Mixture state and size of Asian dust particles collected at southwestern Japan in spring 2000
Mixture state and size of Asian dust particles collected at southwestern Japan in spring 2000
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DOI：
10.1029/2003jd003869
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发表时间：
2003-12
影响因子：
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通讯作者：
Daizhou Zhang;Y. Iwasaka;G. Shi;J. Zang;A. Matsuki;D. Trochkine
中科院分区：
文献类型：
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作者：
Daizhou Zhang;Y. Iwasaka;G. Shi;J. Zang;A. Matsuki;D. Trochkine
[1]对2000年春季日本西南部沿海城市熊本（32°48′n, 130°45′e）三次沙尘暴期间的大气颗粒进行了采集。利用电子显微镜和能量色散x射线光谱仪分析了单个粉尘颗粒的元素组成和大小，以及它们与海盐、硫酸盐和硝酸盐的混合状态。60 ~ 85%的粉尘颗粒与海盐混合在一起。气象记录表明，这些颗粒极有可能是由尘埃颗粒和海盐颗粒的碰撞和凝结形成的。单个颗粒中矿物成分与海盐的相对重量比表明，颗粒混合物以矿物成分为主，或以海盐为主，或两者兼有。3次沙尘事件中矿物和海盐混合水平分离的颗粒粒径分布相似，分布范围均为1 ~ 8 μm，最大模态约为3 μm。在1 ~ 8 μm范围内，几乎没有灰尘颗粒。沙尘颗粒与海盐的结合使沙尘颗粒的大小增大。因此，在直径> ~ 3 μm范围内颗粒浓度的下降表明，在3 μm附近可能是粉尘颗粒分散的临界直径，当粉尘颗粒在海洋大气中大于这个尺度时，可能会被迅速清除。硫酸盐和硝酸盐检测表明，91%以上的粉尘颗粒含有硫酸盐，27%以下的粉尘颗粒含有硝酸盐。对混合颗粒和海盐颗粒中钠、硫和氯的相对重量比的比较证实了先前的结果，即矿物材料可以促进颗粒硫酸盐和硝酸盐的形成，并抑制混合颗粒中海盐成分的氯消耗。
[1] Atmospheric particles were collected at Kumamoto (32°48′N, 130°45′E), a coastal city in southwestern Japan, during three dust storm events in spring 2000. The elemental composition and size of individual dust particles and their mixture state with sea salt, sulfate, and nitrate were analyzed using electron microscopes and an energy dispersive X-ray spectrometer. About 60 ∼ 85% of dust particles were internally mixed with sea salt. Weather records indicated these particles were most probably formed by the collisions and coagulations of dust particles and sea-salt particles. The relative weight ratios of mineral components to sea salt in individual particles showed that the mixtures of particles were dominated by mineral, by sea salt, or by both. Size distributions of the particles segregated by the mixture levels of mineral and sea salt in the three dust storm events were similar and all distributions showed a diameter range of 1 ∼ 8 μm with maximum mode around 3 μm. Out of 1 ∼ 8 μm, dust particles were rarely detected. The combination of dust particles with sea salt caused an increase in size of the dust particles. Therefore the decrease of particle concentrations in the range of diameter >3 μm suggests the critical diameter for dust particle dispersion was possibly around 3 μm and a dust particle might be removed rapidly if it became larger than this scale in the marine atmosphere. Detection of sulfate and nitrate revealed that 91% or more dust particles contained sulfate and 27% or less contained nitrate. The comparisons of the relative weight ratios of sodium, sulfur, and chlorine in mixture particles and in sea-salt particles confirmed previous results that mineral materials could enhance particulate sulfate and nitrate formation and restrain chlorine depletion from the sea-salt components in mixture particles.