Emission ratio and isotopic signatures of molecular hydrogen emissions from tropical biomass burning
Item
Title (Dublin Core)
Emission ratio and isotopic signatures of molecular hydrogen emissions from tropical biomass burning
Description (Dublin Core)
In this study, we identify a biomass-burning signal in molecular hydrogen (H<sub>2</sub>) over the Amazonian tropical rainforest. To quantify this signal, we measure the mixing ratios of H<sub>2</sub> and several other species as well as the H<sub>2</sub> isotopic composition in air samples that were collected in the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) aircraft campaign during the dry season. We derive a relative H<sub>2</sub> emission ratio with respect to carbon monoxide (CO) of 0.31 ± 0.04 ppb ppb<sup>−1</sup> and an isotopic source signature of −280 ± 41‰ in the air masses influenced by tropical biomass burning. In order to retrieve a clear source signal that is not influenced by the soil uptake of H<sub>2</sub>, we exclude samples from the atmospheric boundary layer. This procedure is supported by data from a global chemistry transport model. The ΔH<sub>2</sub> / ΔCO emission ratio is significantly lower than some earlier estimates for the tropical rainforest. In addition, our results confirm the lower values of the previously conflicting estimates of the H<sub>2</sub> isotopic source signature from biomass burning. These values for the emission ratio and isotopic source signatures of H<sub>2</sub> from tropical biomass burning can be used in future bottom-up and top-down approaches aiming to constrain the strength of the biomass-burning source for H<sub>2</sub>. Hitherto, these two quantities relied only on combustion experiments or on statistical relations, since no direct signal had been obtained from in-situ observations.
Creator (Dublin Core)
Haumann, F. A.
Batenburg, A. M.
Pieterse, G.
Gerbig, C.
Krol, M. C.
Röckmann, T.
Date (Dublin Core)
2018-01-15
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-13-9401-2013
https://acp.copernicus.org/articles/13/9401/2013/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
