Circulation, retention, and mixing of waters within the W eddell‐ S cotia C onfluence, S outhern O cean: The role of stratified T aylor columns
| Autor: | Loïc Jullion, Andrew Meijers, Hugh J. Venables, E. Povl Abrahamsen, Peter J. Brown, Marie-José Messias, Michael P. Meredith, Alberto C. Naveira Garabato |
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| Rok vydání: | 2015 |
| Předmět: |
0106 biological sciences
geography Water mass Isopycnal geography.geographical_feature_category 010504 meteorology & atmospheric sciences 010604 marine biology & hydrobiology Oceanography 01 natural sciences Current (stream) Geophysics Taylor column 13. Climate action Space and Planetary Science Geochemistry and Petrology Ridge Ocean gyre Confluence Earth and Planetary Sciences (miscellaneous) Bathymetry 14. Life underwater Geology 0105 earth and related environmental sciences |
| Zdroj: | Journal of Geophysical Research: Oceans. 120:547-562 |
| ISSN: | 2169-9291 2169-9275 |
| Popis: | The waters of the Weddell-Scotia Confluence (WSC) lie above the rugged topography of the South Scotia Ridge in the Southern Ocean. Meridional exchanges across the WSC transfer water and tracers between the Antarctic Circumpolar Current (ACC) to the north and the subpolar Weddell Gyre to the south. Here, we examine the role of topographic interactions in mediating these exchanges, and in modifying the waters transferred. A case study is presented using data from a free-drifting, intermediate-depth float, which circulated anticyclonically over Discovery Bank on the South Scotia Ridge for close to 4 years. Dimensional analysis indicates that the local conditions are conducive to the formation of Taylor columns. Contemporaneous ship-derived transient tracer data enable estimation of the rate of isopycnal mixing associated with this column, with values of O(1000 m2/s) obtained. Although necessarily coarse, this is of the same order as the rate of isopycnal mixing induced by transient mesoscale eddies within the ACC. A picture emerges of the Taylor column acting as a slow, steady blender, retaining the waters in the vicinity of the WSC for lengthy periods during which they can be subject to significant modification. A full regional float data set, bathymetric data, and a Southern Ocean state estimate are used to identify other potential sites for Taylor column formation. We find that they are likely to be sufficiently widespread to exert a significant influence on water mass modification and meridional fluxes across the southern edge of the ACC in this sector of the Southern Ocean. |
| Databáze: | OpenAIRE |
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