气候变化领域集成服务门户(CCPortal): Using ship-borne observations of methane isotopic ratio in the Arctic Ocean to understand methane sources in the Arctic

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DOI	10.5194/acp-20-3987-2020
	Using ship-borne observations of methane isotopic ratio in the Arctic Ocean to understand methane sources in the Arctic
	Berchet A.; Pison I.; M. Crill P.; Thornton B.; Bousquet P.; Thonat T.; Hocking T.; Thanwerdas J.; Paris J.-D.; Saunois M.
发表日期	2020
ISSN	1680-7316
起始页码	3987
结束页码	3998
卷号	20 期号:6
英文摘要	Characterizing methane sources in the Arctic remains challenging due to the remoteness, heterogeneity and variety of such emissions. In situ campaigns provide valuable datasets to reduce these uncertainties. Here we analyse data from the summer 2014 SWERUS-C3 campaign in the eastern Arctic Ocean, off the shore of Siberia and Alaska. Total concentrations of methane, as well as relative concentrations of 12CH4 and 13CH4, were measured continuously during this campaign for 35 d in July and August. Using a chemistry-transport model, we link observed concentrations and isotopic ratios to regional emissions and hemispheric transport structures. A simple inversion system helped constrain source signatures from wetlands in Siberia and Alaska, and oceanic sources, as well as the isotopic composition of lower-stratosphere air masses. The variation in the signature of lower-stratosphere air masses, due to strongly fractionating chemical reactions in the stratosphere, was suggested to explain a large share of the observed variability in isotopic ratios. These results point towards necessary efforts to better simulate large-scale transport and chemistry patterns to make relevant use of isotopic data in remote areas. It is also found that constant and homogeneous source signatures for each type of emission in a given region (mostly wetlands and oil and gas industry in our case at high latitudes) are not compatible with the strong synoptic isotopic signal observed in the Arctic. A regional gradient in source signatures is highlighted between Siberian and Alaskan wetlands, the latter having lighter signatures (more depleted in 13C). Finally, our results suggest that marine emissions of methane from Arctic continental-shelf sources are dominated by thermogenic-origin methane, with a secondary biogenic source as well. © 2020 EDP Sciences. All rights reserved.
语种	英语
scopus关键词	air mass; concentration (composition); emission; isotopic ratio; methane; stratosphere; Alaska; Arctic Ocean; Siberia; United States
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/247869
作者单位	Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ, IPSL, Gif-sur-Yvette, France; Department of Geological Sciences, Stockholm University, Stockholm, 10691, Sweden
推荐引用方式 GB/T 7714	Berchet A.,Pison I.,M. Crill P.,et al. Using ship-borne observations of methane isotopic ratio in the Arctic Ocean to understand methane sources in the Arctic[J],2020,20(6).
APA	Berchet A..,Pison I..,M. Crill P..,Thornton B..,Bousquet P..,...&Saunois M..(2020).Using ship-borne observations of methane isotopic ratio in the Arctic Ocean to understand methane sources in the Arctic.ATMOSPHERIC CHEMISTRY AND PHYSICS,20(6).
MLA	Berchet A.,et al."Using ship-borne observations of methane isotopic ratio in the Arctic Ocean to understand methane sources in the Arctic".ATMOSPHERIC CHEMISTRY AND PHYSICS 20.6(2020).