Comparison of sources and nature of the tropical aerosol with the summer high Arctic aerosol
Comparison of sources and nature of the tropical aerosol with the summer high Arctic aerosol
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DOI：
10.1111/j.1600-0889.2007.00315.x
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发表时间：
2008-01
期刊：
影响因子：
--
通讯作者：
C. Leck;E. Keith Bigg
中科院分区：
文献类型：
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作者：
C. Leck;E. Keith Bigg
1998年9月和2005年7月，在澳大利亚大堡礁外缘下风向约15公里处，南纬15度的一个岛屿的上风海岸收集了海洋气溶胶，并用电子显微镜进行了检查。外聚合物凝胶、有机颗粒的聚集体、海洋微生物和海洋生物的碎片形成了累积模式气溶胶的很大一部分。凝胶的透明度、轮廓和形状的硬度以及有机蒸汽对它们的影响的差异，表明随着大气停留时间的推移，会发生渐进的物理和化学变化。有机聚集体组分的粒径分布非常接近北冰洋中部类似颗粒的粒径分布，峰值为30-40 nm。在至少75%的外观类似于硫酸铵的颗粒中发现了这些聚集体的单一组分或小组，这表明聚集体在大气中破碎。在直径小于200纳米的颗粒中没有检测到海盐，这与许多观察结果显示它是一种主要成分不同，这一结果与北极的发现完全一致。从海洋进入大气层的颗粒物的变化推断序列也与北极发现的非常相似，这表明这是海洋上的一种常见模式。这一结论将需要修改气候模型中使用的海洋气溶胶参数和可能的气候反馈效应。
Marine aerosol was collected in September 1998 and July 2005 on the upwind coast of an island at latitude 15◦S, about 15 km downwind from the outer edge of the Great Barrier Reef, Australia, and examined by electron microscopy. Exopolymer gels, aggregates of organic particles, marine micro-organisms and fragments of marine life formed a substantial part of the accumulation mode aerosol. Differences in transparency, firmness of outlines and shape of gels and the influence of organic vapours on them, suggested progressive physical and chemical changes with atmospheric residence time. The organic aggregate components had a size distribution remarkably close to that found in similar particles over the central Arctic Ocean peaking at diameters of 30–40 nm. Single components or small groups of these aggregates were found within at least 75% of particles resembling ammonium sulphate in appearance, indicating that aggregates fragmented in the atmosphere. Sea salt was not detected in particles <200 nm diameter unlike many observations showing it to be a major component, a result that was entirely consistent with the Arctic findings. The deduced sequence of changes to particles entering the atmosphere from the ocean is also very similar to that found in the Arctic, suggesting that it is a common pattern over the oceans. That conclusion would require modification of the parametrization of the marine aerosol used in climate models and of possible climate feedback effects.