Circulation in the Hauraki Gulf, New Zealand

Abstract

Abstract Results from five current meters moored in Hauraki Gulf are analysed. Tidal flows and the tidal constituents M2, S2, and N2 are deduced. Time series techniques are used to examine the effects of wind stress and the spatial coherence in the flow. It is found that currents of oceanic water, set up under south‐west to southerly directed winds, flow into the Gulf through Jellicoe and Cradock Channels, with those through Cradock Channel probably passing more or less directly out through Colville Channel. A net anti‐clockwise circulation is suggested to occur in the inner Gulf, south of the latitude of Kawau Island. A lack of any particular spectral features and limited spatial coherence suggests that in the Hauraki Gulf, variations in circulation in the 2‐ to 15‐day time band considered are not well defined but that the Gulf responds to external forcing events with transient currents which last typically from 2 to 5 days.