From Offshore Copernicus Wave Products to Beach-Scale Digital Twins: Integrating Nearshore Wave Modelling and Field Observations Along the Cork Coastline

Digital Twins of the Ocean aim to provide integrated, observation-informed representations of ocean systems; however, the performance of models that underpin their potential  often degrades in nearshore environments where wave transformation, sediment transport, and morphological change occur at higher resolution spatial and temporal scales. This study presents an integrated observation–modelling framework designed to strengthen coastal components of the European Digital Twin of the Ocean (DTO) by linking Copernicus Marine products with validated nearshore modelling and sustained field observations to support decision making by a municipal authority.

 

The municipal authority is seeking actionable information on the study area’s coastal dynamics, and a better understanding of the areas dynamism. To aid this understanding, a long-term nearshore wave dataset was developed for the entire Cork coastline using the MIKE 21 SW (Spectral Wave) model. Here, the connection between global and local that is a key element of DTO application has been explored, whereby Copernicus Marine offshore wave reanalysis data were applied as boundary conditions for the period 2000–2023. The model represents key offshore-to-nearshore wave transformation processes, including refraction, shoaling, and directional changes, and provides hourly wave parameters along the 15 m depth contour at 400 m intervals. Model performance was evaluated against significant wave height observations from the Bantry Bay wave buoy, showing good agreement (RMSE < 0.4 m; correlation coefficient > 0.8) and supporting the reliability of the derived nearshore wave dataset.

 

In parallel, the wave modelling framework is supported by extensive field observations collected through the Atlantic–Arctic Agora (A-A Agora) project and a parallel PhD study on Coastal Vulnerability Assessment, both of which are being delivered in partnership with the local municipal authority. This enables the activity to provide potentially actionable information, while also improving understanding of the shore itself. In parallel, the wave modelling framework is supported by extensive field observations collected through the Atlantic–Arctic Agora (A-A Agora) project and a parallel PhD study on Coastal Vulnerability Assessment, both delivered in partnership with the local municipal authority. This collaboration enables the development of potentially actionable information, while also improving understanding of nearshore and beach-scale processes. Monthly cross-shore beach profile surveys capture short-term morphological variability, while seasonal and post-storm measurements extend the analysis across a range of exposed and sheltered coastal settings. Seasonal sediment grain-size data collected at multiple locations per beach provide additional context for interpreting sediment transport processes and shoreline response.

 

The combined wave, morphology, and sediment datasets are used to inform and assess local beach-scale morphodynamic models based on the LITPACK modelling suite, enabling scenario-based simulations of sediment transport and shoreline evolution. These models are further applied to explore future coastal evolution scenarios aligned with nationally adopted climate change pathways. By connecting Copernicus offshore wave products with validated nearshore modelling and sustained in situ observations, this work provides practical and transferable insights to guide efforts regarding global-to-coastal model configurations, systematic verification, and scenario-based DTO coastal services that support regional and local authority decision making.