1School of Environmental Sciences, University of East Anglia, Norwich, UK
2Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), CNRS, Université Joseph Fourier-Grenoble, Grenoble, France
3Grenoble Image Parole Signal Automatique (GIPSA-lab), Université Joseph Fourier/CNRS, Grenoble, France
4Centre for Ice and Climate, University of Copenhagen, Copenhagen, Denmark
5Physics Institute, University of Berne, Bern, Switzerland
6Max Planck Institute for Chemistry, Air Chemistry Division, Mainz, Germany
7Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, The Netherlands
8Institute for Atmosphere and Environment, University of Frankfurt, Frankfurt, Germany
Received: 16 Mar 2010 – Discussion started: 24 Mar 2010
Abstract. We report the first measurements of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), a substitute for ozone depleting compounds, in air samples originating from remote regions of the atmosphere and present evidence for its accelerating growth. Observed mixing ratios ranged from below 0.01 ppt in deep firn air to 0.59 ppt in the current northern mid-latitudinal upper troposphere. Firn air samples collected in Greenland were used to reconstruct a history of atmospheric abundance. Year-on-year increases were deduced, with acceleration in the growth rate from 0.029 ppt per year in 2000 to 0.056 ppt per year in 2007. Upper tropospheric air samples provide evidence for a continuing growth until late 2009. Furthermore we calculated a stratospheric lifetime of 370 years from measurements of air samples collected on board high altitude aircraft and balloons. Emission estimates were determined from the reconstructed atmospheric trend and suggest that current "bottom-up" estimates of global emissions for 2005 are too high by a factor of three.
Revised: 16 Jun 2010 – Accepted: 30 Jun 2010 – Published: 02 Jul 2010
Laube, J. C., Martinerie, P., Witrant, E., Blunier, T., Schwander, J., Brenninkmeijer, C. A. M., Schuck, T. J., Bolder, M., Röckmann, T., van der Veen, C., Bönisch, H., Engel, A., Mills, G. P., Newland, M. J., Oram, D. E., Reeves, C. E., and Sturges, W. T.: Accelerating growth of HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) in the atmosphere, Atmos. Chem. Phys., 10, 5903-5910, doi:10.5194/acp-10-5903-2010, 2010.