Dense shelf water formation along the south-west Australian inner shelf

Abstract

[1] Hydrological data from a repeated cross-shore transect obtained using Teledyne Webb Research Slocum Electric gliders offshore Two Rocks in south-western Australia over 13 months are presented. The data revealed that formation of dense water inshore and its transport across the shelf as a near bed gravity current (defined as Dense Shelf Water Cascade, DSWC) was a regular occurrence, particularly during autumn and winter months. In autumn, the dense water is mainly formed through changes in salinity resulting from evaporation, whilst in winter; temperature change through surface cooling was the dominant factor. The mean wind speeds also decrease during the transition during autumn. The speed of the DSWC was estimated to be 0.01–0.02 m s−1, and similar to that measured in other selected regions globally. The offshore transport from the shelf is a significant component of the alongshore wind-driven transport.