New Developments in the New Zealand Ocean Operational Forecast System – The Moana Project.

New Zealand’s maritime domain is one of the largest on the planet, with an exclusive economic zone of approximately 4,300,000 km2. MetService is the institution responsible for providing a national ocean forecast system to respond to such demand. To accomplish this, a comprehensive system of different ocean models and information endpoint delivery mechanisms has been developed. Downscaling from global ocean models presents a problem due to the lack of key phenomena important for local users and common misrepresentation of the local dynamics not focused on the global simulations. Through the Moana Project, the largest initiative in oceanographic research in New Zealand to date, we are bringing the operational ocean forecast system to the state-of-the-art by including recent developments in the model physics and developing the Data Assimilation (DA) capability. This includes the generation of an open-access high-resolution 25 year ocean hindcast product, presently being used for research and consulting purposes, a new approach for a coastal ocean forecast including important coastal physical processes usually missing in global simulations, the generation of a reanalysis of the ocean using a 4DVar data assimilation scheme, and the operationalization of the DA to provide optimal initial conditions for the forecast cycles.

A general description of the operational forecast system with its unique architecture is presented, including recent developments in ocean circulation modeling and future plans. The focus is on the impact of the inclusion of coastal physical phenomena and the assimilation of ocean observations. The steps taken in the design and implementation of this system are discussed. This effort is part of the Moana Project – a national collaborative research project including all the main oceanographic institutes in New Zealand.