Influence of climate variability modes over wind-sea and swell generated wave energy

Wave energy is one of the cleanest renewable sources of energy generated through the motion of wind-sea and swell waves. This study examines the influence of different climate variability modes over global wave energy generated from wind-sea (PW) and swell waves (PS) during 1950–2021 using the ERA5 reanalysis dataset. The major climate modes, such as El Niño Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Indian Ocean Dipole (IOD), and Southern Annular Mode (SAM) are considered during four boreal seasons. Wave energy extremes are determined using a non-stationary generalized extreme value analysis. The significant positive influence of ENSO on mean and extreme PS is evident over the northeast and central Pacific Ocean (PO) during December–February (DJF), and weakens during March–May (MAM). The strongest NAO response to PW and PS is evident during DJF as a tripolar and dipolar pattern over the north Atlantic Ocean, respectively. Further, PW responses due to IOD include significant increases over the Bay of Bengal and eastern Indian Ocean (IO) during JJA, which extend towards the central IO during SON. Lastly, SAM influence over PW occurs as a dipole pattern in the Southern Ocean (SO), i.e., positive anomalies in between 55°S and 65°S and negative anomalies in between 30°S and 55°S.