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Impacts of bromine and iodine chemistry on tropospheric OH and HO2: Comparing observations with box and global model perspectives

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Impacts of bromine and iodine chemistry on tropospheric OH and HO2 : Comparing observations with box and global model perspectives. / Stone, Daniel; Sherwen, Toms; Evans, Mathew J.; Vaughan, Stewart; Ingham, Trevor; Whalley, Lisa K.; Edwards, Peter M.; Read, Katie A.; Lee, James D.; Moller, Sarah J.; Carpenter, Lucy J.; Lewis, Alastair C.; Heard, Dwayne E.

In: Atmospheric Chemistry and Physics, Vol. 18, No. 5, 12.03.2018, p. 3541-3561.

Research output: Contribution to journalArticle

Harvard

Stone, D, Sherwen, T, Evans, MJ, Vaughan, S, Ingham, T, Whalley, LK, Edwards, PM, Read, KA, Lee, JD, Moller, SJ, Carpenter, LJ, Lewis, AC & Heard, DE 2018, 'Impacts of bromine and iodine chemistry on tropospheric OH and HO2: Comparing observations with box and global model perspectives', Atmospheric Chemistry and Physics, vol. 18, no. 5, pp. 3541-3561. https://doi.org/10.5194/acp-2017-892, https://doi.org/10.5194/acp-18-3541-2018

APA

Stone, D., Sherwen, T., Evans, M. J., Vaughan, S., Ingham, T., Whalley, L. K., ... Heard, D. E. (2018). Impacts of bromine and iodine chemistry on tropospheric OH and HO2: Comparing observations with box and global model perspectives. Atmospheric Chemistry and Physics, 18(5), 3541-3561. https://doi.org/10.5194/acp-2017-892, https://doi.org/10.5194/acp-18-3541-2018

Vancouver

Stone D, Sherwen T, Evans MJ, Vaughan S, Ingham T, Whalley LK et al. Impacts of bromine and iodine chemistry on tropospheric OH and HO2: Comparing observations with box and global model perspectives. Atmospheric Chemistry and Physics. 2018 Mar 12;18(5):3541-3561. https://doi.org/10.5194/acp-2017-892, https://doi.org/10.5194/acp-18-3541-2018

Author

Stone, Daniel ; Sherwen, Toms ; Evans, Mathew J. ; Vaughan, Stewart ; Ingham, Trevor ; Whalley, Lisa K. ; Edwards, Peter M. ; Read, Katie A. ; Lee, James D. ; Moller, Sarah J. ; Carpenter, Lucy J. ; Lewis, Alastair C. ; Heard, Dwayne E. / Impacts of bromine and iodine chemistry on tropospheric OH and HO2 : Comparing observations with box and global model perspectives. In: Atmospheric Chemistry and Physics. 2018 ; Vol. 18, No. 5. pp. 3541-3561.

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@article{30dc3aa49af9440f8280ad02420467ca,
title = "Impacts of bromine and iodine chemistry on tropospheric OH and HO2: Comparing observations with box and global model perspectives",
abstract = "The chemistry of the halogen species bromine and iodine has a range of impacts on tropospheric composition, and can affect oxidising capacity in a number of ways. However, recent studies disagree on the overall sign of the impacts of halogens on the oxidising capacity of the troposphere. We present simulations of OH and HO2 radicals for comparison with observations made in the remote tropical ocean boundary layer during the Seasonal Oxidant Study at the Cape Verde Atmospheric Observatory in 2009. We use both a constrained box model, using detailed chemistry derived from the Master Chemical Mechanism (v3.2), and the three-dimensional global chemistry transport model GEOS-Chem. Both model approaches reproduce the diurnal trends in OH and HO2. Absolute observed concentrations are well reproduced by the box model but are overpredicted by the global model, potentially owing to incomplete consideration of oceanic sourced radical sinks. The two models, however, differ in the impacts of halogen chemistry. In the box model, halogen chemistry acts to increase OH concentrations (by 9.8{\%} at midday at the Cape Verde Atmospheric Observatory), while the global model exhibits a small increase in OH at the Cape Verde Atmospheric Observatory (by 0.6{\%} at midday) but overall shows a decrease in the global annual mass-weighted mean OH of 4.5{\%}. These differences reflect the variety of timescales through which the halogens impact the chemical system. On short timescales, photolysis of HOBr and HOI, produced by reactions of HO2 with BrO and IO, respectively, increases the OH concentration. On longer timescales, halogen-catalysed ozone destruction cycles lead to lower primary production of OH radicals through ozone photolysis, and thus to lower OH concentrations. The global model includes more of the longer timescale responses than the constrained box model, and overall the global impact of the longer timescale response (reduced primary production due to lower O3 concentrations) overwhelms the shorter timescale response (enhanced cycling from HO2 to OH), and thus the global OH concentration decreases. The Earth system contains many such responses on a large range of timescales. This work highlights the care that needs to be taken to understand the full impact of any one process on the system as a whole.",
keywords = "halogens, BOX MODEL, modelling, bromine, iodine, cape verde, OH, HO2, oxidants, global modelling, GEOSChem",
author = "Daniel Stone and Toms Sherwen and Evans, {Mathew J.} and Stewart Vaughan and Trevor Ingham and Whalley, {Lisa K.} and Edwards, {Peter M.} and Read, {Katie A.} and Lee, {James D.} and Moller, {Sarah J.} and Carpenter, {Lucy J.} and Lewis, {Alastair C.} and Heard, {Dwayne E.}",
note = "{\circledC} The Author(s), 2017.",
year = "2018",
month = "3",
day = "12",
doi = "10.5194/acp-2017-892",
language = "English",
volume = "18",
pages = "3541--3561",
journal = "Atmospheric Chemistry and Physics",
issn = "1680-7316",
publisher = "Copernicus Publications",
number = "5",

}

RIS (suitable for import to EndNote) - Download

TY - JOUR

T1 - Impacts of bromine and iodine chemistry on tropospheric OH and HO2

T2 - Comparing observations with box and global model perspectives

AU - Stone, Daniel

AU - Sherwen, Toms

AU - Evans, Mathew J.

AU - Vaughan, Stewart

AU - Ingham, Trevor

AU - Whalley, Lisa K.

AU - Edwards, Peter M.

AU - Read, Katie A.

AU - Lee, James D.

AU - Moller, Sarah J.

AU - Carpenter, Lucy J.

AU - Lewis, Alastair C.

AU - Heard, Dwayne E.

N1 - © The Author(s), 2017.

PY - 2018/3/12

Y1 - 2018/3/12

N2 - The chemistry of the halogen species bromine and iodine has a range of impacts on tropospheric composition, and can affect oxidising capacity in a number of ways. However, recent studies disagree on the overall sign of the impacts of halogens on the oxidising capacity of the troposphere. We present simulations of OH and HO2 radicals for comparison with observations made in the remote tropical ocean boundary layer during the Seasonal Oxidant Study at the Cape Verde Atmospheric Observatory in 2009. We use both a constrained box model, using detailed chemistry derived from the Master Chemical Mechanism (v3.2), and the three-dimensional global chemistry transport model GEOS-Chem. Both model approaches reproduce the diurnal trends in OH and HO2. Absolute observed concentrations are well reproduced by the box model but are overpredicted by the global model, potentially owing to incomplete consideration of oceanic sourced radical sinks. The two models, however, differ in the impacts of halogen chemistry. In the box model, halogen chemistry acts to increase OH concentrations (by 9.8% at midday at the Cape Verde Atmospheric Observatory), while the global model exhibits a small increase in OH at the Cape Verde Atmospheric Observatory (by 0.6% at midday) but overall shows a decrease in the global annual mass-weighted mean OH of 4.5%. These differences reflect the variety of timescales through which the halogens impact the chemical system. On short timescales, photolysis of HOBr and HOI, produced by reactions of HO2 with BrO and IO, respectively, increases the OH concentration. On longer timescales, halogen-catalysed ozone destruction cycles lead to lower primary production of OH radicals through ozone photolysis, and thus to lower OH concentrations. The global model includes more of the longer timescale responses than the constrained box model, and overall the global impact of the longer timescale response (reduced primary production due to lower O3 concentrations) overwhelms the shorter timescale response (enhanced cycling from HO2 to OH), and thus the global OH concentration decreases. The Earth system contains many such responses on a large range of timescales. This work highlights the care that needs to be taken to understand the full impact of any one process on the system as a whole.

AB - The chemistry of the halogen species bromine and iodine has a range of impacts on tropospheric composition, and can affect oxidising capacity in a number of ways. However, recent studies disagree on the overall sign of the impacts of halogens on the oxidising capacity of the troposphere. We present simulations of OH and HO2 radicals for comparison with observations made in the remote tropical ocean boundary layer during the Seasonal Oxidant Study at the Cape Verde Atmospheric Observatory in 2009. We use both a constrained box model, using detailed chemistry derived from the Master Chemical Mechanism (v3.2), and the three-dimensional global chemistry transport model GEOS-Chem. Both model approaches reproduce the diurnal trends in OH and HO2. Absolute observed concentrations are well reproduced by the box model but are overpredicted by the global model, potentially owing to incomplete consideration of oceanic sourced radical sinks. The two models, however, differ in the impacts of halogen chemistry. In the box model, halogen chemistry acts to increase OH concentrations (by 9.8% at midday at the Cape Verde Atmospheric Observatory), while the global model exhibits a small increase in OH at the Cape Verde Atmospheric Observatory (by 0.6% at midday) but overall shows a decrease in the global annual mass-weighted mean OH of 4.5%. These differences reflect the variety of timescales through which the halogens impact the chemical system. On short timescales, photolysis of HOBr and HOI, produced by reactions of HO2 with BrO and IO, respectively, increases the OH concentration. On longer timescales, halogen-catalysed ozone destruction cycles lead to lower primary production of OH radicals through ozone photolysis, and thus to lower OH concentrations. The global model includes more of the longer timescale responses than the constrained box model, and overall the global impact of the longer timescale response (reduced primary production due to lower O3 concentrations) overwhelms the shorter timescale response (enhanced cycling from HO2 to OH), and thus the global OH concentration decreases. The Earth system contains many such responses on a large range of timescales. This work highlights the care that needs to be taken to understand the full impact of any one process on the system as a whole.

KW - halogens

KW - BOX MODEL

KW - modelling

KW - bromine

KW - iodine

KW - cape verde

KW - OH

KW - HO2

KW - oxidants

KW - global modelling

KW - GEOSChem

UR - http://www.scopus.com/inward/record.url?scp=85043569591&partnerID=8YFLogxK

U2 - 10.5194/acp-2017-892

DO - 10.5194/acp-2017-892

M3 - Article

VL - 18

SP - 3541

EP - 3561

JO - Atmospheric Chemistry and Physics

JF - Atmospheric Chemistry and Physics

SN - 1680-7316

IS - 5

ER -