Change of size distribution of snowflakes caused by melting-disintegration process

1993 Fiscal Year Final Research Report Summary

• Project/Area Number: 04640413
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 気象・海洋・陸水学
• Research Institution: Nagoya University
• Principal Investigator: FUJIYOSHI Yasushi Nagoya University, Institute for Hydrospheric-Atmospheric Sciences, Associate Professor, 大気水圏科学研究所, 助教授 (40142749)
• Project Period (FY): 1992 – 1993
• Keywords: snowflake / melting / rain drop / size distribution

Research Abstract

The author measured size distributions of water droplets which were made by melting snowflakes in kerosene. The number of water droplets increases almost linearly with increasing the mass of snowflakes. As the number of water droplets incteases largely with increase in the mass of snowflakes, average size of water droplets decreases with increasing the mass of snowflakes. The stanbard deviation of the size distribution of water droplets decreases with increasing the mass of snowflakes, and the heavy snowflakes tend to make relatively small water droplets.
The snowflakes which disintegrated into large number of water droplets have large characteristic factors, that is, diameter, mass, cross sectional area and the degree of ruggedness. However, the snowflakes with large characteristic factors written above did not necessarily disintegrate into large number of water droplets. The correlations between the degree of raggedness and cross sectional area, and moment and mass were poor. These results indicate that the moment and the degree of raggedness do not depend on the mass and size of snowflakes. The moment and the reggedness of snowflakes closely relate to coalescence process of ice crystals in the air. Therefore, ice crystals randomly coalesce and the way of coalescence does not depend on the mass and size of snowflakes.