Decay of eddies at the South-West Indian Ridge
The South-West Indian Ridge in the Indian sector of the Southern Ocean is a region recognised for the creation of particularly intense eddy disturbances in the mean flow of the Antarctic Circumpolar Current. Eddies formed at this ridge have been extensively studied over the past decade using hydrogr...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Academy of Science of South Africa
2011-11-01
|
| Series: | South African Journal of Science |
| Subjects: | |
| Online Access: | http://192.168.0.121/index.php/sajs/article/view/9789 |
| _version_ | 1818644263701839872 |
|---|---|
| author | Jonathan Durgadoo Isabelle Ansorge Beverly de Cuevas Johann Lutjeharms Andrew Coward |
| author_facet | Jonathan Durgadoo Isabelle Ansorge Beverly de Cuevas Johann Lutjeharms Andrew Coward |
| author_sort | Jonathan Durgadoo |
| collection | DOAJ |
| description | The South-West Indian Ridge in the Indian sector of the Southern Ocean is a region recognised for the creation of particularly intense eddy disturbances in the mean flow of the Antarctic Circumpolar Current. Eddies formed at this ridge have been extensively studied over the past decade using hydrographic, satellite, drifter and float data and it is hypothesised that they could provide a vehicle for localised meridional heat and salt exchange. The effectiveness of this process is dependent on the rate of decay of the eddies. However, in order to investigate eddy decay, logistically difficult hydrographic monitoring is required. This study presents the decay of cold eddies at the South-West Indian Ridge, using outputs from a high-resolution ocean model. The model's representation of the dynamic nature of this region is fully characteristic of observations. On average, 3-4 intense and well-defined cold eddies are generated per year; these eddies have mean longevities of 5.0±2.2 months with average advection speeds of 5±2 km/day. Most simulated eddies reach their peak intensity within 1.5-2.5 months after genesis and have depths of 2000 m - 3000 m. Thereafter they dissipate within approximately 3 months. The decay of eddies is generally characterised by a decrease in their sea surface height signature, a weakening in their rotation rates and a modification in their temperature-salinity characteristics. Subantarctic top predators are suspected to forage preferentially along the edges of eddies. The process of eddy dissipation may thus influence their feeding behaviour. |
| first_indexed | 2024-12-17T00:12:04Z |
| format | Article |
| id | doaj.art-e977c65b41894491bc50abd86f5fc5ba |
| institution | Directory Open Access Journal |
| issn | 1996-7489 |
| language | English |
| last_indexed | 2024-12-17T00:12:04Z |
| publishDate | 2011-11-01 |
| publisher | Academy of Science of South Africa |
| record_format | Article |
| series | South African Journal of Science |
| spelling | doaj.art-e977c65b41894491bc50abd86f5fc5ba2022-12-21T22:10:48ZengAcademy of Science of South AfricaSouth African Journal of Science1996-74892011-11-0110711/12Decay of eddies at the South-West Indian RidgeJonathan Durgadoo0Isabelle Ansorge1Beverly de Cuevas2Johann Lutjeharms3Andrew Coward4Department of Oceanography, University of Cape TownDepartment of Oceanography, University of Cape TownMarine Systems Modelling Group, National Oceanography Centre, University of SouthamptonDepartment of Oceanography, University of Cape TownMarine Systems Modelling Group, National Oceanography Centre, University of SouthamptonThe South-West Indian Ridge in the Indian sector of the Southern Ocean is a region recognised for the creation of particularly intense eddy disturbances in the mean flow of the Antarctic Circumpolar Current. Eddies formed at this ridge have been extensively studied over the past decade using hydrographic, satellite, drifter and float data and it is hypothesised that they could provide a vehicle for localised meridional heat and salt exchange. The effectiveness of this process is dependent on the rate of decay of the eddies. However, in order to investigate eddy decay, logistically difficult hydrographic monitoring is required. This study presents the decay of cold eddies at the South-West Indian Ridge, using outputs from a high-resolution ocean model. The model's representation of the dynamic nature of this region is fully characteristic of observations. On average, 3-4 intense and well-defined cold eddies are generated per year; these eddies have mean longevities of 5.0±2.2 months with average advection speeds of 5±2 km/day. Most simulated eddies reach their peak intensity within 1.5-2.5 months after genesis and have depths of 2000 m - 3000 m. Thereafter they dissipate within approximately 3 months. The decay of eddies is generally characterised by a decrease in their sea surface height signature, a weakening in their rotation rates and a modification in their temperature-salinity characteristics. Subantarctic top predators are suspected to forage preferentially along the edges of eddies. The process of eddy dissipation may thus influence their feeding behaviour.http://192.168.0.121/index.php/sajs/article/view/9789eddy kinetic energy hotspotSouthern OceanDEIMECOCCAMPrince Edward Islands |
| spellingShingle | Jonathan Durgadoo Isabelle Ansorge Beverly de Cuevas Johann Lutjeharms Andrew Coward Decay of eddies at the South-West Indian Ridge South African Journal of Science eddy kinetic energy hotspot Southern Ocean DEIMEC OCCAM Prince Edward Islands |
| title | Decay of eddies at the South-West Indian Ridge |
| title_full | Decay of eddies at the South-West Indian Ridge |
| title_fullStr | Decay of eddies at the South-West Indian Ridge |
| title_full_unstemmed | Decay of eddies at the South-West Indian Ridge |
| title_short | Decay of eddies at the South-West Indian Ridge |
| title_sort | decay of eddies at the south west indian ridge |
| topic | eddy kinetic energy hotspot Southern Ocean DEIMEC OCCAM Prince Edward Islands |
| url | http://192.168.0.121/index.php/sajs/article/view/9789 |
| work_keys_str_mv | AT jonathandurgadoo decayofeddiesatthesouthwestindianridge AT isabelleansorge decayofeddiesatthesouthwestindianridge AT beverlydecuevas decayofeddiesatthesouthwestindianridge AT johannlutjeharms decayofeddiesatthesouthwestindianridge AT andrewcoward decayofeddiesatthesouthwestindianridge |