On the Transference of Heat in Ice-formation

[摘要] If a supercooled water droplet strikes an object, only a small portion of it freezes immediately. It is generally recognized that the remaining portion in liquid state turns gradually into ice by cooling due to the convective heat transfer and the evaporation from the surface. The author's computation, however, shows that the heat of conduction to the body also amounts to a considerable valuc.Calculating the rate of these three cooling processes, the author estimates the “icing time”.Until now the “icing time” has been considered to be an important factor that determines the type of ice deposit. The author introduces a new concept “collision interval”. Possibly by the relative magnitude of these two quantities the character of ice may be decided.If the collision interval is sufficiently longer than the “icing time” at the temperature close to zero, the rate of growth of ice does not depend on the density of cloud, while the exces_??_ive amount of water may flow away. This explains the fact that the amount of ice decreases rapidly at the neighbourhood of freezing point.

[学科分类] 大气科学