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

在开阔海域的观测表明，垂直结构由层层水团组成，层界面上的混合很少。为了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，其垂直混合程度比在公海观察到的要高得多。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，因为它们依赖于无法解决这些过程的数学模型和数值分辨率。为了在这些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彻底的数值研究。为了探索小尺度海洋过程，提出了一种基于现代多尺度湍流模拟方法和高度数值模式的新的模拟框架。将开发新的数学和物理指导方法，以处理分层流动中突出的特征。他们将利用这一框架对两个海洋案例进行原始调查：(1)红海溢流，(2)波托菲诺角附近的海岸流，其中分层混合过程是动力学的关键组成部分。这一模拟框架将构成小规模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。对于不同区域之间的双向耦合和精确的边界条件，将开发出新的数学解。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。参与的科学家的主题和专业知识的融合将有助于对学生进行跨学科培训。

ABSTRACTOCE-0620646Observations 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.