Atmospheric Chemistry and Physics the Isotopic Fingerprint of the Pre-industrial and the Anthropogenic N 2 O Source
Atmospheric Chemistry and Physics the Isotopic Fingerprint of the Pre-industrial and the Anthropogenic N 2 O Source
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发表时间：
2003
影响因子：
4.6
通讯作者：
T. Röckmann;J. Kaiser;C. Brenninkmeijer
中科院分区：
文献类型：
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作者：
T. Röckmann;J. Kaiser;C. Brenninkmeijer
我们进行了高精度测量的18o和位置依赖于15n同位素组成的二氧化氮从南极大气样品。通过将这些数据与大气扩散模型的模拟结果进行比较，我们重建了前工业时代以来氮氧同位素特征的时间演变。大气中氮氧的重同位素含量目前正以1 δ 15 N的- 0.038‰yr - 1、2 δ 15 N的- 0.046‰yr - 1和δ 18 O的- 0.025‰yr - 1的速率下降。自工业化前以来，估计1 δ 15 N的总下降量约为- 1.8‰。2 δ 15 N为−2.2‰，δ 18 O为−1.2‰。利用这些趋势和最近的平流层测量进行的同位素收支计算，可以用同位素方法表征当前和工业化前全球平均氮氧源，以及自工业化前时代以来导致全球氮氧增加的额外氮氧排放。仅地表枯竭源的通量增加不足以解释推断的时间同位素变化。此外，与工业化前的值相比，计算出的全球平均氮氧源特征今天明显枯竭，这与最近土壤排放测量的结果一致。
We have performed high-precision measurements of the 18 O and position dependent 15 N isotopic composition of N 2 O from Antarctic firn air samples. By comparing these data to simulations carried out with a firn air diffusion model, we have reconstructed the temporal evolution of the N 2 O isotope signatures since pre-industrial times. The heavy isotope content of atmospheric N 2 O is presently decreasing for all signatures at rates of about −0.038‰ yr −1 for 1 δ 15 N, −0.046‰ yr −1 for 2 δ 15 N and −0.025‰ yr −1 for δ 18 O. The total decrease since pre-industrial times is estimated to be about −1.8‰ for 1 δ 15 N, −2.2‰ for 2 δ 15 N and −1.2‰ for δ 18 O. Isotope budget calculations using these trends and recent stratospheric measurements allow to isotopically characterize the present and the pre-industrial global average N 2 O source, as well as the additional N 2 O emissions that have caused the global N 2 O increase since pre-industrial times. The increased fluxes from the depleted surface sources alone are insufficient to explain the inferred temporal isotope changes. In addition, the global average N 2 O source signature is calculated to be significantly depleted today relative to the pre-industrial value, in agreement with recent indications from soil emission measurements.