Hydrographic observations during the Tasman boundary experiment off the west coast of South Island, New Zealand

Abstract

Hydrographic observations over the west coast shelf during the Tasman Boundary Experiment (TASBEX) in 1986/87 are presented. Temperature dianges over the shelf were related to mixed‐layer development, shelf waves, and seasonal changes, with wind‐driven upwelling being important close to the coast. During upwelling, a surface coastal current was observed and at times a weak undercurrent or countercurrent developed. Changes in freshwater inflow resulted in changes in the depth of the low‐salinity surface layer. In the north, flows were generally weaker than in the south, where the shelf is narrow and the Southland Current dominates. Changes in the position and strength of the Southland Current were observed and on one occasion the response to a wind change event was a relaxation of the flow to a coastal Southland Current regime.

Keywords:

• South Island
• west coast
• currents
• temperature
• salinity
• density
• upwelling