天山乌鲁木齐河源1号冰川大气气溶胶的微观形貌及元素组成分析

Morphological and Element Composition Characteristics of the Aerosol Particles Collected from the Glacier No.1 at the Headwaters of rümqi River,Tianshan Mountains

为研究冰川区大气气溶胶单颗粒物的物理化学特征,使用带能谱的扫描电镜(SEM-EDX)对2007年在天山乌鲁木齐河源1号冰川东支积累区海拔4 130m(86°49′E,43°06′N)处采集的38个气溶胶样品中的38 861个单颗粒物进行了微观形貌和元素组成的分析.结果表明:天山乌鲁木齐河源1号冰川区大气气溶胶主要以粒径在0.6～2.5μm之间的不规则的非圆形矿物颗粒为主,其中以富含Si、Ca的粘土矿物颗粒为主,与人类活动密切相关的含S颗粒物及烟尘飞灰等含量较少.这与其它沙尘源区的气溶胶特征相似,其中含Ca颗粒多于其它沙尘源区,主要受西风带的影响.气团轨迹显示,来自于西面中亚地区的高空气流影响了1号冰川区的大气环境,表明天山乌鲁木齐河源1号冰川区的气溶胶主要代表了中亚沙尘源区对流层中上部大气的本底状况.

In order to study the chemical and physical characteristics of individual aerosol particles over the glacierized fields,38 aerosol samples were collected during 2007 on the east branch of the Glacier No.1 at the Headwaters of rümqi River,Tianshan Mountains（Glacier No.1）（43°06＇ N,86°49＇ E,4 130 m a.s.l.）.Micromorphology and element compositions of about 38 861 particles were determined by scanning electron microscopy combined with energy dispersive spectrometer（SEM-EDX）.Results suggest that most of the particles collected in the whole year are irregular mineral ones with the sizes between 0.6 and 2.5 μm and circularities between 1.1 and 1.4.Si-rich and Ca-rich particles are the dominant particles;S-rich particles,soot and fly ash such anthropogenic species are scarce.Most of the aerosol particles here are from natural sources,and anthropogenic pollutions in this area are very weak.Aerosol characteristics in this area are similar to other dust source areas,but Ca content higher than other areas,owing to the effect of westerly.Back trajectories also suggest that most of the air masses arriving to this area are the high-altitude air currents from the west,the Central Asia,which have an important influence on the atmospheric environment over the Glacier No.1.Characteristics of the aerosol collected from the Glacier No.1 may represent the troposphere background conditions of the Central Asia dust source areas.