Air–snow exchange of nitrate: a modelling approach to investigate physicochemical processes in surface snow at Dome C, Antarctica
Snowpack is a multiphase (photo)chemical reactor that strongly influences the air composition in polar and snow-covered regions. Snowpack plays a special role in the nitrogen cycle, as it has been shown that nitrate undergoes numerous recycling stages (including photolysis) in the snow before being...
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Copernicus Publications
2016
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00043138 2023-05-15T14:02:33+02:00 Air–snow exchange of nitrate: a modelling approach to investigate physicochemical processes in surface snow at Dome C, Antarctica Bock, Josué Savarino, Joël Picard, Ghislain 2016-10 electronic https://doi.org/10.5194/acp-16-12531-2016 https://noa.gwlb.de/receive/cop_mods_00043138 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00042758/acp-16-12531-2016.pdf https://acp.copernicus.org/articles/16/12531/2016/acp-16-12531-2016.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-16-12531-2016 https://noa.gwlb.de/receive/cop_mods_00043138 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00042758/acp-16-12531-2016.pdf https://acp.copernicus.org/articles/16/12531/2016/acp-16-12531-2016.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2016 ftnonlinearchiv https://doi.org/10.5194/acp-16-12531-2016 2022-02-08T22:40:43Z Snowpack is a multiphase (photo)chemical reactor that strongly influences the air composition in polar and snow-covered regions. Snowpack plays a special role in the nitrogen cycle, as it has been shown that nitrate undergoes numerous recycling stages (including photolysis) in the snow before being permanently buried in the ice. However, the current understanding of these physicochemical processes remains very poor. Several modelling studies have attempted to reproduce (photo)chemical reactions inside snow grains, but these have relied on strong assumptions to characterise snow reactive properties, which are not well defined. Air–snow exchange processes such as adsorption, solid-state diffusion, or co-condensation also affect snow chemical composition. Here, we present a physically based model of these processes for nitrate. Using as input a 1-year-long time series of atmospheric nitrate concentration measured at Dome C, Antarctica, our model reproduces with good agreement the nitrate measurements in the surface snow. By investigating the relative importance of the main exchange processes, this study shows that, on the one hand, the combination of bulk diffusion and co-condensation allows a good reproduction of the measurements (correlation coefficient r = 0.95), with a correct amplitude and timing of summer peak concentration of nitrate in snow. During winter, nitrate concentration in surface snow is mainly driven by thermodynamic equilibrium, whilst the peak observed in summer is explained by the kinetic process of co-condensation. On the other hand, the adsorption of nitric acid on the surface of the snow grains, constrained by an already existing parameterisation for the isotherm, fails to fit the observed variations. During winter and spring, the modelled concentration of adsorbed nitrate is respectively 2.5 and 8.3-fold higher than the measured one. A strong diurnal variation driven by the temperature cycle and a peak occurring in early spring are two other major features that do not match the measurements. This study clearly demonstrates that co-condensation is the most important process to explain nitrate incorporation in snow undergoing temperature gradient metamorphism. The parameterisation developed for this process can now be used as a foundation piece in snowpack models to predict the inter-relationship between snow physical evolution and snow nitrate chemistry. Article in Journal/Newspaper Antarc* Antarctica Niedersächsisches Online-Archiv NOA Atmospheric Chemistry and Physics 16 19 12531 12550 |
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article Verlagsveröffentlichung Bock, Josué Savarino, Joël Picard, Ghislain Air–snow exchange of nitrate: a modelling approach to investigate physicochemical processes in surface snow at Dome C, Antarctica |
topic_facet |
article Verlagsveröffentlichung |
description |
Snowpack is a multiphase (photo)chemical reactor that strongly influences the air composition in polar and snow-covered regions. Snowpack plays a special role in the nitrogen cycle, as it has been shown that nitrate undergoes numerous recycling stages (including photolysis) in the snow before being permanently buried in the ice. However, the current understanding of these physicochemical processes remains very poor. Several modelling studies have attempted to reproduce (photo)chemical reactions inside snow grains, but these have relied on strong assumptions to characterise snow reactive properties, which are not well defined. Air–snow exchange processes such as adsorption, solid-state diffusion, or co-condensation also affect snow chemical composition. Here, we present a physically based model of these processes for nitrate. Using as input a 1-year-long time series of atmospheric nitrate concentration measured at Dome C, Antarctica, our model reproduces with good agreement the nitrate measurements in the surface snow. By investigating the relative importance of the main exchange processes, this study shows that, on the one hand, the combination of bulk diffusion and co-condensation allows a good reproduction of the measurements (correlation coefficient r = 0.95), with a correct amplitude and timing of summer peak concentration of nitrate in snow. During winter, nitrate concentration in surface snow is mainly driven by thermodynamic equilibrium, whilst the peak observed in summer is explained by the kinetic process of co-condensation. On the other hand, the adsorption of nitric acid on the surface of the snow grains, constrained by an already existing parameterisation for the isotherm, fails to fit the observed variations. During winter and spring, the modelled concentration of adsorbed nitrate is respectively 2.5 and 8.3-fold higher than the measured one. A strong diurnal variation driven by the temperature cycle and a peak occurring in early spring are two other major features that do not match the measurements. This study clearly demonstrates that co-condensation is the most important process to explain nitrate incorporation in snow undergoing temperature gradient metamorphism. The parameterisation developed for this process can now be used as a foundation piece in snowpack models to predict the inter-relationship between snow physical evolution and snow nitrate chemistry. |
format |
Article in Journal/Newspaper |
author |
Bock, Josué Savarino, Joël Picard, Ghislain |
author_facet |
Bock, Josué Savarino, Joël Picard, Ghislain |
author_sort |
Bock, Josué |
title |
Air–snow exchange of nitrate: a modelling approach to investigate physicochemical processes in surface snow at Dome C, Antarctica |
title_short |
Air–snow exchange of nitrate: a modelling approach to investigate physicochemical processes in surface snow at Dome C, Antarctica |
title_full |
Air–snow exchange of nitrate: a modelling approach to investigate physicochemical processes in surface snow at Dome C, Antarctica |
title_fullStr |
Air–snow exchange of nitrate: a modelling approach to investigate physicochemical processes in surface snow at Dome C, Antarctica |
title_full_unstemmed |
Air–snow exchange of nitrate: a modelling approach to investigate physicochemical processes in surface snow at Dome C, Antarctica |
title_sort |
air–snow exchange of nitrate: a modelling approach to investigate physicochemical processes in surface snow at dome c, antarctica |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/acp-16-12531-2016 https://noa.gwlb.de/receive/cop_mods_00043138 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00042758/acp-16-12531-2016.pdf https://acp.copernicus.org/articles/16/12531/2016/acp-16-12531-2016.pdf |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
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-16-12531-2016 https://noa.gwlb.de/receive/cop_mods_00043138 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00042758/acp-16-12531-2016.pdf https://acp.copernicus.org/articles/16/12531/2016/acp-16-12531-2016.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/acp-16-12531-2016 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
16 |
container_issue |
19 |
container_start_page |
12531 |
op_container_end_page |
12550 |
_version_ |
1766272856735350784 |