期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2020
卷号：117
期号：34
页码：20447-20452
DOI：10.1073/pnas.2007260117
出版社：The National Academy of Sciences of the United States of America
摘要：Carbonyl sulfide (OCS), the most abundant sulfur-containing gas in the atmosphere, is used as a proxy for photosynthesis rate estimation. However, a large missing source of atmospheric OCS has been inferred. Sulfur isotope measurements ( 34 S/ 32 S ratio and δ 34 S) on OCS are a feasible tool to distinguish OCS sources from oceanic and anthropogenic emissions. Here we present the latitudinal (north–south) observations of OCS concentration and δ 34 S within Japan. The observed δ 34 S of OCS of 9.7 to 14.5‰ reflects source and sink effects. Particularly in winter, latitudinal decreases in δ 34 S values of OCS were found to be correlated with increases in OCS concentrations, resulting an intercept of (4.7 ± 0.8)‰ in the Keeling plot approach. This result implies the transport of anthropogenic OCS emissions from the Asian continent to the western Pacific by the Asian monsoon outflow. The estimated background δ 34 S of OCS in eastern Asia is consistent with the δ 34 S of OCS previously reported in Israel and the Canary Islands, suggesting that the background δ 34 S of OCS in the Northern Hemisphere ranges from 12.0 to 13.5‰. Our constructed sulfur isotopic mass balance of OCS revealed that anthropogenic sources, not merely oceanic sources, account for much of the missing source of atmospheric OCS.
