Detection and Warning System for Sudden high Swells on the east Coast of the Korean Peninsula

Over the past few years, sudden high swells (SHSs) have often occurred on the east coast of the Korean Peninsula (KP), especially during the winter season, causing many casualties and considerable property damage. High waves can be generated suddenly even in the absence of strong winds, sweeping away unsuspecting people on breakwaters or causing damage to properties such as ports and fish farms located on coasts. In this study, we developed a detection and warning system for SHSs on the KP’s east coast. First, we developed a method for separating waves into the wind sea and swell components based on one-dimensional wave spectra, wind speed, wind direction, and mean wave direction data obtained from coastal buoys. Using the calculated significant wave height difference between swells and wind seas, as well as wind speed, we developed a SHS alert system with three levels: “Attention,” “Watch,” and “Warning.” This system successfully detected three recent swell events on the east coast of the KP. Applying this system to an operational wave prediction model, it successfully issued an alert 72 h before the SHS reached the coast. The proposed system can provide consistent quantitative forecast information that can greatly contribute to preventing casualties and property damage caused by SHSs.