>> Nitrate deposition and preservation in the snowpack along a traverse from coast to the ice sheet summit (Dome A) in East Antarctica
题名：Nitrate deposition and preservation in the snowpack along a traverse from coast to the ice sheet summit (Dome A) in East Antarctica
来源：The Cryosphere
发表年代：2018年
作者：Guitao Shi, Meredith G. Hastings, JinhaiYu, Tianming Ma, Zhengyi Hu, Chunlei An, Chuanjin Li, Hongmei Ma, Su Jiang, and Yuansheng Li
Abstract Antarctic ice core nitrate (NO− 3 ) can provide a unique record of the atmospheric reactive nitrogen cycle. However, the factors influencing the deposition and preservation of NO− 3 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 ∼3cm), 20 snow pits with depths of 150 to 300cm, 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 NO− 3 concentrations in the snow in different environments. Results show that an increasing trend of NO− 3 concentrations with distance inland is present in surface snow, and NO− 3 is extremely enriched in the topmost crystal ice (with a maximum of 16.1µeqL−1). NO− 3 concentration profiles for snowpitsvarybetweencoastalandinlandsites.Onthecoast, the deposited NO− 3 was largely preserved, and the archived NO− 3 fluxes are dominated by snow accumulation. The relationship between the archived NO− 3 and snow accumulation rate can be depicted well by a linear model, suggesting a homogeneity of atmospheric NO− 3 levels. It is estimated that dry deposition contributes 27–44% of the archived NO− 3 fluxes, and the dry deposition velocity and scavenging ratio for NO− 3 were relatively constant near the coast. Compared to the coast, the inland snow shows a relatively weak correlation between archived NO− 3 and snow accumulation, and the archived NO− 3 fluxes were more dependent on concentration. The relationship between NO− 3 and coexisting ions (nssSO2− 4 , Na+ and Cl−) was also investigated, and the results show a correlation between nssSO2− 4 (fine aerosol particles) and NO− 3 in surface snow, while the correlation between NO− 3 and Na+ (mainly associated with coarse aerosol particles)isnotsignificant.Ininlandsnow,therewerenosignificantrelationshipsfoundbetweenNO− 3 andthecoexisting ions, suggesting a dominant role of NO− 3 recycling in determining the concentrations.
