Characteristics and robustness of Agulhas leakage estimates: an inter-comparison study of Lagrangian methods
The inflow of relatively warm and salty water from the Indian Ocean into the South Atlantic via Agulhas leakage is important for the global overturning circulation and the global climate. In this study, we analyse the robustness of Agulhas leakage estimates as well as the thermohaline property modif...
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Copernicus Publications
2021
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Online Access: | https://doi.org/10.5194/os-17-1067-2021 https://doaj.org/article/25cc9c6302a04f92a7e7e1cbb5444e1f |
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ftdoajarticles:oai:doaj.org/article:25cc9c6302a04f92a7e7e1cbb5444e1f 2023-05-15T18:18:53+02:00 Characteristics and robustness of Agulhas leakage estimates: an inter-comparison study of Lagrangian methods C. Schmidt F. U. Schwarzkopf S. Rühs A. Biastoch 2021-08-01T00:00:00Z https://doi.org/10.5194/os-17-1067-2021 https://doaj.org/article/25cc9c6302a04f92a7e7e1cbb5444e1f EN eng Copernicus Publications https://os.copernicus.org/articles/17/1067/2021/os-17-1067-2021.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 doi:10.5194/os-17-1067-2021 1812-0784 1812-0792 https://doaj.org/article/25cc9c6302a04f92a7e7e1cbb5444e1f Ocean Science, Vol 17, Pp 1067-1080 (2021) Geography. Anthropology. Recreation G Environmental sciences GE1-350 article 2021 ftdoajarticles https://doi.org/10.5194/os-17-1067-2021 2022-12-31T06:00:56Z The inflow of relatively warm and salty water from the Indian Ocean into the South Atlantic via Agulhas leakage is important for the global overturning circulation and the global climate. In this study, we analyse the robustness of Agulhas leakage estimates as well as the thermohaline property modifications of Agulhas leakage south of Africa. Lagrangian experiments with both the newly developed tool Parcels and the well established tool Ariane were performed to simulate Agulhas leakage in the eddy-rich ocean–sea-ice model INALT20 ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">1</mn><mo>/</mo><mn mathvariant="normal">20</mn></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="27pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="eb44dc7215fab272447585860bb94269"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="os-17-1067-2021-ie00001.svg" width="27pt" height="14pt" src="os-17-1067-2021-ie00001.png"/></svg:svg> ∘ horizontal resolution) forced by the JRA55-do atmospheric boundary conditions. The average transport, its variability, trend and the transit time from the Agulhas Current to the Cape Basin of Agulhas leakage is simulated comparably with both Lagrangian tools, emphasizing the robustness of our method. Different designs of the Lagrangian experiment alter in particular the total transport of Agulhas leakage by up to 2 Sv, but the variability and trend of the transport are similar across these estimates. During the transit from the Agulhas Current at 32 ∘ S to the Cape Basin, a cooling and freshening of Agulhas leakage waters occurs especially at the location of the Agulhas Retroflection, resulting in a density increase as the thermal effect dominates. Beyond the strong air–sea exchange around South Africa, Agulhas leakage warms and salinifies the water masses below the thermocline in the ... Article in Journal/Newspaper Sea ice Directory of Open Access Journals: DOAJ Articles Indian Ocean Science 17 4 1067 1080 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
spellingShingle |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 C. Schmidt F. U. Schwarzkopf S. Rühs A. Biastoch Characteristics and robustness of Agulhas leakage estimates: an inter-comparison study of Lagrangian methods |
topic_facet |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
description |
The inflow of relatively warm and salty water from the Indian Ocean into the South Atlantic via Agulhas leakage is important for the global overturning circulation and the global climate. In this study, we analyse the robustness of Agulhas leakage estimates as well as the thermohaline property modifications of Agulhas leakage south of Africa. Lagrangian experiments with both the newly developed tool Parcels and the well established tool Ariane were performed to simulate Agulhas leakage in the eddy-rich ocean–sea-ice model INALT20 ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">1</mn><mo>/</mo><mn mathvariant="normal">20</mn></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="27pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="eb44dc7215fab272447585860bb94269"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="os-17-1067-2021-ie00001.svg" width="27pt" height="14pt" src="os-17-1067-2021-ie00001.png"/></svg:svg> ∘ horizontal resolution) forced by the JRA55-do atmospheric boundary conditions. The average transport, its variability, trend and the transit time from the Agulhas Current to the Cape Basin of Agulhas leakage is simulated comparably with both Lagrangian tools, emphasizing the robustness of our method. Different designs of the Lagrangian experiment alter in particular the total transport of Agulhas leakage by up to 2 Sv, but the variability and trend of the transport are similar across these estimates. During the transit from the Agulhas Current at 32 ∘ S to the Cape Basin, a cooling and freshening of Agulhas leakage waters occurs especially at the location of the Agulhas Retroflection, resulting in a density increase as the thermal effect dominates. Beyond the strong air–sea exchange around South Africa, Agulhas leakage warms and salinifies the water masses below the thermocline in the ... |
format |
Article in Journal/Newspaper |
author |
C. Schmidt F. U. Schwarzkopf S. Rühs A. Biastoch |
author_facet |
C. Schmidt F. U. Schwarzkopf S. Rühs A. Biastoch |
author_sort |
C. Schmidt |
title |
Characteristics and robustness of Agulhas leakage estimates: an inter-comparison study of Lagrangian methods |
title_short |
Characteristics and robustness of Agulhas leakage estimates: an inter-comparison study of Lagrangian methods |
title_full |
Characteristics and robustness of Agulhas leakage estimates: an inter-comparison study of Lagrangian methods |
title_fullStr |
Characteristics and robustness of Agulhas leakage estimates: an inter-comparison study of Lagrangian methods |
title_full_unstemmed |
Characteristics and robustness of Agulhas leakage estimates: an inter-comparison study of Lagrangian methods |
title_sort |
characteristics and robustness of agulhas leakage estimates: an inter-comparison study of lagrangian methods |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/os-17-1067-2021 https://doaj.org/article/25cc9c6302a04f92a7e7e1cbb5444e1f |
geographic |
Indian |
geographic_facet |
Indian |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
Ocean Science, Vol 17, Pp 1067-1080 (2021) |
op_relation |
https://os.copernicus.org/articles/17/1067/2021/os-17-1067-2021.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 doi:10.5194/os-17-1067-2021 1812-0784 1812-0792 https://doaj.org/article/25cc9c6302a04f92a7e7e1cbb5444e1f |
op_doi |
https://doi.org/10.5194/os-17-1067-2021 |
container_title |
Ocean Science |
container_volume |
17 |
container_issue |
4 |
container_start_page |
1067 |
op_container_end_page |
1080 |
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1766195634572886016 |