CAREER: Ready to Resolve: Subgridscale Physics for Mesoscale Ocean Large Eddy Simulations

气候模型是理解我们的世界和我们在其中所扮演的角色的关键工具。这些模型的大部分记忆，从四季到几个世纪，都是海洋的组成部分，而大部分次表层海洋能量被保存在中尺度涡流中。这些涡流输送能量、动量、盐度和其他示踪物，从而影响气候。然而，直到现在，计算能力才使气候模型能够以足够的分辨率运行，以允许或解决更大的涡流，避免了许多不确定的参数，这些参数近似于未解析(次网格)尺度上的涡流的影响。这种被PI称为“中尺度海洋大涡模拟(MOLES)”的新模型将伴随我们几十年，但很少有专家接受过理解和改进它们的培训。即使在鼹鼠身上，一些现象也是悬而未决的。因此，仍然需要一种形式的子网格建模，但在没有解决涡流时设计的旧方法在一些涡流得到解决和一些涡流没有得到解决时将不能很好地执行。原型模型显示，即使是鼹鼠也对亚格子模型的选择有些敏感，因此需要小心。该项目在Fox-Kemper和Menemenlis(2008)已证实的次级网格模型的基础上进行扩展，将建立和培训一个新的团队，以实施和评估适用于提高现代模拟分辨率的次级网格模型。MOLE子网格模型将结合过去为粗分辨率应用(水团保留、系统提取势能、平流和扩散输送以及中性物理)开发的涡流子网格模型的优点和大涡模拟子网格模型的主要优势；自调节幅度、尺度感知、稳健的数值稳定性、随着分辨率的提高而收敛，以及避免重复计算。有待进一步开发的子网格模型似乎结合了上述所有功能。这项职业研究将承担这两项任务，使用一组本科生、研究生和博士后研究人员：1)将使用新的诊断方法来评估和区分子网格模型的行为。这些诊断也为全球能源预算和潜在涡度提供了线索。2)主要成果是这类新的亚网格模型，这是当代和未来几代海洋环流建模所急需的，将在本奖项的过程中进行评估、增强和实施。广泛的影响为了建立和培训这支未来的科学家团队，将开发一套新的课程来教育布朗大学地质学(包括地球物理)、物理、工程和应用数学系的学生。一名职业生涯早期的教员、一名研究生、一名博士后，以及一组STEM和非STEM本科生研究人员将在该奖项的终生期限内获得支持。这一努力将为自20世纪50年代以来失踪的布朗重新引入物理海洋学。与拯救海湾组织一起，面向公众和K-12受众的外联活动将教育全球和罗德岛州的气候建模。拯救海湾的教育工作者将接受培训，并与非STEM布朗和罗德岛设计学院的本科生合作，提供由PI和小组开发的教材。将评估和改进下一代气候模型的基本原理。

Climate models are a key tool in understanding our world and our role in it. Much of the memory of these models, from seasons to centuries, is the oceanic component, and the majority of the subsurface ocean energy is held in mesoscale eddies. These eddies transport energy, momentum, salinity, and other tracers, and thereby affect the climate. Yet, it is only now that computational capabilities have made it possible to run climate models at sufficient resolution to permit or resolve larger eddies, avoiding many uncertain parameters approximating the influence of eddies at unresolved (subgrid) scales. This new class of models called by the PI "Mesoscale Ocean Large Eddy Simulations (MOLES)" will be with us for decades to come, yet few experts are trained to understand and improve them. Even in MOLES, some phenomena are unresolved. Thus, a form of subgrid modeling is still required, but the old approaches designed when no eddies were resolved will not perform well when some eddies are resolved and some are not. Prototype models show even MOLES are somewhat sensitive to choice of subgrid models, so care is required. This project, expanding on the proven subgrid model of Fox-Kemper and Menemenlis (2008), will build and train a new team to implement and evaluate subgrid models appropriate for the improving resolution of modern simulations. The subgrid models for MOLES will combine the advantages of past eddy subgrid models developed for coarse resolution use (water mass preservation, systematic extraction of potential energy, advective and diffusive transport, and neutral physics) with the key advantages of Large Eddy Simulation subgrid models; self-adjusting magnitude, scale-awareness, robust numerical stability, convergence with increasing resolution, and avoidance of double-counting.Intellectual Merit:The PI is already evaluating MOLES subgrid models in idealized settings, and suggests a viable pathway to implementation in realistic models. The subgrid model to be further developed seems to combine all features mentioned above. This CAREER research will take on these two tasks, using a team of undergraduate, graduate, and postdoctoral researchers: 1) New diagnostic approaches will be used to evaluate and differentiate the subgrid models' behavior. These diagnoses offer clues for global budgets of energy and potential vorticity as well. 2) The primary deliverable is this new class of subgrid models, greatly needed for the present and future generations of ocean circulation modeling, which will be evaluated, enhanced, and implemented during the course of this award.Broader ImpactsTo build and train this team of future scientists, a new suite of courses will be developed to educate students from Brown University's departments of geology (including geophysics), physics, engineering, and applied mathematics. One early-career faculty member, one graduate student, one postdoc, and a group of STEM and non-STEM undergraduate researchers will be supported though the lifetime of the award. This effort will reintroduce physical oceanography to Brown, missing since the 1950s. Outreach activities to the public and K-12 audiences in conjunction with Save the Bay will educate about climate modeling globally and in Rhode Island. Save The Bay educators will be trained and supplied with teaching materials developed by the PI and group, in collaboration with a group of non-STEM Brown & Rhode Island School of Design undergraduates. The fundamentals of the next generation of climate models will be evaluated and improved.