Modeling of ocean overflows using statically and dynamically adaptive vertical discretization techniques

该项目的目标是开发一种新的垂直离散化方法，这种方法可以大大减轻或解决当前通用循环模型中使用的标准垂直坐标的一些缺点。以计算效率高的方式获得的垂直近似质量的任何重大改进都可以极大地帮助解决几个严重影响数值海洋模式性能的问题，特别是在气候研究的背景下。这包括不规则地形、溢流和垂直混合的物理一致性处理。新的离散化将被构造来捕捉最重要的流动特征，使用局部适应的垂直网格结构在非结构化棱柱网格内。这些想法将通过添加一个程序进一步发展，使垂直网格层能够根据流动条件动态变化。新方法的计算开销可以忽略不计，并且保留了算法的所有局部守恒性质；将使用包括直布罗陀海峡和北欧海溢流在内的溢流情景对其进行测试和评估。该数值方案基于在UTBEST3D中实现的不连续伽辽金有限元方法，该方法具有高效利用大规模并行计算机系统的良好记录。

The goal of the project is the development of a novel vertical discretization that can substantially alleviate or resolve a number of shortcomings associated with the standard vertical coordinates used in the current general circulation models. Any significant improvement in the quality of the vertical approximation achieved in a computationally efficient way can greatly help to address several issues seriously affecting the performance of numerical ocean models, particularly in the context of climate studies. This includes physically consistent treatment of irregular topography, overflows, and vertical mixing. The new discretization will be constructed to capture the most important flow features using locally adapted vertical grid structure within an unstructured prismatic mesh. Those ideas will be further developed by adding a procedure that enables the vertical mesh layers to dynamically change according to the flow conditions. The new methodology incurs negligible computational overhead and preserves all local conservation properties of the algorithm; it will be tested and evaluated using overflow scenarios including the Strait of Gibraltar and the Nordic Seas Overflows. The numerical scheme is based on the discontinuous Galerkin finite element method implemented in UTBEST3D that has a proven track record of highly efficient utilization of massively parallel computer systems.