IUGG 2003 Abstract
P05
The Physical Oceanography of the Indian Ocean
Monday, June 30 AM
Location: Site B, Room 23
Presiding Chairs:F. Schott, J. Lutjeharms
TIME [ 1130 ] [ P05/30A/B23-007 ]
VENTILATION AND MIXING OF INDIAN OCEAN BOTTOM WATERS
Rana A. FINE(Rosenstiel School, University of Miami)
William M. SMETHIE(Lamont Doherty Earth Observatory, Columbia University)
John L. BULLISTER ( National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory )
Dong-Ha MIN ( School of Oceanography, University of Washington )
Mark J. WARNER ( School of Oceanography, University of Washington )
Monika RHEIN ( Institute for Environmental Physics, Department of Oceanography, University of Bremen )
Alain POISSON ( Laboratoire d'Oceanographie Dynamique et de Climatologie, CNRS/IRD/Universite Pierce Marie Curie )
Ray F. WEISS ( Scripps Institution of Oceanography, University of California San Diego )
The WOCE data provide the opportunity for a basin scale examination of how variations in CFC concentrations in bottom waters entering the Southern Ocean Indian sector and subsequently the subtropical Indian Ocean are influenced by proximity to source regions, circulation, and mixing. Bottom waters from the Australia-Antarctic Basin flow equatorward through the South Australia Basin into the Perth Basin. Whereas, the Weddell Sea source is strongest, higher CFC concentrations in the southeast subpolar Indian Ocean during WOCE were due to proximity to the Adelie and Ross sources. Subsequent local mixing in the southeast appears to be the reason for lower CFC concentrations in the Perth Basin as compared with measurable CFCs extending into the southwest Indian Mascarene Basin at 20ZS. Thus, the high dilutions and low CFC concentrations in bottom waters of the subtropical Indian Ocean are due to the relative effectiveness of local mixing and distance to water mass sources. Bottom water CFC concentrations are lower in the southern Indian Ocean than in the southern Atlantic and Pacific oceans. The difference between oceans could be due to tidal related mixing in the subtropical southwest Indian Ocean being more effective in diluting bottom waters there than the Atlantic or Pacific.