Gases in Firn Air and Shallow Ice at the Proposed WAIS Drilling Site

These data are trace gas measurements of air extracted from ice core samples from the West Antarctic Ice Sheet Divide A core (WAIS-D 05A). This core was dry-drilled at the WAIS site during the 2005-2006 field season. A total of 57 ice core samples were analyzed for nine trace gas species: ethane (C2H6), propane (C3H8), n-butane (n-C4H10), carbonyl sulfide (COS), carbon disulfide (CS2), methyl chloride (CH3Cl), methyl bromide (CH3Br), acetonitrile (CH3CN), and chlorofluorocarbon-12 (CFC-12). The analyses were conducted in a gas chromatography/mass spectrometry system at the University of California, Irvine. Details of the ice extraction and analytical methods can be found in Aydin et al., 2007.

The data in this file are currently unpublished and should be considered preliminary. Mixing ratios could reflect the impact of analytical or sampling artifacts in addition to real temporal variations in atmospheric levels of these trace gases. Based on prior studies (Aydin et al., 2008; Saltzman et al., 2009; Williams et al., 2007), it is expected that Antarctic ice cores in general preserve a real atmospheric record of CH3Cl, CH3Br, COS, CS2, and CFC-12. However, there are no prior published ice core records for any of the other compounds reported here. It is not recommended that the light alkane and CH3CN data be interpreted as paleo-atmospheric gas records.