Influence of the Leeuwin current on the water exchange between Shark Bay and the adjacent west Australian continental shelf

Shark Bay is the largest semi-enclosed embayment on the Australian Coast. Like much of the Western Australian coastline, the adjacent shelf region is strong- ly influenced by the Leeuwin Current a warm, low salinity, poleward (north to south flowing current. The Current has a strong seasonal variance in terms of both transport and cross-shelf location. Satellite observations of surface temperature have shown that a quasi-steady intrusion of Leeuwin Current water through the major western opening to the shelf. Numerical modelling of the dynamics of this exchange process indicates that the intrusion is tidally forced, and maintained by persistent southerly winds. Consequently, significant exchange through the western opening of the Bay is likely to be restricted to periods of light, or northerly, winds and strong Leeuwin Current flow. These conditions are typ- ical of the winter months. During summer, majority of the Bay-shelf exchange is expected to occur through the northern opening of Shark Bay.