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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ftunivwollongong:oai:ro.uow.edu.au:smhpapers-4563 2023-05-15T13:58:42+02:00 Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice Humphries, Ruhi S Klekociuk, A R Schofield, Robyn Keywood, Melita Ward, J Wilson, Stephen R 2016-01-01T08:00:00Z application/pdf https://ro.uow.edu.au/smhpapers/3540 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=4563&context=smhpapers unknown Research Online https://ro.uow.edu.au/smhpapers/3540 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=4563&context=smhpapers Faculty of Science, Medicine and Health - Papers: part A Medicine and Health Sciences Social and Behavioral Sciences article 2016 ftunivwollongong 2020-02-25T11:23:20Z 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 a handful 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 (CN3) concentrations exhibited a five-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, a similar 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 University of Wollongong, Australia: Research Online Antarctic Southern Ocean The Antarctic |
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Open Polar |
collection |
University of Wollongong, Australia: Research Online |
op_collection_id |
ftunivwollongong |
language |
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topic |
Medicine and Health Sciences Social and Behavioral Sciences |
spellingShingle |
Medicine and Health Sciences Social and Behavioral Sciences Humphries, Ruhi S Klekociuk, A R Schofield, Robyn Keywood, Melita Ward, J Wilson, Stephen R Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice |
topic_facet |
Medicine and Health Sciences Social and Behavioral Sciences |
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 a handful 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 (CN3) concentrations exhibited a five-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, a similar 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, Ruhi S Klekociuk, A R Schofield, Robyn Keywood, Melita Ward, J Wilson, Stephen R |
author_facet |
Humphries, Ruhi S Klekociuk, A R Schofield, Robyn Keywood, Melita Ward, J Wilson, Stephen R |
author_sort |
Humphries, Ruhi S |
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 |
Research Online |
publishDate |
2016 |
url |
https://ro.uow.edu.au/smhpapers/3540 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=4563&context=smhpapers |
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_source |
Faculty of Science, Medicine and Health - Papers: part A |
op_relation |
https://ro.uow.edu.au/smhpapers/3540 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=4563&context=smhpapers |
_version_ |
1766267049067151360 |