Energy Pathways and Scale Interactions in the Ocean

大范围的洋流和涡流弥漫在海洋中，并在大气环流和气候中发挥主要作用。从一万公里到一毫米的尺度之间的耦合是理解、模拟和预测海洋环流和混合的主要困难。维持海洋中的湍流和混合所需的功率是什么？它的源汇是什么？有哪些机制可以在不同的尺度上传递这种能量？由于缺乏严格的定量方法来探测和测量海洋中不同尺度之间的能量转移速率，我们对海洋能量收支的理解至少在两倍之内是不确定的，甚至可能高达十倍。这对我们的气候预测能力造成了严重的限制。使用一种新的数学尺度分析框架，我们建议研究尺度之间的耦合，并从真实的海洋模型数据中绘制出能量路径。这种方法非常通用，允许在尺度和空间上同时探测动力学，并且不受通常的同质性或各向同性假设的限制，因此使其非常适合于研究海洋流动。一个主要的目标是检验这种路径的公认地转模式在海洋中的有效性。将研究各种非线性机制对跨尺度能量转移的贡献，例如斜压和正压不稳定、正压作用、Rossby波的产生以及内波的产生和破裂。如果成功，这项研究将为海洋学家提供一套有希望的工具，用于分析和解释来自模拟、卫星测量和实验的数据。智力价值：理解和量化作为尺度函数的海洋能量路径和平衡是海洋学中一个具有挑战性的基本问题。为此，将进一步开发严格的分析工具，并将其应用于来自全球、区域和理想化数值模拟的数据。理解海洋中的非线性相互作用是一个重大的智力挑战，将应用新的技术和思想来更好地量化海洋的能量。广泛的影响：绘制和量化供应和消耗中尺度流动的能量路径将减少目前海洋能源收支的不确定性。这项工作还有望提供对海洋中正在发挥作用的尺度物理的洞察，为诸如Gent-McWilliams等当前参数化方案的参数调整提供先验约束，对可能应用于允许涡流的海洋模型的拟议方案提供先验约束，并将有助于开发一类新的海洋参数化，这是位置和分辨率的函数。这项工作将支持处于有前途的职业生涯的初级科学家。最后，P.I.将修订一本通用教科书，该教科书已被多所大学采用，用于教授大气和海洋动力学。这本书将有助于广泛的地球科学教育，在这个项目下进行的研究将为学生提供背景和例子。

Large-scale currents and eddies pervade the ocean and play a prime role in the general circulation and climate. The coupling between scales ranging from ten thousand kilometers to a millimeter presents a major difficulty in understanding, modeling, and predicting oceanic circulation and mixing. What are the power requirements to sustain turbulence and mixing in the ocean? What are its sources and sinks? What are the mechanisms to transfer such energy across scales? Due to the lack of rigorous quantitative methods for detecting and measuring energy transfer rates between scales in the ocean, our understanding of the oceanic energy budget is uncertain within at least a factor of two and possibly as large as ten. This poses serious limitations on our climate prediction capabilities. Using a novel mathematical scale-analysis framework, we propose to study the coupling between scales and map out the energy pathways from realistic ocean model data. The approach is very general, allows for probing the dynamics simultaneously in scale and in space, and is not restricted by the usual assumptions of homogeneity or isotropy, thus making it ideally suited for studying oceanic flows. A primary goal is to examine the extent to which the accepted geostrophic model for such pathways is valid in the ocean.The contribution of various nonlinear mechanisms to the transfer of energy across scales such as baroclinic and barotropic instabilities, barotropization, Rossby wave generation, and internal wave generation and breaking will be investigated. If successful, this research will provide oceanographers with a promising set of tools with which to analyze and interpret data from simulations, satellite measurements, and experiments.Intellectual Merit: Understanding and quantifying the oceanic energy pathways and balances as a function of scale is a challenging fundamental problem in oceanography. To this end, rigorous analytical tools will be further developed and to applied to data from global, regional, and idealized numerical simulations. The problem of understanding nonlinear interactions in the ocean is a major intellectual challenge and new techniques and ideas will be applied to better quantify the energetics of the ocean.Broader Impacts:Mapping and quantifying the energy pathways supplying and depleting the mesoscale flow will reduce the current uncertainty in the oceanic energy budget. The work also promises to provide insights into the scale-physics at play in the ocean, offer a priori constraints on parameter tuning of current parameterization schemes such as Gent-McWilliams, on proposed schemes that may be applied to eddy permitting ocean models, and will help in the development of a new class of ocean parameterizations that are a function of location and resolution.The work will support a junior scientist at the threshold of a promising career. Finally, the P.I. will be revising a general textbook that has been adopted by a number of universities for the teaching of atmospheric and oceanic dynamics. The book will help education in the geosciences broadly, and the research conducted under this project will provide context and examples for the students.