Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry
Post-depositional processes alter nitrate concentration and nitrate isotopic composition in the top layers of snow at sites with low snow accumulation rates, such as Dome C, Antarctica. Available nitrate ice core records can provide input for studying past atmospheres and climate if such processes a...
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craippubl:10.1063/1.4882898 2024-06-23T07:47:05+00:00 Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry Meusinger, Carl Berhanu, Tesfaye A. Erbland, Joseph Savarino, Joel Johnson, Matthew S. European Commission European Commission Agence Nationale de la Recherche Labex OSUG@2020 Institut Polaire Française Paul Emile Victor Institut National des Sciences de l'Univers 2014 http://dx.doi.org/10.1063/1.4882898 https://pubs.aip.org/aip/jcp/article-pdf/doi/10.1063/1.4882898/14082314/244305_1_online.pdf en eng AIP Publishing The Journal of Chemical Physics volume 140, issue 24 ISSN 0021-9606 1089-7690 journal-article 2014 craippubl https://doi.org/10.1063/1.4882898 2024-05-24T12:55:49Z Post-depositional processes alter nitrate concentration and nitrate isotopic composition in the top layers of snow at sites with low snow accumulation rates, such as Dome C, Antarctica. Available nitrate ice core records can provide input for studying past atmospheres and climate if such processes are understood. It has been shown that photolysis of nitrate in the snowpack plays a major role in nitrate loss and that the photolysis products have a significant influence on the local troposphere as well as on other species in the snow. Reported quantum yields for the main reaction spans orders of magnitude – apparently a result of whether nitrate is located at the air-ice interface or in the ice matrix – constituting the largest uncertainty in models of snowpack NOx emissions. Here, a laboratory study is presented that uses snow from Dome C and minimizes effects of desorption and recombination by flushing the snow during irradiation with UV light. A selection of UV filters allowed examination of the effects of the 200 and 305 nm absorption bands of nitrate. Nitrate concentration and photon flux were measured in the snow. The quantum yield for loss of nitrate was observed to decrease from 0.44 to 0.003 within what corresponds to days of UV exposure in Antarctica. The superposition of photolysis in two photochemical domains of nitrate in snow is proposed: one of photolabile nitrate, and one of buried nitrate. The difference lies in the ability of reaction products to escape the snow crystal, versus undergoing secondary (recombination) chemistry. Modeled NOx emissions may increase significantly above measured values due to the observed quantum yield in this study. The apparent quantum yield in the 200 nm band was found to be ∼1%, much lower than reported for aqueous chemistry. A companion paper presents an analysis of the change in isotopic composition of snowpack nitrate based on the same samples as in this study. Article in Journal/Newspaper Antarc* Antarctic Antarctica ice core AIP Publishing Antarctic The Journal of Chemical Physics 140 24 244305 |
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AIP Publishing |
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craippubl |
language |
English |
description |
Post-depositional processes alter nitrate concentration and nitrate isotopic composition in the top layers of snow at sites with low snow accumulation rates, such as Dome C, Antarctica. Available nitrate ice core records can provide input for studying past atmospheres and climate if such processes are understood. It has been shown that photolysis of nitrate in the snowpack plays a major role in nitrate loss and that the photolysis products have a significant influence on the local troposphere as well as on other species in the snow. Reported quantum yields for the main reaction spans orders of magnitude – apparently a result of whether nitrate is located at the air-ice interface or in the ice matrix – constituting the largest uncertainty in models of snowpack NOx emissions. Here, a laboratory study is presented that uses snow from Dome C and minimizes effects of desorption and recombination by flushing the snow during irradiation with UV light. A selection of UV filters allowed examination of the effects of the 200 and 305 nm absorption bands of nitrate. Nitrate concentration and photon flux were measured in the snow. The quantum yield for loss of nitrate was observed to decrease from 0.44 to 0.003 within what corresponds to days of UV exposure in Antarctica. The superposition of photolysis in two photochemical domains of nitrate in snow is proposed: one of photolabile nitrate, and one of buried nitrate. The difference lies in the ability of reaction products to escape the snow crystal, versus undergoing secondary (recombination) chemistry. Modeled NOx emissions may increase significantly above measured values due to the observed quantum yield in this study. The apparent quantum yield in the 200 nm band was found to be ∼1%, much lower than reported for aqueous chemistry. A companion paper presents an analysis of the change in isotopic composition of snowpack nitrate based on the same samples as in this study. |
author2 |
European Commission European Commission Agence Nationale de la Recherche Labex OSUG@2020 Institut Polaire Française Paul Emile Victor Institut National des Sciences de l'Univers |
format |
Article in Journal/Newspaper |
author |
Meusinger, Carl Berhanu, Tesfaye A. Erbland, Joseph Savarino, Joel Johnson, Matthew S. |
spellingShingle |
Meusinger, Carl Berhanu, Tesfaye A. Erbland, Joseph Savarino, Joel Johnson, Matthew S. Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry |
author_facet |
Meusinger, Carl Berhanu, Tesfaye A. Erbland, Joseph Savarino, Joel Johnson, Matthew S. |
author_sort |
Meusinger, Carl |
title |
Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry |
title_short |
Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry |
title_full |
Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry |
title_fullStr |
Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry |
title_full_unstemmed |
Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry |
title_sort |
laboratory study of nitrate photolysis in antarctic snow. i. observed quantum yield, domain of photolysis, and secondary chemistry |
publisher |
AIP Publishing |
publishDate |
2014 |
url |
http://dx.doi.org/10.1063/1.4882898 https://pubs.aip.org/aip/jcp/article-pdf/doi/10.1063/1.4882898/14082314/244305_1_online.pdf |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Antarctica ice core |
genre_facet |
Antarc* Antarctic Antarctica ice core |
op_source |
The Journal of Chemical Physics volume 140, issue 24 ISSN 0021-9606 1089-7690 |
op_doi |
https://doi.org/10.1063/1.4882898 |
container_title |
The Journal of Chemical Physics |
container_volume |
140 |
container_issue |
24 |
container_start_page |
244305 |
_version_ |
1802650686750457856 |