Late summer transition from a free-tropospheric to boundary layer source of Aitken mode aerosol in the high Arctic
In the Arctic, the aerosol budget plays a particular role in determining the behaviour of clouds, which are important for the surface energy balance and thus for the region’s climate. A key question is the extent to which cloud condensation nuclei in the high Arctic summertime boundary layer are con...
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Online Access: | https://doi.org/10.5194/acp-23-2927-2023 https://acp.copernicus.org/articles/23/2927/2023/ |
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ftcopernicus:oai:publications.copernicus.org:acp107013 2023-05-15T14:38:48+02:00 Late summer transition from a free-tropospheric to boundary layer source of Aitken mode aerosol in the high Arctic Price, Ruth Baccarini, Andrea Schmale, Julia Zieger, Paul Brooks, Ian M. Field, Paul Carslaw, Ken S. 2023-03-06 application/pdf https://doi.org/10.5194/acp-23-2927-2023 https://acp.copernicus.org/articles/23/2927/2023/ eng eng doi:10.5194/acp-23-2927-2023 https://acp.copernicus.org/articles/23/2927/2023/ eISSN: 1680-7324 Text 2023 ftcopernicus https://doi.org/10.5194/acp-23-2927-2023 2023-03-13T17:23:11Z In the Arctic, the aerosol budget plays a particular role in determining the behaviour of clouds, which are important for the surface energy balance and thus for the region’s climate. A key question is the extent to which cloud condensation nuclei in the high Arctic summertime boundary layer are controlled by local emission and formation processes as opposed to transport from outside. Each of these sources is likely to respond differently to future changes in ice cover. Here we use a global model and observations from ship and aircraft field campaigns to understand the source of high Arctic aerosol in late summer. We find that particles formed remotely, i.e. at latitudes outside the Arctic, are the dominant source of boundary layer Aitken mode particles during the sea ice melt period up to the end of August. Particles from such remote sources, entrained into the boundary layer from the free troposphere, account for nucleation and Aitken mode particle concentrations that are otherwise underestimated by the model. This source from outside the high Arctic declines as photochemical rates decrease towards the end of summer and is largely replaced by local new particle formation driven by iodic acid created during freeze-up. Such a local source increases the simulated Aitken mode particle concentrations by 2 orders of magnitude during sea ice freeze-up and is consistent with strong fluctuations in nucleation mode concentrations that occur in September. Our results suggest a high-Arctic aerosol regime shift in late summer, and only after this shift do cloud condensation nuclei become sensitive to local aerosol processes. Text Arctic Sea ice Copernicus Publications: E-Journals Aitken ENVELOPE(-44.516,-44.516,-60.733,-60.733) Arctic Atmospheric Chemistry and Physics 23 5 2927 2961 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
In the Arctic, the aerosol budget plays a particular role in determining the behaviour of clouds, which are important for the surface energy balance and thus for the region’s climate. A key question is the extent to which cloud condensation nuclei in the high Arctic summertime boundary layer are controlled by local emission and formation processes as opposed to transport from outside. Each of these sources is likely to respond differently to future changes in ice cover. Here we use a global model and observations from ship and aircraft field campaigns to understand the source of high Arctic aerosol in late summer. We find that particles formed remotely, i.e. at latitudes outside the Arctic, are the dominant source of boundary layer Aitken mode particles during the sea ice melt period up to the end of August. Particles from such remote sources, entrained into the boundary layer from the free troposphere, account for nucleation and Aitken mode particle concentrations that are otherwise underestimated by the model. This source from outside the high Arctic declines as photochemical rates decrease towards the end of summer and is largely replaced by local new particle formation driven by iodic acid created during freeze-up. Such a local source increases the simulated Aitken mode particle concentrations by 2 orders of magnitude during sea ice freeze-up and is consistent with strong fluctuations in nucleation mode concentrations that occur in September. Our results suggest a high-Arctic aerosol regime shift in late summer, and only after this shift do cloud condensation nuclei become sensitive to local aerosol processes. |
format |
Text |
author |
Price, Ruth Baccarini, Andrea Schmale, Julia Zieger, Paul Brooks, Ian M. Field, Paul Carslaw, Ken S. |
spellingShingle |
Price, Ruth Baccarini, Andrea Schmale, Julia Zieger, Paul Brooks, Ian M. Field, Paul Carslaw, Ken S. Late summer transition from a free-tropospheric to boundary layer source of Aitken mode aerosol in the high Arctic |
author_facet |
Price, Ruth Baccarini, Andrea Schmale, Julia Zieger, Paul Brooks, Ian M. Field, Paul Carslaw, Ken S. |
author_sort |
Price, Ruth |
title |
Late summer transition from a free-tropospheric to boundary layer source of Aitken mode aerosol in the high Arctic |
title_short |
Late summer transition from a free-tropospheric to boundary layer source of Aitken mode aerosol in the high Arctic |
title_full |
Late summer transition from a free-tropospheric to boundary layer source of Aitken mode aerosol in the high Arctic |
title_fullStr |
Late summer transition from a free-tropospheric to boundary layer source of Aitken mode aerosol in the high Arctic |
title_full_unstemmed |
Late summer transition from a free-tropospheric to boundary layer source of Aitken mode aerosol in the high Arctic |
title_sort |
late summer transition from a free-tropospheric to boundary layer source of aitken mode aerosol in the high arctic |
publishDate |
2023 |
url |
https://doi.org/10.5194/acp-23-2927-2023 https://acp.copernicus.org/articles/23/2927/2023/ |
long_lat |
ENVELOPE(-44.516,-44.516,-60.733,-60.733) |
geographic |
Aitken Arctic |
geographic_facet |
Aitken Arctic |
genre |
Arctic Sea ice |
genre_facet |
Arctic Sea ice |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-23-2927-2023 https://acp.copernicus.org/articles/23/2927/2023/ |
op_doi |
https://doi.org/10.5194/acp-23-2927-2023 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
23 |
container_issue |
5 |
container_start_page |
2927 |
op_container_end_page |
2961 |
_version_ |
1766310819630415872 |