Projections of Directional Spectra Help to Unravel the Future Behavior of Wind Waves

ABSTRACT: Based on a novel approach, present-day and future spectral wind-wave conditions in a high-emission scenario from a seven-member wave climate projection ensemble are compared. The spectral analysis at the selected locations aids in understanding the propagation of swell projected changes from the generation areas across the ocean basins. For example, a projected increase in the energy from Southern Ocean swells can be observed in all ocean basins and both hemispheres, which is especially relevant in the west coast of North America due to the penetration of these swells beyond 30°N. Similarly, a consistent decrease in the energy of large northern Atlantic swells is noted close to the equator. This work provides evidence that assessments based on only integrated wave parameters (e.g., significant wave height and mean wave period) can mask information about the sign, magnitude, and robustness of the actual wave climate changes due to the offset of positive and negative variations within the spectrum, leading to a significant underestimation of the change associated with certain wave systems.HL and MM acknowledge the support by the Spanish Ministry of Science and Innovation (MICINN, grants FPU17/06203 and RYC-2014-16469, respectively). This work is funded by EXCEED (grant RTI2018-096449-B-I00) from the Spanish State Research Agency