A theory of internal gravity wave in the atmospheric two-layer model on the rotating earth is presented in relation to the microbarometric wave, from the viewpoint that Coriolis force, which is not taken in the usual treatment, cannot be neglected for the solution with wave velocity nearly or exactly equal to the undisturbed wind velocity in the stably stratified upper layer. Possibility of such stable wave solution, which is rejected in the case of nonrotating earth, is theoretically confirmed. It is suggested from computation of the energy of wave motion that the solution can most predominantly produce a pressure wave.
Without regard to the seasons, the disturbances on the monthly mean charts lose their kinetic energy constantly through transfer to both the time averaged zonal current and the transient eddies. The loss of the kinetic energy seems to be compensated for by the conversion from the available potential energy of the disturbances in question.
When radioactive gas is discharged into the free air at the time of accident or ordinary operation of atomic plants, discharged effluent is dispersed by atmospheric turbulent diffusion. The concentrations of radioactive airborne substances are governed partly by the source characteristics (height of source, temperature and velocity of emission of the discharged gases) and partly by meteorological parameters. Many studies for dispersion formula have been presented by O. G. Sutton (1947), F. Pasquill (1958), P. J. Meade (1958, 1960), J. Sakagami (1960) and others. In this paper, first a brief description is given of PbI2 smoke experiments that have been tried within a few kilometers range at Tokai-Mura (Ibaraki Pref., Japan) from 1958 to 1959. The results of experiments show a good agreement with those of computations which are obtained by Meade's method (1958). Next, the author describes of 41A gas release experiments (1961) in use of JRR-2 at JAERI, in which we measured of ray total external ex-posure on the ground surface during 41A cloud passage by a network extended 2 km downwind. As a result, we have certified that measured exposure shows a good agreement with ones which are calculated under the assumption of spatial concentration distributions obtained by Meade's method (1958).
The fluctuations of lateral wind direction were measured at the U.S. Weather Bureau Observation Test and Development Center in Sterling, Virginia. Four sets of light weight anemometer and wind vane were installed along the observation tower at the heights of 2, 4, 8 and 16 m above the ground. During the observations nine runs were taken and these were then analyzed. Results are as follows : (1) The standard deviation generally decreases both with stability and with height. The value in the neutral condition is about 12 degrees. (2) The variance spectra in nondimensional form is likely to unify the original ones over the wide stability. They can be roughly represented as a " -5/3 power" in higher frequencies (larger than 0.2 ƒz /U, say ; ƒ=frequency, z=height, and U=mean wind speed at z), while they separate in lower ranges according to the stability. Some explanations are given from the standpoint of the similarity theory. Furthermore, from the angle of "selective method ", a filter after Brier (1961) is applied to the data, and the standard deviation and the cross correlation coefficients both with and without lag are calculated for a few processed data of a single run, and thus some tentativeresults are obtained. Among them are the relations of time-lag with height and height difference.
Horizontal distribution of the amounts of precipitation during local heavy snowfalls in the lower Ishikari Plain, Hokkaido, does show a band shape, its direction being from NW to SE or from W to E. In this paper, such a band is denominated as ″snowfall band ″. The first factor effective upon the occurrence of snowfall band in this area is the formation of cloudstreets in the northern area of the Sea of Japan. The formation of such cloudstreets can be explained as due to the convection in heated air flows with restoring force by the wind shear, as suggested by Kuettner. Some features of a snowfall band are described under four headings, i.e., a) synoptic situation and snowfall, b) cloudstreets, c) snow crystals, and d) colder air under clouds precipitating graupels.