Abstract
The growth mechanism of ice crystals growing at low air pressure is experimentally studied and the mechanism of the habit change with temperature of ice crystals is discussed. By repeating the growth and the evaporation of the same ice crystal at a constant temperature, the normal growth rates of the {1010} an {0001} faces of the ice crystal versus supersaturation are measured and compared with the various growth theories. The surface structure of an ice crystal growing or evaporating at a constant temperature is studied in situ. It is found from the present experiments that at a temperature of 0 to -2℃, the {1010} and {0001} faces of ice crystals growing at low air pressure grow by the V-QL-S mechanism, while at a temperature of -2 to -30℃, they grow by the BCF mechanism.
