A hydrodynamic model of Chatham Rise, New Zealand

Abstract

A three-dimensional hydrodynamic ocean model, the Regional Ocean Modelling System (ROMS), was applied to a region encompassing the Chatham Rise, New Zealand and forced by surface fluxes from an atmospheric reanalysis data set. The model outputs fields were validated against a number of observation-based data sets, including the CSIRO Atlas of Regional Seas 2000 (CARS 2000) climatology of sub-surface temperature and salinity, a sea surface temperature (SST) climatology from the NIWA SST Archive (NSA), and sea surface height (SSH) from the Archiving, Validation and Interpretation of Satellite data in Oceanography (AVISO) Mapped Sea Level Anomalies (MSLA) data set. The model reproduced the flow around Chatham Rise well and had a realistic seasonal cycle in the upper ocean. Its biggest deficiency was that the Wairarapa Eddy was too steady and pushed warm water too far south towards the head of Hikurangi Trough. This exercise confirms the need to validate a model against multiple data sets and shows the value of SST data for revealing underlying oceanographic features. © 2007, Copyright Taylor & Francis Group, LLC.