Tuesday, 4 June 2002: 9:00 AM
Growth Characteristics of Laboratory Grown Ice Crystals Between -20 C and -70 C
The linear, projected area, and volume growth rates have been measured for ice crystals grown to a few hundred micrometers in size in a static diffusion chamber between -20 C and -70 C. Crystals were nucleated and grown on narrow glass filaments at pressures typical of the standard atmosphere for this temperature range. Ice supersaturations ranged from as low as 1% to values which simulated the ventilated growth of crystals in the atmosphere under conditions of approximately maximum supersaturation. Habit distributions were determined and reveal that polycrystalline forms dominate the distributions except at very low ice supersaturation where single crystals are observed with somewhat larger or similar frequency. Growth rates were determined for specific crystal habits and average growth rates were determined based on habit distributions. A scheme for converting projected area growth rates into total surface area growth rates as a function of habit type is discussed.