A descriptive analysis of the genesis and translation of a dipole vortex from the Agulhas retroflection region
Bibliography: leaves 111-126. An anomalous leakage of Agulhas Current water into the south-east Atlantic Ocean, exhibiting a mushroom-like shape, was observed during routine observations of A VHRR satellite imagery in early December 1996. The development of this anomaly was followed on the sea surfa...
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ftunivcapetownir:oai:localhost:11427/6445 2023-05-15T18:21:15+02:00 A descriptive analysis of the genesis and translation of a dipole vortex from the Agulhas retroflection region Whittle, Christo Peter Shillington, Frank Rae, Christopher Duncombe 2000 application/pdf http://hdl.handle.net/11427/6445 https://open.uct.ac.za/bitstream/11427/6445/1/thesis_sci_2000_whittle_cp.pdf eng eng University of Cape Town Faculty of Science Department of Oceanography http://hdl.handle.net/11427/6445 https://open.uct.ac.za/bitstream/11427/6445/1/thesis_sci_2000_whittle_cp.pdf Oceanography Master Thesis Masters MSc 2000 ftunivcapetownir 2022-09-13T05:54:30Z Bibliography: leaves 111-126. An anomalous leakage of Agulhas Current water into the south-east Atlantic Ocean, exhibiting a mushroom-like shape, was observed during routine observations of A VHRR satellite imagery in early December 1996. The development of this anomaly was followed on the sea surface temperature (SST) imagery and it was tentatively identified as a consequence of filament interaction between the Agulhas retroflection and an occluding Agulhas ring. This interpretation prompted a cruise onboard the FR.S Africana with the objective of conducting a hydrographic survey of the Agulhas ring and the associated filament near Cape Town. A descriptive analysis, gleaned from A VHRR satellite imagery and in situ data, of the hydrographic characteristics of a vortex dipole, surveyed during this cruise, is presented in this thesis. An analysis of water mass properties and geostrophic flow patterns determined that an Agulhas ring and a cyclonic eddy, containing Benguela Current water in its core, constituted a dipole vortex in the south-eastern Atlantic Ocean. During the period of the hydrographic survey, the secondary vortex exhibited an anticlockwise rotation of 8. 6°/day around the Agulhas ring A warm filament, originating from the western Agulhas Bank, was entrained between the two counter-rotating eddies, thus resulting in the mixing of Agulhas Bank water into the South Atlantic Ocean. Satellite altimetry and A VHRR imagery were used to "backtrack" the vortex dipole to its origin at the Agulhas retroflectiOn. By combining interpretations from the altimetry and A VHRR imagery, it was possible to describe the complex interactions the dipole displayed with the retroflection and the Agulhas Bank as it franslated in a north-westerly direction. The mushroom configuration, identified earlier on SST imagery, betrayed the presence of an adjacent pair of circulatory features of opposing spm. As the dipole translated northward, it interacted with the Agulhas Bank and the cyclone was strained, becoming a filament as ... Master Thesis South Atlantic Ocean University of Cape Town: OpenUCT |
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University of Cape Town: OpenUCT |
op_collection_id |
ftunivcapetownir |
language |
English |
topic |
Oceanography |
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Oceanography Whittle, Christo Peter A descriptive analysis of the genesis and translation of a dipole vortex from the Agulhas retroflection region |
topic_facet |
Oceanography |
description |
Bibliography: leaves 111-126. An anomalous leakage of Agulhas Current water into the south-east Atlantic Ocean, exhibiting a mushroom-like shape, was observed during routine observations of A VHRR satellite imagery in early December 1996. The development of this anomaly was followed on the sea surface temperature (SST) imagery and it was tentatively identified as a consequence of filament interaction between the Agulhas retroflection and an occluding Agulhas ring. This interpretation prompted a cruise onboard the FR.S Africana with the objective of conducting a hydrographic survey of the Agulhas ring and the associated filament near Cape Town. A descriptive analysis, gleaned from A VHRR satellite imagery and in situ data, of the hydrographic characteristics of a vortex dipole, surveyed during this cruise, is presented in this thesis. An analysis of water mass properties and geostrophic flow patterns determined that an Agulhas ring and a cyclonic eddy, containing Benguela Current water in its core, constituted a dipole vortex in the south-eastern Atlantic Ocean. During the period of the hydrographic survey, the secondary vortex exhibited an anticlockwise rotation of 8. 6°/day around the Agulhas ring A warm filament, originating from the western Agulhas Bank, was entrained between the two counter-rotating eddies, thus resulting in the mixing of Agulhas Bank water into the South Atlantic Ocean. Satellite altimetry and A VHRR imagery were used to "backtrack" the vortex dipole to its origin at the Agulhas retroflectiOn. By combining interpretations from the altimetry and A VHRR imagery, it was possible to describe the complex interactions the dipole displayed with the retroflection and the Agulhas Bank as it franslated in a north-westerly direction. The mushroom configuration, identified earlier on SST imagery, betrayed the presence of an adjacent pair of circulatory features of opposing spm. As the dipole translated northward, it interacted with the Agulhas Bank and the cyclone was strained, becoming a filament as ... |
author2 |
Shillington, Frank Rae, Christopher Duncombe |
format |
Master Thesis |
author |
Whittle, Christo Peter |
author_facet |
Whittle, Christo Peter |
author_sort |
Whittle, Christo Peter |
title |
A descriptive analysis of the genesis and translation of a dipole vortex from the Agulhas retroflection region |
title_short |
A descriptive analysis of the genesis and translation of a dipole vortex from the Agulhas retroflection region |
title_full |
A descriptive analysis of the genesis and translation of a dipole vortex from the Agulhas retroflection region |
title_fullStr |
A descriptive analysis of the genesis and translation of a dipole vortex from the Agulhas retroflection region |
title_full_unstemmed |
A descriptive analysis of the genesis and translation of a dipole vortex from the Agulhas retroflection region |
title_sort |
descriptive analysis of the genesis and translation of a dipole vortex from the agulhas retroflection region |
publisher |
University of Cape Town |
publishDate |
2000 |
url |
http://hdl.handle.net/11427/6445 https://open.uct.ac.za/bitstream/11427/6445/1/thesis_sci_2000_whittle_cp.pdf |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_relation |
http://hdl.handle.net/11427/6445 https://open.uct.ac.za/bitstream/11427/6445/1/thesis_sci_2000_whittle_cp.pdf |
_version_ |
1766200428360368128 |