In situ measurements of cloud microphysics and aerosol over coastal Antarctica during the MAC campaign
During austral summer 2015, the Microphysics of Antarctic Clouds (MAC) field campaign collected unique and detailed airborne and ground-based in situ measurements of cloud and aerosol properties over coastal Antarctica and the Weddell Sea. This paper presents the first results from the experiment an...
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ftdoajarticles:oai:doaj.org/article:74494036f2ba45f490ffe5061ff0f74e 2023-05-15T13:35:16+02:00 In situ measurements of cloud microphysics and aerosol over coastal Antarctica during the MAC campaign S. J. O'Shea T. W. Choularton M. Flynn K. N. Bower M. Gallagher J. Crosier P. Williams I. Crawford Z. L. Fleming C. Listowski A. Kirchgaessner R. S. Ladkin T. Lachlan-Cope 2017-11-01T00:00:00Z https://doi.org/10.5194/acp-17-13049-2017 https://doaj.org/article/74494036f2ba45f490ffe5061ff0f74e EN eng Copernicus Publications https://www.atmos-chem-phys.net/17/13049/2017/acp-17-13049-2017.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-17-13049-2017 1680-7316 1680-7324 https://doaj.org/article/74494036f2ba45f490ffe5061ff0f74e Atmospheric Chemistry and Physics, Vol 17, Pp 13049-13070 (2017) Physics QC1-999 Chemistry QD1-999 article 2017 ftdoajarticles https://doi.org/10.5194/acp-17-13049-2017 2022-12-30T23:06:37Z During austral summer 2015, the Microphysics of Antarctic Clouds (MAC) field campaign collected unique and detailed airborne and ground-based in situ measurements of cloud and aerosol properties over coastal Antarctica and the Weddell Sea. This paper presents the first results from the experiment and discusses the key processes important in this region, which is critical to predicting future climate change. The sampling was predominantly of stratus clouds, at temperatures between −20 and 0 °C. These clouds were dominated by supercooled liquid water droplets, which had a median concentration of 113 cm −3 and an interquartile range of 86 cm −3 . Both cloud liquid water content and effective radius increased closer to cloud top. The cloud droplet effective radius increased from 4 ± 2 µm near cloud base to 8 ± 3 µm near cloud top. Cloud ice particle concentrations were highly variable with the ice tending to occur in small, isolated patches. Below approximately 1000 m, glaciated cloud regions were more common at higher temperatures; however, the clouds were still predominantly liquid throughout. When ice was present at temperatures higher than −10 °C, secondary ice production most likely through the Hallett–Mossop mechanism led to ice concentrations 1 to 3 orders of magnitude higher than the number predicted by commonly used primary ice nucleation parameterisations. The drivers of the ice crystal variability are investigated. No clear dependence on the droplet size distribution was found. The source of first ice in the clouds remains uncertain but may include contributions from biogenic particles, blowing snow or other surface ice production mechanisms. The concentration of large aerosols (diameters 0.5 to 1.6 µm) decreased with altitude and were depleted in air masses that originated over the Antarctic continent compared to those more heavily influenced by the Southern Ocean and sea ice regions. The dominant aerosol in the region was hygroscopic in nature, with the hygroscopicity parameter κ having a median value ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Sea ice Southern Ocean Weddell Sea Directory of Open Access Journals: DOAJ Articles Antarctic Southern Ocean The Antarctic Weddell Sea Austral Weddell Hallett ENVELOPE(170.217,170.217,-72.317,-72.317) Atmospheric Chemistry and Physics 17 21 13049 13070 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 S. J. O'Shea T. W. Choularton M. Flynn K. N. Bower M. Gallagher J. Crosier P. Williams I. Crawford Z. L. Fleming C. Listowski A. Kirchgaessner R. S. Ladkin T. Lachlan-Cope In situ measurements of cloud microphysics and aerosol over coastal Antarctica during the MAC campaign |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
During austral summer 2015, the Microphysics of Antarctic Clouds (MAC) field campaign collected unique and detailed airborne and ground-based in situ measurements of cloud and aerosol properties over coastal Antarctica and the Weddell Sea. This paper presents the first results from the experiment and discusses the key processes important in this region, which is critical to predicting future climate change. The sampling was predominantly of stratus clouds, at temperatures between −20 and 0 °C. These clouds were dominated by supercooled liquid water droplets, which had a median concentration of 113 cm −3 and an interquartile range of 86 cm −3 . Both cloud liquid water content and effective radius increased closer to cloud top. The cloud droplet effective radius increased from 4 ± 2 µm near cloud base to 8 ± 3 µm near cloud top. Cloud ice particle concentrations were highly variable with the ice tending to occur in small, isolated patches. Below approximately 1000 m, glaciated cloud regions were more common at higher temperatures; however, the clouds were still predominantly liquid throughout. When ice was present at temperatures higher than −10 °C, secondary ice production most likely through the Hallett–Mossop mechanism led to ice concentrations 1 to 3 orders of magnitude higher than the number predicted by commonly used primary ice nucleation parameterisations. The drivers of the ice crystal variability are investigated. No clear dependence on the droplet size distribution was found. The source of first ice in the clouds remains uncertain but may include contributions from biogenic particles, blowing snow or other surface ice production mechanisms. The concentration of large aerosols (diameters 0.5 to 1.6 µm) decreased with altitude and were depleted in air masses that originated over the Antarctic continent compared to those more heavily influenced by the Southern Ocean and sea ice regions. The dominant aerosol in the region was hygroscopic in nature, with the hygroscopicity parameter κ having a median value ... |
format |
Article in Journal/Newspaper |
author |
S. J. O'Shea T. W. Choularton M. Flynn K. N. Bower M. Gallagher J. Crosier P. Williams I. Crawford Z. L. Fleming C. Listowski A. Kirchgaessner R. S. Ladkin T. Lachlan-Cope |
author_facet |
S. J. O'Shea T. W. Choularton M. Flynn K. N. Bower M. Gallagher J. Crosier P. Williams I. Crawford Z. L. Fleming C. Listowski A. Kirchgaessner R. S. Ladkin T. Lachlan-Cope |
author_sort |
S. J. O'Shea |
title |
In situ measurements of cloud microphysics and aerosol over coastal Antarctica during the MAC campaign |
title_short |
In situ measurements of cloud microphysics and aerosol over coastal Antarctica during the MAC campaign |
title_full |
In situ measurements of cloud microphysics and aerosol over coastal Antarctica during the MAC campaign |
title_fullStr |
In situ measurements of cloud microphysics and aerosol over coastal Antarctica during the MAC campaign |
title_full_unstemmed |
In situ measurements of cloud microphysics and aerosol over coastal Antarctica during the MAC campaign |
title_sort |
in situ measurements of cloud microphysics and aerosol over coastal antarctica during the mac campaign |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/acp-17-13049-2017 https://doaj.org/article/74494036f2ba45f490ffe5061ff0f74e |
long_lat |
ENVELOPE(170.217,170.217,-72.317,-72.317) |
geographic |
Antarctic Southern Ocean The Antarctic Weddell Sea Austral Weddell Hallett |
geographic_facet |
Antarctic Southern Ocean The Antarctic Weddell Sea Austral Weddell Hallett |
genre |
Antarc* Antarctic Antarctica Sea ice Southern Ocean Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctica Sea ice Southern Ocean Weddell Sea |
op_source |
Atmospheric Chemistry and Physics, Vol 17, Pp 13049-13070 (2017) |
op_relation |
https://www.atmos-chem-phys.net/17/13049/2017/acp-17-13049-2017.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-17-13049-2017 1680-7316 1680-7324 https://doaj.org/article/74494036f2ba45f490ffe5061ff0f74e |
op_doi |
https://doi.org/10.5194/acp-17-13049-2017 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
17 |
container_issue |
21 |
container_start_page |
13049 |
op_container_end_page |
13070 |
_version_ |
1766063637565276160 |