Modeling Studies of Eddies in the Leeuwin Current: The Role of Thermal Forcing

Abstract
A high resolution, multilevel, primitive equation (PE) model is used to investigate the generation and stability of the Leeuwin Current and eddies off the west coast of Australia. Two numerical experiments are conducted to investigate the roles of the Indian Ocean temperature field and the North West (NW) Shelf waters in generating both the current and eddies. In the first experiment an alongshore temperature gradient, typical of the Indian Ocean temperature field, is imposed, while in the second experiment the additional effects of the NW Shelf waters are considered. In the first experiment, the meridional Indian Ocean temperature gradient is sufficient to drive a poleward surface flow (the Leeuwin Current) and an equatorial undercurrent. The surface flow is augmented by onshore geostrophic flow and accelerates downstream. In the second experiment, the inclusion of the NW Shelf waters completely dominates in the NW Shelf equatorial source region. The effects of the NW Shelf waters weaken away fr... Abstract A high resolution, multilevel, primitive equation (PE) model is used to investigate the generation and stability of the Leeuwin Current and eddies off the west coast of Australia. Two numerical experiments are conducted to investigate the roles of the Indian Ocean temperature field and the North West (NW) Shelf waters in generating both the current and eddies. In the first experiment an alongshore temperature gradient, typical of the Indian Ocean temperature field, is imposed, while in the second experiment the additional effects of the NW Shelf waters are considered. In the first experiment, the meridional Indian Ocean temperature gradient is sufficient to drive a poleward surface flow (the Leeuwin Current) and an equatorial undercurrent. The surface flow is augmented by onshore geostrophic flow and accelerates downstream. In the second experiment, the inclusion of the NW Shelf waters completely dominates in the NW Shelf equatorial source region. The effects of the NW Shelf waters weaken away fr...