Study on atmospheric methane variations based on its carbon and hydrogen isotope measurements

在全球尺度上测量了大气CH_4浓度及其碳、氢同位素比值。将观测数据应用于全球CH_4循环模型，估算出生物源、化石源和生物质燃烧源的CH_4排放比分别为70%、16%和13%。此外，我们还利用从冰芯和冰芯中提取的空气样本揭示了近250年来CH_4浓度和这些同位素比值的变化。结果表明，自19世纪下半叶以来、20世纪初以来和近几十年来，生物源、化石源和生物质燃烧源的CH_4排放量分别呈快速增长趋势。

Atmospheric CH_4 concentration and its carbon and hydrogen isotopic ratios have been measured on the global scale. By applying the observed data to a global CH_4 cycle model, respective emission ratios of CH_4 from biogenic, fossil and biomass burning sources are estimated to be 70, 16 and 13%. In addition, we revealed variations of CH_4 concentration and these isotopic ratios for the last 250 years by using air samples extracted from firn and ice cores. As a result of the measurements, CH_4 emission from biogenic, fossil and biomass burning sources have increased rapidly since the latter half of 19 century, since the beginning of 20 century and for the last several decades, respectively.