Shenfu Dong, S. ., University of Miami, Miami, USA, shenfu.dong@noaa.gov
Janet Sprintall, . ., University of California, San Diego, San Diego, USA, jsprintall@ucsd.edu
Sarah Gille, . ., University of California, San Diego, San Diego, USA, sgille@ucsd.edu
Lynne Talley, . ., University of California, San Diego, San Diego, USA, ltalley@ucsd.edu
DEEP MIXED LAYERS AND MODE WATER FORMATION FROM ARGO FLOAT PROFILES IN THE SOUTHERN OCEAN
Argo float temperature and salinity profiles are used to determine the mixed-layer depth (MLD) in the Southern Ocean. The deepest mixed layers are found from June to October in the Pacific and Indian Oceans just north of the Antarctic Circumpolar Current (ACC) where Antarctic Intermediate Water and Subantarctic Mode Water (SAMW) are formed. Examination of individual MLDs indicates that deep mixed layers are concentrated in a narrow surface density band corresponding to the density range of SAMW. The deep mixed layers are within the region of strong wintertime cooling just to the north of the ACC, consistent with the idea that deep convection from wintertime cooling leads to the formation of mode water. Although the wintertime cooling from air-sea heat fluxes in the Pacific and Indian Oceans are comparable, the Indian Ocean experiences strong cooling from the Ekman advection, whereas the vertical entrainment in the Pacific is stronger than that in the Indian Ocean. Those differences suggest that the mode water formation in each region may be preconditioned by different processes.