100 巻 (1991) 2 号 p. 234-239
Some solid particle in a snow crystal is active as ice nuclei on which snow are generated in the atmosphere. From the analysis of center nuclei in the snow crystal by use of the electron microscope, it was found that they consist of the soil particles such as kaolinite, montmorillonite and so on. Moreover, the origin of these particles was the arid area of the North China. Nucleating ability of the particle was investigated by the count of ice crystals formed in a cold box at given temperature. Number of ice crystal formed per Er particles collected on a filter paper was 0.3 at-150 °C and 4 at-20 °C.