Holte, J. W., Scripps Institution of Oceanography, La Jolla, USA, jholte@ucsd.edu
Talley, L. D., Scripps Institution of Oceanography, La Jolla, USA, ltalley@ucsd.edu
Chereskin, T. K., Scripps Institution of Oceanography, La Jolla, USA, tchereskin@ucsd.edu
Sloyan, B. M., CSIRO, Hobart, Australia, Bernadette.Sloyan@csiro.au
OBSERVATIONS OF SUBANTARCTIC MODE WATER MIXED LAYERS AND ANTARCTIC INTERMEDIATE WATER DURING AUSTRAL WINTER 2005
Two hydrographic surveys from the Southeast Pacific Ocean provided high quality, synoptic views of the Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW) formation region during austral winter and summer. The winter cruise, from August 23 to October 5, 2005, occupied 135 full depth CTD/Rosette stations and deployed 371 XCTDs. The data set was used to examine the mixed layer and frontal and eddy structure in the SAMW and AAIW formation region. Forty two mixed layers deeper than 400 m were found. The deepest mixed layers occurred immediately north of the Subantarctic Front (SAF) and were associated with oceanic heat loss to the atmosphere (maximum of 250 W m-2). Active mixing zones were identified from mixing signatures such as oxygen saturation. The SAF and eddies were identified and characterized using hydrographic sections and satellite altimetry and related to the SAMW mixed layers. The zonal variations in mixed layer properties (down-front change in potential density of 0.05 kg m-3) were examined. The SAMW mixed layers were related to the AAIW layer with property comparisons.