동해의 이상파랑 수치 시뮬레이션

Abstract

The East Sea is under the direct influences of the East Asian winter monsoon and rough wave conditions are normally observed along the coasts of the East Sea in wintertime together with high storm waves during the passage of typhoons. In February 2008, abnormal high waves were generated and propagated to Korea and Japan coast in the East Sea due to a quasi-stationary strong atmospheric low pressure near Hokkaido, Japan. Large damages to coastal structure and harbor were reported along the east coast of Korea and Sado Island and Toyama Prefecture, Japan. The objectives of this study are to investigate the generation mechanism of abnormal high swell waves in the East Sea in wintertime and to simulate such an abnormal meteorological condition and wave field using a mesoscale atmospheric model (MM5) and the third generation wind wave models (WW3 and SWAN) with modification of wave energy sink term.The observed and simulated significant wave height and period at Fushiki Toyama, Wajima in Japan and at Anmok in Korea are compared. During the simulations of wave field with WW3 and SWAN, it was found that the wave energy sink term by whitecapping in lower frequency (0.05~0.19 Hz) in SWAN is overestimated. In wave field simulation of SWAN, two counter-measures can be taken as suggested by Roger et al., (2003); 1) by considering a whitecapping sink term for arbitrary water depth (Donelan and Yuan, 1994) with tunable parameters and 2) by suggesting new criteria to distinguish swell and reduce the swell energy dissipation.