Calculations of droplet growth are made based on a model of cloud, through the cloud base of which upward current does not enter. If raindrops form on large sea-salt particles in this cloud, it can be shown that the larger raindrops form on the larger sea-salt particles. Using this model of cloud, functional relations are presented between the size distribution of large sea-salt particles and various quantities concerning the rainfall from a warm cloud. The rainfall intensity, the flux density distribution of raindrops with respect to radius, the salinity of rain water in bulk, and the salinity of individual raindrops are deduced. The function expressing the salinity of raindrops is found to have a minimum at a certain radius. This may be considered to show one of the tentative explanations for the appearance of minimum value of raindrop salinity found by Turner (1955) in the case of warm rains. Derived raindrop spectrum changes with rainfall intensity in a manner for some aspects resembling that found by Blanchard (1953) in Hawaii. The present calculations seem to be useful to some extent for quantitative estimations on some features of rainfall from orographic warm clouds.
A preliminary study of the size distribution of raindrops from layer type precipitation in tropics has been made. The large deviations in the size distribution which have been ignored by the past workers, in their attempt to develop an emperical relationship between the dropsize and intensity of rainfall, have been examined. The large deviations from ‘Marshall-Palmer distribution’ in the observed spectral distribution of drops at the ground level are explained in terms of the modification the dropsize spectrum undergoes, in the intervening space between the level of origin of raindrops and ground due to the following factors: (a) Growth of raindrops by accretion with cloud droplets, (b) Differential rates of evaporation of raindrops of different sizes in falling from cloud to ground and (c) Coalescence between raindrops of different sizes during their fall from cloud to ground.
In this paper, the author treated the distribution of the Zonal wind with constant absolute vorticity, and gave some remarks on the position of the jet-stream. The vertical relative vorticity and its distribution on the globe is discussed in detail. The author's relations contain Rossby's and Kasahara's results as its special cases.
Discussed is the errors of height tendency and vertical velocity caused by assumptions of fictitious boundary conditions, i.e. the height tendency or the vertical velocity vanishes on the side-boundary or at the lower boundary respectively. Generally speaking, errors penetrate farther into the domains with increase of the scales of errors on and at boundaries. The distributions of errors in the domains are given for various type of boundary errors. Comparison between the exact solution and the result of prediction by the barotropic model is made for a disturbance of Haurwitz's type.
The following subjects are statistically studied to give the indirect evidences which sustain Namekawa's theory of main and secondary typhoons; frequency distribution of the minimum central pressure, areal distribution of the formation of severe typhoon, relative position of the centers of main and secondary typhoons, and dimension of the inner core of main typhoon.