The rotating flow system such as tropical cyclone or typhoon with nearly circular isobaric pattern is treated from the view point of the lateral mixing process and some basic physical relations are derived to interpret the characteristic behaviours of Namekawa's Main and Secondary Typhoons. The same idea is applied to the rotation of the fluid shell to explain the observed tonal motion at the sun's surface and of the earth's atmosphere at the tropopause level in the south of the polar cap.
A case study is made on the so-called Northeasterly pressure pattern accompanied by persistent cold-outbreak over the Far East. The period of investigation covers late September and early October 1954, when this peculiar pattern appeared with unusual distinctness. It is found that an intense cold vortex of Arctic origin, which is displaced southward to northeast Siberia in the course of world-wide decline of zonal index, gives rise to a strong cold air advection eastward along its southern margin. This cold advection is responsible to the establishment of the Northeasterly pattern and continues until the great store of cold air trapped by a blocking high is exhausted. The nature of cold vortex as to its vertical extent and its successive formation in lower latitudes is described. Also, the role of the strong westerlies as the generator of the cold air advection is discussed.
In order to obtain the materials appropriate for the study of extended forecasting, we calculated the six-day change of the height of 500-mb isobaric surface by the barotropic model, where the height z is expressed by one-dimensional Fourier coefficients along each latitude circle.
An experiment on the growth of ice crystals in a super-cooled fog (-4.4°C) was conducted. The replicas of ice crystals which had fallen on glass slides were measured. The slides were held horizontally and exposed one minute at 50, 100, 200, 500 and 700 metres leewards of the seeding point. When the seeding was made with a lump of dry ice, ice crystals were produced and grew to columnar form. During about the first 2 minutes, the crystals grew in both directions, i.e., along their principal and lateral axes, but thereafter they grew only along their principal axes. The rate of increase of the length of columnar crystals was about 2μ/sec. The length attained to 550μ in about 5 minutes, which was observed at the position 700 metres leewards of the seeding point, while the width of the same crystals remained at about 50μ. The obtained growth rate is compared with that calculated by Houghton.
Using the equations of motion on the moving coordinate which moves with the angular velocity of the westerlies, we made barotropic forecasts over the Far East, and the results of these forecasts are presented. In these computations, the Double Fourier Series method which we have reported already in this Journal, is used.
The present author treated tentatively the relation between the wind wave scales and the surface water temperatures in an open sea using the data of oceanographical observations taken at the Northern Fixed Point (39°N, 153°E) in the North Pacific Ocean in view of the foaming of sea water, and the following results were obtained; (1) The general features of the annual variation in wind waves were discussed (§3). (2) The probability (P3) of the appearance of the wind wave scale 3 has a tendency to decrease with increasing surface water temperature, that is to say, the lower the surface water temperature becomes, the stronger the foaming ability (§4). (3) He defined a quantity S(= τh0), which is physically significant, in order to indicate the degree of foaming in actual cases, where r and h0 represent the half life and the initial height of foam layer, respectively. Using the values of the quantity calculated from the results of his laboratory experiments, he could ascertain that the relationship mentioned above holds good approximately (§5).