Tide observations in the Korea-Tsushima Strait

Tides are analyzed in the Korea-Tsushima Strait using measurements from 11 moorings, each containing an acoustic Doppler current profiler (ADCP) and a pressure gauge. These instruments were bottom moored at depths ranging fro m 59 to 142 m from May 1999 until October 1999 along two lines across the S trait, northeast and southwest of Tsushima Island. Tide amplitudes range ov er 3 m along the southern line but only range about 0.7 m along the norther n line. Maximum total current velocities exceed 100 cm/s in the surface lay ers and typically exceed 50 cm/s at mid-depths along both lines. These data are analyzed for eight tidal constituents, which are found to account for about 88% of the sea surface height variability along the southern line and 70% along the northern line. M2, S2, K1, and O1 are the dominant constitue nts. Their amplitudes are generally 10-20% smaller than amplitudes from tid e charts. M2 tidal velocities range from 17 to 25 cm/s along the line north east of Tsushima Island, and are largest at the mooring on the western side of the Strait, nearest to Korea. Southeast of Tsushima Island, either M2 o r K1 dominates the tidal contribution to the current, with tidal velocities ranging between 13 and 23 cm/s. Tidal velocities are fairly depth independ ent at mid-depths but exhibit varying degrees of depth dependence in the ne ar-surface and near-bottom layers. While tidal currents are responsible for about 25% of the eddy kinetic energy in the near surface layer, they accou nt for more than 50% of the eddy kinetic energy at mid-depths and about 70% near the bottom. (C) 2001 Elsevier Science Ltd. All rights reserved.