Triple isotope composition of oxygen in atmospheric water vapor
Triple isotope composition of oxygen in atmospheric water vapor
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DOI：
10.1029/2009gl041960
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发表时间：
2010-02
影响因子：
5.2
通讯作者：
R. Uemura;E. Barkan;O. Abe;B. Luz
中科院分区：
文献类型：
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作者：
R. Uemura;E. Barkan;O. Abe;B. Luz
最近，在大气水和冰芯中发现了过量的17 O（17 O-过量）。基于理论和实验，有人认为这种过量来自于海水蒸发到欠饱和空气中。然而，从来没有直接证明海洋蒸气中的这种过量。在这里，我们提出的第一次测量结果的δ 17 O和δ 18 O的蒸汽样品收集在南印度洋和南大洋。我们的数据表明，海洋蒸气中存在17 O-过量，并且17 O-过量与相对湿度之间存在明显的负相关性。因此，17 O-过量对于限制水文和气候模型中的海洋湿度是有用的。利用获得的17 O-过量值，我们估算了H218 O和H216 O在海洋上空空气中扩散的分馏因子（18αdiff）。18αdiff（1.008）的新估计值大于水文研究中广泛接受的值。
Recently, an excess of 17O (17O‐excess) has been demonstrated in meteoric water and ice cores. Based on theory and experiments, it has been suggested that this excess originates from evaporation of ocean water into under‐saturated air. However, there has never been direct demonstration of this excess in marine vapor. Here, we present results of the first measurements of δ17O and δ18O in vapor samples collected over the South Indian and the Southern Oceans. Our data show the existence of 17O‐excess in marine vapor and also clear negative correlation between 17O‐excess and relative humidity. Thus, 17O‐excess is useful for constraining oceanic humidity in hydrological and climatic models. Using the obtained values of 17O‐excess, we estimated the fractionation factor between H218O and H216O for diffusion in air above the ocean (18αdiff). The new estimation of 18αdiff (1.008) is larger than the widely accepted value in hydrological studies.