Variability of the East Australian Current over most of its depth and a comparison with other regions

Abstract

A knowledge of the structure of current systems over their total depth, especially of western boundary currents such as the East Australian Current, is important in assessing global transports. Many measurements have been performed on these currents and the generation of climatological statistics for them should assist in assessing the representativeness of conditions obtained in any particular study. To examine the structure, in a statistical sense, of the East Australian Current system over most of its depth, archived hydrological station data are analyzed to produce profiles of various statistics of temperature and dynamic height perturbations (e.g., means, standard deviations, and correlation coefficients as a function of vertical separation). These are compared with the same statistics derived for two other locations with less vigorous mesoscale perturbations. Nondimensionalized geostrophic velocity profiles are also obtained. The method uses all the individual profiles from a given area and does not need series of oceanographic sections or areal surveys. It is found that the magnitude of perturbations and their vertical length scales are larger in the East Australian Current region than in either of the other two locations.