High summertime aerosol organic functional group concentrations from marine and seabird sources at Ross Island, Antarctica, during AWARE
High summertime aerosol organic functional group concentrations from marine and seabird sources at Ross Island, Antarctica, during AWARE
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DOI：
10.5194/acp-18-8571-2018
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发表时间：
2018-06-18
影响因子：
6.3
通讯作者：
Lubin, Dan
中科院分区：
文献类型：
--
作者：
Liu, Jun;Dedrick, Jeramy;Lubin, Dan
在南极洲，对天然气溶胶的有机成分的观测很少，这限制了我们对天然气溶胶及其与该地区云层的季节和空间格局的联系的理解。2015年11月至2016年12月，ARM西南极辐射实验（AWARE）测量了罗斯岛南端麦默多站附近的亚微米气溶胶特性。亚微米有机质（OM），粒子数，云凝结核浓度在夏季高于其他季节。测量包括一系列可能反映当地人为排放和自然背景来源的成分和浓度。我们通过分离天然因子和局部燃烧因子来分离天然有机组分。天然有机质夏季比冬季高150倍。当地人为排放不吸湿，对云凝结核浓度的贡献很小。自然源，包括海洋浪花和海鸟排放贡献了56%的OM在夏季，但在冬季只有3%。天然有机质具有高羟基分数（55%），6%烷烃和6%胺基质量，与海洋有机组成一致。此外，傅里叶变换红外光谱（FTIR）分析表明，大气中有机气溶胶的天然来源具有酰胺基吸收特征，可能来自海鸟种群。羧酸基团的贡献在夏季高，与自然来源，可能形成的二次反应。
Observations of the organic components of the natural aerosol are scarce in Antarctica, which limits our understanding of natural aerosols and their connection to seasonal and spatial patterns of cloud albedo in the region. From November 2015 to December 2016, the ARM West Antarctic Radiation Experiment (AWARE) measured submicron aerosol properties near McMurdo Station at the southern tip of Ross Island. Submicron organic mass (OM), particle number, and cloud condensation nuclei concentrations were higher in summer than other seasons. The measurements included a range of compositions and concentrations that likely reflected both local anthropogenic emissions and natural background sources. We isolated the natural organic components by separating a natural factor and a local combustion factor. The natural OM was 150 times higher in summer than in winter. The local anthropogenic emissions were not hygroscopic and had little contribution to the CCN concentrations. Natural sources that included marine sea spray and seabird emissions contributed 56 % OM in summer but only 3 % in winter. The natural OM had high hydroxyl group fraction (55 %), 6 % alkane, and 6 % amine group mass, consistent with marine organic composition. In addition, the Fourier transform infrared (FTIR) spectra showed the natural sources of organic aerosol were characterized by amide group absorption, which may be from seabird populations. Carboxylic acid group contributions were high in summer and associated with natural sources, likely forming by secondary reactions.