Jury is still out on the radiative forcing by black carbon
International audience Peng et al. (1) conclude that a fast increase in the mass absorption cross-section (MAC) of black carbon (BC) in urban environments leads to significantly increased estimates of the BC radiative forcing (RF). Their chamber measurements are highly valuable and complement observ...
Published in: | Proceedings of the National Academy of Sciences |
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Main Authors: | , , , , , , , , , |
Other Authors: | , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2016
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Online Access: | https://hal.science/hal-02875486 https://hal.science/hal-02875486/document https://hal.science/hal-02875486/file/PNAS-2016-Boucher-1607005113.pdf https://doi.org/10.1073/pnas.1607005113 |
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HAL-CEA (Commissariat à l'énergie atomique et aux énergies alternatives) |
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[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] [SDE.MCG]Environmental Sciences/Global Changes [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] [SDE.MCG]Environmental Sciences/Global Changes [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Boucher, Olivier Balkanski, Yves Hodnebrog, Øivind Lund Myhre, Cathrine Myhre, Gunnar Quaas, Johannes Hallvard Samset, Bjørn Schutgens, Nick Stier, Philip Wang, Rong Jury is still out on the radiative forcing by black carbon |
topic_facet |
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] [SDE.MCG]Environmental Sciences/Global Changes [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
International audience Peng et al. (1) conclude that a fast increase in the mass absorption cross-section (MAC) of black carbon (BC) in urban environments leads to significantly increased estimates of the BC radiative forcing (RF). Their chamber measurements are highly valuable and complement observations performed in ambient conditions, but their "enhancement factor" relative to an unspec-ified baseline may not be directly comparable to values used or simulated in global aerosol models. MAC, a key parameter in our understanding of the net BC climate impact, is indeed a more relevant quantity to examine. A fast MAC enhancement in polluted environments as the BC gets coated with organic and inorganic species is consistent with recent findings (2, 3). Global models used in AeroCom [table S1 in Peng et al. (1), ref. 4] have an average MAC of ∼8 m 2 ·g −1 at 550 nm. This value is reflecting reported measurements, although there is a large spatial and seasonal variability in ambient MAC for aged particles, with values of ∼10 m 2 ·g −1 at a rural Northern Chinese site (2) (at 678 nm); 6-14 m 2 ·g −1 at rural, urban, and high-altitude Indian locations (5) (at 678 nm); and ∼6 m 2 ·g −1 at an Arctic site (6) (at 522 nm). Coating of BC by soluble species not only enhances absorption of solar radiation but also reduces the BC atmospheric lifetime (7). Fig. 1 shows an offset between the increase in average MAC value with faster BC aging and an overall shorter BC lifetime, resulting in a near-constant BC aerosol absorption optical depth and RF with aging time. Furthermore, current global aerosol models frequently have a too long BC lifetime and consequently overestimate BC concentrations downwind from source regions (8). According to Peng et al. (1), their BC absorption enhancement factor of 2.4 is also an upper bound, only reached after 5 (Beijing) to 18 (Houston) h, and possibly longer in cleaner environments. Such timescales are not small compared with the BC atmospheric lifetime of 3-5 d, especially considering that ... |
author2 |
Institut Pierre-Simon-Laplace (IPSL (FR_636)) École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité) Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Center for International Climate and Environmental Research Oslo (CICERO) University of Oslo (UiO) Fudan University Shanghai |
format |
Article in Journal/Newspaper |
author |
Boucher, Olivier Balkanski, Yves Hodnebrog, Øivind Lund Myhre, Cathrine Myhre, Gunnar Quaas, Johannes Hallvard Samset, Bjørn Schutgens, Nick Stier, Philip Wang, Rong |
author_facet |
Boucher, Olivier Balkanski, Yves Hodnebrog, Øivind Lund Myhre, Cathrine Myhre, Gunnar Quaas, Johannes Hallvard Samset, Bjørn Schutgens, Nick Stier, Philip Wang, Rong |
author_sort |
Boucher, Olivier |
title |
Jury is still out on the radiative forcing by black carbon |
title_short |
Jury is still out on the radiative forcing by black carbon |
title_full |
Jury is still out on the radiative forcing by black carbon |
title_fullStr |
Jury is still out on the radiative forcing by black carbon |
title_full_unstemmed |
Jury is still out on the radiative forcing by black carbon |
title_sort |
jury is still out on the radiative forcing by black carbon |
publisher |
HAL CCSD |
publishDate |
2016 |
url |
https://hal.science/hal-02875486 https://hal.science/hal-02875486/document https://hal.science/hal-02875486/file/PNAS-2016-Boucher-1607005113.pdf https://doi.org/10.1073/pnas.1607005113 |
genre |
black carbon |
genre_facet |
black carbon |
op_source |
ISSN: 0027-8424 EISSN: 1091-6490 Proceedings of the National Academy of Sciences of the United States of America https://hal.science/hal-02875486 Proceedings of the National Academy of Sciences of the United States of America, 2016, ⟨10.1073/pnas.1607005113⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1073/pnas.1607005113 hal-02875486 https://hal.science/hal-02875486 https://hal.science/hal-02875486/document https://hal.science/hal-02875486/file/PNAS-2016-Boucher-1607005113.pdf doi:10.1073/pnas.1607005113 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1073/pnas.1607005113 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
113 |
container_issue |
35 |
container_start_page |
E5092 |
op_container_end_page |
E5093 |
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1810437091304144896 |
spelling |
ftceafr:oai:HAL:hal-02875486v1 2024-09-15T17:59:58+00:00 Jury is still out on the radiative forcing by black carbon Boucher, Olivier Balkanski, Yves Hodnebrog, Øivind Lund Myhre, Cathrine Myhre, Gunnar Quaas, Johannes Hallvard Samset, Bjørn Schutgens, Nick Stier, Philip Wang, Rong Institut Pierre-Simon-Laplace (IPSL (FR_636)) École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité) Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Center for International Climate and Environmental Research Oslo (CICERO) University of Oslo (UiO) Fudan University Shanghai 2016-08-30 https://hal.science/hal-02875486 https://hal.science/hal-02875486/document https://hal.science/hal-02875486/file/PNAS-2016-Boucher-1607005113.pdf https://doi.org/10.1073/pnas.1607005113 en eng HAL CCSD National Academy of Sciences info:eu-repo/semantics/altIdentifier/doi/10.1073/pnas.1607005113 hal-02875486 https://hal.science/hal-02875486 https://hal.science/hal-02875486/document https://hal.science/hal-02875486/file/PNAS-2016-Boucher-1607005113.pdf doi:10.1073/pnas.1607005113 info:eu-repo/semantics/OpenAccess ISSN: 0027-8424 EISSN: 1091-6490 Proceedings of the National Academy of Sciences of the United States of America https://hal.science/hal-02875486 Proceedings of the National Academy of Sciences of the United States of America, 2016, ⟨10.1073/pnas.1607005113⟩ [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] [SDE.MCG]Environmental Sciences/Global Changes [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/article Journal articles 2016 ftceafr https://doi.org/10.1073/pnas.1607005113 2024-07-22T13:18:55Z International audience Peng et al. (1) conclude that a fast increase in the mass absorption cross-section (MAC) of black carbon (BC) in urban environments leads to significantly increased estimates of the BC radiative forcing (RF). Their chamber measurements are highly valuable and complement observations performed in ambient conditions, but their "enhancement factor" relative to an unspec-ified baseline may not be directly comparable to values used or simulated in global aerosol models. MAC, a key parameter in our understanding of the net BC climate impact, is indeed a more relevant quantity to examine. A fast MAC enhancement in polluted environments as the BC gets coated with organic and inorganic species is consistent with recent findings (2, 3). Global models used in AeroCom [table S1 in Peng et al. (1), ref. 4] have an average MAC of ∼8 m 2 ·g −1 at 550 nm. This value is reflecting reported measurements, although there is a large spatial and seasonal variability in ambient MAC for aged particles, with values of ∼10 m 2 ·g −1 at a rural Northern Chinese site (2) (at 678 nm); 6-14 m 2 ·g −1 at rural, urban, and high-altitude Indian locations (5) (at 678 nm); and ∼6 m 2 ·g −1 at an Arctic site (6) (at 522 nm). Coating of BC by soluble species not only enhances absorption of solar radiation but also reduces the BC atmospheric lifetime (7). Fig. 1 shows an offset between the increase in average MAC value with faster BC aging and an overall shorter BC lifetime, resulting in a near-constant BC aerosol absorption optical depth and RF with aging time. Furthermore, current global aerosol models frequently have a too long BC lifetime and consequently overestimate BC concentrations downwind from source regions (8). According to Peng et al. (1), their BC absorption enhancement factor of 2.4 is also an upper bound, only reached after 5 (Beijing) to 18 (Houston) h, and possibly longer in cleaner environments. Such timescales are not small compared with the BC atmospheric lifetime of 3-5 d, especially considering that ... Article in Journal/Newspaper black carbon HAL-CEA (Commissariat à l'énergie atomique et aux énergies alternatives) Proceedings of the National Academy of Sciences 113 35 E5092 E5093 |