2006년 9월 울릉분지 해수특성 구조

Abstract

Korea Ocean Research and Development Institute conducted a hydrographic survey in the Ulleung Basin in the East Sea in September 2006. A small warm eddy characterized by homogeneous 10℃ water appeared in 100 - 200 m depths in the region southwest of Ulleungdo. The value of salinity inside the eddy reached to 34.3 psu. The low sanity < 34.0 psu and high DO > 230 μmol/l water which is an indicative of the East Sea Intermediate Water (ESIW) was distributed below the eddy and the East Korean Warm Current. Overall distribution patterns of water properties suggested that the ESIW shown in the southern Uleung Basin was supplied from the Japan Basin through the Ulleung Interplain Gap. Measurements of turbulent energy dissipation rate ε based on the velocity shear obtained from a microstructure profiler show different vertical structures of ε with wide range from 10-10 to close to 10-5 Wkg-1 within the survey area. The largest value of ε, 10-5 Wkg-1, appears in the surface layer. It reaches 10-7 Wkg-1 along the lower thermocline indicating possible direct effects of internal waves on the generation of turbulence. Values of the vertical eddy diffusivity Kz estimated from ε and buoyancy frequency are O(10-3 m2s-1) but it exceeds 10-2 near the surface.