气候变化领域集成服务门户(CCPortal): Source-specific light absorption by carbonaceous components in the complex aerosol matrix from yearly filter-based measurements

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DOI	10.5194/acp-21-12809-2021
	Source-specific light absorption by carbonaceous components in the complex aerosol matrix from yearly filter-based measurements
	Moschos V.; Gysel-Beer M.; Modini R.L.; Corbin J.C.; Massabò D.; Costa C.; Danelli S.G.; Vlachou A.; Daellenbach K.R.; Szidat S.; Prati P.; Prévôt A.S.H.; Baltensperger U.; El Haddad I.
发表日期	2021
ISSN	1680-7316
起始页码	12809
结束页码	12833
卷号	21 期号:17
英文摘要	Understanding the sources of light-absorbing organic (brown) carbon (BrC) and its interaction with black carbon (BC) and other non-refractory particulate matter (NR-PM) fractions is important for reducing uncertainties in the aerosol direct radiative forcing. In this study, we combine multiple filter-based techniques to achieve long-term, spectrally resolved, source- and species-specific atmospheric absorption closure. We determine the mass absorption efficiency (MAE) in dilute bulk solutions at 370gnm to be equal to 1.4gm2gg-1 for fresh biomass smoke, 0.7gm2gg-1 for winter-oxygenated organic aerosol (OA), and 0.13gm2gg-1 for other less absorbing OA. We apply Mie calculations to estimate the contributions of these fractions to total aerosol absorption. While enhanced absorption in the near-UV has been traditionally attributed to primary biomass smoke, here we show that anthropogenic oxygenated OA may be equally important for BrC absorption during winter, especially at an urban background site. We demonstrate that insoluble tar balls are negligible in residential biomass burning atmospheric samples of this study and thus could attribute the totality of the NR-PM absorption at shorter wavelengths to methanol-extractable BrC. As for BC, we show that the mass absorption cross-section (MAC) of this fraction is independent of its source, while we observe evidence for a filter-based lensing effect associated with the presence of NR-PM components. We find that bare BC has a MAC of 6.3gm2gg-1 at 660gnm and an absorption Ångström exponent of 0.93g±g0.16, while in the presence of coatings its absorption is enhanced by a factor of ĝ1/4g1.4. Based on Mie calculations of closure between observed and predicted total light absorption, we provide an indication for a suppression of the filter-based lensing effect by BrC. The total absorption reduction remains modest, ĝ1/4g10g%-20g% at 370gnm, and is restricted to shorter wavelengths, where BrC absorption is significant. Overall, our results allow an assessment of the relative importance of the different aerosol fractions to the total absorption for aerosols from a wide range of sources and atmospheric ages. When integrated with the solar spectrum at 300-900gnm, bare BC is found to contribute around two-thirds of the solar radiation absorption by total carbonaceous aerosols, amplified by the filter-based lensing effect (with an interquartile range, IQR, of 8g%-27g%), while the IQR of the contributions by particulate BrC is 6g%-13g% (13g%-20g% at the rural site during winter). Future studies that will directly benefit from these results include (a) optical modelling aiming at understanding the absorption profiles of a complex aerosol composed of BrC, BC and lensing-inducing coatings; (b) source apportionment aiming at understanding the sources of BC and BrC from the aerosol absorption profiles; (c) global modelling aiming at quantifying the most important aerosol absorbers. © Authors 2021.
语种	英语
scopus关键词	absorption; aerosol; biomass burning; black carbon; measurement method; Mie theory; organic carbon; radiative forcing
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/246625
作者单位	Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, 5232, Switzerland; Metrology Research Centre, National Research Council Canada, Ottawa, ON K1A 0R6, Canada; Department of Physics, University of Genoa, Genoa, 16146, Italy; National Institute for Nuclear Physics (INFN), University of Genoa, Genoa, 16146, Italy; Department of Chemistry and Industrial Chemistry, University of Genoa, Genoa, 16146, Italy; Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, 3012, Switzerland; Oeschger Centre for Climate Change Research, University of Bern, Bern, 3012, Switzerland
推荐引用方式 GB/T 7714	Moschos V.,Gysel-Beer M.,Modini R.L.,et al. Source-specific light absorption by carbonaceous components in the complex aerosol matrix from yearly filter-based measurements[J],2021,21(17).
APA	Moschos V..,Gysel-Beer M..,Modini R.L..,Corbin J.C..,Massabò D..,...&El Haddad I..(2021).Source-specific light absorption by carbonaceous components in the complex aerosol matrix from yearly filter-based measurements.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(17).
MLA	Moschos V.,et al."Source-specific light absorption by carbonaceous components in the complex aerosol matrix from yearly filter-based measurements".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.17(2021).