Interannual and seasonal variability in atmospheric N2O
Interannual and seasonal variability in atmospheric N2O
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DOI：
10.1029/2006gb002755
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发表时间：
2007-09
影响因子：
5.2
通讯作者：
C. Nevison;N. Mahowald;R. Weiss;R. Prinn
中科院分区：
文献类型：
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作者：
C. Nevison;N. Mahowald;R. Weiss;R. Prinn
在上个世纪观测到的大气中N2 O的增加反映了人类对全球氮循环的大规模扰动。在过去十年中，对大气N2 O的高精度测量揭示了叠加在更突出的增长趋势上的年际变化（IAV）的微妙信号。人为来源驱动的N2 O的潜在增长，但可能过于单调，解释大多数观察到的IAV。大气中N2 O的季节性和年际变化的原因进行了探讨的基础上比较1993-2004年的大气传输模拟N2 O在五个站的高级全球大气气体实验（AGAGE）的观测。补充示踪剂氯氟烃（CFCs）11和12和SF6也进行了检查。该模型模拟不包括平流层汇，因此隔离了地面源和对流层传输的影响。模型和观测结果都产生了物种间季节和年际变化的相关性，但只有在少数情况下，模型和观测到的变化相互相关。结果表明，对流层运输大大有助于观测到的变化，特别是在萨摩亚站。然而，观测到的变率的某些特征并没有被模式模拟所解释，似乎更符合平流层的影响。在梅斯头，爱尔兰，N2 O和CFC的增长率异常弱相关的IAV在极地冬季平流层温度较低，平均纬向平流层环流的强度代理。N2 O自然来源的季节和年际变化也可能有助于观察到的大气N2 O的变化。
The increase in atmospheric N2O observed over the last century reflects large‐scale human perturbations to the global nitrogen cycle. High‐precision measurements of atmospheric N2O over the last decade reveal subtle signals of interannual variability (IAV) superimposed upon the more prominent growth trend. Anthropogenic sources drive the underlying growth in N2O, but are probably too monotonic to explain most of the observed IAV. The causes of both seasonal and interannual variability in atmospheric N2O are explored on the basis of comparisons of a 1993–2004 atmospheric transport simulation to observations of N2O at five stations of the Advanced Global Atmospheric Gases Experiment (AGAGE). The complementary tracers chlorofluorocarbons (CFCs) 11 and 12 and SF6 also are examined. The model simulation does not include a stratospheric sink and thus isolates the effects of surface sources and tropospheric transport. Both model and observations yield correlations in seasonal and interannual variability among species, but only in a few cases are model and observed variability correlated to each other. The results suggest that tropospheric transport contributes substantially to observed variability, especially at Samoa station. However, some features of observed variability are not explained by the model simulation and appear more consistent with a stratospheric influence. At Mace Head, Ireland, N2O and CFC growth rate anomalies are weakly correlated to IAV in polar winter lower stratospheric temperature, a proxy for the strength of the mean meridional stratospheric circulation. Seasonal and interannual variability in the natural sources of N2O may also contribute to observed variability in atmospheric N2O.