HR: 17:35h
AN: OS24A-05    [Abstracts]
TI: Impacts of no Agulhas leakage on the Tropical Atlantic in a coupled Ocean-Atmosphere simulation
AU: * Campos, E J
EM: edmo@io.usp.br
AF: Oceanographic Institute of the University of Sao Paulo (IOUSP), Praca do Oceanografico, 191 Cidade Universitaria, Sao Paulo, SP 05508-900, Brazil
AU: Haarsma, R J
EM: haarsma@knmi.nl
AF: Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, De Bilt, 3730 AE, Netherlands
AU: Hazeleger, W
EM: hazelege@knmi.nl
AF: Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, De Bilt, 3730 AE, Netherlands
AU: Drijfhout, S
EM: drijfhou@knmi.nl
AF: Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, De Bilt, 3730 AE, Netherlands
AB: The filaments and rings at the retroflection of the Agulhas Current constitute the mechanism for the transport of subtropical Indian Ocean waters into the Atlantic. Paleo-oceanographic records indicate that the extinction and reappearance of species of foraminifera in the SA in the last glacial period seem to be associated with the closing and reopening of the connection between the subtropical gyres of the South Indian and Atlantic Oceans. These records even suggest that there have been a common start-up of the NADW formation, the reappearance of the species in the SE Atlantic and a poleward displacement of the zero wind stress curl line some 10K years ago. This has motivated us to use a coupled ocean-atmosphere model to investigate the impact of shutting off the Agulhas leakage on the the South Atlantic circulation and on the Tropical Atlantic variability. Our experiments show that the resulting temperature and salinity anomalies would increase the stability of the Equatorial Atlantic mixed layer, which, in consequence, would inhibit the upwelling in the cold tongue region. Unable to reach the surface, after reaching the eastern side of the basin, the anomalous signal transported by the Equatorial Undercurrent would spread away from the Equator in the thermocline and upwells in the Guinea and Beguella Domes.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 4215 Climate and interannual variability (1616, 1635, 3305, 3309, 4513)
DE: 4513 Decadal ocean variability (1616, 1635, 3305, 4215)
DE: 4572 Upper ocean and mixed layer processes
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly