Mesoscale eddies in the Subantarctic Front - Southwest Atlantic*

Satellite and ship observations in the southern southwest Atlantic (SSWA) reveal an intense eddy field and highlight the potential for using continuous real-time satellite altimetry to detect and monitor mesoscale phenomena with a view to understanding the regional circulation. The examples presented suggest that mesoscale eddies are a dominant feature of the circulation and play a fundamental role in the transport of properties along and across the Antarctic Circumpolar Current (ACC). The main ocean current in the SSWA, the Falkland-Malvinas Current (FMC), exhibits numerous embedded eddies south of 50°S which may contribute to the patchiness, transport and mixing of passive scalars by this strong, turbulent current. Large eddies associated with meanders are observed in the ACC fronts, some of them remaining stationary for long periods. Two particular cases are examined using a satellite altimeter in combination with in situ observations, suggesting that cross-frontal eddy transport and strong meandering occur where the ACC flow intensifies along the sub-Antarctic Front (SAF) and the Southern ACC Front (SACCF).

[1]  A. Longhurst.  Seasonal cycles of pelagic production and consumption , 1995 .

[2]  D. Sandwell,et al.  Global correlation of mesoscale ocean variability with seafloor roughness from satellite altimetry , 2000 .

[3]  R. Leben,et al.  Eddy energy and shelf interactions in the Gulf of Mexico , 2001 .

[4]  E. Murphy,et al.  Southern ACC Front to the northeast of South Georgia: Pathways, characteristics, and fluxes , 2003 .

[5]  C. Provost,et al.  Volume transport of the Malvinas Current: Can the flow be monitored by TOPEX/POSEIDON? , 1999 .

[6]  R. Pollard,et al.  Physical controls on biogeochemical zonation in the Southern Ocean , 2002 .

[7]  A. Gordon,et al.  Intermediate waters in the southwest South Atlantic , 1989 .

[8]  A. Longhurst.  Ecological Geography of the Sea , 1998 .

[9]  Worth D. Nowlin,et al.  Structure and Transport of the Antarctic Circumpolar Current at Drake Passage from Short-Term Measurements , 1977 .

[10]  P. Ressler,et al.  Cetacean habitat in the northern oceanic Gulf of Mexico , 2002 .

[11]  D. Stammer.  Global Characteristics of Ocean Variability Estimated from Regional TOPEX/POSEIDON Altimeter Measurements , 1997 .

[12]  Frank O. Bryan,et al.  What sets the mean transport through Drake Passage , 2001 .

[13]  D. Stevens,et al.  The Antarctic Circumpolar Current between the Falkland Islands and South Georgia , 2002 .

[14]  P. Glorioso.  Modelling the South West Atlantic , 2002 .

[15]  Gustavo Goni,et al.  Investigation of the Brazil Current front variability from altimeter data , 2001 .

[16]  H. Garcia,et al.  Observed variability of water properties and transports on the World Ocean Circulation Experiment SR1b section across the Antarctic Circumpolar Current , 2002 .

[17]  W. R. Holland,et al.  A description of numerical antarctic circumpolar currents , 1978 .

[18]  M. Tomczak.  A multi-parameter extension of temperature/salinity diagram techniques for the analysis of non-isopycnal mixing , 1981 .

[19]  E. Maier‐Reimer,et al.  Wind-Driven Flow over Topography in a Zonal β-Plane Channel: A Quasi-geostrophic Model of the Antarctic Circumpolar Current , 1991 .

[20]  R. Peterson.  The boundary currents in the western Argentine Basin , 1992 .

[21]  George H. Born,et al.  Operational Altimeter Data Processing for Mesoscale Monitoring , 2002 .

[22]  S. Thatje,et al.  First record of anomuran and brachyuran larvae (Crustacea: Decapoda) from Antarctic waters , 2003, Polar Biology.

[23]  A. Orsi,et al.  On the meridional extent and fronts of the Antarctic Circumpolar Current , 1995 .