Extreme Sea Level Variations in the Sea of Japan Caused by the Passage of Typhoons Maysak and Haishen in September 2020.

This study investigates extreme sea level variations recorded by tide gauges in the coastal regions of the Sea of Japan during the passage of the typhoons Maysak and Haishen in September 2020. Specific focus is on storm surges, seiches and infragravity waves (IG waves) identified in the time series using tidal and statistical analyses. In most cases, storm surges formed through the combined effect of atmospheric pressure changes and strong winds were the major contributors to the extreme sea level rise. The first typhoon, Maysak, was the most significant in strength at the Russian and Japanese coasts, while the largest sea level variations at the southeastern coast of the Korean Peninsula were caused by the second cyclone Haishen. At all sites, the passing storms generated eigen oscillations in bays and harbors. The maximum range of high-frequency oscillations with periods of two to seven minutes, caused by IG waves, was recorded in Preobrazheniye and amounted to 2 m. The observed differences in sea level variations arise from differences in the topographic features of the corresponding coastal sites. Statistical analysis of the atmospheric pressure and wind speed series from weather stations and from the ERA5 reanalysis shows that the atmospheric pressure is reproduced by the reanalysis with high accuracy, whereas the wind speed at different stations has significant discrepancies related to the differences in local features of specific areas. [ABSTRACT FROM AUTHOR]