Reconstruction of Northern Hemisphere 1950-2010 atmospheric non-methane hydrocarbons
Reconstruction of Northern Hemisphere 1950-2010 atmospheric non-methane hydrocarbons
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DOI：
10.5194/acp-14-1463-2014
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发表时间：
2014-01-01
影响因子：
6.3
通讯作者：
Tans, P.
中科院分区：
文献类型：
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作者：
Helmig, D.;Petrenko, V.;Tans, P.
短链非甲烷烃（NMHC）主要通过人为过程排放到大气中。最近的研究指出，大气中NMHC乙烷的摩尔分数与大气中甲烷的增长率之间存在着密切的联系。因此，大气NMHC是跟踪人为排放、光化学臭氧产生和温室气体变化的有价值的指标。本研究对1950-2010年北半球大气C-2-C-5 NMHC乙烷、丙烷、i-丁烷、正丁烷、i-戊烷和正戊烷进行了研究，方法是：(a)利用2008年和2009年在北格陵兰Eemian冰钻探（NEEM）场地的三个钻孔提取的大气中微量气体的摩尔分数，并应用最先进的微量气体在firn中的输送模型，重建这些微量气体的大气摩尔分数；(b)考虑NOAA全球监测部门（GMD）合作空气采样网络内五个北极站点8年的NMHC环境监测数据。结果表明，这些NMHC在1950年后增加了40-120%，在1980年左右达到峰值（乙烷除外，其峰值大约早于10年），此后急剧下降，现在回到接近1950年的水平。与C-3-C-5 NMHC相比，乙烷的峰值时间更早，这表明不同的过程和排放减缓措施促成了这些NMHC的下降。60年的记录还表明，异丁烷/正丁烷和异丁烷/正戊烷的异构体比值显著增加。将重建的NMHC历史数据与1950 - 2000年挥发性有机化合物（VOC）排放数据和其他最近发表的太平洋环境空气样带数据的乙烷趋势分析进行比较，结果表明：(a)与北美和西欧排放数据比与北半球总排放数据更吻合；(b)与其他格陵兰岛陆地空气数据重建的NMHC历史数据比与太平洋地区趋势更吻合。这些分析强调，对于NMHC，其大气寿命约为
The short-chain non-methane hydrocarbons (NMHC) are mostly emitted into the atmosphere by anthropogenic processes. Recent studies have pointed out a tight linkage between the atmospheric mole fractions of the NMHC ethane and the atmospheric growth rate of methane. Consequently, atmospheric NMHC are valuable indicators for tracking changes in anthropogenic emissions, photochemical ozone production, and greenhouse gases. This study investigates the 1950-2010 Northern Hemisphere atmospheric C-2-C-5 NMHC ethane, propane, i-butane, n-butane, i-pentane, and n-pentane by (a) reconstructing atmospheric mole fractions of these trace gases using firn air extracted from three boreholes in 2008 and 2009 at the North Greenland Eemian Ice Drilling (NEEM) site and applying state-of-the-art models of trace gas transport in firn, and by (b) considering eight years of ambient NMHC monitoring data from five Arctic sites within the NOAA Global Monitoring Division (GMD) Cooperative Air Sampling Network. Results indicate that these NMHC increased by similar to 40-120% after 1950, peaked around 1980 (with the exception of ethane, which peaked approximately 10 yr earlier), and have since dramatically decreased to be now back close to 1950 levels. The earlier peak time of ethane vs. the C-3-C-5 NMHC suggests that different processes and emissions mitigation measures contributed to the decline in these NMHC. The 60 yr record also illustrates notable increases in the ratios of the isomeric iso-/n-butane and iso-/n-pentane ratios. Comparison of the reconstructed NMHC histories with 19502000 volatile organic compounds (VOC) emissions data and with other recently published ethane trend analyses from ambient air Pacific transect data showed (a) better agreement with North America and Western Europe emissions than with total Northern Hemisphere emissions data, and (b) better agreement with other Greenland firn air data NMHC history reconstructions than with the Pacific region trends. These analyses emphasize that for NMHC, having atmospheric lifetimes on the order of