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

The formation and outflow of dense shelf water (DSW) from the Adlie 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 syste...

Full description

Bibliographic Details
Published in:Ocean Modelling
Main Authors: Kusahara, K, Hasumi, H, Williams, GD
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier Sci Ltd 2011
Subjects:
Earth Sciences
Atmospheric Sciences
Climate Change Processes
East Antarctica
George V Land
Antarc*
Antarctica
Sea ice
Online Access:https://doi.org/10.1016/j.ocemod.2011.01.008
http://ecite.utas.edu.au/109889
Description
Summary:The formation and outflow of dense shelf water (DSW) from the Adlie 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 Adlie Depression, enhanced sea-ice production in the coastal polynya regime, and seasonal variation in the export of DSW through the Adlie Sill. We find two distinct seasonal circulation patterns in the Adlie 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 Adlie 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)kgm −3 for outflowing DSW, the annual mean export from the Adlie 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 Adlie and Mertz Depressions, consistent with recent observational analysis over the continental slope and rise.

Similar Items