Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017
Seasonal biomass burning (BB) from June to October in central and southern Africa leads to absorbing aerosols being transported over the South Atlantic Ocean every year and contributes significantly to the regional climate forcing. The vertical distribution of submicron aerosols and their properties...
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Online Access: | https://research.manchester.ac.uk/en/publications/6fbb24aa-7cb5-48ec-8a84-abd88d427367 https://doi.org/10.5194/acp-20-12697-2020 https://pure.manchester.ac.uk/ws/files/185527165/acp_20_12697_2020.pdf |
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ftumanchesterpub:oai:pure.atira.dk:publications/6fbb24aa-7cb5-48ec-8a84-abd88d427367 2023-11-12T04:26:14+01:00 Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017 Wu, Huihui Taylor, J. W. Szpek, Kate Langridge, Justin M. Williams, Paul Flynn, Michael Allan, James Abel, Steven J. Pitt, Joseph Cotterell, Michael I. Fox, Cathryn Davies, Nicholas W. Haywood, Jim Coe, Hugh 2020-11-03 application/pdf https://research.manchester.ac.uk/en/publications/6fbb24aa-7cb5-48ec-8a84-abd88d427367 https://doi.org/10.5194/acp-20-12697-2020 https://pure.manchester.ac.uk/ws/files/185527165/acp_20_12697_2020.pdf eng eng info:eu-repo/semantics/openAccess Wu , H , Taylor , J W , Szpek , K , Langridge , J M , Williams , P , Flynn , M , Allan , J , Abel , S J , Pitt , J , Cotterell , M I , Fox , C , Davies , N W , Haywood , J & Coe , H 2020 , ' Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017 ' , Atmospheric Chemistry and Physics , vol. 20 , no. 21 , pp. 12697-12719 . https://doi.org/10.5194/acp-20-12697-2020 article 2020 ftumanchesterpub https://doi.org/10.5194/acp-20-12697-2020 2023-10-30T09:14:23Z Seasonal biomass burning (BB) from June to October in central and southern Africa leads to absorbing aerosols being transported over the South Atlantic Ocean every year and contributes significantly to the regional climate forcing. The vertical distribution of submicron aerosols and their properties were characterized over the remote southeast Atlantic, using airborne in situ measurements made during the CLoud-Aerosol-Radiation Interactions and Forcing for Year 2017 (CLARIFY-2017) campaign. BB aerosols emitted from flaming-controlled fires were intensively observed in the region surrounding Ascension Island, in the marine boundary layer (MBL) and free troposphere (FT) up to 5 km. We show that the aerosols had undergone a significant ageing process during > 7 d transit from source, as indicated by the highly oxidized organic aerosol. The highly aged BB aerosols in the far-field CLARIFY region were also especially rich in black carbon (BC), with relatively low singlescattering albedos (SSAs), compared with those from other BB transported regions. The column-weighted dry SSAs during CLARIFY were observed to be 0.85, 0.84 and 0.83 at 405, 550 and 658 nm respectively. We also found significant vertical variation in the dry SSA, as a function of relative chemical composition and size. The lowest SSA in the column was generally in the low FT layer around 2000 m altitude (averages: 0.82, 0.81 and 0.79 at 405, 550 and 658 nm). This finding is important since it means that BB aerosols across the southeast Atlantic region are more absorbing than currently represented in climate models, implying that the radiative forcing from BB may be more strongly positive than previously thought. Furthermore, in the FT, average SSAs at 405, 550 and 658 nm increased to 0.87, 0.86 and 0.85 with altitude up to 5 km. This was associated with an enhanced inorganic nitrate mass fraction and aerosol size, likely resulting from increased partitioning of ammonium nitrate to the existing particles at higher altitude with lower temperature and ... Article in Journal/Newspaper South Atlantic Ocean The University of Manchester: Research Explorer Atmospheric Chemistry and Physics 20 21 12697 12719 |
institution |
Open Polar |
collection |
The University of Manchester: Research Explorer |
op_collection_id |
ftumanchesterpub |
language |
English |
description |
Seasonal biomass burning (BB) from June to October in central and southern Africa leads to absorbing aerosols being transported over the South Atlantic Ocean every year and contributes significantly to the regional climate forcing. The vertical distribution of submicron aerosols and their properties were characterized over the remote southeast Atlantic, using airborne in situ measurements made during the CLoud-Aerosol-Radiation Interactions and Forcing for Year 2017 (CLARIFY-2017) campaign. BB aerosols emitted from flaming-controlled fires were intensively observed in the region surrounding Ascension Island, in the marine boundary layer (MBL) and free troposphere (FT) up to 5 km. We show that the aerosols had undergone a significant ageing process during > 7 d transit from source, as indicated by the highly oxidized organic aerosol. The highly aged BB aerosols in the far-field CLARIFY region were also especially rich in black carbon (BC), with relatively low singlescattering albedos (SSAs), compared with those from other BB transported regions. The column-weighted dry SSAs during CLARIFY were observed to be 0.85, 0.84 and 0.83 at 405, 550 and 658 nm respectively. We also found significant vertical variation in the dry SSA, as a function of relative chemical composition and size. The lowest SSA in the column was generally in the low FT layer around 2000 m altitude (averages: 0.82, 0.81 and 0.79 at 405, 550 and 658 nm). This finding is important since it means that BB aerosols across the southeast Atlantic region are more absorbing than currently represented in climate models, implying that the radiative forcing from BB may be more strongly positive than previously thought. Furthermore, in the FT, average SSAs at 405, 550 and 658 nm increased to 0.87, 0.86 and 0.85 with altitude up to 5 km. This was associated with an enhanced inorganic nitrate mass fraction and aerosol size, likely resulting from increased partitioning of ammonium nitrate to the existing particles at higher altitude with lower temperature and ... |
format |
Article in Journal/Newspaper |
author |
Wu, Huihui Taylor, J. W. Szpek, Kate Langridge, Justin M. Williams, Paul Flynn, Michael Allan, James Abel, Steven J. Pitt, Joseph Cotterell, Michael I. Fox, Cathryn Davies, Nicholas W. Haywood, Jim Coe, Hugh |
spellingShingle |
Wu, Huihui Taylor, J. W. Szpek, Kate Langridge, Justin M. Williams, Paul Flynn, Michael Allan, James Abel, Steven J. Pitt, Joseph Cotterell, Michael I. Fox, Cathryn Davies, Nicholas W. Haywood, Jim Coe, Hugh Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017 |
author_facet |
Wu, Huihui Taylor, J. W. Szpek, Kate Langridge, Justin M. Williams, Paul Flynn, Michael Allan, James Abel, Steven J. Pitt, Joseph Cotterell, Michael I. Fox, Cathryn Davies, Nicholas W. Haywood, Jim Coe, Hugh |
author_sort |
Wu, Huihui |
title |
Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017 |
title_short |
Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017 |
title_full |
Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017 |
title_fullStr |
Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017 |
title_full_unstemmed |
Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017 |
title_sort |
vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast atlantic during clarify-2017 |
publishDate |
2020 |
url |
https://research.manchester.ac.uk/en/publications/6fbb24aa-7cb5-48ec-8a84-abd88d427367 https://doi.org/10.5194/acp-20-12697-2020 https://pure.manchester.ac.uk/ws/files/185527165/acp_20_12697_2020.pdf |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_source |
Wu , H , Taylor , J W , Szpek , K , Langridge , J M , Williams , P , Flynn , M , Allan , J , Abel , S J , Pitt , J , Cotterell , M I , Fox , C , Davies , N W , Haywood , J & Coe , H 2020 , ' Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017 ' , Atmospheric Chemistry and Physics , vol. 20 , no. 21 , pp. 12697-12719 . https://doi.org/10.5194/acp-20-12697-2020 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/acp-20-12697-2020 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
20 |
container_issue |
21 |
container_start_page |
12697 |
op_container_end_page |
12719 |
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1782340289788116992 |