Choji Magono

Design of “Snow Crystal Sondes”

Abstract A sampling and recording sonde, called a “Snow Crystal Sonde,” was designed to observe the vertical distribution of snow crystals in a snow cloud. The shape of snow crystals was recorded on the surface of a circulating film coated with polyvinyl formvar solution during the ascent of the sonde. A radiosonde was released at the same time and place as the snow crystal sonde, in order to render a precise comparison between the snow crystal shape and the air temperature in the cloud. As the result of observation it was ascertained that Nakayas Ta−s diagram was completely applicable to the growth of natural snow crystals. The snow crystal sonde was also found to be useful to measure the growth rate of snow crystals, and the space density of snow crystals and supercooled cloud droplets.

Some Observations of Snowfall and Meteorological Conditions in Arctic Canada

Abstract Observations of snow crystals were made in mid-winter at Inuvik, N.W.T., Canada, in order to study the snow crystal of cold temperature type. The following results were obtained: 1) The cloud temperature was, in general, warmer than expected during the observation period, that is, nearly the same as observed in snow clouds in midlatitudes, although the surface temperature was lowered to −30 or −40°C. 2) Regarding the type of snow crystals, Nakayas Ta-s diagram was well applicable to the snow crystal in Arctic Canada. 3) Almost every day during the observation period, snowfalls were observed; however the fall intensity was as light as 1 or 2 cm day−1. In the case of a moderate snowfall of 5.1 cm day−1, the snowfall was caused by an arctic front at the 850 mb level. The vapor for the snowfall was supplied from the warm surface of the eastern or northern Pacific Ocean. 4) One day, small supercooled raindrops were observed, but no cloud region of temperature warmer than 0°C was detected in the cloud...

Unusual Types of Single Ice Crystals Originating from Frozen Cloud Droplets

Abstract Laboratory experiments were conducted to study the formation process of unusual types of ice crystals, using a cold chamber in the temperature range −15 to −25°C. Ice crystals of the bottle type seem to originate from frozen water droplets with spicules. Ice crystals of twin columns (or twin bullets) with plates were found. By observing the various stages of development of pyramidal faces of ice crystals with plates and ice crystals of “single bullet” type–it was concluded that these pyramidal portions of ice crystals may originate from the spicule of frozen droplets or from hemispherical frozen droplets, and that the pyramidal faces can survive further growth at temperatures colder that −25°C.

THE ELECTRIC CHARGE ON CONDENSATE AND WATER DROPLETS

Abstract It was found that dew produced artificially on a thin wire was electrified negatively when the water temperature of the reservoir for supplying water vapor was lower than about 80C and positively when the temperature was higher than about 85C. The electrification phenomena of the condensate were considered to be originated from the electric charge on individual water droplets, because it was observed that the droplets were electrified when they rose from the water surface of the reservoir, and the sign of charge on the individual droplets agreed well with that of the condensate.

An Experiment on Fog Dispersion by the Use of Downward Air Current Caused by the Fall of Water Drops

Abstract In July 1961 an artificial fog dissipation experiment was carried out, using a helicopter. The experiment was based on the idea that fog will be dissipated by downward air current caused by fall of water drops sprinkled from the helicopter. The preliminary experiment showed that the effective width of distribution area of water drops was about 20 m under the sprinkling condition used. The vertical distributions of air temperature and humidity in sea fog were observed at the sea side near where the fog dissipation experiment was made. According to the observation, it was seen to be general in the sea fog in the daytime that strong temperature inversion existed near the fog top and that the air layer under the fog base was unstable with respect to the dry adiabatic. The sprinkling of water drops was carried out on the top of the advected sea fog, a smooth and flat area being selected; it was found that a few minutes after the sprinkling treatment, the flat and smooth fog layer changed to fracto-cum...