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Stable carbon and nitrogen isotopic composition of fine mode aerosols (PM2.5) over the Bay of Bengal: impact of continental sources
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Title: | Stable carbon and nitrogen isotopic composition of fine mode aerosols (PM2.5) over the Bay of Bengal: impact of continental sources |
Authors: | Bikkina, Srinivas Browse this author | Kawamura, Kimitaka Browse this author | Sarin, Manmohan Browse this author |
Keywords: | stable C- and N-isotopes | Bay of Bengal | aerosols | biomass burning | fossil-fuel combustion | South Asia | South-east Asia | Indo-Gangetic Plain |
Issue Date: | 12-Jul-2016 |
Publisher: | Co-Action Publishing |
Journal Title: | Tellus. Series B, Chemical and physical meteorology |
Volume: | 68 |
Start Page: | 31518 |
Publisher DOI: | 10.3402/tellusb.v68.31518 |
Abstract: | This study reports on stable carbon (delta C-13(TC)) and nitrogen (delta N-15(TN)) isotopic composition of total carbon and nitrogen (TC and TN) in the fine mode aerosols (PM2.5; N = 31) collected over the Bay of Bengal (BoB). The samples represent two distinct wind regimes during the cruise (27 December 2008-28 January 2009); one from the Indo-Gangetic Plain (referred as IGP-outflow) and another from Southeast Asia (SEA-outflow). The PM2.5 samples from the IGP-outflow show higher delta C-13(TC) (-25.0 to -22.8 parts per thousand; -23.8 +/- 0.6 parts per thousand) than those from the SEA-outflow (-27.4 to -24.7 parts per thousand; -25.3 +/- 0.9 parts per thousand). Similarly, delta N-15(TN) varied from +11.8 to +30.6 parts per thousand (+20.4 +/- 5.4 parts per thousand) and +10.4 to +31.7 parts per thousand (+19.4 +/- 6.1 parts per thousand) for IGP-and SEA-outflows, respectively. Based on the literature data, MODIS-derived fire hotspots and back trajectories, we infer that higher delta C-13(TC) in the IGP-outflow is predominantly associated with fossil fuel and biofuel combustion. In contrast, contribution of primary organic aerosols from the combustion of C-3 plants or secondary organic aerosol (SOA) formation from biomass/biofuel-burning emissions (BBEs) can explain the lower delta C-13(TC) values in the SEA-outflow. This inference is based on the significant linear correlations among delta C-13(TC), water-soluble organic carbon and non-sea-salt potassium (nss-K+, a proxy for BBEs) in the SEA-outflow. A significant linear relationship of delta N-15 with NH4+and equivalent mass ratio of NH4+/SO42-is evident in both the continental outflows. Since NH4+abundance dominates the TN over the BoB (>90 %), atmospheric processes affecting its concentration in fine mode aerosols can explain the observed large variability of delta N-15(TN). |
Rights: | http://creativecommons.org/licenses/by/4.0/ |
Type: | article |
URI: | http://hdl.handle.net/2115/62718 |
Appears in Collections: | 低温科学研究所 (Institute of Low Temperature Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 河村 公隆
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