Source partitioning of atmospheric methane using stable carbon isotope measurements in the Reuss Valley, Switzerland.
Isotopes Environ Health Stud
; 55(1): 1-24, 2019 Mar.
Article
em En
| MEDLINE
| ID: mdl-30626219
ABSTRACT
Measurements of methane ( CH4 ) mole fractions and δ13 C-CH4 that resolve the diel cycle in the agriculturally dominated Reuss Valley, Switzerland, were used to quantify the contributions of different CH4 sources to the atmospheric CH4 source mix. Both a nocturnal (NBL) and a diurnal convective boundary layer (CBL) approach were employed. A diel course of CH4 mole fractions was found with a daytime minimum (background around 1900 ppb) and a nocturnal maximum (up to 3500 ppb). The δ13 C value in CH4 only showed small variations during the day (9-21 hours CET, -45.0±0.2 mean±SE ) when the atmosphere was well mixed, but decreased by -4.8±0.1 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 CH4 sink, dominated by tropospheric OH oxidation and only to a minor extend by soil surface uptake, was quantified at roughly 4% of local emissions.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Isótopos de Carbono
/
Poluentes Atmosféricos
/
Metano
País/Região como assunto:
Europa
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article