Measurements of OH and HO2 concentrations in the Southern Ocean marine boundary layer

Field measurements of hydroxyl (OH) and hydroperoxy (HO2) radicals have been made in the remote Southern Ocean marine boundary layer at the Cape Grim Baseline Air Pollution Station in northwestern Tasmania. Measurements were made with a time resolution of 30 s over a period of 4 weeks during austral...

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Published in:Journal of Geophysical Research
Main Authors: Creasey, D.J., Evans, G.E., Heard, D.E., Lee, J.D.
Format: Article in Journal/Newspaper
Language:unknown
Published: American Geophysical Union 2003
Subjects:
Online Access:https://eprints.whiterose.ac.uk/6696/
https://doi.org/10.1029/2002JD003206
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spelling ftleedsuniv:oai:eprints.whiterose.ac.uk:6696 2024-06-02T07:56:50+00:00 Measurements of OH and HO2 concentrations in the Southern Ocean marine boundary layer Creasey, D.J. Evans, G.E. Heard, D.E. Lee, J.D. 2003-08-13 https://eprints.whiterose.ac.uk/6696/ https://doi.org/10.1029/2002JD003206 unknown American Geophysical Union Creasey, D.J., Evans, G.E., Heard, D.E. et al. (1 more author) (2003) Measurements of OH and HO2 concentrations in the Southern Ocean marine boundary layer. Journal of Geophysical Research: Atmospheres, 108 (D15). pp. 4475-4486. ISSN 0148-0227 Article NonPeerReviewed 2003 ftleedsuniv https://doi.org/10.1029/2002JD003206 2024-05-06T12:32:12Z Field measurements of hydroxyl (OH) and hydroperoxy (HO2) radicals have been made in the remote Southern Ocean marine boundary layer at the Cape Grim Baseline Air Pollution Station in northwestern Tasmania. Measurements were made with a time resolution of 30 s over a period of 4 weeks during austral summer 1999 in the second Southern Ocean Photochemistry Experiment. Laser-induced fluorescence at reduced pressure was used to measure [OH] with an average detection limit at noon of (1.4 ± 0.5) × 105 molecule cm−3 (1σ), for a 2.5 min integration period, and HO2 was measured following its conversion to OH via the addition of NO, with an average detection limit of (5.4 ± 1.7) × 105 molecule cm−3 (1σ). Air masses arriving at Cape Grim originated from the Australian continent, Tasmania, and Southern Ocean/Antarctic regions, the latter (“Baseline” air) characterized by extremely low [NO] allowing a study of the chemistry of the unperturbed background atmosphere. In Baseline air, daytime average maxima for OH and HO2 of 3.5 × 106 molecule cm−3 (0.14 parts per trillion by volume (pptv)) and 2 × 108 molecule cm−3 (8 pptv) were observed, and a very high correlation coefficient (r = 0.95) was observed between the OH concentration and the rate of OH production from ozone photolysis. A steady state expression for OH, assuming production only from ozone photolysis and loss only by reaction with CO and CH4, overestimates the observed daytime maximum concentration in Baseline air by 20%. The HO2 concentration was found to depend upon the square root of the rate of O3 photolysis, as expected at very low concentrations of NO. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean White Rose Research Online (Universities of Leeds, Sheffield & York) Antarctic Austral Grim ENVELOPE(-64.486,-64.486,-65.379,-65.379) Southern Ocean Journal of Geophysical Research 108 D15
institution Open Polar
collection White Rose Research Online (Universities of Leeds, Sheffield & York)
op_collection_id ftleedsuniv
language unknown
description Field measurements of hydroxyl (OH) and hydroperoxy (HO2) radicals have been made in the remote Southern Ocean marine boundary layer at the Cape Grim Baseline Air Pollution Station in northwestern Tasmania. Measurements were made with a time resolution of 30 s over a period of 4 weeks during austral summer 1999 in the second Southern Ocean Photochemistry Experiment. Laser-induced fluorescence at reduced pressure was used to measure [OH] with an average detection limit at noon of (1.4 ± 0.5) × 105 molecule cm−3 (1σ), for a 2.5 min integration period, and HO2 was measured following its conversion to OH via the addition of NO, with an average detection limit of (5.4 ± 1.7) × 105 molecule cm−3 (1σ). Air masses arriving at Cape Grim originated from the Australian continent, Tasmania, and Southern Ocean/Antarctic regions, the latter (“Baseline” air) characterized by extremely low [NO] allowing a study of the chemistry of the unperturbed background atmosphere. In Baseline air, daytime average maxima for OH and HO2 of 3.5 × 106 molecule cm−3 (0.14 parts per trillion by volume (pptv)) and 2 × 108 molecule cm−3 (8 pptv) were observed, and a very high correlation coefficient (r = 0.95) was observed between the OH concentration and the rate of OH production from ozone photolysis. A steady state expression for OH, assuming production only from ozone photolysis and loss only by reaction with CO and CH4, overestimates the observed daytime maximum concentration in Baseline air by 20%. The HO2 concentration was found to depend upon the square root of the rate of O3 photolysis, as expected at very low concentrations of NO.
format Article in Journal/Newspaper
author Creasey, D.J.
Evans, G.E.
Heard, D.E.
Lee, J.D.
spellingShingle Creasey, D.J.
Evans, G.E.
Heard, D.E.
Lee, J.D.
Measurements of OH and HO2 concentrations in the Southern Ocean marine boundary layer
author_facet Creasey, D.J.
Evans, G.E.
Heard, D.E.
Lee, J.D.
author_sort Creasey, D.J.
title Measurements of OH and HO2 concentrations in the Southern Ocean marine boundary layer
title_short Measurements of OH and HO2 concentrations in the Southern Ocean marine boundary layer
title_full Measurements of OH and HO2 concentrations in the Southern Ocean marine boundary layer
title_fullStr Measurements of OH and HO2 concentrations in the Southern Ocean marine boundary layer
title_full_unstemmed Measurements of OH and HO2 concentrations in the Southern Ocean marine boundary layer
title_sort measurements of oh and ho2 concentrations in the southern ocean marine boundary layer
publisher American Geophysical Union
publishDate 2003
url https://eprints.whiterose.ac.uk/6696/
https://doi.org/10.1029/2002JD003206
long_lat ENVELOPE(-64.486,-64.486,-65.379,-65.379)
geographic Antarctic
Austral
Grim
Southern Ocean
geographic_facet Antarctic
Austral
Grim
Southern Ocean
genre Antarc*
Antarctic
Southern Ocean
genre_facet Antarc*
Antarctic
Southern Ocean
op_relation Creasey, D.J., Evans, G.E., Heard, D.E. et al. (1 more author) (2003) Measurements of OH and HO2 concentrations in the Southern Ocean marine boundary layer. Journal of Geophysical Research: Atmospheres, 108 (D15). pp. 4475-4486. ISSN 0148-0227
op_doi https://doi.org/10.1029/2002JD003206
container_title Journal of Geophysical Research
container_volume 108
container_issue D15
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