Wave Climate Analysis near the Irish Coast: SWAN-WAM Modeling from Present to the Future.

Abstract

Coastal regions are dynamic environments influenced by various atmospheric and oceanic processes. Understanding the complex interplay of these forces is crucial for coastal management, navigation, and impact assessments. This becomes especially crucial when investigating climatological scale dynamics. In this study, two state-of-the-art third-generation wave models, WAM-Cycle 6 (Wave Action Model) and SWAN 41.45 (Simulating Waves Nearshore – Version 41.45) are utilized for numerical wave projection. The methodology involves nested modeling approach by configuring SWAN within WAM to simulate waves at finer resolution near the Irish coast. This setup involves WAM operating on a coarser grid (1.0 degree), an intermediate WAM grid with a resolution of 0.5 degree, and SWAN running on a finer grid (0.025 degree). Wind forcing (10 m wind speed) from climate reanalysis produced by ECMWF (ERA5) is used to drive the wave model. A comparison with wave buoys at different locations around Ireland showed that models agreed on the significant wave height with bias and RMSE differing at most 0.6m. Statistical techniques are utilized to connect the Max Planck Institute Earth System Model to ERA5 wind data, which is employed as forcing for the wave models to predict waves on climatological scales. The current model setup not only focuses on the present wave conditions but extends to provide future predictions and projections utilizing input data from climate models. By combining the insights from the present with the predictions and projections for the future, the current study aims to provide valuable information for decision-makers in the near and long-term future.