Winter oceanographic observations in some New Zealand fiords

Abstract

The winter oceanography of four New Zealand fiords is discussed using data obtained from July 1983, and comparisons are made with data collected on previous summers. Surface waters were more saline in winter than in summer and were everywhere cooler than the underlying water. Deep water renewal in the fiord basins was re‐examined using all available data. For Milford Sound and the other deep silled fiords renewal appears to be related to the arrival of dense water at sill depth offshore by an as yet unknown advective or meteorologically forced process. In the more isolated Long Sound, Preservation Inlet, deep water renewal requires the subtle interplay of tidal flows and mixing processes over the shallow double sill. Complete renewal of Long Sound bottom water appears to be a slow process.

Keywords:

• oceanography
• winter
• fiords
• salinity
• temperature
• freshwater inflow
• Milford Sound
• George Sound
• Thompson Sound
• Preservation Inlet