Assimilating TOPEX/Poseidon data into an adjoint numerical tidal model in the East China Sea

Eleven tidal constituents: O₁, K₁, P₁, Q₁, M₂, S₂, N₂, K₂, M₄, MS₄ and M₆ are extracted from 10-year TOPEX/Poseidon altimetry data along track points in the East China Sea. Then the eight major tidal constituents (O₁, K₁, P₁, Q₁, M₂, S₂, N₂ and K₂) are assimilated into a two-dimension non-linear tidal model with the adjoint method. In this paper, two different experiments are applied for different kinds of assimilating data and the results show that, assimilating the altimetry data and the in situ data simultaneously is better than assimilating the altimetry data alone. And the bias between calculations and observations are provided. The deviations of M₂ are 3.5 cm in amplitude and 2.9 deg in phase-lag. Those of O₁ are 1.3 cm and 5.8 deg accordingly. The co-tidal charts of the eight constituents are also drawn. The general patterns are in good agreement with those literatures cited.