Turbulence in the sea ice impacted Southern Ocean and its implications for primary production and carbon export
The sea-ice impacted Southern Ocean, south of the Antarctic Circumpolar Current, is one of the most important regions on earth for the cycling of carbon and distribution of heat and freshwater around the globe. Here, along-isopycnal upwelling of warm, carbon-rich circumpolar deep water coincides wit...
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Department of Oceanography
2023
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ftunivcapetownir:oai:open.uct.ac.za:11427/38103 2023-12-03T10:13:55+01:00 Turbulence in the sea ice impacted Southern Ocean and its implications for primary production and carbon export Nunes, Da Costa Isabelle Ansorge, Isabel Swart, Sebastiaan Nicholson, Sarah-Anne 2023 application/pdf http://hdl.handle.net/11427/38103 eng eng Department of Oceanography Faculty of Science http://hdl.handle.net/11427/38103 Marine Sciences Oceanography Doctoral Thesis Doctoral PhD 2023 ftunivcapetownir 2023-11-03T00:16:32Z The sea-ice impacted Southern Ocean, south of the Antarctic Circumpolar Current, is one of the most important regions on earth for the cycling of carbon and distribution of heat and freshwater around the globe. Here, along-isopycnal upwelling of warm, carbon-rich circumpolar deep water coincides with the annual growth and melt of Antarctic sea ice that represents one of the world's largest surface water transformations. The air-sea-ice buoyancy exchanges and biological processes that change the surface water properties therefore have global consequences, as they set the properties of downwelling intermediate waters that enter the upper branch of the global thermohaline circulation. The region hosts some of the largest uncertainties in global climate models. The reason for this stems from two sources. Firstly, the spatio-temporal resolution of global climate models is limited by computational constraints such that smaller scale processes need to be parameterized. Secondly, the challenges associated with making observations in or near sea ice and in the harsh and remote conditions of the Southern Ocean means that the region is sparsely sampled, and as such, the parameterizations of the small scale and turbulent terms in global climate models are validated based only on a few in situ samples. This thesis concerns the observation and interpretation of (sub)meso- to micro scale turbulence and its implications in the sea ice impacted Southern Ocean. I aimed to understand the 0.01-1 km scale physical and biological processes that drive changes in the properties of the upper ocean following sea ice melt, using groundbreaking sustained high temporal and spatial resolution observations made by gliders. There are three main findings. Firstly, we find that sea ice melt by introducing a lateral freshwater gradient enhances stirring of submesoscale flows (0.1-10 km) and therefore lateral variability in the upper ocean, but simultaneously constrains vertical fluxes between the ocean interior and surface by enhancing ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Sea ice Southern Ocean University of Cape Town: OpenUCT Antarctic Southern Ocean The Antarctic |
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Open Polar |
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University of Cape Town: OpenUCT |
op_collection_id |
ftunivcapetownir |
language |
English |
topic |
Marine Sciences Oceanography |
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Marine Sciences Oceanography Nunes, Da Costa Isabelle Turbulence in the sea ice impacted Southern Ocean and its implications for primary production and carbon export |
topic_facet |
Marine Sciences Oceanography |
description |
The sea-ice impacted Southern Ocean, south of the Antarctic Circumpolar Current, is one of the most important regions on earth for the cycling of carbon and distribution of heat and freshwater around the globe. Here, along-isopycnal upwelling of warm, carbon-rich circumpolar deep water coincides with the annual growth and melt of Antarctic sea ice that represents one of the world's largest surface water transformations. The air-sea-ice buoyancy exchanges and biological processes that change the surface water properties therefore have global consequences, as they set the properties of downwelling intermediate waters that enter the upper branch of the global thermohaline circulation. The region hosts some of the largest uncertainties in global climate models. The reason for this stems from two sources. Firstly, the spatio-temporal resolution of global climate models is limited by computational constraints such that smaller scale processes need to be parameterized. Secondly, the challenges associated with making observations in or near sea ice and in the harsh and remote conditions of the Southern Ocean means that the region is sparsely sampled, and as such, the parameterizations of the small scale and turbulent terms in global climate models are validated based only on a few in situ samples. This thesis concerns the observation and interpretation of (sub)meso- to micro scale turbulence and its implications in the sea ice impacted Southern Ocean. I aimed to understand the 0.01-1 km scale physical and biological processes that drive changes in the properties of the upper ocean following sea ice melt, using groundbreaking sustained high temporal and spatial resolution observations made by gliders. There are three main findings. Firstly, we find that sea ice melt by introducing a lateral freshwater gradient enhances stirring of submesoscale flows (0.1-10 km) and therefore lateral variability in the upper ocean, but simultaneously constrains vertical fluxes between the ocean interior and surface by enhancing ... |
author2 |
Ansorge, Isabel Swart, Sebastiaan Nicholson, Sarah-Anne |
format |
Doctoral or Postdoctoral Thesis |
author |
Nunes, Da Costa Isabelle |
author_facet |
Nunes, Da Costa Isabelle |
author_sort |
Nunes, Da Costa Isabelle |
title |
Turbulence in the sea ice impacted Southern Ocean and its implications for primary production and carbon export |
title_short |
Turbulence in the sea ice impacted Southern Ocean and its implications for primary production and carbon export |
title_full |
Turbulence in the sea ice impacted Southern Ocean and its implications for primary production and carbon export |
title_fullStr |
Turbulence in the sea ice impacted Southern Ocean and its implications for primary production and carbon export |
title_full_unstemmed |
Turbulence in the sea ice impacted Southern Ocean and its implications for primary production and carbon export |
title_sort |
turbulence in the sea ice impacted southern ocean and its implications for primary production and carbon export |
publisher |
Department of Oceanography |
publishDate |
2023 |
url |
http://hdl.handle.net/11427/38103 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Sea ice Southern Ocean |
op_relation |
http://hdl.handle.net/11427/38103 |
_version_ |
1784260899000811520 |