1. Characterisation of methane sources in Lutjewad, The Netherlands, using quasi-continuous isotopic composition measurements
- Author
-
Menoud, M., van der Veen, C., Scheeren, Bert, Chen, Huilin, Szénási, Barbara, Morales, Randulph P., Pison, Isabelle, Bousquet, Philippe, Brunner, Dominik, Röckmann, Thomas, Sub Atmospheric physics and chemistry, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), 722479 National Aeronautics and Space Administration, NASA National Oceanic and Atmospheric Administration, NOAA Horizon 2020 Framework Programme, H2020 Department for Business, Energy and Industrial Strategy, UK Government, BEIS University of Bristol Commonwealth Scientific and Industrial Research Organisation, CSIRO China Meteorological Administration, CMA National Institute for Environmental Studies, NIES Shenyang Normal University, SNU, This work was supported by the ITN project Methane goes Mobile?Measurements and Modelling (MEMO2, CSIRO and BoM (Australia): FOEN grants to Empa (Switzerland), NILU (Norway), SNU (Korea), CMA (China), NIES (Japan), and Urbino University (Italy). We specially thank Bert Kers and Marcel de Vries at CIO for the technical support they provided during the measurements at Lutjewad., Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Sub Atmospheric physics and chemistry, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, and Isotope Research
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,lcsh:QC851-999 ,Atmospheric sciences ,in-situ measurements ,01 natural sciences ,7. Clean energy ,Methane ,chemistry.chemical_compound ,isotope ratio mass spectrometry ,in-situmeasurements ,Isotope-ratio mass spectrometry ,0105 earth and related environmental sciences ,[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,Thesaurus (information retrieval) ,methane ,source isotopic signatures ,Isotopic composition ,emission inventories ,Climate change mitigation ,chemistry ,13. Climate action ,Environmental science ,Spatial variability ,lcsh:Meteorology. Climatology - Abstract
Despite the importance of methane for climate change mitigation, uncertainties regarding the temporal and spatial variability of the emissions remain. Measurements of CH4 isotopic composition are used to partition the relative contributions of different emission sources. We report continuous isotopic measurements during 5 months at the Lutjewad tower (north of the Netherlands). Time-series of χ(CH4), δ13C-CH4, and δD-CH4 in ambient air were analysed using the Keeling plot method. Resulting source signatures ranged from −67.4 to −52.4‰ vs V-PDB and from −372 to −211‰ vs V-SMOW, for δ13C and δD respectively, indicating a prevalence of biogenic sources. Analysis of isotope and wind data indicated that (i) emissions from off-shore oil and gas platforms in the North Sea were not detected during this period, (ii) CH4 from fossil fuel related sources was usually advected from the east, pointing towards the Groningen gas field or regions further east in Germany. The results from two atmospheric transport models, CHIMERE and FLEXPART-COSMO, using the EDGAR v4.3.2 and TNO-MACC III emission inventories, reproduce χ(CH4) variations relatively well, but the isotope signatures were over-estimated by the model compared to the observations. Accounting for geographical variations of the δ13C signatures from fossil fuel emissions improved the model results significantly. The difference between model and measured isotopic signatures was larger when using TNO-MACC III compared to EDGAR v4.3.2 inventory. Uncertainties in the isotope signatures of the sources could explain a significant fraction of the discrepancy, thus a better source characterisation could further strengthen the use of isotopes in constraining emissions.
- Published
- 2020