Collaborative Research: Origin, Dynamics and Transport Characteristics of the Large-Scale Eddy-Driven Patterns

合作研究：大尺度涡驱动模式的起源、动力学和输运特征

• 批准号: 1154923
• 负责人: Igor Kamenkovich
• 金额: $ 34.86万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1154923&HistoricalAwards=false
• 关键词: Collaborative; Research; Origin; Dynamics; Transport

One of the principal consequences of mesoscale variability in the ocean is the spontaneous generation of coherent, slowly evolving patterns on spatial scales significantly exceeding the dominant scale of primary baroclinic instability. These Large-Scale Eddy-Driven Patterns (LEDPs) are generated and maintained by mesoscale eddies and preliminary results indicate that LEDPs represent a substantial fraction of variability in the oceans. Furthermore, LEDPs can play an important role in the transport of heat, salinity, bio-geo-chemical tracers, and momentum. Thus, it is vital to improve our understanding of these indirect eddy effects, especially in light of the need for the increased accuracy of future climate projections.Analytical models for the interaction between primary (mesoscale) and secondary (LEDP) structures will be developed using multi-scale techniques. Multi-scale methods are ideally suited to this task due to their transparency and ability to represent interactions between phenomena operating on distinct spatial and temporal scales. The novelty of our approach lies in the application of multi-scale methods to the primary eddy patterns realized in typical oceanic flows. This will make it possible to offer a realistic description of LEDPs, directly applicable to, and testable by, observations and comprehensive models. Theoretical models will be guided and validated by a hierarchy of numerical simulations with an increasing degree of realism, which will also focus on the properties and dynamics of LEDPs. Analytical studies, in turn, will be used extensively for interpretation of the numerical results. The combination of these approaches will reveal the complex interplay between mesoscale eddies and LEDPs, not possible through numerical simulation alone, and describe the eddy transport characteristics induced by the action of LEDPs. Specific research tasks include the analysis of: the formation mechanisms of LEDPs; the anisotropic dispersion of tracers induced by these structures; and the effects of the background state on LEDP dynamics.Oceanic variability plays an important, but poorly understood role in climate dynamics. Lateral eddy transfer is a fundamental component of the oceanic transport heat, nutrients, pollutants and other tracers. Thus, advances in the understanding of eddy-induced transport and low frequency variability in the oceans are needed to improve climate prediction capabilities, ultimately leading to societal benefits. Inferences from the theory and model runs will aid in the interpretation of observational data sets and in the planning of future observational strategies aimed at explaining large scale flow variability. In addition to its oceanographic importance, this study will have significant implications for fundamental fluid mechanics, geophysics and climate science. During this project, one Ph.D. student at RSMAS and a postdoctoral associate at NPS will participate in the planned research activities and develop expertise in eddying ocean dynamics. In addition, two graduate (MS) Navy students will perform their thesis research at NPS on topics related to this proposal at no cost to the project.

海洋中尺度变化的主要后果之一是在空间尺度上自发产生连贯的、缓慢演变的模式，大大超过主要的斜压不稳定的主导尺度。这些大尺度涡动驱动的模式(LEDPs)是由中尺度涡旋产生和维持的，初步结果表明，LEDPs代表了海洋中相当大一部分可变性。此外，LEDPS可以在热量、盐度、生物地球化学示踪剂和动量的传输中发挥重要作用。因此，提高我们对这些间接涡旋效应的理解是至关重要的，特别是考虑到未来气候预测需要更高的精度。将使用多尺度技术开发初级(中尺度)和次级(LEDP)结构之间相互作用的分析模型。多尺度方法非常适合于这项任务，因为它们的透明度和表示在不同的空间和时间尺度上运行的现象之间的相互作用的能力。我们方法的创新之处在于将多尺度方法应用于典型洋流中实现的初级涡型。这将使我们有可能对LEDP提供现实的描述，直接适用于观测和综合模型，并可由观测和综合模型检验。理论模型将由一系列数值模拟来指导和验证，数值模拟的真实度越来越高，这也将侧重于LEDP的性质和动力学。反过来，分析研究将被广泛用于解释数值结果。这些方法的结合将揭示中尺度涡旋和LEDPs之间复杂的相互作用，这是单靠数值模拟不可能的，并描述了LEDPs作用下的涡旋输送特征。具体的研究任务包括：LEDP的形成机制；由这些结构引起的示踪剂的各向异性弥散；以及背景状态对LEDP动态的影响。海洋变化在气候动力学中发挥着重要但知之甚少的作用。侧向涡动输送是海洋热量、营养物质、污染物等示踪物质的基本组成部分。因此，需要在了解涡流引起的海洋输运和低频变化方面取得进展，以提高气候预测能力，最终产生社会效益。来自理论和模型运行的推论将有助于解释观测数据集，并有助于规划未来旨在解释大尺度流量变异性的观测策略。除了它在海洋学上的重要性，这项研究还将对基础流体力学、地球物理和气候科学产生重大影响。在这个项目中，RSMAS的一名博士生和NPS的一名博士后助理将参与计划中的研究活动，并发展涡流海洋动力学方面的专业知识。此外，两名海军硕士研究生将在NPS进行与这项提案相关的主题的论文研究，该项目不收取任何费用。