【摘要】 在中国第22次南极科学考察期间,用Tedlar气袋采集了"雪龙号"考察船航线上海洋边界层大气样品,在室内分析了样品中CH4浓度及其分子的δ13C值,结果表明:在28.5°N~40°S区域,海洋边界层大气CH4浓度波动较大,峰值较多,平均值为(2.97±1.51)×10-6,明显高于全球大气CH4的平均浓度(约1.8×10-6),这主要与该区域的航迹靠近陆地,受人为源的影响有关;在40°S~69.17°S航迹,远离人类活动区,洋面大气CH4的浓度较稳定,平均浓度值为(1.92±0.14)×10-6,接近于目前全球大气CH4平均浓度.航线上CH4分子的δ13C的变化范围为:-37.49‰~-24.87‰,平均为-34.5±3.0‰.在28.5°N~40°S区域,边界层大气中CH4分子的δ13C值较高且波动较大,表明洋面大气的CH4浓度受到来自富13C的化石燃料、生物质燃烧等人为源的强烈影响;在40°S~69.17°S区域,δ13C值较稳定.海洋边界层大气的CH4浓度分布与大气温度也存在相关性.更多还原

【Abstract】 During the 22nd Chinese Antarctic Research Expedition(CHINARE-22),air samples in the marine boundary layer were collected as the research ship Xuelong from Shanghai to Antarctica using Tedlar gas bags.The methane(CH4) concentration and its δ13C in these air samples were analyzed in the laboratory.In the latitudinal range of 28.5°N~40°S,the CH4 concentrations in the marine atmosphere showed a strong fluctuation with an average of(2.97±1.51)×10-6,evidently higher than the average level(about 1.8×10-6) for CH4 in the global atmosphere,suggesting that anthropogenic sources have a great impact on marine atmospheric CH4 concentrations since the track of the ship was very close to the land.In the remote latitudinal areas of 40°S~69.17°S,the CH4 concentrations in the marine atmosphere were very stable with an average of(1.92±0.14)×10-6(close to the global average of CH4 concentration).The δ13C of CH4 ranged from-37.49‰ to-24.87‰ with an average of-34.5±3.0‰.In the latitudinal range of 28.5°N~40°S,the δ13C of CH4 also showed higher values,suggesting that the major proportion of CH4 was from fossil fuel and biomass burning.In the range of 40°S~69.17°S,the δ13C of CH4 was very stable.A significant correlation exists between marine atmospheric CH4 concentration and air temperature.更多还原