O2/N2/Ar ratios, and the isotopic composition of O2 and N2, in firn air from the Megadunes site, Antarctica

In a program led by Jeffrey Severinghaus, Scripps Institiution of Oceanography,
firn air samples were collected at the Megadunes site, Antarctica. This site
is marked by actively migrating snow dunes and very large ice crystals develop
on the windward side. Severinghaus' objective was to examine the extent of
convection in these dunes, and the possibility that firn air at depth could be
very old. We analyzed the firn air samples for the O2/N2/Ar ratio and the
isotopic composition of O2 and N2. The isotopic and elemental data define the
extent of convection in the firn and give information about the degree of
graviational fractionation, with which a gravitational correction can be made
for the abundance of other species.