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Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition

Black carbon (BC) absorbs solar radiation, leading to a strong but uncertain warming effect on climate. A key challenge in modeling and quantifying BC’s radiative effect on climate is predicting enhancements in light absorption that result from internal mixing between BC and other aerosol components...

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Autores principales: Fierce, Laura, Onasch, Timothy B., Cappa, Christopher D., Mazzoleni, Claudio, China, Swarup, Bhandari, Janarjan, Davidovits, Paul, Fischer, D. Al, Helgestad, Taylor, Lambe, Andrew T., Sedlacek, Arthur J., Smith, Geoffrey D., Wolff, Lindsay
Formato: Online Artículo Texto
Lenguaje:English
Publicado: National Academy of Sciences 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071900/
https://www.ncbi.nlm.nih.gov/pubmed/32098848
http://dx.doi.org/10.1073/pnas.1919723117
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author Fierce, Laura
Onasch, Timothy B.
Cappa, Christopher D.
Mazzoleni, Claudio
China, Swarup
Bhandari, Janarjan
Davidovits, Paul
Fischer, D. Al
Helgestad, Taylor
Lambe, Andrew T.
Sedlacek, Arthur J.
Smith, Geoffrey D.
Wolff, Lindsay
author_facet Fierce, Laura
Onasch, Timothy B.
Cappa, Christopher D.
Mazzoleni, Claudio
China, Swarup
Bhandari, Janarjan
Davidovits, Paul
Fischer, D. Al
Helgestad, Taylor
Lambe, Andrew T.
Sedlacek, Arthur J.
Smith, Geoffrey D.
Wolff, Lindsay
author_sort Fierce, Laura
collection PubMed
description Black carbon (BC) absorbs solar radiation, leading to a strong but uncertain warming effect on climate. A key challenge in modeling and quantifying BC’s radiative effect on climate is predicting enhancements in light absorption that result from internal mixing between BC and other aerosol components. Modeling and laboratory studies show that BC, when mixed with other aerosol components, absorbs more strongly than pure, uncoated BC; however, some ambient observations suggest more variable and weaker absorption enhancement. We show that the lower-than-expected enhancements in ambient measurements result from a combination of two factors. First, the often used spherical, concentric core-shell approximation generally overestimates the absorption by BC. Second, and more importantly, inadequate consideration of heterogeneity in particle-to-particle composition engenders substantial overestimation in absorption by the total particle population, with greater heterogeneity associated with larger model–measurement differences. We show that accounting for these two effects—variability in per-particle composition and deviations from the core-shell approximation—reconciles absorption enhancement predictions with laboratory and field observations and resolves the apparent discrepancy. Furthermore, our consistent model framework provides a path forward for improving predictions of BC’s radiative effect on climate.
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spelling pubmed-70719002020-03-22 Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition Fierce, Laura Onasch, Timothy B. Cappa, Christopher D. Mazzoleni, Claudio China, Swarup Bhandari, Janarjan Davidovits, Paul Fischer, D. Al Helgestad, Taylor Lambe, Andrew T. Sedlacek, Arthur J. Smith, Geoffrey D. Wolff, Lindsay Proc Natl Acad Sci U S A Physical Sciences Black carbon (BC) absorbs solar radiation, leading to a strong but uncertain warming effect on climate. A key challenge in modeling and quantifying BC’s radiative effect on climate is predicting enhancements in light absorption that result from internal mixing between BC and other aerosol components. Modeling and laboratory studies show that BC, when mixed with other aerosol components, absorbs more strongly than pure, uncoated BC; however, some ambient observations suggest more variable and weaker absorption enhancement. We show that the lower-than-expected enhancements in ambient measurements result from a combination of two factors. First, the often used spherical, concentric core-shell approximation generally overestimates the absorption by BC. Second, and more importantly, inadequate consideration of heterogeneity in particle-to-particle composition engenders substantial overestimation in absorption by the total particle population, with greater heterogeneity associated with larger model–measurement differences. We show that accounting for these two effects—variability in per-particle composition and deviations from the core-shell approximation—reconciles absorption enhancement predictions with laboratory and field observations and resolves the apparent discrepancy. Furthermore, our consistent model framework provides a path forward for improving predictions of BC’s radiative effect on climate. National Academy of Sciences 2020-03-10 2020-02-25 /pmc/articles/PMC7071900/ /pubmed/32098848 http://dx.doi.org/10.1073/pnas.1919723117 Text en Copyright © 2020 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/ https://creativecommons.org/licenses/by-nc-nd/4.0/This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) .
spellingShingle Physical Sciences
Fierce, Laura
Onasch, Timothy B.
Cappa, Christopher D.
Mazzoleni, Claudio
China, Swarup
Bhandari, Janarjan
Davidovits, Paul
Fischer, D. Al
Helgestad, Taylor
Lambe, Andrew T.
Sedlacek, Arthur J.
Smith, Geoffrey D.
Wolff, Lindsay
Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition
title Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition
title_full Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition
title_fullStr Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition
title_full_unstemmed Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition
title_short Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition
title_sort radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition
topic Physical Sciences
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071900/
https://www.ncbi.nlm.nih.gov/pubmed/32098848
http://dx.doi.org/10.1073/pnas.1919723117
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