Frontal structure and Antarctic Bottom Water flow through the Princess Elizabeth Trough, Antarctica (original) (raw)
1999, Deep Sea Research Part I: Oceanographic Research Papers
Hydrographic, current meter and ADCP data collected during two recent cruises in the South Indian Ocean (RRS Discovery cruise 200 in February 1993 and RRS Discovery cruise 207 in February 1994) are used to investigate the current structure within the Princess Elizabeth Trough (PET), near the Antarctic continent at 853E, 63}663S. This gap in topography between the Kerguelen Plateau and the Antarctic continent, with sill depth 3750 m, provides a route for the exchange of Antarctic Bottom Water between the Australian}Antarctic Basin and the Weddell}Enderby Basin. Shears derived from ADCP and hydrographic data are used to deduce the barotropic component of the velocity "eld, and thus the volume transports of the water masses. Both the Southern Antarctic Circumpolar Current Front (SACCF) and the Southern Boundary of the Antarctic Circumpolar Current (SB) pass through the northern PET (latitudes 63 to 64.53S) associated with eastward transports. These are deep-reaching fronts with associated bottom velocities of several cm s\. Antarctic Bottom water (AABW) from the Wed-dell}Enderby Basin is transported eastwards in the jets associated with these fronts. The transport of water with potential temperatures less than 03C is 3 ($1) Sv. The SB is shown to meander in the PET, caused by the cyclonic gyre immediately west of the PET in Prydz Bay. The AABW therefore also meanders before continuing eastwards. In the southern PET (latitudes 64.5 to 663S) a bottom intensi"ed #ow of AABW is observed #owing west. This AABW has most likely formed not far from the PET, along the Antarctic continental shelf and slope to the east. Current meters show that speeds in this #ow have an annual scalar mean of 10 cm s\. The transport of water with potential temperatures less than 03C is 20 ($3) Sv. The southern PET features westward #ow throughout the water column, since the shallower depths 0967-0637/99/$ } see front matter 1999 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 7 -0 6 3 7 ( 9 8 ) 0 0 0 1 0 8 -3 #ow of bottom water, the total westward transport of the whole water column in the southern PET is 45 ( $6) Sv.
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