ABSTRACT Measurements of methane () mole fractions and that resolve the diel cycle in the agriculturally dominated Reuss Valley, Switzerland, were used to quantify the contributions of different sources to the atmospheric source mix. Both a nocturnal (NBL) and a diurnal convective boundary layer (CBL) approach were employed. A diel course of mole fractions was found with a daytime minimum (background around 1900 ppb) and a nocturnal maximum (up to 3500 ppb). The C value in only showed small variations during the day (9–21 hours CET, ‰ ) when the atmosphere was well mixed, but decreased by ‰ during the night. Biogenic emissions dominated in both approaches (ranging from 60 to 94%), but non-biogenic sources were rather important (42.2% and 46.0% with CBL, 5.8% and 40% with NBL approach in 2011 and 2012, respectively, of total emissions). The sink, dominated by tropospheric OH oxidation and only to a minor extend by soil surface uptake, was quantified at roughly 4% of local emissions.

中文翻译：

---

在瑞士罗伊斯谷使用稳定碳同位素测量对大气甲烷进行源分配

摘要 在以农业为主的瑞士罗伊斯谷，甲烷 () 摩尔分数的测量和解决日循环的测量被用来量化不同来源对大气来源混合的贡献。采用了夜间 (NBL) 和昼夜对流边界层 (CBL) 方法。发现摩尔分数的变化过程具有白天最小值（背景约为 1900 ppb）和夜间最大值（高达 3500 ppb）。当大气混合良好时，C 值在白天（欧洲中部时间 9-21 小时，‰）仅显示出很小的变化，但在夜间下降了 ‰。生物源排放在两种方法中都占主导地位（从 60% 到 94%），但非生物源相当重要（2011 年和 2012 年，CBL 分别为 42.2% 和 46.0%，NBL 方法分别为 5.8% 和 40% ）。水槽，