Deep-Sea Research II 49 (2002) 4715–4742 On the export of Antarctic Bottom Water from the

• Main Authors: Weddell Sea, Alberto C. Naveira Garabatoa, Elaine L. Mcdonagha, David P. Stevensb, Karen J. Heywooda, Richard J. S
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2002
• Subjects: Antarctic; Indian; Scotia Sea; South Scotia Ridge; The Antarctic; Weddell; Weddell Sea; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.510.9459; http://www.uea.ac.uk/~dps/publications/NGMSHS02.pdf

A survey of the current field over the South Scotia Ridge, obtained with a lowered Acoustic Doppler Current Profiler (LADCP), is presented. There is a pattern of northward (southward) flow on the western (eastern) side of each of four deep passages in the ridge, which is supported by tracer measurements. The net full-depth LADCP-referenced geostrophic transport over the ridge is 2277 Sv (1 Sv=106m3 s1) northward, with the jets on either side of the passages transporting 5–10 Sv in alternating directions. The corresponding Weddell Sea Deep Water (WSDW) transport over the ridge is 6.771.7 Sv. This is a factor of 4 larger than the only previous estimate in the literature, and suggests that a significant proportion of the Antarctic Bottom Water (AABW) invading the world ocean abyss escapes the Weddell Sea via the Scotia Sea. The net full-depth and WSDW transports over the ridge are modified to 776 and 4.770.7 Sv, respectively, by a box inverse model of the western Weddell Gyre. The model incorporates the WOCE A23 crossing of the central part of the gyre and a set of five constraints synthesizing our previous oceanographic knowledge of the region. It diagnoses that 9.773.7 Sv of AABW are formed in the Weddell Sea, and that comparable amounts are exported over the South Scotia Ridge (B48%) and further east (B52%) assuming that no AABW enters the Weddell Gyre from the Indian Ocean. The WSDW fraction with neutral density gn> 28:31 kgm3 transported over the ridge upwells in the Scotia Sea at a rate of