CSIRO Marine and Atmospheric Research
Past Seminars

Monday 11th August 2003 at 11.30am

CSIRO Auditorium

Simon Marsland
CSIRO Marine Research

Modelling water mass formation in the Mertz Glacier Polynya.

The Max Planck Institute Ocean Model (MPI-OM1) has an orthogonal curvilinear grid allowing for arbitrary placement of the model's poles. The Mertz-HOPE version has a small radius 'south pole' just inland of the Mertz Glacier Polynya (MGP), East Antarctica, and a large radius 'north pole' over Siberia. The resulting mesh gives high horizontal resolution (~15 km) in the region of interest, while maintaining a global domain that avoids the non-trivial problems of open or closed boundaries. The model is capable of simulating many of the observed features of the ocean and sea ice system in and around the MGP.

Results show annually integrated net sea ice growth within the MGP in the range of 5-15 m.

The associated brine rejection is responsible for the production of High Salinity Shelf Water (HSSW) in the Adelie Depression, which in turn is a source of Antarctic Bottom Water.

The model was integrated with NCEP-NCAR daily forcing for the 1990's. There is considerable interannual variability in the model response, with peak HSSW outflow from the Adelie Depression of around 1 Sv. Sensitivity experiments address the impact of changes in temperature and precipitation forcing on the areal extent of the MGP, the net surface fluxes through the MGP, and the rate of HSSW outflow from the Adelie Depression.