Kilometric Scale Modeling of the North West European Shelf Seas: Exploring the Spatial and Temporal Variability of Internal Tides
Kilometric Scale Modeling of the North West European Shelf Seas: Exploring the Spatial and Temporal Variability of Internal Tides
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DOI：
10.1002/2017jc012960
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发表时间：
2018-01-01
影响因子：
3.6
通讯作者：
Holt, J.
中科院分区：
文献类型：
--
作者：
Guihou, K.;Polton, J.;Holt, J.
西北欧大陆架断裂是开阔洋与大陆架海之间运输和交换的障碍。这些交换过程的强空间变异性很难利用观测充分探索，而且模拟通常过于粗略，无法模拟整个区域的精细尺度过程。在这方面，在FASTNEt方案下，已经制定了西北欧大陆架和大西洋边缘1/60度（约1.8公里）的新的NEMO配置，目的是更好地了解和量化大陆架断裂过程的季节和年际变化。该配置再现SST、正压潮汐和精细分辨率温度廓线的季节循环的能力针对流域尺度（1/12度，约9公里）配置和标准区域配置（7公里分辨率）进行了评估。季节性循环在所有配置中都能很好地再现，尽管精细分辨率允许模拟较小尺度的过程。在货架上的不同位置的温度的时间序列显示存在的内波具有很强的时空变化。内波的频谱分析揭示了峰值在周日，半日，惯性，和四分之一日带，这是只有现实中再现的新的配置。潮汐引起的密度跃层的变化被诊断在模型中，并显示出不同的弹簧小潮周期的平均位移振幅超过2米的30%的分层域。足够精细的分辨率，内潮被证明是在许多测深功能产生一个复杂的密度跃层位移叠加模式。
The North West European Shelf break acts as a barrier to the transport and exchange between the open ocean and the shelf seas. The strong spatial variability of these exchange processes is hard to fully explore using observations, and simulations generally are too coarse to simulate the fine-scale processes over the whole region. In this context, under the FASTNEt program, a new NEMO configuration of the North West European Shelf and Atlantic Margin at 1/60 degrees (approximate to 1.8 km) has been developed, with the objective to better understand and quantify the seasonal and interannual variability of shelf break processes. The capability of this configuration to reproduce the seasonal cycle in SST, the barotropic tide, and fine-resolution temperature profiles is assessed against a basin-scale (1/12 degrees, approximate to 9 km) configuration and a standard regional configuration (7 km resolution). The seasonal cycle is well reproduced in all configurations though the fine-resolution allows the simulation of smaller scale processes. Time series of temperature at various locations on the shelf show the presence of internal waves with a strong spatiotemporal variability. Spectral analysis of the internal waves reveals peaks at the diurnal, semidiurnal, inertial, and quarter-diurnal bands, which are only realistically reproduced in the new configuration. Tidally induced pycnocline variability is diagnosed in the model and shown to vary with the spring neap cycle with mean displacement amplitudes in excess of 2 m for 30% of the stratified domain. With sufficiently fine resolution, internal tides are shown to be generated at numerous bathymetric features resulting in a complex pycnocline displacement superposition pattern.