An accurate measurement of densities of snowflakes using 3-D microphotographs

A 3-D microphotographic method was developed to measure densities of snowflakes accurately. Microscopic observations and photographs were taken in the field. The volume of a snowflake which is an aggregate of snow crystals was estimated from the 3-D photo by polyhedron approximation. The weight of the snowflake was measured with an electro-balance. The density values obtained were compared with the degree of riming and the size of each snowflake. The results clearly show that riming is a prime factor in increasing the density of the snowflake. The density of a snowflake is not sensitive to the change of size of the flake itself, but depends slightly on the size of its constituent snow crystals. The technique developed here will be applied in the future to study of the density of falling snowflakes.