Coastal numerical modelling of tides: Sensitivity to domain size and remotely generated internal tide
Coastal numerical modelling of tides: Sensitivity to domain size and remotely generated internal tide
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DOI：
10.1016/j.ocemod.2012.11.007
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发表时间：
2013-02
期刊：
影响因子：
3.2
通讯作者：
A. Ponte;B. Cornuelle
中科院分区：
文献类型：
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作者：
A. Ponte;B. Cornuelle
远距离产生的超惯性内潮汐的传播对区域海洋潮汐变率的模拟构成了困难，我们用几种方法来说明这一点。首先，随着数值域范围的扩大(最大为512×512公里)，对南加州海湾海岸线控制区内的M2潮汐解进行监测。虽然该区域平均海平面的幅度和相位对域大小几乎不敏感，但随着域大小的增加，动能稳步增加，主要是斜压动能。进入控制区的能量流量的增加表明，这一趋势是由能够向上传播到控制区的远距离内潮发源地的贡献越来越大所解释的。不断增加的粘度通过降低斜压能级并限制它们随区域大小的增加而证实了这一解释。将网格间距加倍允许考虑两倍大的数值域。虽然粗网格的能量水平比精细网格低，但对于粗网格模拟中最大的区域，能量随域大小的增加速度似乎变慢了。在最大区域中强迫具有变深度潮汐边界条件的最小区域在控制区域内产生与最大区域控制区域中的能级相当的能级，从而证实了嵌套方法的可行性。相反，用亚惯性潮汐分量(K1)强迫的模拟表明，当内潮传播受到限制时，控制区动能主要是正压的，动能随域大小的变化幅度减小。
The propagation of remotely generated superinertial internal tides constitutes a difficulty for the modelling of regional ocean tidal variability which we illustrate in several ways. First, the M2 tidal solution inside a control region located along the Southern California Bight coastline is monitored while the extent of the numerical domain is increased (up to 512×512km). While the amplitude and phase of sea level averaged over the region is quasi-insensitive to domain size, a steady increase of kinetic energy, predominantly baroclinic, is observed with increasing domain size. The increasing flux of energy into the control region suggests that this trend is explained by the growing contribution from remote generation sites of internal tide which can propagate up to the control region. Increasing viscosities confirms this interpretation by lowering baroclinic energy levels and limiting their rate of increase with domain size. Doubling the grid spacing allows consideration of numerical domains 2 times larger. While the coarse grid has lower energy levels than the finer grid, the rate of energy increase with domain size appears to be slowing for the largest domain of the coarse grid simulations. Forcing the smallest domain with depth-varying tidal boundary conditions from the simulation in the largest domain produces energy levels inside the control region comparable to those in the control region for the largest domain, thereby confirming the feasibility of a nested approach. In contrast, simulations forced with a subinertial tidal constituent (K1) show that when the propagation of internal tide is limited, the control region kinetic energy is mostly barotropic and the magnitudes of variations of the kinetic energy with domain size are reduced.