Winter-Spring flushing of Bass Strait, South-Eastern Australia: a numerical modelling study

Abstract

This study investigates winter-spring flushing of Bass Strait with a two dimensional non-linear depth-averaged shallow-water model. The model is driven with a 180-day wind time-series. An advection-diffusion scheme for several tracers is used to reveal the flushing pattern/timescale of the region. The study considers how external water masses flush strait waters. It shows that shelf-water entering the strait through the passage between King Island and Cape Grim makes the largest contribution to strait waters. Results show that the central area of the strait is a stagnation-area of weak currents and long flushing times (>160 days). The influence of external water masses on the stagnation-area is estimated. The findings have implications for marine ecosystems, residence times, air-sea modifications of water mass properties and dense water formation in the region.