Abnormally high storm waves in the east coast of Korea

Abstract

Abnormally high waves occurring at the east coast of Korea were observed at five field measurement stations and their characteristics were analyzed with the use of wind data provided by the Korean Meteorological Administration. The high waves occurred because strong Donghae twister that was developed by extratropical cyclone blew while high swell arrived at the east coast of Korea. At Sokcho, the northest site among the five measurement stations, maximum gust speed was 63.7 m/s and significant wave height reached at its maximum of 9.69 m with the corresponding peak wave period of 12.8 s. The reason for appearance of the abnormally high waves is that high swell continued while the Donghae twister blew strongly. Moreover, the wind direction was the same as the direction of swell propagation, which maximizes the increase of wave height due to superposition of swell and wind-generated waves. In the east coast of Korea, outbreak of this type of storm waves is very probable in winter season so that it is requested to establish a countermeasure of minimizing possible damage caused by the storm waves.