On the Characteristic Features of Snow Crystals Developed along c-axis

[摘要] Characteristic features, such as the mass, bulk density, riming states and the ratio of the length along c-axis to that along a-axis of snow crystals developed along c-axis (column, sheath and needle) are discussed on the basis of observations at Shiga Heights (about 1600 m above sea level), in central Japan.The masses of needles were found to be small compared with those of columns of the same volume, that is the values of the bulk density of needles were smaller than those of columns. The values of the bulk density of needles ranged between 0.2 to 0.4 grcm-3, irrespective of the length along c-axis. On the other hand, the values of the bulk density of columns were widely scattered. The crystals whose masses exceed 1-3×10-3mg were mostly rimed. Riming properties of columnar crystals are in good agreement with the observations by Ono (1969).

[学科分类] 大气科学