Sensitivity of Tropospheric Chemical Composition to Halogen-Radical Chemistry Using a Fully Coupled Size-Resolved Multiphase Chemistry/Global Climate System: Halogen Distributions, Aerosol Composition, and Sensitivity of Climate-Relevant Gases
Observations and model calculations indicate that highly non-linear multiphase atmospheric processes involving inorganic Cl and Br significantly impact tropospheric chemistry and composition, aerosol evolution, and radiative transfer. The sensitivity of global atmospheric chemistry to the production...
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ftmountainschol:oai:mountainscholar.org:20.500.11919/715 2023-05-15T18:26:01+02:00 Sensitivity of Tropospheric Chemical Composition to Halogen-Radical Chemistry Using a Fully Coupled Size-Resolved Multiphase Chemistry/Global Climate System: Halogen Distributions, Aerosol Composition, and Sensitivity of Climate-Relevant Gases Long, M. S. Keene, W.C. Easter, R. C. Sander, R. Liu, Xiaohong Kerkweg, A. Erickson, D. 2014-04-07 application/pdf https://hdl.handle.net/20.500.11919/715 https://doi.org/10.5194/acpd-13-6067-2013 English eng eng University of Wyoming. Libraries Faculty Publications - Atmospheric Science https://hdl.handle.net/20.500.11919/715 doi:10.5194/acpd-13-6067-2013 http://creativecommons.org/licenses/by/3.0/ CC-BY Atmospheric Science Faculty Publications Engineering Journal contribution 2014 ftmountainschol https://doi.org/20.500.11919/715 https://doi.org/10.5194/acpd-13-6067-2013 2022-03-07T21:19:56Z Observations and model calculations indicate that highly non-linear multiphase atmospheric processes involving inorganic Cl and Br significantly impact tropospheric chemistry and composition, aerosol evolution, and radiative transfer. The sensitivity of global atmospheric chemistry to the production of marine aerosol and the associated activation and cycling of inorganic Cl and Br was investigated using a size-resolved multiphase coupled chemistry–global climate model (National Center for Atmospheric Research's Community Atmosphere Model (CAM) v3.6.33). Simulated results revealed strong meridional and vertical gradients in Cl and Br species. They also point to possible physicochemical mechanisms that may account for several previously unexplained phenomena, including the enrichment of Br− in submicron aerosol and the presence of a BrO maximum in the polar free troposphere. However, simulated total volatile inorganic Br mixing ratios in the troposphere were generally higher than observed, due in part to the overly efficient net production of BrCl. In addition, the emission scheme for marine aerosol and associated Br−, which is the only source for Br in the model, overestimates emission fluxes from the high-latitude Southern Ocean. Br in the stratosphere was lower than observed due to the lack of long-lived precursor organobromine species in the simulation. Comparing simulations using chemical mechanisms with and without reactive Cl and Br species demonstrates a significant temporal and spatial sensitivity of primary atmospheric oxidants (O3, HOx, NOx), CH4, non-methane hydrocarbons (NMHCs), and dimethyl sulfide (DMS) to halogen cycling. Globally, halogen chemistry had relatively less impact on SO2 and non-sea-salt (nss) SO2−4 although significant regional differences were evident. Although variable geographically, much of this sensitivity is attributable to either over-vigorous activation of Br (primarily BrCl) via the chemical mechanism or overproduction of sea-salt aerosol simulated under higher-wind regimes. In regions where simulated mixing ratios of reactive Br and Cl fell within observed ranges, though, halogen chemistry drove large changes in oxidant fields and associated chemical processes relative to simulations with no halogens. However, the overall simulated impacts of Br chemistry globally are overestimated and thus caution is warranted in their interpretation. Other Non-Article Part of Journal/Newspaper Southern Ocean Mountain Scholar (Digital Collections of Colorado and Wyoming) Southern Ocean |
institution |
Open Polar |
collection |
Mountain Scholar (Digital Collections of Colorado and Wyoming) |
op_collection_id |
ftmountainschol |
language |
English |
topic |
Engineering |
spellingShingle |
Engineering Long, M. S. Keene, W.C. Easter, R. C. Sander, R. Liu, Xiaohong Kerkweg, A. Erickson, D. Sensitivity of Tropospheric Chemical Composition to Halogen-Radical Chemistry Using a Fully Coupled Size-Resolved Multiphase Chemistry/Global Climate System: Halogen Distributions, Aerosol Composition, and Sensitivity of Climate-Relevant Gases |
topic_facet |
Engineering |
description |
Observations and model calculations indicate that highly non-linear multiphase atmospheric processes involving inorganic Cl and Br significantly impact tropospheric chemistry and composition, aerosol evolution, and radiative transfer. The sensitivity of global atmospheric chemistry to the production of marine aerosol and the associated activation and cycling of inorganic Cl and Br was investigated using a size-resolved multiphase coupled chemistry–global climate model (National Center for Atmospheric Research's Community Atmosphere Model (CAM) v3.6.33). Simulated results revealed strong meridional and vertical gradients in Cl and Br species. They also point to possible physicochemical mechanisms that may account for several previously unexplained phenomena, including the enrichment of Br− in submicron aerosol and the presence of a BrO maximum in the polar free troposphere. However, simulated total volatile inorganic Br mixing ratios in the troposphere were generally higher than observed, due in part to the overly efficient net production of BrCl. In addition, the emission scheme for marine aerosol and associated Br−, which is the only source for Br in the model, overestimates emission fluxes from the high-latitude Southern Ocean. Br in the stratosphere was lower than observed due to the lack of long-lived precursor organobromine species in the simulation. Comparing simulations using chemical mechanisms with and without reactive Cl and Br species demonstrates a significant temporal and spatial sensitivity of primary atmospheric oxidants (O3, HOx, NOx), CH4, non-methane hydrocarbons (NMHCs), and dimethyl sulfide (DMS) to halogen cycling. Globally, halogen chemistry had relatively less impact on SO2 and non-sea-salt (nss) SO2−4 although significant regional differences were evident. Although variable geographically, much of this sensitivity is attributable to either over-vigorous activation of Br (primarily BrCl) via the chemical mechanism or overproduction of sea-salt aerosol simulated under higher-wind regimes. In regions where simulated mixing ratios of reactive Br and Cl fell within observed ranges, though, halogen chemistry drove large changes in oxidant fields and associated chemical processes relative to simulations with no halogens. However, the overall simulated impacts of Br chemistry globally are overestimated and thus caution is warranted in their interpretation. |
format |
Other Non-Article Part of Journal/Newspaper |
author |
Long, M. S. Keene, W.C. Easter, R. C. Sander, R. Liu, Xiaohong Kerkweg, A. Erickson, D. |
author_facet |
Long, M. S. Keene, W.C. Easter, R. C. Sander, R. Liu, Xiaohong Kerkweg, A. Erickson, D. |
author_sort |
Long, M. S. |
title |
Sensitivity of Tropospheric Chemical Composition to Halogen-Radical Chemistry Using a Fully Coupled Size-Resolved Multiphase Chemistry/Global Climate System: Halogen Distributions, Aerosol Composition, and Sensitivity of Climate-Relevant Gases |
title_short |
Sensitivity of Tropospheric Chemical Composition to Halogen-Radical Chemistry Using a Fully Coupled Size-Resolved Multiphase Chemistry/Global Climate System: Halogen Distributions, Aerosol Composition, and Sensitivity of Climate-Relevant Gases |
title_full |
Sensitivity of Tropospheric Chemical Composition to Halogen-Radical Chemistry Using a Fully Coupled Size-Resolved Multiphase Chemistry/Global Climate System: Halogen Distributions, Aerosol Composition, and Sensitivity of Climate-Relevant Gases |
title_fullStr |
Sensitivity of Tropospheric Chemical Composition to Halogen-Radical Chemistry Using a Fully Coupled Size-Resolved Multiphase Chemistry/Global Climate System: Halogen Distributions, Aerosol Composition, and Sensitivity of Climate-Relevant Gases |
title_full_unstemmed |
Sensitivity of Tropospheric Chemical Composition to Halogen-Radical Chemistry Using a Fully Coupled Size-Resolved Multiphase Chemistry/Global Climate System: Halogen Distributions, Aerosol Composition, and Sensitivity of Climate-Relevant Gases |
title_sort |
sensitivity of tropospheric chemical composition to halogen-radical chemistry using a fully coupled size-resolved multiphase chemistry/global climate system: halogen distributions, aerosol composition, and sensitivity of climate-relevant gases |
publisher |
University of Wyoming. Libraries |
publishDate |
2014 |
url |
https://hdl.handle.net/20.500.11919/715 https://doi.org/10.5194/acpd-13-6067-2013 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Atmospheric Science Faculty Publications |
op_relation |
Faculty Publications - Atmospheric Science https://hdl.handle.net/20.500.11919/715 doi:10.5194/acpd-13-6067-2013 |
op_rights |
http://creativecommons.org/licenses/by/3.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/20.500.11919/715 https://doi.org/10.5194/acpd-13-6067-2013 |
_version_ |
1766207795081773056 |