气候变化领域集成服务门户(CCPortal): Sonar gas flux estimation by bubble insonification: Application to methane bubble flux from seep areas in the outer Laptev Sea

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DOI	10.5194/tc-11-1333-2017
	Sonar gas flux estimation by bubble insonification: Application to methane bubble flux from seep areas in the outer Laptev Sea
	Leifer I.; Chernykh D.; Shakhova N.; Semiletov I.
发表日期	2017
ISSN	19940416
卷号	11 期号:3
英文摘要	Sonar surveys provide an effective mechanism for mapping seabed methane flux emissions, with Arctic submerged permafrost seepage having great potential to significantly affect climate. We created in situ engineered bubble plumes from 40m depth with fluxes spanning 0.019 to 1.1 L s-1 to derive the in situ calibration curve (Q(σ)). These nonlinear curves related flux (Q) to sonar return (σ) for a multibeam echosounder (MBES) and a single-beam echosounder (SBES) for a range of depths. The analysis demonstrated significant multiple bubble acoustic scattering - precluding the use of a theoretical approach to derive Q(σ) from the product of the bubble σ(r) and the bubble size distribution where r is bubble radius. The bubble plume σ occurrence probability distribution function (ψ(σ)) with respect to Q found ψ(σ) for weak σ well described by a power law that likely correlated with small-bubble dispersion and was strongly depth dependent. ψ(σ) for strong σ was largely depth independent, consistent with bubble plume behavior where large bubbles in a plume remain in a focused core. ψ(σ) was bimodal for all but the weakest plumes. Q(σ) was applied to sonar observations of natural arctic Laptev Sea seepage after accounting for volumetric change with numerical bubble plume simulations. Simulations addressed different depths and gases between calibration and seep plumes. Total mass fluxes (Qm) were 5.56, 42.73, and 4.88 mmol s-1 for MBES data with good to reasonable agreement (4-37 %) between the SBES and MBES systems. The seepage flux occurrence probability distribution function (ψ(Q)) was bimodal, with weak ψ(Q) in each seep area well described by a power law, suggesting primarily minor bubble plumes. The seepage-mapped spatial patterns suggested subsurface geologic control attributing methane fluxes to the current state of subsea permafrost. © Author(s) 2017.
学科领域	bubble; echo sounder; estimation method; flux measurement; gas seepage; hydrocarbon seep; methane; permafrost; seafloor; theoretical study; Arctic Ocean; Laptev Sea
语种	英语
scopus关键词	bubble; echo sounder; estimation method; flux measurement; gas seepage; hydrocarbon seep; methane; permafrost; seafloor; theoretical study; Arctic Ocean; Laptev Sea
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119386
作者单位	Bubbleology Research International, Solvang, CA 93463, United States; Russian Academy of Science, Pacific Oceanological Institute, Vladivostok, Russian Federation; Tomsk Polytechnic University, Tomsk, Russian Federation; University Alaska Fairbanks, International Arctic Research Center, Fairbanks, AK 99775, United States
推荐引用方式 GB/T 7714	Leifer I.,Chernykh D.,Shakhova N.,et al. Sonar gas flux estimation by bubble insonification: Application to methane bubble flux from seep areas in the outer Laptev Sea[J],2017,11(3).
APA	Leifer I.,Chernykh D.,Shakhova N.,&Semiletov I..(2017).Sonar gas flux estimation by bubble insonification: Application to methane bubble flux from seep areas in the outer Laptev Sea.Cryosphere,11(3).
MLA	Leifer I.,et al."Sonar gas flux estimation by bubble insonification: Application to methane bubble flux from seep areas in the outer Laptev Sea".Cryosphere 11.3(2017).