NORTHERN BOUNDARY CURRENTS AND ADJACENT RECIRCULATIONS OFF SOUTHWESTERN AUSTRALIA

Full-depth hydrographic and velocity measurements along 115 degrees E south of Australia (WHP section I9S) reveal an active northern boundar y current regime within 200 - 300 km of the Australian continental she lf and an offshore recirculation regime within the South Australian Ba sin. In the upper ocean an oft-described westward-flowing northern bou ndary current, the Flinders Current, extends through the thermocline a nd the salinity minimum strata of Antarctic Intermediate Water, with a n opposing eastward recirculation to its south. The new data shows tha t beneath the Flinders Current, an eastward-flowing deep northern boun dary current transports water of subtropical Indian Ocean origin suppl ied by southward deep now along the western continental slope of Austr alia in the Perth Basin. Between these northern boundary currents and the Antarctic Circumpolar Current, thermocline and deep geostrophic sh ears indicate weak recirculations, eastward at thermocline levels and westward in the deep water. Lowered Acoustic Doppler current profiler data reveal stronger organized recirculations to both the Flinders Cur rent and the deep northern boundary current. with the westward deep re circulation exceeding the eastward transport of the deep northern boun dary current and thus representing a net supply of deep water to the P erth Basin.