VARIATIONS OF THE CO_2,CH_4 AND N_2O CONCENTRATIONS AND δ^<13>C OF CO_2 IN THE GLACIAL PERIOD DEDUCED FROM AN ANTARCTIC ICE CORE, SOUTH YAMATO

To reconstruct variations of atmospheric greenhouse gases in the glacial period, air in an ice core recovered from a bare ice field in the southern part of the Yamato Mountains, Antarctica was extracted and then the CO_2,CH_4 and N_2O concentrations and δ^C of CO_2 were analyzed. The CO_2,CH_4 and N_2O concentrations were obviously lower than the pre-industrial Holocene values, suggesting that this ice core was formed in the glacial period. The variations of the CO_2,CH_4 and N_2O concentrations during the glacial period showed a good correlation with that of δ^O of ice from the core. The CO_2 concentrations varied almost opposite in phase with δ^C, which implies that CO_2 with isotopically light carbon was added to or subtracted from the atmosphere in the glacial period