摘要：A 1/12°, 2-D barotropic tide model was used to examine the characteristics of barotropic tides and to improve the accuracy of predicting tidal sea levels and currents in the seas around Taiwan. The form ratio suggests that tides are predominantly semidiurnal in the northern reaches of the Taiwan Strait and mixed of diurnal and semidiurnal elsewhere around Taiwan. When the dominant M 2 wave enters the Strait from the north, its amplitude is magnified to ~2 m in the middle, and then decreases rapidly toward the south end of the Strait. The predominance of diurnal tides along the southwest to the south coast of Taiwan is attributed to the quasi-resonance of diurnal waves in the South China Sea. The tidal range is small and tidal currents are weak off the east coast of Taiwan. Barotropic tidal energy is mostly dissipated on the shallow banks of the southwestern Strait. Results summarized from sensitivity tests on the bottom drag coefficient ( C D ) and horizontal eddy viscosity ( A M ) indicate that C D = 0.0015 - 0.00175 and A M = 150 m 2 s -1 lead to the best model-data fit when compared to the observed tidal sea levels at ten reference tide-gauge stations around Taiwan. The averaged root-mean-squared (RMS) differences of the simulated tidal sea level for the six principal constituents of O 1 , P 1 , K 1 , N 2 , M 2 , and S 2 are significantly reduced to 1.3, 0.7, 2.0, 1.6, 5.1, and 3.1 cm, respectively, compared to that calculated from a 0.5° resolution global tide harmonic constant database, NAO.99b (Matsumoto et al. 2000). The averaged RMS differences of barotropic tidal currents ( U, V ) for O 1 , K 1 , M 2 , and S 2 are (0.92, 1.64), (1.17, 0.61), (3.88, 2.37), and (1.52, 1.20) cm s -1 . A database of tidal sea levels and current harmonic constants, TWTIDE08, for Q1, O1, P1, K1, J1, OO1, 2N 2 , μ 2 , N 2 , ν 2 , M 2 , L 2 , T 2 , S 2 , and K 2 is established with this study.
