Cross correlations of horizontal wind fluctuations between points separated in space were measured at the Marine Observation Tower with a network of three-dimensionally distributed cup-anemometers. The phase shift of wind fluctuations between vertically separated points, and the coherence of wind fluctuations between points arranged in vertical, lateral and longitudinal directions were calculated. The vertical, lateral and longitudinal sizes of the turbulent eddy were empirically formulated in terms of the vertical, lateral and longitudinal coherences, respectively. A model of three-dimensional structure of horizontal wind components is represented by a distorted cylindrical form. Taylor's hypothesis of frozen turbulence is confirmed to hold for every frequency (0.01 Hz〈n〈0.5 Hz).
Some statistical characters of the turbulent fluctuation in the atmospheric boundary layer are studied experimentally in a stability and frequency domain. The density functions of longitudinal and vertical velocity and temperature fluctuations are expanded in the Gram-Charlier series. The stability dependency of the expansion coefficient is discussed in relation to feature of turbulence. A running mean filter is used to separate the fluctuation into convective and inertial range.
The concentration of aerosols during quiet snowfalls was measured by a minute particle detector of Gardner Assoc. type simultaneously with other relating factors in Sapporo in March 1972, selecting periods from midnight to early morning when the emission rate of aerosols due to human life is small and the effect of sideward divergence was negligible. As a result, the collection efficiency of aerosols by falling snow crystals, the surface emission rate and the dissipation coefficient were determined. The values of collection efficiency determined, were several ten percent. These values are one or two order greater than expected from simple aerodynamical consideration. Accordingly it is considered that the main mechanism in which aerosols are collected by falling snow crystals is the thermal turbulence including Brownian motion and ventilation effect. The apparent scavenging effect by snowfall was one order greater than those reported in foreign countries. The reasons for the great difference were considered.
Extensive observational programs on land and sea breezes were carried out by use of pibal method in the summer of 1971 and 1972 in the Tokai Village area facing the Pacific. Two pibal stations were set up at about one and six kilometers inland. Significant results obtained are as follows : (1) Vertical profiles of wind speed and direction in the lowest few hundred meters layer of the atmosphere in the sea breeze are significantly different between the coastal and the inland station, suggesting the effectiveness of the difference in surface friction over the land and the sea. (2) Low level jet in the evening is observed in this area and its development is deeply connected with the existence of a surface inversion layer. (3) The sea breeze observed is clearly of frontal type, which is about 400 meters thick in the vicinity of the front. The land breeze observed develops gradually from the ground surface upwards, under an opposing overriding flow. Observations of wind and temperature over the sea with a research vessel and those of air trajectories by use of tetroons were carried out as a part of observational programs.
This report describes a monostatic solar system performance conducted by the Radio Research Laboratories in Tokyo. Discussions are extended to the samples of observed records and to the results obtained from one-year continuous observations. It became clear that small-scale ordered motions play an important role in the structure of atmospheric temperature fluctuations in the planetary boundary layer.
Direct measurements of the rainwater structure of Tropical Storm Felice and Hurricane Debbie are presented. The rainwater distributions generally show the Marshall-Palmer characteristic form, N-N0 exp (-λd), with N0 varying from 105 to 106m4 and λ varying between 10 and 25cm-1, though large deviations from the exponential form were found in Hurricane Debbie. Despite the fact that the data were acquired from aircraft, a Z-R relationship almost identical to that for summertime cumulus in south Florida is indicated. Variations of the rainwater parameters during radial passes and spacially coherent data from Hurricane Debbie are also presented. The data show a rainband structure that penetrates to high altitudes and is remarkably persistent. The structure suggested agrees with the radar data indicating some statistical validity in the results, and in fact, the data allow a rough calibration of the radar isocontours. Generally, the data show that little of the rainwater resides in the updrafts. This suggests that the downdrafts are caused by water loading and that the seeding potential of the storms was small at the time the samples we taken.