Key points are not available for this paper at this time.
O 2 /N 2 is measured in the Cape Grim Air Archive (CGAA), a suite of tanks filled with background air at Cape Grim, Tasmania (40.7°S, 144.8°E) between April 1978 and January 1997. Derived trends are compared with published O 2 /N 2 records and assessed against limits on interannual variability of net terrestrial exchanges imposed by trends of δ 13 C in CO 2 . Two old samples from 1978 and 1987 and eight from 1996/97 survive critical selection criteria and give a mean 19‐year trend in δ(O 2 /N 2 ) of −16.7±0.5 per meg yr −1 , implying net storage of +2.3 ± 0.7 GtC (10 15 g carbon) yr −1 of fossil fuel CO 2 in the oceans and +0.2 ± 0.9 GtC yr −1 in the terrestrial biosphere. The uptake terms are consistent for both O 2 /N 2 and δ 13 C tracers if the mean 13 C isotopic disequilibrium flux, combining terrestrial and oceanic contributions, is 93±15 GtC ‰ yr −1 .
Langenfelds et al. (Thu,) studied this question.