CMG Collaborative Research: A New Modeling Framework for Nonhydrostatic Simulations of Small-Scale Oceanic Processes

在公海的观测表明，垂直结构由水团层组成，在层间界面上混合很少。要关闭对气候预测很重要的全球温盐环流，还必须有小规模的海洋过程，这些过程表现出比在开阔海洋中观察到的高得多的垂直混合水平。然而，对于目前的海洋环流模式来说，捕捉这种垂直混合是具有挑战性的，这些模式依赖于数学模式和无法解决这些过程的数值分辨率。为了在这种模式中更真实地表示海洋物理，迫切需要对小尺度海洋过程进行深入的数值研究。然而，目前的数值方法对于这种地球物理环境具有令人望而却步的计算成本。提出了一种基于现代多尺度湍流模拟方法和高数值模式的新的模拟框架，以探索小尺度海洋过程。将发展新的数学和物理指导方法来处理分层流动中突出的特征。他们将采用这一框架对两个海洋案例进行原始调查：(1)红海溢出，(2)波托菲诺角附近的海岸流动，其中分层混合过程是动力学的关键组成部分。这一模式框架将构成小尺度海洋观测与沿海和海洋环流模式之间缺失的一环。拟议工作的结果将对全球和沿海运输问题产生影响。对于不同域之间的双向耦合和精确的边界条件，将开发新的数学解。所有这些都是在数学、物理和数值模拟方面具有挑战性的研究课题。所涉及的科学家的主题和专业知识的融合将有助于学生的跨学科培训。

ABSTRACTOCE-0620541Observations in the open ocean indicate that the vertical structure consists of layers of water masses with very little mixing across the layer interfaces. To close the global thermohaline circulation, which is important for climate prediction, there must also be small-scale oceanic processes which exhibit much higher levels of vertical mixing than that observed in the open ocean. However, capturing such vertical mixing is challenging for the current ocean general circulation models, which rely on mathematical models and numerical resolutions which are unable to resolve these processes. For a more realistic representation of ocean physics in such models, thorough numerical investigations of small-scale oceanic processes are urgently needed. The current numerical approaches, however, have a prohibitive computational cost for this geophysical setting.Development of a new modeling framework based on modern multiscale turbulence modeling approaches and highly numerical models is proposed in order to explore small-scale oceanic processes. New mathematically and physically guided methodologies will be developed to handle characteristics prominent in stratified flows. They will employ this framework for original investigations of two oceanic cases: (1) the Red Sea overflow, and (2) coastal flow near the Portofino Cape, in which stratified mixing processes are a critical component of the dynamics. This modeling framework will form the missing link between small-scale oceanic observations and the coastal and ocean general circulation models. Results from the proposed work will have implications for both global and coastal transport problems. Novel mathematical solutions for the two-way coupling among different domains and accurate boundary conditions will be developed. All are challenging research topics in terms of mathematics, physics and numerical modeling. This blend of topics and expertise of the scientists involved will contribute to interdisciplinary training of students.