Numerical study of the tide and tidal dynamics in the South China Sea

Tides and their dynamic processes in the South China Sea (SCS) are studied by assimilating Topex/Poseidon altimetry data into a barotropic ocean tide model for the eight major constituents (M2 S2 K1 O1 N2 K2 P1 Q1) using a tidal data inversion scheme. High resolution (∼10 km) and large model domain are adopted to better resolve the physical processes involved and to minimize the uncertainty from the open boundary condition. The model results, which are optimized by an inversion scheme, compare well with tidal gauge measurements. The study reveals that the amplitude of the semi-diurnal tide, M2, decreases, while the amplitude of the diurnal tide, K1, increases similar to the Helmholtz resonance after the tidal waves propagate from the western Pacific into the SCS through the Luzon Strait (LS). Analyses of the energy studies show that the LS is a place where both M2 and K1 tidal energy dissipates the most, and strong M2 tidal dissipation also occurs in the Taiwan Strait (TS). The work rate of the tidal generating force in the SCS basin is negative for M2 and positive for K1. It is found that the responses of tides in the SCS are largely associated with the propagating directions of the tides in the Pacific, the tidal frequency, the wavelengths, the local geometry and bottom topography.