Cape Grim air
Archiving of Cape Grim air
Regular collection of Cape Grim air in high pressure metal cylinders for the purpose of maintaining an archive of atmospheric composition has continued since 1978. A history of sampling events, protocols, techniques and re-construction of atmospheric trace gas records through 1995 has been given previously [Langenfelds et al., 1996 and references therein] and updated through 2008 [Lan-genfelds et al., 2011 and references therein].
Recent studies using Cape Grim Air Archive (CGAA) data include reconstruction of the atmospheric and emission histories of sulfur hexafluoride (SF6) [Rigby et al., 2010], hydrofluorocarbons (HFCs) HFC-365mfc, HFC-245fa, HFC-227ea, and HFC-236fa [Vollmer et al., 2011], and various perfluorocarbons (PFCs): n-C4F10, n-C5F12, n-C6F14, and n-C7F16 [Laube et al., 2012], C4F10, C5F12, C6F14, C7F16 and C8F18, [Ivy et al., 2012], CF3SF5, [Sturges et al., 2012] and octafluorocyclobutane (c-C4F8 or PFC-318) [Oram et al., 2012]. Measurements of the oxygen and intra-molecular nitrogen isotopic composition of nitrous oxide (N2O) were used to define trends and seasonal cy-cles of these species, thus constraining the contribution of different sources and sinks to atmospheric N2O varia-tions [Park et al., 2012]. CGAA data continue to be in-strumental in defining and assessing the chemical forcing of stratospheric ozone depletion [Montzka et al., 2011].