Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)
Emissions of nitrogen oxide (NOx = NO + NO2) from the photolysis of nitrate (NO3−) in snow affect the oxidising capacity of the lower troposphere especially in remote regions of high latitudes with little pollution. Current air–snow exchange models are limited by poor understanding of processes and...
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Copernicus Publications on behalf of the European Geosciences Union
2018
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Online Access: | http://nora.nerc.ac.uk/id/eprint/515290/ https://nora.nerc.ac.uk/id/eprint/515290/1/Chan.pdf https://www.atmos-chem-phys.net/18/1507/2018/ |
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ftnerc:oai:nora.nerc.ac.uk:515290 2023-05-15T13:49:33+02:00 Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley) Chan, Hoi Ga Frey, Markus King, Martin 2018-02-02 text http://nora.nerc.ac.uk/id/eprint/515290/ https://nora.nerc.ac.uk/id/eprint/515290/1/Chan.pdf https://www.atmos-chem-phys.net/18/1507/2018/ en eng Copernicus Publications on behalf of the European Geosciences Union https://nora.nerc.ac.uk/id/eprint/515290/1/Chan.pdf Chan, Hoi Ga; Frey, Markus orcid:0000-0003-0535-0416 King, Martin. 2018 Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley). Atmospheric Chemistry and Physics, 18 (3). 1507-1534. https://doi.org/10.5194/acp-18-1507-2018 <https://doi.org/10.5194/acp-18-1507-2018> cc_by CC-BY Publication - Article PeerReviewed 2018 ftnerc https://doi.org/10.5194/acp-18-1507-2018 2023-02-04T19:43:58Z Emissions of nitrogen oxide (NOx = NO + NO2) from the photolysis of nitrate (NO3−) in snow affect the oxidising capacity of the lower troposphere especially in remote regions of high latitudes with little pollution. Current air–snow exchange models are limited by poor understanding of processes and often require unphysical tuning parameters. Here, two multiphase models were developed from physically based parameterisations to describe the interaction of nitrate between the surface layer of the snowpack and the overlying atmosphere. The first model is similar to previous approaches and assumes that below a threshold temperature, To, the air–snow grain interface is pure ice and above To a disordered interface (DI) emerges covering the entire grain surface. The second model assumes that air–ice interactions dominate over all temperatures below melting of ice and that any liquid present above the eutectic temperature is concentrated in micropockets. The models are used to predict the nitrate in surface snow constrained by year-round observations of mixing ratios of nitric acid in air at a cold site on the Antarctic Plateau (Dome C; 75°06′ S, 123°33′ E; 3233 m a.s.l.) and at a relatively warm site on the Antarctic coast (Halley; 75°35′ S, 26°39′ E; 35 m a.s.l). The first model agrees reasonably well with observations at Dome C (Cv(RMSE) = 1.34) but performs poorly at Halley (Cv(RMSE) = 89.28) while the second model reproduces with good agreement observations at both sites (Cv(RMSE) = 0.84 at both sites). It is therefore suggested that in winter air–snow interactions of nitrate are determined by non-equilibrium surface adsorption and co-condensation on ice coupled with solid-state diffusion inside the grain, similar to Bock et al. (2016). In summer, however, the air–snow exchange of nitrate is mainly driven by solvation into liquid micropockets following Henry's law with contributions to total surface snow NO3− concentrations of 75 and 80 % at Dome C and Halley, respectively. It is also found that the liquid volume of ... Article in Journal/Newspaper Antarc* Antarctic Natural Environment Research Council: NERC Open Research Archive Antarctic The Antarctic Atmospheric Chemistry and Physics 18 3 1507 1534 |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Emissions of nitrogen oxide (NOx = NO + NO2) from the photolysis of nitrate (NO3−) in snow affect the oxidising capacity of the lower troposphere especially in remote regions of high latitudes with little pollution. Current air–snow exchange models are limited by poor understanding of processes and often require unphysical tuning parameters. Here, two multiphase models were developed from physically based parameterisations to describe the interaction of nitrate between the surface layer of the snowpack and the overlying atmosphere. The first model is similar to previous approaches and assumes that below a threshold temperature, To, the air–snow grain interface is pure ice and above To a disordered interface (DI) emerges covering the entire grain surface. The second model assumes that air–ice interactions dominate over all temperatures below melting of ice and that any liquid present above the eutectic temperature is concentrated in micropockets. The models are used to predict the nitrate in surface snow constrained by year-round observations of mixing ratios of nitric acid in air at a cold site on the Antarctic Plateau (Dome C; 75°06′ S, 123°33′ E; 3233 m a.s.l.) and at a relatively warm site on the Antarctic coast (Halley; 75°35′ S, 26°39′ E; 35 m a.s.l). The first model agrees reasonably well with observations at Dome C (Cv(RMSE) = 1.34) but performs poorly at Halley (Cv(RMSE) = 89.28) while the second model reproduces with good agreement observations at both sites (Cv(RMSE) = 0.84 at both sites). It is therefore suggested that in winter air–snow interactions of nitrate are determined by non-equilibrium surface adsorption and co-condensation on ice coupled with solid-state diffusion inside the grain, similar to Bock et al. (2016). In summer, however, the air–snow exchange of nitrate is mainly driven by solvation into liquid micropockets following Henry's law with contributions to total surface snow NO3− concentrations of 75 and 80 % at Dome C and Halley, respectively. It is also found that the liquid volume of ... |
format |
Article in Journal/Newspaper |
author |
Chan, Hoi Ga Frey, Markus King, Martin |
spellingShingle |
Chan, Hoi Ga Frey, Markus King, Martin Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley) |
author_facet |
Chan, Hoi Ga Frey, Markus King, Martin |
author_sort |
Chan, Hoi Ga |
title |
Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley) |
title_short |
Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley) |
title_full |
Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley) |
title_fullStr |
Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley) |
title_full_unstemmed |
Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley) |
title_sort |
modelling the physical multiphase interactions of hno3 between snow and air on the antarctic plateau (dome c) and coast (halley) |
publisher |
Copernicus Publications on behalf of the European Geosciences Union |
publishDate |
2018 |
url |
http://nora.nerc.ac.uk/id/eprint/515290/ https://nora.nerc.ac.uk/id/eprint/515290/1/Chan.pdf https://www.atmos-chem-phys.net/18/1507/2018/ |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
https://nora.nerc.ac.uk/id/eprint/515290/1/Chan.pdf Chan, Hoi Ga; Frey, Markus orcid:0000-0003-0535-0416 King, Martin. 2018 Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley). Atmospheric Chemistry and Physics, 18 (3). 1507-1534. https://doi.org/10.5194/acp-18-1507-2018 <https://doi.org/10.5194/acp-18-1507-2018> |
op_rights |
cc_by |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/acp-18-1507-2018 |
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Atmospheric Chemistry and Physics |
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18 |
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3 |
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1507 |
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1534 |
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1766251598129922048 |