Antarctic Circumpolar Current Transport on the Northern Flank of the Kerguelen Plateau

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Antarctic Circumpolar Current Transport on the Northern Flank of the Kerguelen Plateau - Direct Observations

Damerell et al. investigated the standing meander of the Antarctic Circumpolar Current (ACC) that is present on the northern flank of the Kerguelen Plateau during the Southern Ocean Finestructure cruise in November-December 2008. The meander observed during this survey as shown by an 18-year time series of surface geostrophic^* currents by satellite altimetry to be typical for the region. Between 66-75^oE and 43 – 48^oS hydrographic stations were occupied on the shelf (~200 m depth) sloping into deep ocean to the north of Kerguelen (~4700 m), which provided the most detailed survey of the region that has been carried out to date. The first estimates of the total volume transport in this region were arrived at by referencing geostrophic shears to lowered Doppler current profiler velocities, and the transport budget is closed around the survey box. A combined associated transport of the Subtropical Front, Subantarctic Front and the Polar Front is 174 ± 22 Sv eastward. Though when compared with typical Drake Passage transport 174 Sv is large, with the additional 15 Sv of the Indonesian Throughflow. When Baroclinic transport of 119 Sv is referenced to the deepest common level between station pairs it was found to be consistent with other estimates of Baroclinic transport in this area. The fronts of the ACC are exceptionally close together at this longitude. In this article Damerell et al. discuss the exchange of properties across the fronts.

* Geostrophic current is oceanic flow in which the pressure gradient force is balanced by the Coriolis Effect. The Geostrophic flow is parallel to the isobars, the high pressure to the right of the flow in the Northern Hemisphere and to the left in the Southern Hemisphere.

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