| A numerical model for the tide and tidal current simulations has been established to cover the whole sea area adjacent to Zhangzidao Island based on the Finite Volume Coast and Ocean Model(FVCOM).FVCOM adopts an unstructured ,variable resolution triangular grid in the horizontal ,and aσ-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 so on.The model's domain includes the of Zhangzidao,Changshan Islands,Haiyangdao Island and Dalu Island .The coastlines of the domain are very complicate with lots of beys . The horizontal resolution transforms from 1800 meters near the open boundary to 300 meters near the coast of island gradually . There are 6 sigma layers in the vertical direction. The stimulation of water dynamical was adopted from FVCOM ,only tidal forcing was concerned in open boundary. M2,S2,N2,O1,K1,and P1 main tidal were chosen .The simulation results were compared with observed tidal harmonic constants from 5 gaguge stations ,the absolute mean errors of amplitude are 5.16 cm,2.64 cm,1.36 cm and 1.40 cm ,the absolute mean errors of phase-lag are 1.62°,2.11°,1.93°and 4.09°.And the model results were also compared with the tidal currents at 4 locations observed in the domain .It was side that the precision of simulated results are agree and correspond well with the in-situ obervations , so they can be used to analyse the characteristics of tides and tidal current in the sea area adjacent to Zhangzidao Island.The co-tidal charts and the tidal current ellipses of M2 ,S2,K1 and O1 are drawn and discussed based on the calculated results .It is shown that the tidal near the Zhangzidao island is characterized by regular semidiurnal tide .The horizontal flow anticlockwise rotates in the most studied area , while the rotation directions is clockwise in the east of the 123.75°E . The rectilinear flow exists in the nearshore and river channel area .In the south of Daludao island , the horizontal tidal flow reciprocates obviously in the south—north direction . It is found that some cyclonic current are formed around Zhangzidao island and other islands according to the characteristics of the residual current. The residual current velocity averages between 8 cm/s and 12 cm/s .The residual current near the farshore area reduces to 1-2 cm/s .A comparatively thorough understanding of the characteristics of tides and tidal current is obtained near Zhangzidao island after this significant analysis. |
PDF Full Text Request