Articles | Volume 11, issue 7
Atmos. Chem. Phys., 11, 3375–3392, 2011
Atmos. Chem. Phys., 11, 3375–3392, 2011

Research article 11 Apr 2011

Research article | 11 Apr 2011

A new estimation of the recent tropospheric molecular hydrogen budget using atmospheric observations and variational inversion

C. E. Yver1, I. C. Pison1,2, A. Fortems-Cheiney1, M. Schmidt1, F. Chevallier1, M. Ramonet1, A. Jordan3, O. A. Søvde4, A. Engel5, R. E. Fisher6, D. Lowry6, E. G. Nisbet6, I. Levin7, S. Hammer7, J. Necki8, J. Bartyzel8, S. Reimann9, M. K. Vollmer9, M. Steinbacher9, T. Aalto10, M. Maione11, J. Arduini11, S. O'Doherty12, A. Grant12, W. T. Sturges13, G. L. Forster13, C. R. Lunder14, V. Privalov15, N. Paramonova15, A. Werner16, and P. Bousquet1,2 C. E. Yver et al.
  • 1Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Gif-sur-Yvette, France
  • 2Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Versailles, France
  • 3Max-Planck Institut für Biogeochemie, Jena, Germany
  • 4University of Oslo, Oslo, Norway
  • 5Institut für Meteorologie und Geophysik, Goethe-Universität Frankfurt, Frankfurt, Germany
  • 6Department of Earth Sciences, Royal Holloway, University of London, Egham, UK
  • 7Institut für Umweltphysik, Heidelberg Universität, Heidelberg, Germany
  • 8Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, Krakow, Poland
  • 9Empa, Swiss Federal Institute for Materials Science and Technology, Laboratory for Air Pollution/Environmental Technology, Duebendorf, Switzerland
  • 10Finnish Meteorological Institute, Climate Change Research, Helsinki, Finland
  • 11Universitá degli Studi di Urbino, DiSBeF, Sezione di Scienze Chimiche, Urbino, Italy
  • 12School of Chemistry, University of Bristol, UK
  • 13School of Environmental Sciences, University of East Anglia, Norwich, UK
  • 14Norsk Institutt for Luftforskning, Kjeller, Norway
  • 15Voeikov Main Geophysical Observatory, St. Petersburg, Russia
  • 16Deutscher Wetterdienst, Meteorologisches Observatorium, Hohenpeissenberg, Germany

Abstract. This paper presents an analysis of the recent tropospheric molecular hydrogen (H2) budget with a particular focus on soil uptake and European surface emissions. A variational inversion scheme is combined with observations from the RAMCES and EUROHYDROS atmospheric networks, which include continuous measurements performed between mid-2006 and mid-2009. Net H2 surface flux, then deposition velocity and surface emissions and finally, deposition velocity, biomass burning, anthropogenic and N2 fixation-related emissions were simultaneously inverted in several scenarios. These scenarios have focused on the sensibility of the soil uptake value to different spatio-temporal distributions. The range of variations of these diverse inversion sets generate an estimate of the uncertainty for each term of the H2 budget. The net H2 flux per region (High Northern Hemisphere, Tropics and High Southern Hemisphere) varies between −8 and +8 Tg yr−1. The best inversion in terms of fit to the observations combines updated prior surface emissions and a soil deposition velocity map that is based on bottom-up and top-down estimations. Our estimate of global H2 soil uptake is −59±9 Tg yr−1. Forty per cent of this uptake is located in the High Northern Hemisphere and 55% is located in the Tropics. In terms of surface emissions, seasonality is mainly driven by biomass burning emissions. The inferred European anthropogenic emissions are consistent with independent H2 emissions estimated using a H2/CO mass ratio of 0.034 and CO emissions within the range of their respective uncertainties. Additional constraints, such as isotopic measurements would be needed to infer a more robust partition of H2 sources and sinks.

Final-revised paper