An operational hydrodynamic forecast model for Tasman and Golden Bay

MetOcean Solutions has recently operationalised a high resolution hydrodynamic model for Tasman and Golden Bay, New Zealand.

The underlying forecast data is produced by a state-of-the-art unstructured hydrodynamic model (SCHISM), with offshore 3D boundary conditions sourced from a 3-km ROMS implementation of the central NZ region.  This new capability was developed as part of the Sustainable Seas Project together with the  Cawthron Institute and NIWA and will provide valuable information necessary to manage contamination risk in the aquaculture industry and beach water quality forecasts relevant to regional councils and recreational beach users.

General Manager MetOcean Solutions Dr Brett Beamsley says MetOcean Solutions’ science team has many years of experience with the SCHISM model (previously SELFE); applied primarily in high value consultancy services or research projects, with the unstructured domain capability key to representing complex nearshore bathymetries in a computationally efficient manner.

“This particular project has leveraged the strong scientific capabilities in all three research partners (NIWA, Cawthron and MetOcean Solutions) and illustrates what can be achieved when working together collaboratively.

"SCHISM is a valuable addition to our operational hydrodynamic forecast system,” says MetOcean Solutions’ physical oceanographer Phellipe Couto. “It allows our model applications to account for an even better representation of topographic features (e.g. islands, embayments, navigation channels and tidal inlets) and engineering structures (e.g. ports and breakwaters) that pose critical aspects in the modulation of the hydrodynamic regime surrounding nearshore and coastal waters.

“In practical terms, this enable us to resolve multi-scale geophysical processes such as tides, river plume dispersion and storm surge with an extra degree of accuracy and therefore provide better forecast solutions to the end user.

“The impact of storm surges on coastal areas has become highly topical particularly in the last year and the rapid deployment of this type of operational modelling infrastructure has the potential to more accurately predict coastal nearshore water levels.

 SCHISM model grid resolution from approximately 10 m nearshore to 1.5 km offshore.

SCHISM model grid resolution from approximately 10 m nearshore to 1.5 km offshore.

“In this particular project, we developed a model grid with resolution varying from 10 m in the nearshore to approximately 1.5 km offshore, defining estuaries, intertidal areas, channels, streams, major rivers and relevant beaches. The model is a full 3-dimensional implementation with atmospheric and oceanic initial and boundary conditions provided by high resolution in-house models developed for the Central New Zealand oceanic domain encompassing North and South Islands’ coastal areas around the Cook Strait. We also included fluvial discharges from 11 different rivers forecasted by NIWA’s hydrological modelling capability (TOPNET) as an important forcing to our model.”

“SCHISM presents a powerful new capapability for Metocean Solutions in high resolution operational coastal hydrodynamics,” says MetOcean Solutions’ Development Manager Dr Tom Durrant. “This is the first of several planned implementations.”

The project ‘Near real-time forecasting using operational oceanographic forecasting of contamination risk to reduce commercial shellfish harvest and beach closures’ is a collaborative effort of experts from the Cawthron Institute, NIWA and MetOcean Solutions. A project to build connected land-river-sea models and provide a timely risk assessment of contamination to beaches and shellfish growing areas. For more information on Sustainable Seas National Science Challenge click here.

The SCHISM model for Tasman and Golden Bay is freely available at MetOceanView.

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