春季中国近海海表大气中六氟化硫的分布特征

Distribution of sulfur hexafluoride in the China sea-shelf boundary layer in spring

基于2017年春季黄-东海航次,在我国南黄海和东海海域开展了海表大气中六氟化硫离散采样和测定工作。结果显示,观测期间,黄-东海海表大气中六氟化硫摩尔分数范围为(9.5~14.0)×10^(-12),平均值为(10.5±1.3)×10^(-12),总体呈近岸高,远岸低的分布特征。结合现场风速和风向数据及后向轨迹模拟计算分析可得,受短距离和低空陆源气团输送的主导影响,东海东北部和西南部六氟化硫摩尔分数较高。受长距离或来自太平洋地区气团输送的主导影响,南黄海和东海西北部及东南部海表大气六氟化硫摩尔分数较低且分布均匀。本研究所获数据和结论将有助于更深入准确地研究本海域其他大气成分的时空分布特征和调控机制。

The mole fraction of sulfur hexafluoride in the boundary layer of South Yellow Sea and East China Sea was observed based on discrete air samples collection and gas chromatography in spring of 2017. The mole fraction of sulfur hexafluoride ranged from 9. 5 × 10-12 to 14. 0 × 10-12,with an average value of（ 10. 5 ± 1. 3） × 10-12,and showed an significant variation with distance away from land. Combined the underway wind data and back trajectory simulations,the high mole fraction of sulfur hexafluoride in the boundary layer of northeast and southwest areas of East China Sea may influenced directly by land-sea air mass transport from Japan,Korea and southeast part of China,respectively,where the human activities was intensive. However,the low mole fraction of sulfur hexafluoride in the other areas may influence more by air masses transport from the open shelf seas and Pacific Ocean,respectively. This study would be beneficial to the further studies of the spatial-temporal distribution of other atmospheric compounds and their regulate mechanisms in the China sea-shelf boundary layer.