FOCCUS WP9 D9.1 Application Demonstrator: ESC3 - 3.2.3 - Storm surge and extreme water levels forecasts in Portuguese estuaries

Overview This Zenodo item contains the demonstrator for FOCCUS coastal application 3.2.3: Storm surge and extreme water levels forecasts in Portuguese estuaries. The demonstrator illustrates how numerical modelling from regional to local scale, as a physical downscalling approach, can be used to support the implementation of extreme sea level events early warning system (EWS) in areas influenced by estuarine dynamics. Application Demonstrator This demonstrator presents a short-term coastal forecasting service based on a two-tier modelling approach for predicting and assessing the impacts of extreme sea-level events, particularly coastal overtopping, suported by circulation and wave operational models (MOHID, WAVEWATCHIII and SWAN) for the Portuguese coast that capture the large-scale oceanographic processes that drive extreme coastal events. It includes an interactive notebook that describes the numerical modelling system, and demonstrates the application of this product for two coastal areas in the Lisbon Metropolitan Area. All the source code for the notebook is embedded into a GitHub repository (FOCCUS demonstrator) while the model data is kept separate. The demonstrator is developed within FOCCUS Work Package 9, Deliverable 9.1, which focuses on demonstrating the different applications used for open-to-coastal ocean forecasting and observation services. Two-tier approach Tier 1 operates at the national scale, providing a Flooding Hazard Index based on Total Water Level (TWL) forecasts along the Portuguese coast. This operational service serves as an initial forecast layer to identify potential dates where overtopping might occurs and triggers tier 2. Tier 2 focuses on two high-risk coastal areas within the Tagus estuary and its surrounding coastal region that are particularly vulnerable to wave overtopping and flooding. In these local demonstrators, a high-resolution coastal model (XBeach) is used to produce event-specific forecasts with enhanced spatial detail.