Size and compositional dependent effects of marine aerosol on cloud condensation nuclei
This work investigates marine aerosol physico-chemical properties (e.g. size and chemistry) and its Cloud Condensation Nuclei (CCN) properties under natural background conditions. Black carbon (BC), a tracer for anthropogenic pollution, was used to classify Southern Ocean air mass cleanliness, where...
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NUI Galway
2018
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ftnuigalway:oai:aran.library.nuigalway.ie/:10379/14795 2023-06-11T04:06:48+02:00 Size and compositional dependent effects of marine aerosol on cloud condensation nuclei Fossum, Kirsten O'Dowd, Colin Ovadnevaite, Jurgita Ceburnis, Darius Science Foundation Ireland Seventh Framework Programme Marine and Renewable Energy Ireland MaREI 2018-12-06 http://hdl.handle.net/10379/14795 unknown NUI Galway http://hdl.handle.net/10379/14795 Attribution-NonCommercial-NoDerivs 3.0 Ireland https://creativecommons.org/licenses/by-nc-nd/3.0/ie/ North East Atlantic cloud condensation nuclei hygroscopicity marine aerosol Southern Ocean aerosol marine boundary layer atmospheric model aerosol activation primary marine aerosol black carbon supersaturation suppression sea-salt Physics Atmospheric physics Thesis 2018 ftnuigalway 2023-05-28T18:06:11Z This work investigates marine aerosol physico-chemical properties (e.g. size and chemistry) and its Cloud Condensation Nuclei (CCN) properties under natural background conditions. Black carbon (BC), a tracer for anthropogenic pollution, was used to classify Southern Ocean air mass cleanliness, where the study focussed on anthropogenic influences and was compared to the North East Atlantic, which is closer to pollution sources. Despite this, the lowest prevailing BC mass concentration levels were similar for either ocean (~0.1 ng m-3) with extreme pollution levels above 80 ng m-3 for about 0.3 % of the time over both observation periods. In order to elucidate the relative contribution of ‘primary’ wind-produced sea spray and ‘secondary’ gas-to-particle aerosols to marine cloud droplet formation, a novel detailed analysis of droplet activation critical supersaturation versus critical diameter was conducted in remote environmental marine air (i.e. maritime polar and modified continental Antarctic air masses) in parallel to modelled chemically-homogenous aerosols. The analysis revealed that, for realistic marine boundary layer cloud supersaturations, primary CCN contributed 8–51 % to the estimated cloud droplet concentration (as determined by the Hoppel intermodal-minimum) at wind speeds < 16 m s−1. At higher wind speeds, primary marine aerosol could contribute up to 100 % of estimated cloud droplet concentration. It was observed that within air masses enriched with sea spray CCN, the contribution of secondary (mainly non-sea-salt-sulphate) particles to cloud droplet concentration was significantly reduced despite a higher availability of sulphate CCN. Further analysis revealed a highly correlated inverse linear trend between activated sea spray particles and the percentage of activated sulphate particles. In practice, the addition of sea-salt CCN appeared to suppress the activation of sulphate CCN. An ensemble of three 1-D microphysical droplet growth and activation parcel models corroborated this suppression ... Thesis Antarc* Antarctic North East Atlantic Southern Ocean National University of Ireland (NUI), Galway: ARAN Antarctic Southern Ocean |
institution |
Open Polar |
collection |
National University of Ireland (NUI), Galway: ARAN |
op_collection_id |
ftnuigalway |
language |
unknown |
topic |
North East Atlantic cloud condensation nuclei hygroscopicity marine aerosol Southern Ocean aerosol marine boundary layer atmospheric model aerosol activation primary marine aerosol black carbon supersaturation suppression sea-salt Physics Atmospheric physics |
spellingShingle |
North East Atlantic cloud condensation nuclei hygroscopicity marine aerosol Southern Ocean aerosol marine boundary layer atmospheric model aerosol activation primary marine aerosol black carbon supersaturation suppression sea-salt Physics Atmospheric physics Fossum, Kirsten Size and compositional dependent effects of marine aerosol on cloud condensation nuclei |
topic_facet |
North East Atlantic cloud condensation nuclei hygroscopicity marine aerosol Southern Ocean aerosol marine boundary layer atmospheric model aerosol activation primary marine aerosol black carbon supersaturation suppression sea-salt Physics Atmospheric physics |
description |
This work investigates marine aerosol physico-chemical properties (e.g. size and chemistry) and its Cloud Condensation Nuclei (CCN) properties under natural background conditions. Black carbon (BC), a tracer for anthropogenic pollution, was used to classify Southern Ocean air mass cleanliness, where the study focussed on anthropogenic influences and was compared to the North East Atlantic, which is closer to pollution sources. Despite this, the lowest prevailing BC mass concentration levels were similar for either ocean (~0.1 ng m-3) with extreme pollution levels above 80 ng m-3 for about 0.3 % of the time over both observation periods. In order to elucidate the relative contribution of ‘primary’ wind-produced sea spray and ‘secondary’ gas-to-particle aerosols to marine cloud droplet formation, a novel detailed analysis of droplet activation critical supersaturation versus critical diameter was conducted in remote environmental marine air (i.e. maritime polar and modified continental Antarctic air masses) in parallel to modelled chemically-homogenous aerosols. The analysis revealed that, for realistic marine boundary layer cloud supersaturations, primary CCN contributed 8–51 % to the estimated cloud droplet concentration (as determined by the Hoppel intermodal-minimum) at wind speeds < 16 m s−1. At higher wind speeds, primary marine aerosol could contribute up to 100 % of estimated cloud droplet concentration. It was observed that within air masses enriched with sea spray CCN, the contribution of secondary (mainly non-sea-salt-sulphate) particles to cloud droplet concentration was significantly reduced despite a higher availability of sulphate CCN. Further analysis revealed a highly correlated inverse linear trend between activated sea spray particles and the percentage of activated sulphate particles. In practice, the addition of sea-salt CCN appeared to suppress the activation of sulphate CCN. An ensemble of three 1-D microphysical droplet growth and activation parcel models corroborated this suppression ... |
author2 |
O'Dowd, Colin Ovadnevaite, Jurgita Ceburnis, Darius Science Foundation Ireland Seventh Framework Programme Marine and Renewable Energy Ireland MaREI |
format |
Thesis |
author |
Fossum, Kirsten |
author_facet |
Fossum, Kirsten |
author_sort |
Fossum, Kirsten |
title |
Size and compositional dependent effects of marine aerosol on cloud condensation nuclei |
title_short |
Size and compositional dependent effects of marine aerosol on cloud condensation nuclei |
title_full |
Size and compositional dependent effects of marine aerosol on cloud condensation nuclei |
title_fullStr |
Size and compositional dependent effects of marine aerosol on cloud condensation nuclei |
title_full_unstemmed |
Size and compositional dependent effects of marine aerosol on cloud condensation nuclei |
title_sort |
size and compositional dependent effects of marine aerosol on cloud condensation nuclei |
publisher |
NUI Galway |
publishDate |
2018 |
url |
http://hdl.handle.net/10379/14795 |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic North East Atlantic Southern Ocean |
genre_facet |
Antarc* Antarctic North East Atlantic Southern Ocean |
op_relation |
http://hdl.handle.net/10379/14795 |
op_rights |
Attribution-NonCommercial-NoDerivs 3.0 Ireland https://creativecommons.org/licenses/by-nc-nd/3.0/ie/ |
_version_ |
1768378959334998016 |