Measurement of the Mass and Number of Falling Snow Crystals in the Atmosphere

[摘要] By making plastic replicas of snow, the writers measured the mass and number of falling snow crystals in the atmosphere. Experimental work was done in an igloo, half way up Mt. Taisetsu in Hokkaido, at an altitude of 1050m. About one thousand specimens Were obtained in the three winters 1950-52. This paper is concerned with the most interesting 34 specimens which were taken during a 12-hour period from 0000 JCT to 1200 JCT on 2 March, 1951. At that time, the air temperature and the crystal formation of falling snow varied very remarkably; the snowfall in this 12-hour period was 17cm in depth, which corresponds to 13mm of water. A small sheet of black paper or a clean slide glass for microscope was immersed for a moment in the 1-3 per cent solution of formvar dissolved in ethylene dichloride, and then was exposed horizontally to the falling snow crystals for 30 seconds. And replicas of falling snow crystals were obtained as shown in Figs. 3-19.The total mass and the number of snow crystals in the atmosphere were calculated from these replicas. The order of magnitude of the total mass was 102mg/m3 and that of the number was 104 particles/m3. The total mass of snow crystals shown in Table 2 seems to coincide with the liquid water content in the cumulus cloud.

[学科分类] 大气科学