Ocean Swells along the Global Coastlines and Their Climate Projections for the Twenty-First Century

Remotely generated swell waves are the dominant contributor of the coastal wind-wave climate along most of the world coastlines. In this work we describe the characteristics of swells from a coastal perspective. We identify the main regions of formation of swell waves at present and during the late twenty-first century under the RCP8.5 emissions/climate change scenario. We have applied an algorithm that allows one to unequivocally differentiate the swell component from the local wind-waves for a global wave hindcast and for eight CMIP5 state-of-the-art wave model climate projections. We have identified four different regions of swell formation, two in each hemisphere, with the Southern Ocean being by far the main region of swell generation. By the end of this century, the number of swell events generated in the Northern Hemisphere is expected to decrease while the opposite is projected to occur in the Southern Hemisphere. The increase in the Southern Hemisphere is directly associated with a poleward movement and intensification of the wind belts projected by atmospheric climate models.
This study was supported by the ERA4CS INSeaPTION project (grant number: 690462 and PCIN-2017-038) funded by the Spanish Ministerio de Economía, Industria y Competitividad - Agencia Estatal de Investigación.