Anticyclonic and cyclonic eddies of subtropical origin in the subantarctic zone south of Africa
| Type | Article | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Date | 2011-11 | ||||||||
| Language | English | ||||||||
| Author(s) | Arhan Michel1, Speich Sabrina2, Messager Christophe1, 5, Dencausse Guillaume1, Fine Rana3, Boye Marie4 | ||||||||
| Affiliation(s) | 1 : Ifremer Ctr Brest, Lab Phys Oceans, CNRS Ifremer IRD UBO, UMR6523, F-29280 Plouzane, France. 2 : UBO UFR Sci & Tech, Lab Phys Oceans, CNRS Ifremer IRD UBO, UMR6523, F-29238 Brest 3, France. 3 : Univ Miami, RSMAS MAC, Miami, FL 33149 USA. 4 : IUEM, Lab Sci Environm Marin, CNRS IRD UBO, UMR6539, F-29280 Plouzane, France. 5 : CNRS |
||||||||
| Source | Journal Of Geophysical Research-oceans (0148-0227) (Amer Geophysical Union), 2011-11 , Vol. 116 , N. C11004 , P. - | ||||||||
| DOI | 10.1029/2011JC007140 | ||||||||
| WOS© Times Cited | 30 | ||||||||
| Abstract | Two eddies, one anticyclonic and the other cyclonic, intersected in the Subantarctic Zone south of South Africa during a hydrographic transect, are described using a large set of measurements including full depth hydrography, Acoustic Doppler Current Profiler velocities, biogeochemical tracers, air-sea fluxes and altimetric sea surface height. Both eddies have a subtropical origin. The anticyclone is an Agulhas ring with convected core water of similar to 12 degrees C, and swirl velocities of 1 m s(-1). It was 9.5 months old when sampled and had crossed the Agulhas Ridge. Though sampled in summer, it was releasing similar to 200 W m(-2) (sensible plus latent heat flux) to the atmosphere. It was observed adjacent to the Subantarctic Front, illustrating the usual encounters of such structures with this front. The cyclone, marked by pronounced low oxygen and CFC anomalies revealing an origin at the continental slope, was 4.5 months old. It had swirl speeds of 0.3 m s(-1), and was coupled with the anticyclone when observed. From their kinematics and water mass properties both structures were found to transport subtropical water down to similar to 900 m, the water trapped below this depth being either from the northern Subantarctic Zone, or local water. The two structures illustrate the capacity of eddies in the region to transfer subtropical and alongslope water properties into the Subantarctic Zone. | ||||||||
| Full Text |
|