open access

https://hdl.handle.net/2115/1465

Trans-hemispheric contribution of C2–C10 α, ω-dicarboxylic acids, and related polar compounds to water-soluble organic carbon in the western Pacific aerosols in relation to photochemical oxidation reactions

英語

2003-06

American Geophysical Union

Global Biogeochemical Cycles

17(２)

1069

‘An edited version of this paper was published by AGU.’ Copyright 2003, American Geophysical Union, Global Biogeochemical Cycles,17

Marine aerosol samples were collected during a western Pacific cruise covering the latitude range between 35°N and 40°S (140°E–180°E). They were analyzed for total carbon (TC), total nitrogen (TN), water-soluble organic carbon (WSOC) along with the molecular distributions of C2–C10 α, ω-dicarboxylic acids, and related polar compounds, mainly, ω-oxocarboxylic acids (C2–C9) and α-dicarbonyls (C2–C3). Oxalic acid (C2) was the most abundant followed by malonic (C3) and succinic (C4) acids. The total diacid concentration range was 7–605 ng m−3 (av. 85 ng m−3) and the diacid-carbon accounted for 2–15% (average 8%) of WSOC which comprised 29–55% (average 40%) of TC. Dry depositions of total diacids over the northern and southern Pacific Ocean were estimated to be 256–1907 μg m−2 yr−1 (average 735; n = 4) and 22–396 μg m−2 yr−1 (average 134; n = 14), respectively, whereas the air-to-sea flux of oxalic acid was 18–1351 μg m−2 yr−1 (average 466 μg m−2 yr−1) and 7.5–275 μg m−2 yr−1 (average 75 μg m−2 yr−1) in the Northern and Southern Hemispheres. We observed that the concentration ratios of diacid-C/WSOC, azelaic acid (C9)/ω-oxononanoic acid, maleic acid (iC4 cis)/fumaric (iC4 trans) acid and succinic acid (C4)/total diacids were correlated with air temperature. These findings showed that the intensity of photochemical oxidation reactions and thus the variation in sunlight intensity characterized here by air temperature, significantly control the molecular distribution of water-soluble organic compounds during the long-range transport of anthropogenic and/or biogenic higher molecular weight organic compounds.

学術雑誌論文

Accepted Manuscript

0886-6236