Articles | Volume 15, issue 2
Atmos. Chem. Phys., 15, 715–736, 2015
Atmos. Chem. Phys., 15, 715–736, 2015

Research article 19 Jan 2015

Research article | 19 Jan 2015

Top-down estimates of European CH4 and N2O emissions based on four different inverse models

P. Bergamaschi1, M. Corazza1,a, U. Karstens2, M. Athanassiadou3, R. L. Thompson4,b, I. Pison4, A. J. Manning3, P. Bousquet4, A. Segers1,c, A. T. Vermeulen5,d, G. Janssens-Maenhout1, M. Schmidt4,e, M. Ramonet4, F. Meinhardt6, T. Aalto7, L. Haszpra8,9, J. Moncrieff10, M. E. Popa2,f, D. Lowry11, M. Steinbacher12, A. Jordan2, S. O'Doherty13, S. Piacentino14, and E. Dlugokencky15 P. Bergamaschi et al.
  • 1European Commission Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy
  • 2Max-Planck-Institute for Biogeochemistry, Jena, Germany
  • 3Met Office, Exeter, UK
  • 4Laboratoire des Sciences du Climat et de l' Environnement (LSCE), Gif sur Yvette, France
  • 5Energy Research Centre of the Netherlands (ECN), Petten, the Netherlands
  • 6Umweltbundesamt, Messstelle Schauinsland, Kirchzarten, Germany
  • 7Finnish Meteorological Institute (FMI), Helsinki, Finland
  • 8Hungarian Meteorological Service, Budapest, Hungary
  • 9Research Centre for Astronomy and Earth Sciences, Geodetic and Geophysical Institute, Sopron, Hungary
  • 10School of GeoSciences, The University of Edinburgh, Edinburgh, UK
  • 11Dept. of Earth Sciences, Royal Holloway, University of London (RHUL), Egham, UK
  • 12Swiss Federal Laboratories for Materials Science and Technology (Empa), Dübendorf, Switzerland
  • 13Atmospheric Chemistry Research Group, University of Bristol, Bristol, UK
  • 14Italian National Agency for New Technologies, Energy and Sustainable Development (ENEA), Rome, Italy
  • 15NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, CO, USA
  • anow at: Agenzia Regionale per la Protezione dell'Ambiente Ligure, Genoa, Italy
  • bnow at: Norwegian Institute for Air Research (NILU), Kjeller, Norway
  • cnow at: Netherlands Organisation for Applied Scientific Research (TNO), Utrecht, the Netherlands
  • dnow at: Dept. of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
  • enow at: Institut für Umweltphysik, Heidelberg, Germany
  • fnow at: Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, the Netherlands

Abstract. European CH4 and N2O emissions are estimated for 2006 and 2007 using four inverse modelling systems, based on different global and regional Eulerian and Lagrangian transport models. This ensemble approach is designed to provide more realistic estimates of the overall uncertainties in the derived emissions, which is particularly important for verifying bottom-up emission inventories.

We use continuous observations from 10 European stations (including 5 tall towers) for CH4 and 9 continuous stations for N2O, complemented by additional European and global discrete air sampling sites. The available observations mainly constrain CH4 and N2O emissions from north-western and eastern Europe. The inversions are strongly driven by the observations and the derived total emissions of larger countries show little dependence on the emission inventories used a priori.

Three inverse models yield 26–56% higher total CH4 emissions from north-western and eastern Europe compared to bottom-up emissions reported to the UNFCCC, while one model is close to the UNFCCC values. In contrast, the inverse modelling estimates of European N2O emissions are in general close to the UNFCCC values, with the overall range from all models being much smaller than the UNFCCC uncertainty range for most countries. Our analysis suggests that the reported uncertainties for CH4 emissions might be underestimated, while those for N2O emissions are likely overestimated.

Final-revised paper