Operational forecasting of sea level height using an unstructured grid ocean model

Unstructured grid models are often used for modelling coastal problems, due to their efficiency at handling complex coastlines while also not over resolving deeper water. In this paper, we outline how an unstructured grid finite element model has been incorporated into an operational environmental forecast system, EcoConnect, to provide near real-time predictions of storm surge and sea level height. Data transfer methods between the meteorological model, which uses a structured grid, and the storm surge model are described and we present results of verification simulations for the forecasting of sea level height. The model successfully reproduced the storm surge signal at 15 tide gauge locations around New Zealand during December 2006–February 2007, with RMS errors in the range 3–7 cm. Preliminary tests of a tide model using the same unstructured grid are also presented, as a precursor to its inclusion into the operational system.