Leeuwin current and wind distributions on the southern part of the Australian North West Shelf between January 1982 and July 1983

Abstract

Observations of the current and wind distributions on the southern part of the Australian North West Shelf between January 1982 and July 1983 are presented. Maps of monthly averages of winds and currents from a variety of locations are presented as well as some time series spanning 19 months of currents and water temperatures from a shelf-slope location and corresponding winds from a coastal station. The main feature of the observations is the strong flow to the south-west parallel to the bathymetry known as the Leeuwin Current. From the observations across the continental shelf, the low-frequency flow is strongest over the shelf break reaching a maximum speed of approximately 0 25 m s^-1. The current is strongest between February and June. Reversals of the flow to the north- east are usually weak in strength and of short duration and are associated with strong south-west winds. However, observations of water temperature suggest the north-east currents cause weak upwelling events of cold deep water onto the shelf. The south-east trade winds blow from the south- east between March and August, but are shown to be inefficient in generating longshore currents to the south-west and hence in strengthening the Leeuwin Current.