Monitoring atmospheric nitrous oxide background concentrations at Zhongshan Station, east Antarctica.

At present, continuous observation data for atmospheric nitrous oxide (N 2 O) concentrations are still lacking, especially in east Antarctica. In this paper, nitrous oxide background concentrations were measured at Zhongshan Station (69°22′25″S, 76°22′14″E), east Antarctica during the period of 2008–2012, and their interannual and seasonal characteristics were analyzed and discussed. The mean N 2 O concentration was 321.9 nL/L with the range of 320.5–324.8 nL/L during the five years, and it has been increasing at a rate of 0.29% year − 1 . Atmospheric N 2 O concentrations showed a strong seasonal fluctuation during these five years. The concentrations appeared to follow a downtrend from spring to autumn, and then increased in winter. Generally the highest concentrations occurred in spring. This trend was very similar to that observed at other global observation sites. The overall N 2 O concentration at the selected global sites showed an increasing annual trend, and the mean N 2 O concentration in the Northern Hemisphere was slightly higher than that in the Southern Hemisphere. Our result could be representative of atmospheric N 2 O background levels at the global scale. This study provided valuable data for atmospheric N 2 O concentrations in east Antarctica, which is important to study on the relationships between N 2 O emissions and climate change. [ABSTRACT FROM AUTHOR]