In recent years, high-resolution global ocean circulation models have begun to include astronomical tidal forcing to concurrently simulate ocean circulation, barotropic and internal tides. The inclusion of tides is of great significance for understanding three-dimensional (3-D) ocean mixing and developing internal tide prediction. However, due to uncertainty in topography and damping terms, improper representation of the self-attraction and loading term, barotropic tidal estimate cannot match that in the data-constrained barotropic tidal model. In this study, the TPXO8 data are assimilated to optimize the tides embedded in a global 9-km 3-D general circulation model of MITgcm as follows. For each time step of the MITgcm, the previous 25-hour-averaged sea surface height (SSH) is subtracted from the instantaneous SSH to obtain the MITgcm surface tidal elevation. Then, the difference of surface tidal elevation between the MITgcm and TPXO8 together with a damping coefficient acts as an additional term for the right-hand side of the SSH equation in order to correct the SSH field. Results show that the global ${\mathit{M}}_2$ (${\mathit{K}}_1$) error of the corrected surface tidal elevation relative to the TPXO8 reaches 2.12 cm (0.89 cm). Compared with tide gauge data, the accuracy of surface tidal elevation after using the correction scheme is almost the same as that of TPXO8 for all areas except for some continental shelf and coastal areas. The internal tidal signals are subsequently improved compared to the along-track altimetry and TAO observations. Compared to previous tidal assimilation scheme, the implementation of the correction scheme used in this study is simple and more suitable for realistic applications.

近年来，高分辨率的全球海洋环流模型已经开始包括天文学的潮汐强迫，以同时模拟海洋环流，正压和内潮。潮汐的包含对于理解三维（3-D）海洋混合和发展内部潮汐预测具有重要意义。但是，由于地形和阻尼项的不确定性，自吸力和载荷项的不正确表示，正压潮汐估计值与数据受限正压潮汐模型中的估计值不匹配。在这项研究中，对TPXO8数据进行了同化，以优化嵌入MITgcm的全球9公里3-D一般环流模型中的潮汐，如下所示。对于MITgcm的每个时间步，从瞬时SSH中减去之前25小时的平均海面高度（SSH），即可获得MITgcm的表面潮汐高度。然后，MITgcm和TPXO8之间的表面潮汐高度差与阻尼系数一起作为SSH方程右侧的附加项，以校正SSH字段。结果表明，全球${\mathit{中号}}_{\mathrm{2个}}$ （${\mathit{ķ}}_{\mathrm{1个}}$）相对于TPXO8校正后的潮汐高程的误差达到2.12厘米（0.89厘米）。与潮汐仪数据相比，使用校正方案后，除某些大陆架和沿海地区外，所有区域的表面潮汐高程的精度几乎与TPXO8相同。与沿航向测高和TAO观测相比，内部潮汐信号随后得到了改善。与以前的潮汐同化方案相比，本研究中使用的校正方案的实现简单易行，更适合实际应用。