Influence of Sea Bottom Friction Coefficient on tidal modeling around the Coast of China

The China Sea (CS) is located in the northwestern of Pacific Ocean, with tortuous coastlines, complex topography, and strong tidal power. In the tidal numerical simulation, the sea bottom friction in shallow waters has an important impact on the propagation and deformation of tide. In order to evaluate its role in the tidal dynamics system of CS, this paper establishes a three-dimensional tidal dynamics model of CS based on the FVCOM (The Finite Volume Coastal Ocean Model) to simulate the tide elevation change of 8 different sea bottom friction coefficients (SBFC). Through the method of harmonic analysis, the result error of each SBFC is analyzed by comparing the model simulated tidal component amplitude to the tidal tables and the tide harmonic data of TPXO9-atlas v1. It is found that in the deep sea area, the model results of each SBFCs have little change while in the shallow water, with the increase of the friction coefficient, the amplitude of each tidal component shows a decreasing trend. The effect is relatively good when the SBDF value is set to 0.0035 as a constant in the whole simulated area, but there are also large deviations in several parts of CS.