Surveys of the east Auckland and East Cape Currents, New Zealand

Abstract

Several hydrological surveys using expendable bathythermograph probes have been carried out east of the North Island, New Zealand. The presence of a south-easterly directed flow known as the East Auckland Current between 34 and 37ºs. is confirmed. The geographical position of the current core varies with time, but bathymetric steering appears to result in a general anticlockwise flow around 34ºS.,175ºE. South of the main flow there appear to be weak and variable currents associated with the upper continental slope. North of the East Auckland Current core there appear to be either two eddies, one anticyclonic and the other cyclonic, or current meanders. At 37ºs. the flow direction varies with longitude. South of 37% there is always a south-easterly flow around East Cape, giving rise to the East Cape Current. East of 180260E. at 37ºs. there is a return northward flow of modified subtropical water, which can result in strong horizontal gradients of surface temperature and salinity. There is also evidence of warm-core eddies north-east of 40ºS.,180ºE.