The D/H content of methane emitted from biomass burning
The D/H content of methane emitted from biomass burning
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生物质燃烧排放甲烷的D/H含量
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
W. Hao
中科院分区：
文献类型：
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作者：
A. Snover;P. Quay;W. Hao
使用从大规模实验室燃烧实验中收集的烟雾样品以及巴西亚马逊地区原始森林和牧场燃烧的典型火灾中收集的烟雾样品测量了生物质燃烧排放的甲烷的D/H含量。在实验室实验中，美国黄松针叶燃烧释放的甲烷的平均δD（δ DCH 4（bb））为−233 ± 2‰。在巴西的火灾中，δ DCH 4（bb）为−210 ± 16‰。测量的燃料生物质的D/H范围从−59到−125‰，表明在燃烧过程中有显著的氢同位素分馏（H2 O2）。在实验室实验中，CO2 DBURN（=（D/H）CH 4/（D/H）Biomass-1）1000 = −124‰，在实地研究中，CO2 DBURN的范围为−130至−180‰。这些结果与δ 13 C的结果形成对比，δ 13 C在燃烧过程中没有分馏，与早期的研究一致。这里介绍的测量结果表明，在全球范围内，生物质燃烧排放的CH 4的δD存在一个相对较窄的范围，δD是大气CH 4的独立示踪剂。结合δ DCH 4（bb）≈-210 ‰与主要CH 4源的强度和δD的文献值，我们估计全球CH 4源的δD为-283 ± 13‰。这一结果提供了一个约束的D/H动力学同位素效应与大气中的羟基自由基去除大气中的CH 4。
The D/H content of methane emitted from biomass burning was measured using samples of smoke collected from large‐scale laboratory combustion experiments and from fires typical of slash burning of primary forest and of pasture burning in the Brazilian Amazon. In laboratory experiments, the mean δD of methane emitted from Pinus ponderosa needle combustion (δDCH4(bb)) was −233 ± 2‰. In Brazilian fires, δDCH4(bb) was −210 ± 16‰. The measured D/H of the fuel biomass ranged from −59 to −125‰ and indicated a significant hydrogen isotope fractionation (ϵDBURN) during combustion. For the laboratory experiments, ϵDBURN (=(D/H)CH4/(D/H)Biomass‐l)1000 = −124‰ and in the field studies, ϵDBURN ranged from −130 to −180‰. These results contrast those for δ13C which showed no fractionation during combustion, consistent with earlier studies. The measurements presented here suggest that a relatively narrow range exists for the δD of CH4 emitted from biomass burning on a global scale and that δD is an independent tracer for atmospheric CH4. Combining δDCH4(bb) ≈‐210‰ with literature values for the strength and δD of the major CH4 sources, we estimate a δD for the global CH4 source of ‐283 ± 13‰. This result provides a constraint for the D/H kinetic isotope effect associated with removal of atmospheric CH4 by atmospheric hydroxyl radicals.