of front near the Japanese Islands or non-contact of Main Typhoon with the front rejects the formation of accompanying extratropical cyclone.
Concerning the influence of mountains on the large scale isobaric height pattern, most of investigators up to now discussed the subject under the assumption of steady state. But recently the problem of the influence of mountains on non-steady height pattern attracts much interest of investigators in this field, because the results of the numerical weather prediction of the lower layer are not satisfactory in mountain regions. Therefore we examined the influence of the Rocky mountains in non-steady state, by solving the vorticity equation numerically. We adopt typical model height patterns in middle latitudes as the initial conditions, and we compared the patterns obtained for the case, in which we take into account the effect of the mountains, with those for the case in which we do not take into account it.
The observations of surface winds crossing over a valley were made in detail, taking account of the various characters according to the cross-section shape of the valley. The 30 minutes mean wind speed, its decreasing rate at the shadow side and the exposed side of the valley slope, the intensity of turbulence, the mean wind direction, analysis with the aid of isopleths, and the formation processes of the eddies and up-valley winds in the valley were studied from a microclimatological viewpoint. The important results obtained are: the highly correlated experimental equations which connect the decreasing rate of mean wind speed and the valley topography, the difference of relationships between √u'2 and the mean wind speed at the respective side of the valley slope from that at the flat horizontal surface, the clear distinction between mean wind speed and directions in the deep valley from those in the shallow one, and the cyclic deformation of the eddies in the valley.
Sizes of about 54, 000 raindrops are measured for 249 observation periods of 9 rainfalls by filter paper method. Results are analysed according to the rainfall intensity of each period. (1) Rainfall intensity R<1mm/hr Graph of logarithm of raindrop number Nd (per cubic meter, per 0.1mm dropdiameter interval) against diameter d (mm) shows a parabola-like curve. The maximum of Nd occurs at 0.3 or 0.4mm diameter of drops. The curve resembles to the curve (e) of the model calculation by Mason and Ramanadham1). (2) Rainfall intensity R between 1mm/hr and 8mm/hr Number of raindrops larger than 1mm in diameter shows remarkable increase compared with the Marshall-Palmer distribution. The growing, process of the drops larger than 1mm in diameter seems to be different from that of the smaller drops.
More than these ten years, several researches have been made to know the nature and the concentration of freezing nuclei in the actual atmosphere. Most of them were experiments where an expansion or a cold chamber was used to find the concentration of potential nucleating particles. Studies of the actual nuclei in natural snow crystals have been developed along two lines. The one is the electron microscopic study to which Kumai (1951), Okita (1952), and Isono (1955) have made contributions. The other is the study on the freezing temperature of melted snow. Vaughan (1954), Kiryuhkin and Pevzner (1956) measured the freezing temperature of melted snow collected in bulk. Recently Hama and Itoo (1956) measured the freezing temperatures of melted individual snow crystals where volumes of the melted crystals had a variance according to their original sizes. Here the author presents the freezing temperatures of supercooled water drops with a constant volume which contain a melted snow crystal.