Growth of dendrites with adjoining surface transference of water molecules

Abstract

The prism faces of a new snow crystal as a thin plate have been found to grow not only by direct injection of water molecules in the diffusion field but also by adjoining surface transference of water molecules from basal faces. The paper investigates the adjoining surface transference of water molecules from a basal face to prism faces in the growth of dendrites photographed in two experiments. The investigation reveals the following: one of the two basal faces of a growing dendrite is always observable because it has an important role in transferring surface water molecules to prism faces; in a supercooled cloud of about －15 °C，a dendrite typically grows from one of thin plates protruding from a frozen water droplet; the tips of a growing dendrite can remain thin when the growth conditions are kept almost constant; rimed cloud droplets interrupt the growth of prism faces of a dendrite; and generation of ridges on a dendrite is also explicable. These results conclude that the adjoining surface transference of water molecules from a basal face to prism faces is an important factor for the growth of prism faces of a dendrite.