Accelerating growth of HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) in the atmosphere

J. C. Laube (1) , Patricia Martinerie (2) , Emmanuel Witrant (3) , T. Blunier (4) , J. Schwander (5) , C.-A.-M. Brenninkmeijer (6) , T.J. Schuck (6) , M. Bolder (7) , T. Röckmann (7) , C. van Der Veen (7) , H. Bönisch (8) , A. Engel (9) , G.P. Mills (1) , M.J. Newland (1) , D. E. Oram (1) , C.E. Reeves (1) , W. T. Sturges (1)

1 School of Environmental Sciences [Norwich]
2 LGGE - Laboratoire de glaciologie et géophysique de l'environnement
3 GIPSA-SLR - GIPSA - Systèmes linéaires et robustesse
4 Centre for Ice and Climate [Copenhagen]
5 CEP - Climate and Environmental Physics [Bern]
6 MPIC - Max Planck Institute for Chemistry
7 IMAU - Institute for Marine and Atmospheric Research [Utrecht]
8 Institute for Atmosphere and Environment
9 Institut für Physik

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.

Domaines: Glaciologie

J. C. Laube, Patricia Martinerie, Emmanuel Witrant, T. Blunier, J. Schwander, et al.. Accelerating growth of HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) in the atmosphere. Atmospheric Chemistry and Physics, 2010, 10 (13), pp.5903-5910. ⟨10.5194/acp-10-5903-2010⟩. ⟨insu-00554357⟩