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在中国第22次南极科学考察期间,采用Tedlar气袋采集了“雪龙号”考察船航线上洋面大气样品以及东南极米洛半岛近地面大气样品(采样时间分别为地方时上午10:00和夜间22:00),在室内通过带有全自动预GC浓缩接口(PreCon)的Thermo Finnigan MAT-253同位素质谱仪,对这些大气样品中N2O的同位素组成进行了高精度地测量;并分析了其δ15N与δ18O空间变化规律.上海-南极洋面大气N2O的δ15N与δ18O平均分别为(7.21±0.50)‰和(44.52±0.52)‰.由30°N往南极随着纬度的变化,δ15N(6.05‰～7.88‰)呈线性增加趋势,增加率为0.01‰/纬度,δ18O(43.05‰～48.78‰)则呈现较大的波动;且δ15N与气温、N2O浓度呈负相关,而与δ18O呈弱的正相关.东南极米洛半岛近地面大气N2O的δ15N与δ18O夏季变化趋势相一致,且二者呈显著正相关,而与N2O浓度呈显著负相关;不同地点大气N2O的δ15N与δ18O平均分别为(7.46±0.39)‰和(44.63±0.45)‰,略高于洋面大气N2O的δ15N与δ18O;而显著高于北半球低纬度大气N2O的δ15N与δ18O值.分析讨论了引起地面大气N2O的δ15N与δ18O空间变化的主导因素.提供了全球大区域洋面大气N2O的同位素资料,有助于定量评估全球与区域大气N2O的净收支.
During the 22nd Antarctic Scientific Expedition in China, Tedlar airbags were used to collect atmospheric data on the ocean surface of the “Snow Dragon” survey vessel and the near-surface atmospheric samples of the Mole Peninsula in the East Antarctica (sampling time was respectively 10 am : 00 and 22:00 at night), the isotopic composition of N2O in these atmospheric samples was measured indoors indoors using the Thermo Finnigan MAT-253 Isotope Mass Spectrometer with a fully automatic Preconcentration GC (PreCon) interface; and The spatial variations of δ15N and δ18O were analyzed.The δ15N and δ18O values of N2O over the Shanghai-Antarctic ocean surface were (7.21 ± 0.50) ‰ and (44.52 ± 0.52) ‰, respectively.With the latitude from 30 ° N to the Antarctic, δ15N (6.05 ‰ ~ 7.88 ‰) increased linearly with increasing rate of 0.01 ‰ / latitude and δ18O (43.05 ‰ ~ 48.78 ‰) showed a large fluctuation. δ15N was negatively correlated with temperature and N2O concentration, And there was a weak positive correlation between δ15N and δ18O in the near-surface atmosphere of the Mole Peninsula in the southeast Antarctica, but there was a significant negative correlation between N15 and δ18O The average values were (7.46 ± 0.39) ‰ and (44.63 ± 0.45 ) ‰, slightly higher than δ15N and δ18O of oceanic atmosphere N2O and significantly higher than δ15N and δ18O values of N2O in the northern latitudes of low latitudes.The dominant factors causing spatial variations of δ15N and δ18O of surface N2O were analyzed and discussed, The isotopic data of atmospheric N2O in the regional ocean surface contribute to a quantitative assessment of the net balance of N2O in the global and regional atmosphere.