Thursday 25 August 2005

P7
1550-1710 hours

438
Wind driven influence on the development of intrusions along the Subtropical Front south of Australia
Borlace, Simon¹, Tomczak, Matthias¹
1 School of Chemistry, Physics and Earth Science, Flinders University, Adelaide, South Australia
Author email: simon.borlace@flinders.edu.au
South of Australia the Subtropical Front displays a multitude of intrusions and isolated water parcels on horizontal scales of O (10km) and vertical scales of O (10m). Relative frontal movement both in and below the mixed layer is thought to lead to vertical instability and convection at the front. Remnants of this convection are left behind as intrusive water parcels when the frontal mixed layer later returns to its original position. Using a high-resolution atmospherically forced mixed layer model; the following study set out to replicate the development of intrusive features along a frontal interface. A spatially homogenous wind field that varies in direction over time was used as the primary mechanism for forcing the upper ocean mixed layer. This study successfully generated intrusive features along a frontal interface that are comparable to observations. Depth profiles, together with temperature-salinity diagrams have been employed in this study so that comparisons may be made between numerical simulations and field observations. It can therefore be concluded that any study looking at the development of frontal intrusions should take into consideration the wind driven influence on the upper ocean mixed layer together with frontal dynamics.

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