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
Received: 11 Mar 2014 – Discussion started: 16 Jun 2014
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.
Revised: 12 Nov 2014 – Accepted: 22 Nov 2014 – Published: 19 Jan 2015
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.
Bergamaschi, P., Corazza, M., Karstens, U., Athanassiadou, M., Thompson, R. L., Pison, I., Manning, A. J., Bousquet, P., Segers, A., Vermeulen, A. T., Janssens-Maenhout, G., Schmidt, M., Ramonet, M., Meinhardt, F., Aalto, T., Haszpra, L., Moncrieff, J., Popa, M. E., Lowry, D., Steinbacher, M., Jordan, A., O'Doherty, S., Piacentino, S., and Dlugokencky, E.: Top-down estimates of European CH4 and N2O emissions based on four different inverse models, Atmos. Chem. Phys., 15, 715-736, doi:10.5194/acp-15-715-2015, 2015.