OBSERVATION OF WAVE SPECTRUM UNDER TYPHOON CONDITION

Abstract

The spatial and temporal variation of wave spectrum under typhoon SANBA, which was the 16th typhoon originating in the northwestern Pacific Ocean in 2012, was examined. The typhoon SANBA passed through the middle of Korean peninsula whereas most of typhoons passed the Straits of Korea (eastern side of Korean peninsula). This unique path of typhoon SANBA provided interesting features of wave conditions. It was believed that wave heights were larger in the right side of the typhoon path because typhoons translation speed and rotational wind field were in the same direction (i.e., dangerous semicircle). However, observational evidence of wave spectrum under typhoon was still rare because of the difficulty in measurement. In this study, wave spectrum analysis under extreme storm condition of typhoon SANBA is given for the left and right sides of the path, including the information of significant wave height, peak period, and dominant wave direction. Wave measurements were obtained by directional wave rider buoys installed at Yeosu and Namhyeongjedo in Korea. Yeosu and Namhyeongjedo are located in each of the left and right of the path of the typhoon SANBA. The measurements provided distinguished wave conditions in each side of navigable semicircle and dangerous semicircle of the typhoon. Therefore it is possible to observe the spatial differences of the wave spectrum across the path of the typhoon, as well as temporal changes of wave spectrum as the typhoon evolves.