Classification of Snow Flakes and their Structures

[摘要] Many snow flakes were photographed during 1951_??_1954 in Japan, and they were classified according to the purposes by four methods, i.e., their hystorical processes, shapes in falling state, sizes and crystal habits.It was observed that the snow flakes change their crystal states in the process similar to that of the fallen snow. Considering aerodynamically, the shape and velocity of snow flakes in falling state, a clue for presuming the uniformity of crystal habits in snow flakes was acquired. In the photographs of snow flakes hitherto obtained, it was found that in all types of snow crystals one snow flake is formed with the respective type only, while another with almost all combinations between the different types is formed. All the ways geometrically possible for the adhesion of snow crystals, namely, top-top, top-surface, surface-surface, surface-edge line, line-line, intertwined adhesion were found in the snow flakes. The top of branch of dendritic crystals plays a leading role in the adhesion mechanism between the crystals.From those results, it was presumed that the great snow flakes might be composed of snow crystals of dendritic type.

[学科分类] 大气科学