Time and space scales of variations in the East Australian Current, from merchant ship data

Abstract

The along-track components of current for 55 southward passages between Cape Moreton (27º02'S.) and Sugarloaf Pt (32º 27'S.) on the east Australian coast have been analysed. The currents are predominantly towards the south, but their variability is stressed. At any particular time, departures from the mean current show appreciable correlation for distances up to about 100 km. At a particular latitude, departures from the mean current are positively correlated for time differences up to 20 days, and show a slight negative correlation for time differences of the order of 30 or 40 days, indicating a weak periodicity with periods of the order of 70 days. The connection between these and other estimates of space and time scales for the east Australian current is discussed. No evidence of alongshore movement of current patterns was found.