Eastwards oceanic flow past northern New Zealand

Abstract

The geostrophic circulation on the north‐east coast of New Zealand in August 1976, as evaluated from hydrographic station data and confirmed by parachute‐drogue trajectories, is very similar to that found previously in individual segments of the region. Near‐surface current velocities, as given by the drogue trajectories in the south‐east‐directed East Auckland Current, were 0.18–0.3 m.s‐1. Re‐examination of the N.Z. Oceanographic Institute block survey hydrographic station data shows that the waters of the East Auckland Current are derived from the eastwards flow between latitudes 30°S and 40°S west of New Zealand; the fastest flow is located over the Norfolk Rise. This latter flow, and the associated Tasman Front, are enhanced by the strong sea floor relief and, therefore, do not provide confirmation of a zonal jet across the Tasman Sea. Short‐term fluctuations in the position of the Tasman Front over the Norfolk Ridge are consistent with probable variations in volume transports produced by local meteor...