摘要
利用3次沙尘天气期间的气溶胶飞机观测资料,分析了北京地区在3种沙尘天气下气溶胶垂直分布特征。结果显示：逆温层的存在对扬沙个例的垂直分布有影响。数密度谱的分布基本呈单调递减,但边界层内扬沙、浮尘和沙尘暴个例都在0.13-0.3μm间存在峰值,而扬沙个例在0.8μm,浮尘个例在6.5μm以及沙尘暴个例在2.8和6.5μm处出现次峰值。沙尘中细粒子的有效直径是人为源气溶胶粒子的4到10倍。浮尘天气整个粒子谱宽从近地面层开始随高度先增大后减小,到3000m达到最大,这与高空输送有关;扬沙个例沙尘粒子谱分布显示近地面层大于50μm段粒子谱无论数浓度还是谱宽都明显高于浮尘和沙尘暴个例,这与扬沙是局地大风扬尘引起有关;沙尘暴个例谱宽在接近云底达到最大,说明大粒子已经被携带到一定高度,与蒙古气旋云系的上升运动有关。
The characteristics of vertical distribution of aerosols are analyzed with the data observed by airborne instruments in three dust weather events in Beijing.The results show that the vertical distribution of dust particles is influenced by the thermal inversion layer.The spectral distribution is monotone decreasing;within the boundary layer,the diameters of particles for blowing sand,dust and sand storms are concentrated between 0.1and 0.3μm,while another peak of the size distribution for the blowing sand event is about 0.8μm and 6.5μm for the dust storm and 2.8and 6.5μm for the sand storm.The effective diameter of fine particles in the dust event is 4to 10 times as big as particles from anthropogenic sources.During dust weather the whole particle spectrum width from the near-ground layer decreased with height,with maximum at 3000 m,associated with air transportation.The particle distribution for the dust storm shows that in the surface layer,the number of concentration or spectral width in the particle spectrum of 50 μm was significantly higher than that of the dust storm and sandstorm,which was related the local high winds.The sandstorm alone reached the maximum spectrum width near the bottom of the clouds,which indicates that big particles were carried up to a certain height,associated with the upward movement of Mongolia cyclone structures.
出处
《气象科技》
北大核心
2016年第1期95-103,共9页
Meteorological Science and Technology
基金
首都蓝天行动培育专项"北京地区人工影响消减雾霾试验研究"(Z141100001014107)
北京市气象局科技项目(BMBKJ201506001)
国家自然科学基金项目(41205100)
公益性行业(气象)科研专项(GYHY201306065)资助
关键词
沙尘天气
飞机观测
北京地区
sand and dust storm
aircraft measurement
Beijing
