Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice
Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measur...
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Online Access: | https://doi.org/10.5194/acp-16-2185-2016 http://ecite.utas.edu.au/109662 |
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ftunivtasecite:oai:ecite.utas.edu.au:109662 2023-05-15T14:03:26+02:00 Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice Humphries, RS Klekociuk, AR Schofield, R Keywood, M Ward, J Wilson, SR 2016 application/pdf https://doi.org/10.5194/acp-16-2185-2016 http://ecite.utas.edu.au/109662 en eng Copernicus GmbH http://ecite.utas.edu.au/109662/1/Humphries&+ (2016)_ACP [Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice].pdf http://dx.doi.org/10.5194/acp-16-2185-2016 Humphries, RS and Klekociuk, AR and Schofield, R and Keywood, M and Ward, J and Wilson, SR, Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice, Atmospheric Chemistry and Physics, 16, (4) pp. 2185-2206. ISSN 1680-7316 (2016) [Refereed Article] http://ecite.utas.edu.au/109662 Earth Sciences Atmospheric Sciences Atmospheric Aerosols Refereed Article PeerReviewed 2016 ftunivtasecite https://doi.org/10.5194/acp-16-2185-2016 2019-12-13T22:10:19Z Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measurements that are often limited to boundary layer air masses at spatially sparse coastal and continental research stations, with only ahandful of studies in the vast sea-ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the icebreaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN 3 ) concentrations exhibited afive-fold increase moving across the polar front, with mean polar cell concentrations of 1130 cm −3 higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, asimilar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low-pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air masses quickly from the free troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea-ice boundary layer air masses travelled equatorward into the low-albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei which, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between simulations and observations of cloud and aerosol over the Southern Ocean. Article in Journal/Newspaper Antarc* Antarctic Antarctica aurora australis Sea ice Southern Ocean eCite UTAS (University of Tasmania) Antarctic Southern Ocean The Antarctic Atmospheric Chemistry and Physics 16 4 2185 2206 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Atmospheric Sciences Atmospheric Aerosols |
spellingShingle |
Earth Sciences Atmospheric Sciences Atmospheric Aerosols Humphries, RS Klekociuk, AR Schofield, R Keywood, M Ward, J Wilson, SR Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice |
topic_facet |
Earth Sciences Atmospheric Sciences Atmospheric Aerosols |
description |
Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measurements that are often limited to boundary layer air masses at spatially sparse coastal and continental research stations, with only ahandful of studies in the vast sea-ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the icebreaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN 3 ) concentrations exhibited afive-fold increase moving across the polar front, with mean polar cell concentrations of 1130 cm −3 higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, asimilar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low-pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air masses quickly from the free troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea-ice boundary layer air masses travelled equatorward into the low-albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei which, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between simulations and observations of cloud and aerosol over the Southern Ocean. |
format |
Article in Journal/Newspaper |
author |
Humphries, RS Klekociuk, AR Schofield, R Keywood, M Ward, J Wilson, SR |
author_facet |
Humphries, RS Klekociuk, AR Schofield, R Keywood, M Ward, J Wilson, SR |
author_sort |
Humphries, RS |
title |
Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice |
title_short |
Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice |
title_full |
Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice |
title_fullStr |
Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice |
title_full_unstemmed |
Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice |
title_sort |
unexpectedly high ultrafine aerosol concentrations above east antarctic sea ice |
publisher |
Copernicus GmbH |
publishDate |
2016 |
url |
https://doi.org/10.5194/acp-16-2185-2016 http://ecite.utas.edu.au/109662 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Antarctica aurora australis Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica aurora australis Sea ice Southern Ocean |
op_relation |
http://ecite.utas.edu.au/109662/1/Humphries&+ (2016)_ACP [Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice].pdf http://dx.doi.org/10.5194/acp-16-2185-2016 Humphries, RS and Klekociuk, AR and Schofield, R and Keywood, M and Ward, J and Wilson, SR, Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice, Atmospheric Chemistry and Physics, 16, (4) pp. 2185-2206. ISSN 1680-7316 (2016) [Refereed Article] http://ecite.utas.edu.au/109662 |
op_doi |
https://doi.org/10.5194/acp-16-2185-2016 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
16 |
container_issue |
4 |
container_start_page |
2185 |
op_container_end_page |
2206 |
_version_ |
1766274090101899264 |