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The relationship between 18 O/16 O and 13 C/12 C ratios of ambient CO2 in two Amazonian tropical forests
LEONEL DA S. L. STERNBERG MARCELO Z. MOREIRA LUIZ A. MARTINELLI REYNALDO L. VICTORIA EDELCILIO M. BARBOSA LUIZ C. M. BONATES DANIEL NEPSTAD 《Tellus. Series B, Chemical and physical meteorology》1998,50(4):366-376
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C. C. W. LEE J. H. SAVARINO H. CACHIER M. H. THIEMENS 《Tellus. Series B, Chemical and physical meteorology》2002,54(3):193-200
The recent discovery of an anomalous enrichment in 17 O isotope in atmospheric sulfate has opened a new way to investigate the oxidation pathways of sulfur in the atmosphere. From laboratory investigations, it has been suggested that the wet oxidation of sulfur in rain droplets was responsible for the excess 17 O. In order to confirm this theory, sulfur and oxygen isotope ratios of different primary sulfates produced during fossil fuel combustion have been investigated and are reported. None of these samples exhibits any anomalous oxygen or sulfur isotopic content, as compared to urban sulfate aerosols. These results, in agreement with the laboratory investigations, reinforce the idea of an aqueous origin for the oxygen-17 anomaly found in tropospheric sulfates. 相似文献
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By TOBIAS NAEGLER 《Tellus. Series B, Chemical and physical meteorology》2009,61(2):372-384
Oceanic excess radiocarbon data is widely used as a constraint for air–sea gas exchange. However, recent estimates of the global mean piston velocity 〈 k 〉 from Naegler et al., Krakauer et al., Sweeney et al. and Müller et al. differ substantially despite the fact that they all are based on excess radiocarbon data from the GLODAP data base. Here I show that these estimates of 〈 k 〉 can be reconciled if first, the changing oceanic radiocarbon inventory due to net uptake of CO2 is taken into account; second, if realistic reconstructions of sea surface Δ14 C are used and third, if 〈 k 〉 is consistently reported with or without normalization to a Schmidt number of 660. These corrections applied, unnormalized estimates of 〈 k 〉 from these studies range between 15.1 and 18.2 cm h−1 . However, none of these estimates can be regarded as the only correct value for 〈 k 〉 . I thus propose to use the 'average' of the corrected values of 〈 k 〉 presented here (16.5 ± 3.2 cm h−1 ) as the best available estimate of the global mean unnormalized piston velocity 〈 k 〉 , resulting in a gross ocean-to-atmosphere CO2 flux of 76 ± 15 PgC yr−1 for the mid-1990s. 相似文献
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