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标题：Nitrate deposition and preservation in the snowpack along a traverse from coast to the ice sheet summit (Dome A) in East Antarctica
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作者：Guitao Shi ; Meredith G. Hastings ; Jinhai Yu 等
期刊名称：The Cryosphere
印刷版ISSN：1994-0416
电子版ISSN：1994-0424
出版年度：2018
卷号：12
期号：4
页码：1177-1194
DOI：10.5194/tc-12-1177-2018
出版社：Copernicus Publications
摘要：Antarctic ice core nitrate (NO3-) can provide a unique record of the atmospheric reactive nitrogen cycle. However, the factors influencing the deposition and preservation of NO3- at the ice sheet surface must first be understood. Therefore, an intensive program of snow and atmospheric sampling was made on a traverse from the coast to the ice sheet summit, Dome A, East Antarctica. Snow samples in this observation include 120 surface snow samples (top ∼ 3 cm), 20 snow pits with depths of 150 to 300 cm, and 6 crystal ice samples (the topmost needle-like layer on Dome A plateau). The main purpose of this investigation is to characterize the distribution pattern and preservation of NO3- concentrations in the snow in different environments. Results show that an increasing trend of NO3- concentrations with distance inland is present in surface snow, and NO3- is extremely enriched in the topmost crystal ice (with a maximum of 16.1 µeq L−1). NO3- concentration profiles for snow pits vary between coastal and inland sites. On the coast, the deposited NO3- was largely preserved, and the archived NO3- fluxes are dominated by snow accumulation. The relationship between the archived NO3- and snow accumulation rate can be depicted well by a linear model, suggesting a homogeneity of atmospheric NO3- levels. It is estimated that dry deposition contributes 27–44 % of the archived NO3- fluxes, and the dry deposition velocity and scavenging ratio for NO3- were relatively constant near the coast. Compared to the coast, the inland snow shows a relatively weak correlation between archived NO3- and snow accumulation, and the archived NO3- fluxes were more dependent on concentration. The relationship between NO3- and coexisting ions (nssSO42-, Na and Cl−) was also investigated, and the results show a correlation between nssSO42- (fine aerosol particles) and NO3- in surface snow, while the correlation between NO3- and Na (mainly associated with coarse aerosol particles) is not significant. In inland snow, there were no significant relationships found between NO3- and the coexisting ions, suggesting a dominant role of NO3- recycling in determining the concentrations.