Cloud processing and weeklong ageing affect biomass burning aerosol properties over the south-eastern Atlantic
Cloud processing and weeklong ageing affect biomass burning aerosol properties over the south-eastern Atlantic
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DOI：
10.1038/s43247-022-00517-3
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发表时间：
2022-08
影响因子：
7.9
通讯作者：
H. Che;Michal Segal-Rozenhaimer;Luyuan Zhang;Caroline Dang;P. Zuidema;Amie N. Dobracki;A. Sedlacek;H. Coe;Huihui Wu;Jonathan W. Taylor;Xiaoye Zhang;J. Redemann;J. Haywood
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文献类型：
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作者：
H. Che;Michal Segal-Rozenhaimer;Luyuan Zhang;Caroline Dang;P. Zuidema;Amie N. Dobracki;A. Sedlacek;H. Coe;Huihui Wu;Jonathan W. Taylor;Xiaoye Zhang;J. Redemann;J. Haywood
南部非洲产生了全球三分之一的生物质燃烧排放，这些排放具有很长的大气寿命，并影响区域辐射平衡和气候。在这里，我们使用气团轨迹来连接不同的飞机观测，以研究生物质燃烧气溶胶在从非洲南部向西经过大西洋东南部（那里有半永久层积云甲板）的过程中的演变。我们的研究结果表明，在运输的最初3天内，二次有机气溶胶形成，随后在达到平衡之前，有机气溶胶通过光解减少。气溶胶吸收波长依赖性随着老化而降低，这是由于颗粒大小的增加和棕色碳的光化学漂白。云处理，包括水相反应和清除，有助于有机气溶胶的氧化，而它强烈地降低了大直径颗粒和生物质燃烧气溶胶的单散射反照率。综上所述，这些过程形成了一个海洋边界层，其中被氧化和吸收的气溶胶更少，但更多。
Southern Africa produces a third of global biomass burning emissions, which have a long atmospheric lifetime and influence regional radiation balance and climate. Here, we use airmass trajectories to link different aircraft observations to investigate the evolution of biomass-burning aerosols during their westward transport from Southern Africa over the south-eastern Atlantic, where a semi-permanent stratocumulus cloud deck is located. Our results show secondary organic aerosol formation during the initial 3 days of transport, followed by decreases in organic aerosol via photolysis before reaching equilibrium. Aerosol absorption wavelength dependency decreases with ageing, due to an increase in particle size and photochemical bleaching of brown carbon. Cloud processing, including aqueous-phase reaction and scavenging, contributes to the oxidation of organic aerosols, while it strongly reduces large diameter particles and single-scattering albedo of biomass burning aerosols. Together, these processes resulted in a marine boundary layer with fewer yet more oxidized and absorbing aerosols.