7th International Conference on Southern Hemisphere Meteorology and Oceanography

Monday, 24 March 2003: 2:30 PM
An outline of the role of eddies in the New Zealand Subantarctic
Michael Williams, NIWA, Wellington, New Zealand
Eddies make frequent appearances in the New Zealand Subantarctic. They appear to be mainly restricted to two areas, the Subantarctic Slope, where the Antarctic Circumpolar Current (ACC) is topographically steered by the Campbell Plateau, and to the east of the Bounty Plateau, where the Subtropical (STF) and Subantarctic Fronts (SAF) are in close proximity. Additionally there is some evidence that they may have a role in the Bounty Trough. Recent efforts in studying these eddies have focused on using simultaneously acquired sea surface temperature and height data from satellites, and shipboard velocity, temperature, salinity and oxygen data sets. Additionally long-term current meter mooring records have been used to estimate the frequency of eddies. This has allowed a coarse picture of the role of eddies in the New Zealand Subantarctic to be developed. It has been found that they can be as frequent as 9 times a year, have radii in the order of 62.5 km and be up to 1000 m deep. Presently, further examination of the these data sources is occurring with the aim of exploring possible eddy propagation mechanisms in the region and the role that these eddies have in transporting water within the ACC and across the STF and SAF.

Supplementary URL: