Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations
While the hydroxyl radical (•OH) in the snowpack is likely a dominant oxidant for organic species and bromide, little is known about the kinetics or steady-state concentrations of •OH on/in snow and ice. Here we measure the formation rate, lifetime, and concentration of •OH for illuminated polar sno...
Published in: | Atmospheric Chemistry and Physics |
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00043425 2023-05-15T16:28:45+02:00 Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations Chen, Zeyuan Chu, Liang Galbavy, Edward S. Ram, Keren Anastasio, Cort 2016-08 electronic https://doi.org/10.5194/acp-16-9579-2016 https://noa.gwlb.de/receive/cop_mods_00043425 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043045/acp-16-9579-2016.pdf https://acp.copernicus.org/articles/16/9579/2016/acp-16-9579-2016.pdf eng eng Copernicus Publications Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-16-9579-2016 https://noa.gwlb.de/receive/cop_mods_00043425 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043045/acp-16-9579-2016.pdf https://acp.copernicus.org/articles/16/9579/2016/acp-16-9579-2016.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2016 ftnonlinearchiv https://doi.org/10.5194/acp-16-9579-2016 2022-02-08T22:40:33Z While the hydroxyl radical (•OH) in the snowpack is likely a dominant oxidant for organic species and bromide, little is known about the kinetics or steady-state concentrations of •OH on/in snow and ice. Here we measure the formation rate, lifetime, and concentration of •OH for illuminated polar snow samples studied in the laboratory and in the field. Laboratory studies show that •OH kinetics and steady-state concentrations are essentially the same for a given sample studied as ice and liquid; this is in contrast to other photooxidants, which show a concentration enhancement in ice relative to solution as a result of kinetic differences in the two phases. The average production rate of •OH in samples studied at Summit, Greenland, is 5 times lower than the average measured in the laboratory, while the average •OH lifetime determined in the field is 5 times higher than in the laboratory. These differences indicate that the polar snows we studied in the laboratory are affected by contamination, despite significant efforts to prevent this; our results suggest similar contamination may be a widespread problem in laboratory studies of ice chemistry. Steady-state concentrations of •OH in clean snow studied in the field at Summit, Greenland, range from (0.8 to 3) × 10−15 M, comparable to values reported for midlatitude cloud and fog drops, rain, and deliquesced marine particles, even though impurity concentrations in the snow samples are much lower. Partitioning of firn air •OH to the snow grains will approximately double the steady-state concentration of snow-grain hydroxyl radical, leading to an average [•OH] in near-surface, summer Summit snow of approximately 4 × 10−15 M. At this concentration, the •OH-mediated lifetimes of organics and bromide in Summit snow grains are approximately 3 days and 7 h, respectively, suggesting that hydroxyl radical is a major oxidant for both species. Article in Journal/Newspaper Greenland Niedersächsisches Online-Archiv NOA Greenland Atmospheric Chemistry and Physics 16 15 9579 9590 |
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Niedersächsisches Online-Archiv NOA |
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article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Chen, Zeyuan Chu, Liang Galbavy, Edward S. Ram, Keren Anastasio, Cort Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
topic_facet |
article Verlagsveröffentlichung |
description |
While the hydroxyl radical (•OH) in the snowpack is likely a dominant oxidant for organic species and bromide, little is known about the kinetics or steady-state concentrations of •OH on/in snow and ice. Here we measure the formation rate, lifetime, and concentration of •OH for illuminated polar snow samples studied in the laboratory and in the field. Laboratory studies show that •OH kinetics and steady-state concentrations are essentially the same for a given sample studied as ice and liquid; this is in contrast to other photooxidants, which show a concentration enhancement in ice relative to solution as a result of kinetic differences in the two phases. The average production rate of •OH in samples studied at Summit, Greenland, is 5 times lower than the average measured in the laboratory, while the average •OH lifetime determined in the field is 5 times higher than in the laboratory. These differences indicate that the polar snows we studied in the laboratory are affected by contamination, despite significant efforts to prevent this; our results suggest similar contamination may be a widespread problem in laboratory studies of ice chemistry. Steady-state concentrations of •OH in clean snow studied in the field at Summit, Greenland, range from (0.8 to 3) × 10−15 M, comparable to values reported for midlatitude cloud and fog drops, rain, and deliquesced marine particles, even though impurity concentrations in the snow samples are much lower. Partitioning of firn air •OH to the snow grains will approximately double the steady-state concentration of snow-grain hydroxyl radical, leading to an average [•OH] in near-surface, summer Summit snow of approximately 4 × 10−15 M. At this concentration, the •OH-mediated lifetimes of organics and bromide in Summit snow grains are approximately 3 days and 7 h, respectively, suggesting that hydroxyl radical is a major oxidant for both species. |
format |
Article in Journal/Newspaper |
author |
Chen, Zeyuan Chu, Liang Galbavy, Edward S. Ram, Keren Anastasio, Cort |
author_facet |
Chen, Zeyuan Chu, Liang Galbavy, Edward S. Ram, Keren Anastasio, Cort |
author_sort |
Chen, Zeyuan |
title |
Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
title_short |
Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
title_full |
Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
title_fullStr |
Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
title_full_unstemmed |
Hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
title_sort |
hydroxyl radical in/on illuminated polar snow: formation rates, lifetimes, and steady-state concentrations |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/acp-16-9579-2016 https://noa.gwlb.de/receive/cop_mods_00043425 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043045/acp-16-9579-2016.pdf https://acp.copernicus.org/articles/16/9579/2016/acp-16-9579-2016.pdf |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_relation |
Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-16-9579-2016 https://noa.gwlb.de/receive/cop_mods_00043425 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043045/acp-16-9579-2016.pdf https://acp.copernicus.org/articles/16/9579/2016/acp-16-9579-2016.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/acp-16-9579-2016 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
16 |
container_issue |
15 |
container_start_page |
9579 |
op_container_end_page |
9590 |
_version_ |
1766018430409900032 |