The data file contains ethane, propane, and n-butane measurements in firn air from two Antarctic sites (South Pole and WAIS-D) and from Summit, Greenland. The WAIS-D and South Pole samples were collected in Dec-Jan of 05/06 and 08/09, respectively. The Summit firn was sampled in the summer of 2006. All analyses were conducted on a GC-MS system at University of California, Irvine (see Aydin et al., JGR, 2007 for details). All measurements and the associated uncertainties are reported as dry-air molar mixing ratios in part per trillion (ppt). The reported measurements for each sampling depth represent a mean of multiple measurements on more than one flask in most cases. We report 2 s.e. of the mean as the uncertainty. Ethane data were published by Aydin et al. (Nature, 2011).
The data can be used to study changes in ethane, propane, and n-butane levels in the polar atmosphere during the 20th century but requires a separate firn-air modeling effort for each site. The mean age of the firn air at any given depth varies from site to site, and data from similar depths are necessarily contemporaneous.