In-cloud sulfate addition to single particles resolved with sulfur isotope analysis during HCCT-2010
In-cloud sulfate addition to single particles resolved with sulfur isotope analysis during HCCT-2010
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DOI：
10.5194/acp-14-4219-2014
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发表时间：
2014-01-01
影响因子：
6.3
通讯作者：
Herrmann, H.
中科院分区：
文献类型：
--
作者：
Harris, E.;Sinha, B.;Herrmann, H.
云内硫酸盐的产生改变了气溶胶的大小分布，对间接和直接气溶胶冷却的大小以及SO2排放对环境的影响具有重要意义。我们研究了哪些硫酸盐源主导云内硫酸盐添加到不同的颗粒类，当一个空气包裹通过地形云。在2010年秋季图林根山顶云运动（HCCT-2010）的三次云测量活动中，收集了硫酸盐气溶胶、SO2和H2SO4在地形云的逆风、云中和下风。结合SEM和NanoSIMS对单个颗粒的分析，可以分辨出颗粒硫酸盐的δ S-34大小和类型。在HCCT-2010中，最重要的云内二氧化硫氧化途径是过渡金属离子催化的水氧化（TMI催化），单颗粒同位素分析表明，这主要发生在粗矿物粉尘成核的云滴中。而直接吸收H2SO4 (g)和超细颗粒是改性细矿物粉尘最重要的来源，增加了其吸湿性，促进了其活化。硫酸盐添加到“混合”颗粒（二次有机和无机气溶胶）和涂覆烟尘中，主要是云中水溶液SO2被H2O2氧化，并直接吸收H2SO4 (g)和超细颗粒硫酸盐，具体取决于颗粒大小模式和一天中的时间。这些结果为云内硫酸盐生成机制提供了新的见解，并显示了单颗粒测量和模型对准确评估云处理的环境影响的重要性。
In-cloud production of sulfate modifies aerosol size distribution, with important implications for the magnitude of indirect and direct aerosol cooling and the impact of SO2 emissions on the environment. We investigate which sulfate sources dominate the in-cloud addition of sulfate to different particle classes as an air parcel passes through an orographic cloud. Sulfate aerosol, SO2 and H2SO4 were collected upwind, in-cloud and downwind of an orographic cloud for three cloud measurement events during the Hill Cap Cloud Thuringia campaign in autumn 2010 (HCCT-2010). Combined SEM and NanoSIMS analysis of single particles allowed the delta S-34 of particulate sulfate to be resolved for particle size and type.The most important in-cloud SO2 oxidation pathway at HCCT-2010 was aqueous oxidation catalysed by transition metal ions (TMI catalysis), which was shown with single particle isotope analyses to occur primarily in cloud droplets nucleated on coarse mineral dust. In contrast, direct uptake of H2SO4 (g) and ultrafine particulate were the most important sources modifying fine mineral dust, increasing its hygroscopicity and facilitating activation. Sulfate addition to "mixed" particles (secondary organic and inorganic aerosol) and coated soot was dominated by in-cloud aqueous SO2 oxidation by H2O2 and direct uptake of H2SO4 (g) and ultrafine particle sulfate, depending on particle size mode and time of day. These results provide new insight into in-cloud sulfate production mechanisms, and show the importance of single particle measurements and models to accurately assess the environmental effects of cloud processing.