The concentration and isotopic abundances of carbon dioxide in rural and marine air
添加于 2017/3/2 12:37:38 121次阅读 | 0次推荐 | 5个评论
An earlier study of the concentration and isotopic abundances of C13 and O18 of carbon dioxide in rural air (Keeling, 1958) has been extended by reporting the analysis of 106 additional samples of rural air and thirteen samples of air collected over tropical waters of the eastern Pacific Ocean. At locations far removed from terrestrial plants and the influence of cities, the concentration and C13 abundance of carbon dioxide in the air are found to be nearly constant; but the O18 abundance of carbon dioxide, under various circumstances, appears to show a systematic variation with air temperature, ocean water temperature, or season. Extreme values are, concentration: from 0.0303 to 0.0320 volume per cent of original air; C13C12 ratio: from −6.7 to −7.4 per mil; O18O16 ratio: −0.8 to −0.6 per mil. A correlation between C13 abundance and concentration of carbon dioxide previously observed for forest air is again observed. On the basis of this correlation, the C13C12 ratio of the carbon dioxide released by the forest plants has been computed and is found to vary for different stations between −21 and −26 per mil. The O18 abundance of carbon dioxide in forest air is observed to be variable but shows no simple relationship with other measured quantities.