A 3-DIMENSIONAL NUMERICAL-MODEL OF THE RESPONSE OF THE AUSTRALIAN NORTH-WEST SHELF TO TROPICAL CYCLONES

A three-dimensional barotropic and baroclinic model is developed to si mulate currents and temperature changes induced by tropical cyclones t raversing the continental shelf and slope region of the Australian Nor th West Shelf. The model is based on a layered, explicit, finite diffe rence formulation using the nonlinear primitive equations with an embe dded entrainment scheme; a mixed-surface-layer interface is defined, w hich is allowed to shift from one interface to another, depending on t he strength of a storm. The model has been tested by simulating the cu rrents and temperature changes induced by tropical cyclones Orson and lan. The modelled currents and temperatures agreed well with the avail able measured records except near the seabed. It has been found that t he pre-storm currents have very little influence on the peak of the st orm-induced currents and the currents in the wake of a tropical cyclon e. The model contained no coefficients which must be calibrated for a particular application and clearly illustrated the importance of the b aroclinic effects on the storm-induced response over the North West Sh elf of Australia.