The Antarctic Slope Current near 30°E

Abstract

The Antarctic Slope Current flows westward above the continental slope of Antarctica, entering the Weddell Sea near 30°E and supplying dense water to the deep overturning cell there, and contributing to global Antarctic Bottom Water formation. Observations from the 2008 I6S hydrographic section are used to investigate the strength of the Slope Current near 30°E. A prominent topographic feature, the Gunnerus Bank, diverts the Slope Current upstream of this longitude, and has a large effect on the current's structure, splitting it into a coastal and offshore component. The bank also enhances water mass mixing and lateral exchange across the slope. As part of the 2008 occupation, an additional line was made along the crest of the bank, forming a closed volume over the western side. By combining hydrographic and Lowered Acoustic Doppler Current Profiler measurements in this box using an inverse method, the Slope Current transport is estimated to be 9.6 ± 2.3 Sv; the transport associated with the Antarctic Slope Front is 4.0 ± 0.3 Sv, of which 1.8 ± 0.3 Sv enters the Weddell Gyre as recently formed dense water.