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Dense shelf water formation and brine-driven circulation in the Adélie and George V Land region

Citation

Kusahara, K and Hasumi, H and Williams, GD, Dense shelf water formation and brine-driven circulation in the Adelie and George V Land region, Ocean Modelling, 37, (3-4) pp. 122-138. ISSN 1463-5003 (2011) [Refereed Article]

Copyright Statement

Copyright 2011 Elsevier

DOI: doi:10.1016/j.ocemod.2011.01.008

Abstract

The formation and outflow of dense shelf water (DSW) from the Adélie and George V Land region and the seasonal variation in the ocean circulation therein are investigated using a global ice-ocean model with fine resolution around East Antarctica. The model reproduces key elements of the overall system described by previous observational studies: modified Circumpolar Deep Water intrusions into the Adélie Depression, enhanced sea-ice production in the coastal polynya regime, and seasonal variation in the export of DSW through the Adélie Sill. We find two distinct seasonal circulation patterns in the Adélie Depression. The first is a vertical circulation formed over the southwestern flank of the Mertz Bank in winter, with a southeastward inflow of light water in the upper layer and a northwestward outflow of dense water in the lower layer. The second is a surface-intensified clockwise circulation trapped in the Adélie Depression during summer. This seasonal variation is attributed to the spinning-up and down of the haline circulation which is driven by the brine-rejection from enhanced sea ice formation in the coastal polynyas. In the model a similar haline circulation also develops in the Mertz Depression. Assuming a critical density of 27.88 (27.80) kg m−3 for outflowing DSW, the annual mean export from the Adélie and Mertz Sills are 0.21 (0.37) Sv and 0.12 (0.32) Sv, respectively. The model clearly shows a dual-system for DSW formation and export from the Adélie and Mertz Depressions, consistent with recent observational analysis over the continental slope and rise.

Item Details

Item Type:Refereed Article
Keywords:ice-ocean modeling
Research Division:Earth Sciences
Research Group:Atmospheric Sciences
Research Field:Climate Change Processes
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts)
Author:Kusahara, K (Dr Kazuya Kusahara)
Author:Williams, GD (Dr Guy Williams)
ID Code:109889
Year Published:2011
Web of Science® Times Cited:13
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2016-07-06
Last Modified:2016-11-24
Downloads:0

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