Numerical Modeling Of Tides Wave In Margin Seas Near China

The numerical model of margin seas near China coasts is developed in this paper based on the 2-D depth-averaged tidal wave motion equation in spherical coordinates, and the tides propagation in study region included the Bohai Sea, the Yellow Sea, the East China Sea, the South China Sea, Thailand Bay and waters around Taiwan Island is simulated with consideration of globe raising forces. The computational grid is generated by space step 2'×2', and the number is 1175×955. The computed results are compared with the observed tidal harmonic constants at 281 stations around the study region and the forecast current data at 13 tidal current stations and reasonable agreement is found between them. According to the computed results, several co-tidal charts of main tide components include M₂, S₂, K₁, O₁, N₂, M₄ are drawn, and distribution characteristics of amplitudes and phases of tide and tidal current is also given. After comparing with the result of previous studies, the uniform collusion is given as the independent tidal waves of the East China Sea is almost exclusively conditioned by those water-masses which penetrate the canals between the Kyushu and Taiwan island, and the independent tidal waves of the South China Sea is conditioned by Pacific tidal waves which propagate through the Luzon Strait. On Taiwan Strait, the tide waves from East China Sea and South China Sea in exchange for tidal energy. It is also found that the dominant tidal wave in the East China Sea is semidiurnal tide components especially M₂, while it in the South China Sea is diurnal tide components. Due to action of topography, boundary, Coriolis force and bottom friction, there are complex tides systems contain the progressive wave or amphidromic tides system characterized by amphidromic points and current amphidromic in different waters.Based on the simulation of the model, M₂ tide component in the Taiwan Strait is also discussed. The distribution is regard as southward progressive waves in the north and progress-stand waves in south of the strait, and the progress-stand waves systems and enlarge affection by topography are the main cause to it. The tidal energy from the North mouth reaching to the north side of Taiwan shoals is larger than from the South mouth.Besides the following is also discussed as:1. Using the regression analysis the relation between the difference errors of first order and the relative step is argued and the fitted relation is obtained.2. Based on the regression analysis, the method of using the results of theanalysis for calculated and observed data as validated proofs is developed. The method is more compact and considers the amplitude and phase errors at the same time.3. The predictor-corrector methods to determine Manning coefficient in the 2-D tidal wave movement equation is put up through the regression theory of numerical model and prototype. The method is proved effective by the numerical test and practical application. It is helpful to deduce the artificial debugging and improve the precision of the results of numerical calculation.