Author Description

To investigate the effect of the role played by planetary beta in the generation and maintenance of the Leeuwin Current System (LCS), several numerical experiments are conducted with varying Coriolis parameterizations (f- plane or beta-plane). The seasonal effects of thermal gradients, wind forcing and North West Shelf (NWS) waters are also systematically explored in the numerical experiments. Additionally, the generation mechanisms for undercurrents along both the western and southern coasts of Australia are investigated. Although surface currents, undercurrents, and mesoscale activity are present in both the f-plane and beta-plane experiments, those run on a beta-plane show a more realistic depiction of these features due to the significant role played by the planetary beta effect in the LCS. The combination of thermal forcing, wind forcing, and NWS waters were found to be essential to maintain the highly seasonally varying LCS. Alongshore temperature gradients, which are generated at deeper levels by the strong flow of the Leeuwin Current, are sufficient to establish and maintain an equatorward (westward) undercurrent along western (southern) Australia.