TY  - JOUR
AU  - Saito, T.
AU  - Stein, O.
AU  - Tsunogai, U.
AU  - Kawamura, K.
AU  - Nakatsuka, T.
AU  - Gamo, T.
AU  - Yoshida, N.
TI  - Stable carbon isotope ratios of ethane over the North Pacific: Atmospheric measurements and global chemical transport modeling
JO  - Journal of Geophysical Research
VL  - 116
SN  - 0148-0227
CY  - Washington, DC
PB  - Union
M1  - PreJuSER-14236
PY  - 2011
N1  - We thank Masahiro Narukawa and the crews of R/V Shoyo-maru and R/V Mirai for their help in collecting air samples. This study was supported partly by Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists to T.S. and by Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corporation, to the Tokyo Institute of Technology.
AB  - The atmospheric mixing ratios of ethane and its stable carbon isotope ratios (delta C-13) were measured over the North Pacific (2 degrees N to 38 degrees N, 140 degrees E to 90 degrees W) during oceanographic cruises in summer and autumn. The measured mixing ratios were relatively low (mostly < 1 ppbv) over the North Pacific, whereas elevated ethane levels (> 1 ppbv) were observed over the western North Pacific near Japan, with lower delta C-13 values (approximately -25 parts per thousand), suggesting recent emissions from neighboring source regions. The most C-13-enriched values of ethane (approximately -16 parts per thousand) were observed over the western equatorial Pacific rather than the central and eastern equatorial Pacific. This is likely caused by the kinetic isotope effect (KIE) for the removal of ethane during the atmospheric transport from potential upwind source regions to the most remote region under the prevailing trade easterly winds. The measurements were compared with the results of a global chemical transport model including two ethane isotopologues ((C2H6)-C-12 and (C2H6)-C-13). The model-estimated delta C-13 values were too high compared with the observations. It is likely that this discrepancy is partly due to an approximately 40% overestimation of the reported KIE for the reaction between ethane and OH radicals.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000286757300007
DO  - DOI:10.1029/2010JD014602
UR  - https://juser.fz-juelich.de/record/14236
ER  -