Future Wave Climate and Coastal Impacts: Projections for the Northeast Atlantic and the Galway Bay.

This study examines the projected changes in wave heights under the RCP8.5 climate scenario in the Northeast Atlantic (NEA) and along the west coast of Ireland, with a specific focus on the wave climate in Galway Bay. An analogue method was employed to generate surrogate data to downscale wind data from MPI-ESM, using high-resolution ERA5 data as a reference. The surrogate wind data were used to drive the WAM-SWAN model setup for simulating waves in the NEA. This statistical approach provided computationally efficient and reliable wind inputs for wave modelling while effectively capturing the temporal and spatial variability of present and future wind patterns.

Results from the SWAN model simulations reveal distinct spatial and seasonal variability in wave heights, with an intensification of wave activity in the northwest and reductions in the southern and eastern regions of the NEA. While mean significant wave heights are projected to decrease around Ireland, regional variability highlights the complex interactions between large-scale wind patterns and localized wave dynamics. Seasonal analyses indicate significant increases in wave heights during winter and summer, with the largest decreases observed in spring. Localized responses at buoy sites M3 and M4 underscore the spatial heterogeneity of future wave climate changes, with M3 experiencing more energetic conditions and M4 showing increased calm states.

To assess the impacts of waves on coastal processes near Galway Bay, 1D surf zone model was developed. The model was driven by wave conditions derived from SWAN. The primary goal of the 1D model is to study future wave height changes under different sea level rise scenarios. By integrating insights from present conditions with predictions for the future, this study aims to provide valuable information to support decision-making for both short- and long-term coastal management.