Constraining N<sub>2</sub>O emissions since 1940 using firn air isotope measurements in both hemispheres

doi:10.5194/acp-17-4539-2017

GSTDTAP > 地球科学

DOI	10.5194/acp-17-4539-2017
	Constraining N₂O emissions since 1940 using firn air isotope measurements in both hemispheres
	Markella Prokopiou, Patricia Martinerie, Célia J. Sapart, Emmanuel Witrant, Guillaume Monteil, Kentaro Ishijima, Sophie Bernard, Jan Kaiser, Ingeborg Levin, Thomas Blunier, David Etheridge, Ed Dlugokencky, Roderik S. W. van de Wal, and Thomas Röckmann
	2017-04-05
发表期刊	Atmospheric Chemistry and Physics
出版年	2017
英文摘要	N₂O is currently the third most important anthropogenic greenhouse gas in terms of radiative forcing and its atmospheric mole fraction is rising steadily. To quantify the growth rate and its causes over the past decades, we performed a multi-site reconstruction of the atmospheric N₂O mole fraction and isotopic composition using new and previously published firn air data collected from Greenland and Antarctica in combination with a firn diffusion and densification model. The multi-site reconstruction showed that while the global mean N₂O mole fraction increased from (290 ± 1) nmol mol⁻¹ in 1940 to (322 ± 1) nmol mol⁻¹ in 2008, the isotopic composition of atmospheric N₂O decreased by (−2.2 ± 0.2) ‰ for δ¹⁵N^av, (−1.0 ± 0.3) ‰ for δ¹⁸O, (−1.3 ± 0.6) ‰ for δ¹⁵N^α, and (−2.8 ± 0.6) ‰ for δ¹⁵N^β over the same period. The detailed temporal evolution of the mole fraction and isotopic composition derived from the firn air model was then used in a two-box atmospheric model (comprising a stratospheric box and a tropospheric box) to infer changes in the isotopic source signature over time. The precise value of the source strength depends on the choice of the N₂O lifetime, which we choose to fix at 123 years. The average isotopic composition over the investigated period is δ¹⁵N^av =  (−7.6 ± 0.8) ‰ (vs. air-N₂), δ¹⁸O  =  (32.2 ± 0.2) ‰ (vs. Vienna Standard Mean Ocean Water – VSMOW) for δ¹⁸O, δ¹⁵N^α =  (−3.0 ± 1.9) ‰ and δ¹⁵N^β =  (−11.7 ± 2.3) ‰. δ¹⁵N^av, and δ¹⁵N^β show some temporal variability, while for the other signatures the error bars of the reconstruction are too large to retrieve reliable temporal changes. Possible processes that may explain trends in ¹⁵N are discussed. The ¹⁵N site preference ( = δ¹⁵N^α − δ¹⁵N^β) provides evidence of a shift in emissions from denitrification to nitrification, although the uncertainty envelopes are large.
领域	地球科学
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/287887
专题	地球科学
推荐引用方式 GB/T 7714	Markella Prokopiou, Patricia Martinerie, Célia J. Sapart, Emmanuel Witrant, Guillaume Monteil, Kentaro Ishijima, Sophie Bernard, Jan Kaiser, Ingeborg Levin, Thomas Blunier, David Etheridge, Ed Dlugokencky, Roderik S. W. van de Wal, and Thomas Röckmann. Constraining N₂O emissions since 1940 using firn air isotope measurements in both hemispheres[J]. Atmospheric Chemistry and Physics,2017.
APA	Markella Prokopiou, Patricia Martinerie, Célia J. Sapart, Emmanuel Witrant, Guillaume Monteil, Kentaro Ishijima, Sophie Bernard, Jan Kaiser, Ingeborg Levin, Thomas Blunier, David Etheridge, Ed Dlugokencky, Roderik S. W. van de Wal, and Thomas Röckmann.(2017).Constraining N₂O emissions since 1940 using firn air isotope measurements in both hemispheres.Atmospheric Chemistry and Physics.
MLA	Markella Prokopiou, Patricia Martinerie, Célia J. Sapart, Emmanuel Witrant, Guillaume Monteil, Kentaro Ishijima, Sophie Bernard, Jan Kaiser, Ingeborg Levin, Thomas Blunier, David Etheridge, Ed Dlugokencky, Roderik S. W. van de Wal, and Thomas Röckmann."Constraining N₂O emissions since 1940 using firn air isotope measurements in both hemispheres".Atmospheric Chemistry and Physics (2017).