Articles | Volume 10, issue 21
Atmos. Chem. Phys., 10, 10305–10320, 2010
Atmos. Chem. Phys., 10, 10305–10320, 2010

  04 Nov 2010

04 Nov 2010

History of atmospheric SF6 from 1973 to 2008

M. Rigby1, J. Mühle2, B. R. Miller3, R. G. Prinn1, P. B. Krummel4, L. P. Steele4, P. J. Fraser4, P. K. Salameh2, C. M. Harth2, R. F. Weiss2, B. R. Greally5, S. O'Doherty5, P. G. Simmonds5, M. K. Vollmer6, S. Reimann6, J. Kim7, K.-R. Kim7,8, H. J. Wang9, J. G. J. Olivier10, E. J. Dlugokencky11, G. S. Dutton11, B. D. Hall11, and J. W. Elkins11 M. Rigby et al.
  • 1Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
  • 2Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA, USA
  • 3Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
  • 4Centre for Australian Weather and Climate Research, CSIRO Marine and Atmospheric Research, Aspendale, Victoria, Australia
  • 5School of Chemistry, University of Bristol, Bristol, UK
  • 6Empa, Swiss Federal Laboratories for Materials Testing and Research, Switzerland
  • 7School of Earth and Environmental Sciences, Seoul National University, South Korea
  • 8Research Institute of Oceanography, Seoul National University, South Korea
  • 9School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
  • 10Netherlands Environmental Assessment Agency (PBL), Bilthoven, The Netherlands
  • 11Earth System Research Laboratory, NOAA, Boulder, CO, USA

Abstract. We present atmospheric sulfur hexafluoride (SF6) mole fractions and emissions estimates from the 1970s to 2008. Measurements were made of archived air samples starting from 1973 in the Northern Hemisphere and from 1978 in the Southern Hemisphere, using the Advanced Global Atmospheric Gases Experiment (AGAGE) gas chromatographic-mass spectrometric (GC-MS) systems. These measurements were combined with modern high-frequency GC-MS and GC-electron capture detection (ECD) data from AGAGE monitoring sites, to produce a unique 35-year atmospheric record of this potent greenhouse gas. Atmospheric mole fractions were found to have increased by more than an order of magnitude between 1973 and 2008. The 2008 growth rate was the highest recorded, at 0.29 ± 0.02 pmolmol−1 yr−1. A three-dimensional chemical transport model and a minimum variance Bayesian inverse method was used to estimate annual emission rates using the measurements, with a priori estimates from the Emissions Database for Global Atmospheric Research (EDGAR, version 4). Consistent with the mole fraction growth rate maximum, global emissions during 2008 were also the highest in the 1973–2008 period, reaching 7.4 ± 0.6 Gg yr−1 (1-σ uncertainties) and surpassing the previous maximum in 1995. The 2008 values follow an increase in emissions of 48 ± 20% since 2001. A second global inversion which also incorporated National Oceanic and Atmospheric Administration (NOAA) flask measurements and in situ monitoring site data agreed well with the emissions derived using AGAGE measurements alone. By estimating continent-scale emissions using all available AGAGE and NOAA surface measurements covering the period 2004–2008, with no pollution filtering, we find that it is likely that much of the global emissions rise during this five-year period originated primarily from Asian developing countries that do not report detailed, annual emissions to the United Nations Framework Convention on Climate Change (UNFCCC). We also find it likely that SF6 emissions reported to the UNFCCC were underestimated between at least 2004 and 2005.

Final-revised paper