The Study Of The Tidal Numerical Simulation With Assimilation And The Tidal Dissipation In The Bohai Sea, Yellow Sea And East China Sea

Tidal study is very important for science, commerce and society for thousands of years. Satellite altimetry has had a major impact on our knowledge of tides by providing a new method of the sea surface height measurement. Following the launch of TOPEX/POSEIDON in 1992, there has been considerable improvement in the accuracy of the global tidal models. However, the application of global tidal model to the study of shallow sea tides is much worse in the accuracy. Tidal signal in TOPEX/POSEIDON altimetric data is the largest contributor to sea surface height variability and accounts for more than 80% of the signal variance. So it is urgent to develop tide model in the shallow area wi th high accuracy.Orthogonalized convolution method and the harmonic analysis along satellite orbit are used to withdraw tidal wave from TOPEX/POSEIDON satellite altimeter data in the Bohai Sea, Yellow Sea and East China Sea. The results show that the altimetric data can give a good distribution of tides in the Yellow Sea and the East China Sea, especially in the deep region of the East China Sea.The three-dimensional ocean mode, POM, which contains an imbedded second moment turbulence closure sub-model could simulate well the tides in the study region. The result agrees well with observations by comparing the simulated result with the 167 tidal gauge data. The assimilation scheme uses a blending approach based on optimal linearinterpolation. The improvement is 45% for the phase-lag of S2 after assimilating the altimetric data of the crossover points, while the correction for the diurnal constituents is not so good as for semidiurnal constituents. The diurnal constituents at some of the crossover points and all of the semi-diurnal constituents at all of the crossover points as well as 16 tidal gauge data are assimilated in the ocean model, this is because the assimilation of the diurnal constituents at some crossover points make the result worse. The improvement is 36% for M2, 54% for S2, 42% for K,, 30% for 01 compared with the results of dynamic model without assimilation.In the stratified ocean, mixing controls the intensity of the ocean current. The winds and tides are the possible main source of mechanical energy to drive the interior mixing. The tidal energy budget is investigated in this paper based on the result of the numerical model. The energy dissipations of M2 in the East China Sea, Yellow Sea and Bohai Sea are respectively 44.282GW, 59. 828GW and 3. 076GW. Among the tidal energy entering the study region from the Pacific ocean , 36. 1% dissipates in the East China Sea, 48. 8% in the Yellow Sea, 2. 5% in the Bohai Sea and 12.6% in the Taiwan Strait. The energy dissipation of S2 in the East China Sea, Yellow Sea and Bohai Sea are respectively 4. 782GW, 12. 48GW and 0. 630GW, accounting for 22.9%, 59.8% and 3.0 % respectively, about 13.6% of S2 energy enters Taiwan Strait. Most of tidal energy of diurnal tidal constituent dissipates in the East China Sea, and there is 7. 433GW of K, in the East China Sea, accounting for 73% of the total energy from the Pacific. There is 5. 433GW of 0, in the East China Sea, also accounting for 73% of the total energy from the Pacific.For the four major constituents, there is 140. 901GW tidal energyflux into the East China Sea from the Paci fie Ocean. The BBL di ssipat ion accounts for 115.178GW, which is about 82% of the total dissipation. Ahout 18% of the tidal energy dissipates in the interior. The wind energy entering the sea circulation is about 5GW in winter, and 0. 07GW in the summer. So the tidal energy dominates the mixing in summer in the study region, and it also at least as important as the wind stress in the winter.