ECN publication
Validation of methane source strengths
Published by: Publication date:
ECN 1995
ECN report number: Document type:
ECN-C--95-034 ECN publication
Number of pages: Full text:
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The results of ECN-research on methane emissions in NW-Europe, carriedout between January 1990 and March 1995, are summarized. Methane concentrations were monitored at the 200 m meteorological tower at Cabauw in the centre of the Netherlands and near Amsterdam (Durgerdam), also Netherlands. Isotope analysis in methane was carried out in order to reveal methane source types at Cabauw. Methane formation, transport and emissions by landfills was studied by isotope analysis. From the Cabauw methane record, methane emissions for NW-Europe have been deduced by trajectory overlay analysis and transport modelling. It is demonstrated that the calculated emissions compare quite well with national emission inventories if the trajectory density is high. This was the case for the United Kingdom, Belgium and The Netherlands. A large difference with the national inventory was observed for Germany. Also, results are given of methane concentrations at Cabauw predicted by transport modelling on the basis of a provisional methane emission inventory for NW-Europe developed at ECN. Satisfactory agreement is obtained between the predicted and the measured methane concentrations for a case study for April 1993. Transport modelling was used to determine "1"4CH4 emissions by Pressurized Water Reactors (PWRs) in NW-Europe. The modelling indicated that the "1"4C-methane emissions by PWRs are probably higher by a factor of 1.5#+#0.4 than published values. This larger amount of "1"4C from PWR must be diluted with more fossil methane in order to derive the global "1"4C- methane budget. From the monitoring station near Amsterdam (Durgerdam) methane emission for this urban area has been calculated based on a half-year continuous methane record. The estimate amounts to 2-20 kton.yr"-"1. Based on delta"13C-isotope analysis of methane at 4 representative landfill sites it was calculated that the oxidation efficiency in the top-soil cover is in the order of 10-46%. A tunable diode laser system has been installed for determination of ambient concentrations of methane. This system allows the determination of fluxes of methane sources by eddy correlation principle or plume dispersion measurements.

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