An evaluation of three methods for measuring black carbon in Alert, Canada
Absorption of sunlight by black carbon (BC) warms the atmosphere, which may be important for Arctic climate. The measurement of BC is complicated by the lack of a simple definition of BC and the absence of techniques that are uniquely sensitive to BC (e.g., Petzold et al., 2013). At the Global Atmos...
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ftdoajarticles:oai:doaj.org/article:9b225112c24a4b599c20c09551318bb8 2023-05-15T15:17:29+02:00 An evaluation of three methods for measuring black carbon in Alert, Canada S. Sharma W. R. Leaitch L. Huang D. Veber F. Kolonjari W. Zhang S. J. Hanna A. K. Bertram J. A. Ogren 2017-12-01T00:00:00Z https://doi.org/10.5194/acp-17-15225-2017 https://doaj.org/article/9b225112c24a4b599c20c09551318bb8 EN eng Copernicus Publications https://www.atmos-chem-phys.net/17/15225/2017/acp-17-15225-2017.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-17-15225-2017 1680-7316 1680-7324 https://doaj.org/article/9b225112c24a4b599c20c09551318bb8 Atmospheric Chemistry and Physics, Vol 17, Pp 15225-15243 (2017) Physics QC1-999 Chemistry QD1-999 article 2017 ftdoajarticles https://doi.org/10.5194/acp-17-15225-2017 2022-12-31T06:24:07Z Absorption of sunlight by black carbon (BC) warms the atmosphere, which may be important for Arctic climate. The measurement of BC is complicated by the lack of a simple definition of BC and the absence of techniques that are uniquely sensitive to BC (e.g., Petzold et al., 2013). At the Global Atmosphere Watch baseline observatory in Alert, Nunavut (82.5° N), BC mass is estimated in three ways, none of which fully represent BC: conversion of light absorption measured with an Aethalometer to give equivalent black carbon (EBC), thermal desorption of elemental carbon (EC) from weekly integrated filter samples to give EC, and measurement of incandescence from the refractory black carbon (rBC) component of individual particles using a single particle soot photometer (SP2). Based on measurements between March 2011 and December 2013, EBC and EC are 2.7 and 3.1 times higher than rBC, respectively. The EBC and EC measurements are influenced by factors other than just BC, and higher estimates of BC are expected from these techniques. Some bias in the rBC measurement may result from calibration uncertainties that are difficult to estimate here. Considering a number of factors, our best estimate of BC mass in Alert, which may be useful for evaluation of chemical transport models, is an average of the rBC and EC measurements with a range bounded by the rBC and EC combined with the respective measurement uncertainties. Winter-, spring-, summer-, and fall-averaged (± atmospheric variability) estimates of BC mass in Alert for this study period are 49 ± 28, 30 ± 26, 22 ± 13, and 29 ± 9 ng m −3 , respectively. Average coating thicknesses estimated from the SP2 are 25 to 40 % of the 160–180 nm diameter rBC core sizes. For particles of approximately 200–400 nm optical diameter, the fraction containing rBC cores is estimated to be between 10 and 16 %, but the possibility of smaller undetectable rBC cores in some of the particles cannot be excluded. Mass absorption coefficients (MACs) ± uncertainty at 550 nm wavelength, calculated ... Article in Journal/Newspaper Arctic black carbon Nunavut Directory of Open Access Journals: DOAJ Articles Arctic Canada Nunavut Atmospheric Chemistry and Physics 17 24 15225 15243 |
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Physics QC1-999 Chemistry QD1-999 S. Sharma W. R. Leaitch L. Huang D. Veber F. Kolonjari W. Zhang S. J. Hanna A. K. Bertram J. A. Ogren An evaluation of three methods for measuring black carbon in Alert, Canada |
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Physics QC1-999 Chemistry QD1-999 |
description |
Absorption of sunlight by black carbon (BC) warms the atmosphere, which may be important for Arctic climate. The measurement of BC is complicated by the lack of a simple definition of BC and the absence of techniques that are uniquely sensitive to BC (e.g., Petzold et al., 2013). At the Global Atmosphere Watch baseline observatory in Alert, Nunavut (82.5° N), BC mass is estimated in three ways, none of which fully represent BC: conversion of light absorption measured with an Aethalometer to give equivalent black carbon (EBC), thermal desorption of elemental carbon (EC) from weekly integrated filter samples to give EC, and measurement of incandescence from the refractory black carbon (rBC) component of individual particles using a single particle soot photometer (SP2). Based on measurements between March 2011 and December 2013, EBC and EC are 2.7 and 3.1 times higher than rBC, respectively. The EBC and EC measurements are influenced by factors other than just BC, and higher estimates of BC are expected from these techniques. Some bias in the rBC measurement may result from calibration uncertainties that are difficult to estimate here. Considering a number of factors, our best estimate of BC mass in Alert, which may be useful for evaluation of chemical transport models, is an average of the rBC and EC measurements with a range bounded by the rBC and EC combined with the respective measurement uncertainties. Winter-, spring-, summer-, and fall-averaged (± atmospheric variability) estimates of BC mass in Alert for this study period are 49 ± 28, 30 ± 26, 22 ± 13, and 29 ± 9 ng m −3 , respectively. Average coating thicknesses estimated from the SP2 are 25 to 40 % of the 160–180 nm diameter rBC core sizes. For particles of approximately 200–400 nm optical diameter, the fraction containing rBC cores is estimated to be between 10 and 16 %, but the possibility of smaller undetectable rBC cores in some of the particles cannot be excluded. Mass absorption coefficients (MACs) ± uncertainty at 550 nm wavelength, calculated ... |
format |
Article in Journal/Newspaper |
author |
S. Sharma W. R. Leaitch L. Huang D. Veber F. Kolonjari W. Zhang S. J. Hanna A. K. Bertram J. A. Ogren |
author_facet |
S. Sharma W. R. Leaitch L. Huang D. Veber F. Kolonjari W. Zhang S. J. Hanna A. K. Bertram J. A. Ogren |
author_sort |
S. Sharma |
title |
An evaluation of three methods for measuring black carbon in Alert, Canada |
title_short |
An evaluation of three methods for measuring black carbon in Alert, Canada |
title_full |
An evaluation of three methods for measuring black carbon in Alert, Canada |
title_fullStr |
An evaluation of three methods for measuring black carbon in Alert, Canada |
title_full_unstemmed |
An evaluation of three methods for measuring black carbon in Alert, Canada |
title_sort |
evaluation of three methods for measuring black carbon in alert, canada |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/acp-17-15225-2017 https://doaj.org/article/9b225112c24a4b599c20c09551318bb8 |
geographic |
Arctic Canada Nunavut |
geographic_facet |
Arctic Canada Nunavut |
genre |
Arctic black carbon Nunavut |
genre_facet |
Arctic black carbon Nunavut |
op_source |
Atmospheric Chemistry and Physics, Vol 17, Pp 15225-15243 (2017) |
op_relation |
https://www.atmos-chem-phys.net/17/15225/2017/acp-17-15225-2017.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-17-15225-2017 1680-7316 1680-7324 https://doaj.org/article/9b225112c24a4b599c20c09551318bb8 |
op_doi |
https://doi.org/10.5194/acp-17-15225-2017 |
container_title |
Atmospheric Chemistry and Physics |
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17 |
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24 |
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15225 |
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15243 |
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