title: Spatial variability of methane: attributing atmospheric concentrations to emissions.
abstract: Atmospheric methane concentrations were quantified along transects in Switzerland, using a mobile laser spectrometer combined with a GPS, to identify their spatio-temporal patterns and their controlling factors. Based on these measurements in complex terrain dominated by agriculture, three main factors were found to be responsible for the diurnal and regional patterns of atmospheric methane: (1) magnitude and distribution of methane sources within the region, (2) efficiency of vertical exchange, and (3) local wind patterns within the complex topography. An autocorrelation analysis of measured methane concentrations showed that nighttime measurements close to the ground provide information about regional sources (up to 8.3 km), while daytime measurements only carry information about sources located up to 240 m away in the upwind fetch. Compared to daytime concentrations, nighttime methane concentrations do also better reflect emissions obtained from a spatially explicit methane emission inventory and allowed the investigation of inconsistencies in this emission inventory.
authors.affiliation: ETH Zürich, Institute of Agricultural Sciences, Universitätstrasse 2, 8092 Zürich, Switzerland. Electronic address: Ines.Bamberger@usys.ethz.ch.
authors.forename: I
authors.initials: I
authors.lastname: Bamberger
authors.affiliation: ETH Zürich, Institute of Agricultural Sciences, Universitätstrasse 2, 8092 Zürich, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Stieger
authors.affiliation: ETH Zürich, Institute of Agricultural Sciences, Universitätstrasse 2, 8092 Zürich, Switzerland.
authors.forename: N
authors.initials: N
authors.lastname: Buchmann
authors.affiliation: ETH Zürich, Institute of Agricultural Sciences, Universitätstrasse 2, 8092 Zürich, Switzerland.
authors.forename: W
authors.initials: W
authors.lastname: Eugster
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data; D001272:Atmosphere / Q000737:chemistry*; D004784:Environmental Monitoring; D008697:Methane / Q000032:analysis*; D013557:Switzerland; D014919:Wind
chemical_list: D000393:Air Pollutants; D008697:Methane
keywords: Atmospheric transport; Methane concentrations; Methane emission inventory; Spatio-temporal variability; Vertical mixing