Distinguishing summertime atmospheric production of nitrate across the East Antarctic Ice Sheet
Distinguishing summertime atmospheric production of nitrate across the East Antarctic Ice Sheet
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区分南极东部冰盖夏季大气中硝酸盐的产生
DOI：
10.1016/j.gca.2018.03.025
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发表时间：
2018-06
影响因子：
5
通讯作者：
Hastings M G
中科院分区：
文献类型：
--
作者：
Shi G;Buffen A M;Ma H;Hu Z;Sun B;Li C;Yu J;Ma T;An C;Jiang S;Li Y;Hastings M G
沿着从海岸到冰盖顶端(冰盖A)的导线收集的表面雪和大气样本被用来调查整个东南极夏季大气中硝酸盐(NO3-)的产生。地表雪中硝酸盐的δ15N和δ18O之间的强烈关系表明，内陆(沿海)地区硝酸盐的光解程度较大(较小)。硝酸盐氧同位素(δ18O和Δ17O)之间的线性相关性表明，各种氧化剂与NOx(NOx= NO + NO2)反应生成大气中的硝酸盐。在高原上，雪硝酸盐的同位素最好地解释了NOx的局部再氧化化学，可能既发生在凝聚相中，也可能发生在气相中。硝酸盐光解导致雪中硝酸盐的重新分布，高原雪是硝酸盐及其前体的净输出者。我们的结果表明，由于光解来自高原的雪源NOx是沿海雪中硝酸盐收支的重要输入(高达∼35%)，而来自中低纬地区的对流层输送占主导地位(∼65%)。雪硝酸盐的δ18O与Δ17O的线性关系表明，羟基自由基(OH)和臭氧(O3)在硝酸盐产生中起主导作用，尽管需要较高的Δ17O(O3)来解释观察到的结果。在整个南极洲，尽管环境非常干燥，但OH的氧同位素组成似乎以与水蒸气的交换为主。量化硝酸盐生产途径的最大不确定性之一是对大气氧化剂同位素组成的有限了解。
Surface snow and atmospheric samples collected along a traverse from the coast to the ice sheet summit (Dome A) are used to investigate summertime atmospheric production of nitrate (NO3–) across East Antarctica. The strong relationship observed between δ15N and δ18O of nitrate in the surface snow suggests a large (lesser) extent of nitrate photolysis in the interior (coastal) region. A linear correlation between the oxygen isotopes of nitrate (δ18O and Δ17O) indicates mixing of various oxidants that react with NOx(NOx= NO + NO2) to produce atmospheric nitrate. On the plateau, the isotopes of snow nitrate are best explained by local reoxidation chemistry of NOx, possibly occurring in both condensed and gas phases. Nitrate photolysis results in redistribution of snow nitrate, and the plateau snow is a net exporter of nitrate and its precursors. Our results suggest that while snow-sourced NOxfrom the plateau due to photolysis is a significant input to the nitrate budget in coastal snow (up to ∼35%), tropospheric transport from mid-low latitudes dominates (∼65%) coastal snow nitrate. The linear relationship of δ18O vs. Δ17O of the snow nitrate suggests a predominant role of hydroxyl radical (OH) and ozone (O3) in nitrate production, although a high Δ17O(O3) is required to explain the observations. Across Antarctica the oxygen isotope composition of OH appears to be dominated by exchange with water vapor, despite the very dry environment. One of the largest uncertainties in quantifying nitrate production pathways is the limited knowledge of atmospheric oxidant isotopic compositions.
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DOI：
10.1016/j.jphotochem.2006.06.039
发表时间：
2007-01
影响因子：
4.3
作者：
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通讯作者：
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DOI：
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发表时间：
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期刊：
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影响因子：
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DOI：
10.1080/03067310310001640393
发表时间：
2004-05
影响因子：
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作者：
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