The impact of open oceanic processes on the Antarctic Bottom Water outflows

Research output: Contribution to journalArticle

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Abstract

The impact of open oceanic processes on the Antarctic Bottom Water (AABW) outflows is investigated using a numerical model with a focus on outflows that occur through deep channels. A major branch of the AABW outflow is known to occur as an overflow from the Filchner Depression to the Weddell Sea through a deep channel a few hundred kilometers wide and a sill roughly 500 m deep. When this overflow enters the Weddell Sea, it encounters the Antarctic Slope Front (ASF) at the shelf break, a density front commonly found along the Antarctic continental shelf break. The presence of an AABW outflow and the ASF create a v-shaped isopycnal structure across the shelf break, indicating an interaction between the overflow and oceanic processes. Model experiments show the overflow transport to increase significantly when an oceanic wind stress increases the depth of the ASF. This enhancement of overflow transport occurs because the channel walls allow a pressure gradient in the along-slope direction to exist and the overflow transport is geostrophically controlled with its ambient oceanic water at the shelf break. Because the ASF is associated with a lighter water mass that reaches the depth close to that of the channel, an increase in its depth increases the density gradient across the shelf break and therefore the geostrophic overflow transport. The enhancement of overflow transport is also likely to result in a lighter overflow water mass, although such an adjustment of density likely occurs on a much longer time scale than the adjustment of transport.

Original languageEnglish
Pages (from-to)1941-1957
Number of pages17
JournalJournal of Physical Oceanography
Volume41
Issue number10
DOIs
Publication statusPublished - Nov 29 2011
Externally publishedYes

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Antarctic Bottom Water
shelf break
outflow
water mass
density front
wind stress
pressure gradient
sill
continental shelf
timescale
experiment

All Science Journal Classification (ASJC) codes

  • Oceanography

Cite this

The impact of open oceanic processes on the Antarctic Bottom Water outflows. / Kida, Shinichiro.

In: Journal of Physical Oceanography, Vol. 41, No. 10, 29.11.2011, p. 1941-1957.

Research output: Contribution to journalArticle

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