A case study of the size-resolved individual particles collected at a ground-based site on the west coast of Japan during an Asian dust storm event
A case study of the size-resolved individual particles collected at a ground-based site on the west coast of Japan during an Asian dust storm event
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DOI：
10.1016/j.atmosenv.2004.09.073
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发表时间：
2005-02
影响因子：
5
通讯作者：
Chang-Jin Ma;S. Tohno;M. Kasahara
中科院分区：
文献类型：
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作者：
Chang-Jin Ma;S. Tohno;M. Kasahara
为了研究单个亚洲沙尘暴粒子的性质，在2002年3月一次密集的亚洲沙尘暴事件期间，在日本西海岸进行了一次密集的现场测量。巨型粒子(>；5μm)在亚洲沙尘暴事件中的数量浓度是非亚洲沙尘暴期间的124倍。为了定量分析尺寸分辨单个粒子中的超痕量元素，采用了配备超光子环-8GeV(Spring-8)BL-39XU的X射线微探针系统。利用该系统，我们成功地实现了元素图谱的重建和单个粒子中多元素的定量化分析。单个颗粒中出现最大值的硅的质量变化范围为1.2×10−2pg~1.1×100pg，中位数为1.4×10−1pg。S的质量范围为1.6×10−2pg~6.7×10−2pg，中位数为3.9×10−2pg，而V、铬、铜、锌等几种微量元素的质量相对较低。所有元素的元素质量都具有很强的粒度依赖性，尤其是土壤源成分的元素质量在2.05-5.07μm左右出现单峰最大值。从回放的对应于单个颗粒的X射线、荧光图像中，我们可以简单地将可视化的颗粒分为两组，即内部混合颗粒和外部混合颗粒。通过对单个颗粒物中各元素质量变量的因子分析，发现79%的颗粒物被海盐和硫磺修饰。
To investigate the nature of individual Asian dust storm particles, an intensive field measurement was carried out on the west coast of Japan during a dense Asian dust storm event in March 2002. The giant particles (>5μm) marked 124 times higher number concentration in the Asian dust storm event than in a non-Asian dust storm period. For the quantification analysis of the ultratrace elements in the size-resolved individual particles, an X-ray microprobe system equipped with super photon ring-8GeV (SPring-8) BL-39XU was employed. By using this SPring-8 system we could successfully carry out the reconstruction of elemental maps and the quantification analysis of multiple elements in individual particles. The mass of Si showing the maximum value in individual particles was varied in the range from 1.2×10−2pg to 1.1×100pg with median 1.4×10−1pg. In the case of S, mass ranged from 1.6×10−2pg to 6.7×10−2pg with median 3.9×10−2pg, while several minor trace elements like V, Cr, Cu, and Zn show relatively low masses. A strong particle-size dependency of elemental masses was found for all elements, in particular the elemental masses of soil-derived components showed the monomodal maximum values around 2.05–5.07μm particle size. From the X-ray, fluorescence images replayed corresponding to individual particles, we could simply categorize the visualized particles into two groups, namely internally mixed particles and externally mixed particles. From the factor analysis with variables of each elemental mass in individual particles, 79% of total particle population was found to be modified by sea-salt and sulfur.