Crystal Size in Ice Grown by Droplet Accretion

Abstract

The size of crystal grains in ice formed by accretion of supercooled droplets has been determined for a wide range of air (?11 to ?25°C) and deposit (0 to ?16°C) temperatures. At air temperatures of ?14°C and below, the dependence of the crystal size on both air and deposit temperatures has been determined and found to be more marked at the lower temperatures. The aspect ratio (as the average of the ratios of the length to maximum width of the crystals) has also been determined for the same accretions. This parameter, too, has been found to depend on air and deposit temperatures, in a way which could help in resolving the ambiguity deriving from the analysis of crystal size alone, when investigating the growth conditions of hailstones.