Investigation of post-depositional processing of nitrate in East Antarctic snow: isotopic constraints on photolytic loss, re-oxidation, and source inputs (SCI)

CORC > 寒区旱区环境与工程研究所 > 中科院寒区旱区环境与工程研究所（未分类） > 期刊论文

	Investigation of post-depositional processing of nitrate in East Antarctic snow: isotopic constraints on photolytic loss, re-oxidation, and source inputs (SCI)
	Shi G.; Buffen A. M.; Hastings M. G.; Li C.; Ma H.; Li Y.; Sun B.; An C.; Jiang S.
刊名	Atmospheric Chemistry and Physics
	2015
卷号	15 期号:16 页码:9435-9453
英文摘要	Snowpits along a traverse from coastal East Antarctica to the summit of the ice sheet (Dome Argus) are used to investigate the post-depositional processing of nitrate (NO3-) in snow. Seven snowpits from sites with accumulation rates between 24 and 172 kg m(-2) a(-1) were sampled to depths of 150 to 300 cm. At sites from the continental interior (low accumulation, < 55 kg m(-2) a(-1)), nitrate mass fraction is generally > 200 ng g(-1) in surface snow and decreases quickly with depth to < 50 ng g(-1). Considerably increasing values of delta N-15 of nitrate are also observed (16-461% vs. air N-2), particularly in the top 20 cm, which is consistent with predicted fractionation constants for the photolysis of nitrate. The delta O-18 of nitrate (17-84% vs. VSMOW (Vienna Standard Mean Ocean Water)), on the other hand, decreases with increasing delta N-15, suggestive of secondary formation of nitrate in situ (following photolysis) with a low delta O-18 source. Previous studies have suggested that delta N-15 and delta O-18 of nitrate at deeper snow depths should be predictable based upon an exponential change derived near the surface. At deeper depths sampled in this study, however, the relationship between nitrate mass fraction and delta O-18 changes, with increasing delta O-18 of nitrate observed between 100 and 200 cm. Predicting the impact of post-depositional loss, and therefore changes in the isotopes with depth, is highly sensitive to the depth interval over which an exponential change is assumed. In the snowpits collected closer to the coast (accu-mulation > 91 kg m(-2) a(-1)), there are no obvious trends detected with depth and instead seasonality in nitrate mass fraction and isotopic composition is found. In comparison to the interior sites, the coastal pits are lower in delta N-15 (-15-71 parts per thousand vs. air N-2) and higher in delta O-18 of nitrate (53-111 parts per thousand vs. VSMOW). The relationships found amongst mass fraction, delta N-15, delta O-18 and Delta O-17 (Delta O-17 = delta O-17-0.52 x delta O-18) of nitrate cannot be explained by local post-depositional processes alone, and are instead interpreted in the context of a primary atmospheric signal. Consistent with other Antarctic observational and modeling studies, the isotopic results are suggestive of an important influence of stratospheric ozone chemistry on nitrate formation during the cold season and a mix of tropospheric sources and chemistry during the warm season. Overall, the findings in this study speak to the sensitivity of nitrate isotopic composition to post-depositional processing and highlight the strength of combined use of the nitrogen and oxygen isotopes for a mechanistic understanding of this processing.
收录类别	SCI
语种	英语
内容类型	期刊论文
源URL	[http://ir.casnw.net/handle/362004/27692]
专题	寒区旱区环境与工程研究所_中科院寒区旱区环境与工程研究所（未分类）_期刊论文
推荐引用方式 GB/T 7714	Shi G.,Buffen A. M.,Hastings M. G.,et al. Investigation of post-depositional processing of nitrate in East Antarctic snow: isotopic constraints on photolytic loss, re-oxidation, and source inputs (SCI)[J]. Atmospheric Chemistry and Physics,2015,15(16):9435-9453.
APA	Shi G..,Buffen A. M..,Hastings M. G..,Li C..,Ma H..,...&Jiang S..(2015).Investigation of post-depositional processing of nitrate in East Antarctic snow: isotopic constraints on photolytic loss, re-oxidation, and source inputs (SCI).Atmospheric Chemistry and Physics,15(16),9435-9453.
MLA	Shi G.,et al."Investigation of post-depositional processing of nitrate in East Antarctic snow: isotopic constraints on photolytic loss, re-oxidation, and source inputs (SCI)".Atmospheric Chemistry and Physics 15.16(2015):9435-9453.