Scaling laws for parameterisations of subgrid eddy–eddy interactions in simulations of oceanic circulations
Scaling laws for parameterisations of subgrid eddy–eddy interactions in simulations of oceanic circulations
复制标题
海洋环流模拟中亚网格涡旋相互作用参数化的标度定律
DOI：
10.1016/j.ocemod.2013.05.001
复制
发表时间：
2013
期刊：
影响因子：
3.2
通讯作者：
M. Zidikheri
中科院分区：
文献类型：
--
作者：
V. Kitsios;J. Frederiksen;M. Zidikheri
发展了具有自相似尺度律的确定性和随机性参数化方法来描述用准地转模式模拟的大涡模拟(LES)中的子格子涡旋相互作用。具体地说，该参数化是针对广泛代表平均南极绕极洋流的气流而开发的。随机参数由排水沟涡粘性和随机后向散射噪声组成，而确定性参数仅由代表排水沟和后向散射净效应的净涡粘性所控制。所有的涡粘性系数都是根据高分辨率基准数值模拟的统计数据自洽地计算出来的。各垂直层上的子格子相互作用用位涡空间的涡粘标度律表示，层间的耦合用斜压涡度空间的涡粘标度律表示(与温度有关)。涡粘性依赖于LES分辨率、拟能通量、Rossby半径和能量包含范围的大小。对于较少的子网格，由比例律定义的参数化系数也被显示以重现基准模拟的动能谱。这些尺度律使得子网格参数化更加适用，因为它们消除了从更高分辨率的模拟中产生涡流粘性的需要，并对更复杂的海洋模型具有影响。
Deterministic and stochastic parameterisations with self-similar scaling laws are developed to represent the subgrid eddy–eddy interactions in the large eddy simulation (LES) of oceanic flows simulated with a quasi-geostrophic model. Specifically the parameterisations are developed for flows broadly representative of the mean Antarctic Circumpolar Current. The stochastic parameterisation consists of a drain eddy viscosity and stochastic backscatter noise, whilst the deterministic parameterisation is governed solely by a net eddy viscosity representing the net effect of the drain and backscatter. All of the eddy viscosities are calculated self consistently from the statistics of high resolution benchmark numerical simulations. The subgrid interactions at each vertical level are represented by eddy viscosity scaling laws in potential vorticity space, and the coupling between levels is represented by eddy viscosity scaling laws in baroclinic vorticity space (related to the temperature). The eddy viscosities are dependent on the LES resolution, enstrophy flux, Rossby radius, and the extent of the energy containing range. LESs with the subgrid parameterisation coefficients defined by the scaling laws are also shown to reproduce the kinetic energy spectra of the benchmark simulation. These scaling laws make the subgrid parameterisations more widely applicable as they remove the need to generate the eddy viscosities from higher resolution simulations, and have implications for more complex ocean models.