Abstract The effects of horizontal resolution and wave drag damping on the semidiurnal M 2 tidal energetics are studied for two realistically-forced global HYbrid Coordinate Ocean Model (HYCOM) simulations with 41 layers and horizontal resolutions of 8 km ( 1 ∕ 12 . 5 ∘ ; H12) and 4 km ( 1 ∕ 25 ∘ ; H25). In both simulations, the surface tidal error is minimized by tuning the strength of the linear wave drag, which is a parameterization of the surface-tide energy conversion to the unresolved baroclinic wave modes. In both simulations the M 2 surface tide error with TPXO8-atlas, an altimetry constrained model, is 2.6 cm. Compared to H12, the surface tide energy conversion to the resolved vertical modes is increased by 50% in H25. This coincides with an equivalent reduction in the tuned loss of energy from the surface tide to the wave drag. For the configurations studied here, the horizontal and not the vertical resolution is the factor limiting the number of vertical modes that are resolved in most of the global ocean: modes 1–2 in H12 and modes 1–5 in H25. The wave drag also dampens the resolved internal tides. The 40% reduction in wave-drag strength does not result in a proportional increase in the mode-1 energy density in H25. In the higher-resolution simulations, topographic mode-scattering and wave–wave interactions are better resolved. This allows for an energy flux out of mode 1 to the higher modes, mitigating the need for an internal tide damping term. The HYCOM simulations are validated with analytical conversion models and altimetry-inferred sea-surface height, fluxes, and surface tide dissipation. H25 agrees best with these data sets to within ∼ 10%. To facilitate the comparison of stationary tide signals extracted from time series with different durations, we successfully apply a spatially-varying correction factor.

中文翻译：

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在真实的全球海洋模拟中水平分辨率和波浪阻力之间的相互作用及其对潮汐斜压模式波的影响

摘要 研究了水平分辨率和波浪阻力阻尼对半日 M 2 潮汐能学的影响，用于 41 层水平分辨率为 8 km ( 1 ∕ 12 . 5 ∘ ; 1 ∕ 12 . 5 ∘ ; H12) 和 4 公里（1 ∕ 25 ∘；H25）。在这两个模拟中，通过调整线性波浪阻力的强度来最小化表面潮汐误差，这是将表面潮汐能量转换为未解析的斜压波模式的参数化。在两个模拟中，使用 TPXO8-atlas（一种高度测量约束模型）的 M 2 表面潮汐误差为 2.6 厘米。与 H12 相比，H25 中表面潮汐能量转换为解析的垂直模式增加了 50%。这与从表面潮汐到波浪阻力的调谐能量损失的等效减少相吻合。对于此处研究的配置，水平分辨率而非垂直分辨率是限制在全球大部分海洋中解析的垂直模式数量的因素：H12 中的模式 1-2 和 H25 中的模式 1-5。波浪阻力还抑制了已解决的内部潮汐。波阻强度降低 40% 不会导致 H25 中模式 1 能量密度成比例增加。在更高分辨率的模拟中，地形模式散射和波波相互作用得到了更好的解决。这允许从模式 1 到更高模式的能量通量，减少对内部潮汐阻尼项的需要。HYCOM 模拟已通过分析转换模型和测高推断的海面高度、通量和表面潮汐消散进行验证。H25 与这些数据集的最佳吻合度在 10% 以内。