摘要
利用2010年3月31日—4月2日冷锋天气系统影响下湛江海雾综合观测资料,分析了海雾的微物理特征及海雾过程中气溶胶粒子谱的演变特征。结果表明,海雾的生消与风场密切相关,海雾生成和发展与较强的ESE气流相联系,而弱的NE气流则会促使海雾减弱或消散。湛江海雾的雾滴数浓度为100~102 cm-3,液态含水量为0.001~0.232 g·m-3,雾滴平均半径小于10 μm,雾滴峰值半径多位于1.4 μm。海雾雾滴谱分布以单调递减谱为主,谱宽超过20 μm,且雾发展过程中雾滴谱谱宽存在突然增宽和迅速减小的现象。海雾过程中雾滴数浓度的变化主要是由半径小于5 μm的雾滴数密度变化引起的。海雾过程对气溶胶粒子的湿清除效果并不显著,雾过程中粒径小于0.1 μm和大于4 μm的气溶胶粒子数密度显著减少,但在雾消散后又迅速恢复到雾发生前的水平。
Based on the observational data at Zhanjiang from 31 March to 2 April 2010,microphysical characteristics and evolution of aerosol particle size distribution for a sea fog which was influenced by cold front were analyzed.The results showed that the formation and dissipation of sea fogs was closely related to wind field.The formation and development of sea fogs usually occurred in east southeast wind,while weak northeast wind was the main factor to dissipate the persistent sea fog.The variation range of fog droplet number concentration and liquid water content were 100—102 cm-3 and 0.001—0.232 g·m-3,respectively.The mean radius was less than 10 μm and the peak radius was mostly near 1.4 μm.The fog droplet size distribution of the sea fog events was mainly of a monotonically decreasing type with the spectrum width larger than 20 μm.The fog droplet spectrum width presented abrupt broadening and rapid reducing phases during the sea fog events whereas the change in fog droplet number concentration was mainly caused by the number density variation of fog droplets with radiuses of less than 5 μm.Sea fogs exerted insignificant wet scavenging effect on aerosols.The number density of aerosol particles with diameters of less than 0.1 μm or more than 4 μm decreased dramatically during sea fogs,but quickly returned to their normal levels before the formation of sea fogs.
出处
《大气科学学报》
CSCD
北大核心
2014年第2期208-215,共8页
Transactions of Atmospheric Sciences
基金
公益性行业(气象)科研专项(GYHY20070626)
国家自然科学基金资助项目(41275151)
江苏省青蓝工程"云雾降水与气溶胶研究创新团队"资助项目
江苏高校优势学科建设工程资助项目(PAPD)
关键词
海雾
微物理特征
雾滴谱
气溶胶粒子谱
sea fog
microphysical characteristics
fog droplet size distribution
aerosol particle size dis-tribution