Abstract: In order to disperse supercooled fogs developed in autumn and winter of Beijing, a performance of liquid nitrogen as ice nucleant was evaluated in a cold chamber. Liquid nitrogen which doesn't pollute environment, has a low price and a rich reservoir. The experimental results show that the relation between the performances of liquid nitrogen as ice nucleant and cloud temperatures is not obvious. During a temperature range from 0℃ to -17.0℃, 10¹¹g^-1 represents the performance of liquid nitrogen as ice nucleant which is related to seeding amount. 26.3mg/m³ is a suitable seeding amount for liquid nitrogen weight. After two minutes of seeding liquid nitrogen, ice crystals about 90% of the total number will produce. The effective time for producing ice crystals may exceed 4-5 minutes.

Key words: liquid nitrogen, to disperse fogs, ice nucleant, seeding amount

摘要： 为消除北京秋冬季节的过冷雾，采用冷云室对资源丰富、价格低廉、使用安全、方便和没有环境污染的液氮进行了成冰性能的鉴定，实验结果表明：液氮成核率与云雾温度的相关不明显，但与液氮的播撒量有关，当云雾的温度在0--17.0℃ 范围，液氮的适宜播撒量可取26.3mg/m³，成核率为10¹¹g^-1。液氮能使过冷雾迅速冰晶化，播撒液氮2min后，占总量90%左右的冰晶生成，冰晶生成的有效时间可延续到4min或5min以后。

关键词: 液氮, 消雾, 成冰核, 播撒量