摘要
液氮已广泛用于外场的人工增雨和消雾，是“十五”人工影响天气攻关研究和推荐的催化剂之一；其优势在于价廉，对环境无污染，资源丰富，-8℃以上成冰率高于AgI。文章介绍用液氮在首都机场的消雾试验，讨论和分析了消雾前后雾微结构的演变。对地跨北京14个区县，持续48h，能见度最低时达20～30m的气团平流雾连续播撒液氮，35min后下风方4．8km的测立占出现冰雪晶，形状以柱状为主，平均浓度为0．35个／cm^3。冰雪晶的出现破坏了雾的胶性稳定性，能见度很快得以改善，水平能见度增加到300～600m。
The results of field experiment in 17—18 Dec. 1997 and indoor little cloud chambers experiment conducted by Weather Modification Institute of Chinese Academy of Meteorological Sciences and Peking University in 1994-1995 are analyzed. It is shown that whether indoor or in the field, liquid nitrogen is an ideal catalyst because it obviously affects the visibility well.The microphysical structure observed at a site shows when successively seeding liquid nitrogen into the natural super-cooled fog whose horizontal visibility is 50-100m and number concentration is 1206/cm^3, ice crystal will appear at the leeward side of the observation station about 4. 5-5km after 35 minutes, it is mainly columnar, and its mean concentration is 0. 35/cm^3. The appearances of ice crystal disputed the stability of fog colloid structure, and changed the visibility well. When liquid nitrogen was seeded the second circle, wind direction turns to 210°-240° （NNW）, no ice crystal appeared, concentration of fog drop decreased a little, small one decreased, and spectrum turned wide.
出处
《气象》
CSCD
北大核心
2006年第3期27-31,共5页
Meteorological Monthly
基金
国家"十五"科技攻关项目(2001BA610A-06)
国家自然科学基金(40205001)
人工影响天气联合开放实验室课题
关键词
液氮
冷雾
微结构
人工消雾
liquid nitrogen （LN） artificial dissipation cold fog microstructure
