| A numerical model for the tide and tidal current simulations has been established to cover the whole marginal seas adjacent to China based on the Finite Volume Coast and Ocean Model (FVCOM). FVCOM adopts an unstructured, variable resolution triangular grid in the horizontal, and a s-coordinate transformation in the vertical to better represent irregular bottom slope and land boundary. In the same time, FVCOM takes into account the effects of vertical mixing, bottom friction, non-linear and the gravitational-centrifugal potential and so on. The model's domain includes the of Bohai Sea, the Yellow Sea, the East China Sea(BYES), the Japan Sea, the Okhotsk Sea, the northern part of South China Sea(SCS) and the part of Northwest Pacific Ocean. The horizontal resolution transforms from 50 kilometers near the open boundary to 1.5 kilometers near the coast of China gradually. There are 11 sigma layers in the vertical direction. Additionally, tidal elevations from 120 tide gauge stations was assimilated using nudging techniques. The simulation results were compared with observed tidal harmonic constants from 314 gauge stations, the absolute mean errors of amplitude and phase-lag over 314 stations are 4.2cm and 6.5o for M2 constituent, 3.0cm and 8.6o for S2 constituent, 3.4cm and 8.3o for K1 constituent, 2.0cm and 5.9o for O1 constituent, respectively. And the model results were also compared with the tidal currents harmonic constants at 90 locations calculated from Fang et. al (1986,1988) in the east of Yellow Sea, the absolute mean errors of amplitude and phase-lag are 5.1cm/s and 16.0o, 4.9cm/s and 7.2o for M2 constituent east and north components, 1.3cm/s and 29.8o, 2.1cm/s and 21.5o for K1 constituent east and north components, respectively. It was side that the precision of simulated results are famous and correspond well with the observed results, so they can be used to research the tide and tidal currents in the margin seas near China.By analyzing and discussing the simulated results, eight semidiurnal and five diurnal rotary tidal systems, and two degraded rotary systems for semidiurnal constituent and one for diurnal constituent appear in the whole model area, and are all anticlockwise. The positions of all tidal amphidromic points have been computed. Three semidiurnal tidal amphidromic points in the Okhotsk Sea have been found for the first time, and two diurnal tidal amphidromic points have been verified to exist in the Soya Strait and the Tsugaru Strait. In the marginal seas adjacent to China, twenty-two semidiurnal tidal current-amphidromic points have been found from the model simulation, while three in Bohai Sea, eight in Yellow Sea, six in East China sea, five in South China Sea; While eight of them have been found for the first time with one in the top of Liaodong bay, three in the middle of Yellow Sea, one in the east of Okinawa island, one on each side of Amami island, one in the southeast of Hainan island. twenty-eight diurnal tidal current-amphidromic points have been found with two in Bohai Sea, seven in Yellow Sea, nine in East China sea, ten in South China Sea. While seven of the diurnal tidal current-amphidromic points are found for the first time, two in the coast of Tsingdao, one in west and three in southwest of Kyushu island, one in the east of Hainan island.In addition, the patterns of four main constituents on tidal energy flux are presented for the whole area. Tidal energy dissipations are calculated exactly for each sea area respectively. The results indicate that the tidal energy flux mainly transmits to west from Northwest Pacific to the margin seas near China, and to north to the Okhotsk Sea, all that is dissipated at last; to the tidal energy in the margin seas near China, respectively, semidiurnal tidal energy is dissipated in the BYES, but the diurnal tidal energy is dissipated in the SCS mainly.
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