Variability of wave heights in marginal seas around Korea analyzed using ERA5 Reanalysis data

Ocean Wave conditions play a crucial role in the coastal region, influencing coastal communities and human activities. In this study, a 42-year data with the period of 1980-2021 from ERA-5 Reanalysis has been employed to investigate the various temporal scale of significant wave height (Hs) variability in the surrounding seas of Korean Peninsula. The signal decomposition of long-term data has been done using Empirical Mode Decomposition (EMD). In the seasonal scale, the highest (lowest) Hs occurs in the winter (summer) season with the averaged value of 1.1 (0.4) meter. These variations were related to monsoonal winds, with the stronger winds during winter season leading to the higher Hs. Year-to-year variation displays the contribution of ENSO events; the appearance of El Nino could significantly reduce the Hs by weakening the magnitude of winter monsoon in which are statistically found in the East Sea and East China Sea. The long-term changes of Hs in the region show a clear trend in which summer (winter) season have increased (decreased) trend, owing to the enhanced typhoon activities and weakened winter monsoon respectively.