Abstract. There is a large variability in environmental conditions across the Antarctic ice sheet, and it is of significance to investigate the snow chemistry at as many locations as possible and over time, given that the ice sheet itself, and precipitation and deposition patterns and trends are changing. The China inland Antarctic traverse from coastal Zhongshan Station to the ice sheet summit (Dome A) covers a variety of environments, allowing for a vast collection of snow chemistry conditions across East Antarctica. Surface snow and snow pit samples were collected on this traverse during five campaigns, to comprehensively investigate the spatial and temporal variations in chemical ions (Cl−, NO3−, SO42−, Na+, NH4+, K+, Mg2+, and Ca2+) and the related controlling factors. Results show that spatial patterns of ions in surface snow are consistent among the five campaigns, with Cl−, Na+, K+, and Mg2+ decreasing rapidly with distance from the coast and NO3− showing an opposite pattern. No clear spatial trends in SO42−, NH4+ and Ca2+ were found. In the interior areas, an enrichment of Cl− versus Na+ with respect to seawater composition is ubiquitous as a result of the deposition of HCl, which can account for up to ~40 % of the total Cl− budget, while enriched K+ and Mg2+ are associated with terrestrial particle mass. Ca2+ and SO42− in surface snow are significantly enriched relative to Na+, related to terrestrial dust inputs and marine biogenic emissions, respectively. Snow NH4+ is mainly associated with marine biological activities, with higher concentrations in summer than in winter. On the coast, parts of the winter snow are characterized with a depletion of SO42− versus Na+, and a significant negative correlation between nssSO42− and Na+ was found, suggesting that sea salts originated from the sea ice. In the interior areas, the negative nssSO42− signal in winter snow resulted from inputs of sea salts being completely swamped by the contribution of marine biogenic emissions. Ternary plots of Cl−, Na+, and SO42− suggest that sea salt modification is generally negligible on the coast, while the degree of modification processes to sea salts is high in the interior areas, especially during the summertime. Ion flux assessment suggests an efficient transport of nssSO42− to at least as far inland as the ~2800 m contour line. The interannual variations in ion concentrations in surface snow on the traverse are likely linked to the changes in the Southern Indian Ocean low (SIOL) from year to year, and the deepening of the SIOL in summer tends to promote the transport of marine aerosols to Princess Elizabeth Land.
Supplementary material to "Nitrate deposition and preservation in the snowpack along a traverse
from coast to the ice sheet summit (Dome A) in East Antarctica"