Atmospheric nitrous oxide observations above the oceanic surface during CHIN ARE-18

摘要

The gas samples in the marine boundary layer were collected from the track for research ship Xuelong during the 18th Chinese Antarctic Research Expedition (CHINARE-18) and nitrous oxide measurements were made by HP5890ECD-GC in the laboratory. The results represent the shipboard N_2O data set obtained within the lower troposphere with the average concentration of (313. 5 ± 2.6)nL·L~(-1) from 31°N to 69°S. The results showed a latitudinally weighted, mean interhemispheric difference of 0.61 nL·L~(-1). The latitudinal distribution of atmospheric N_2O concentration was analyzed from northern midlatitudes to Southern Ocean around the Antarctic continent and it was showed that N_2O concentration in the current confluences was higher than that in other oceanic areas. This indicated that strong N_2O emissions occurred there. The longitudinal distribution of N_2O concentrations in the Southern Ocean also showed similar situation. According to the interhemispheric difference of atmospheric N_2O concentrations and the two-box model, we estimated that 2/5 of the global flux of N_2O into the atmosphere is derived from the sources in the southern hemisphere.