Internal waves, submesoscale currents and their interactions in the ocean

海洋表面下的最初几十米包含的热量比整个大气层还要多。因此，了解海洋对世界气候的影响至关重要。密度变化和地球自转决定了洋流的形状和命运。当湍流出现时，混合将水和营养物质从寒冷的深渊中移上来，并将热量从阳光沐浴的表面移下来。湍流过程中水分子之间发生的摩擦也会消除海洋中多余的能量，关闭其能量预算。 在过去几年中，物理海洋学家越来越相信，几十公里宽或更小的水流对我们了解这些交换至关重要。这些尺度比目前数值气候模式的分辨率至少小一个数量级，导致许多未解决的过程。为了正确地包含它们，我们的社区需要提出基于对底层物理学的严格理解的算法，以弥补这种分辨率的不足。这项建议的重点是提高我们对这些尺度上发生的海洋物理学的基本理解。我们的目标是研究海洋边界附近湍流的可能途径，无论是风驱动的海洋表面还是粗糙的底部。当涉及到海洋表面时，该提案还旨在伴随预计将于2022年发射的未来地表水和海洋地形卫星使命的准备和第一阶段。我和我的团队将使用数学理论，流体运动的数值模拟和机器学习算法来回答四个（类别）问题：1。内潮如何与较慢的次中尺度海流相互作用？内潮是内波，在海洋体积中传播的波，它们以与潮汐相同的频率振荡。次中尺度洋流通常有几公里宽，其旋转速度与地球自转速度一样快。这两个过程是SWOT的十字准线，对制造动荡至关重要。2.亚中尺度气流是如何产生湍流的？也就是说，是什么使洋流不稳定，内波能加速它们的灭亡吗？3.当水流遇到水下地形时会产生什么样的湍流？内部潮汐或水下山波发挥作用？4.当海冰消退时，内波和洋流是如何在北冰洋产生湍流的？有了这个建议，我们计划雇用四名研究生和他们的替代品，一旦他们毕业，并支持每年少数本科生的研究经验。

The first few tens of meters under the ocean surface contain more heat than the entire atmosphere. It is therefore crucial to understand the influence of the oceans on the world's climate. Density variations and the rotation of the Earth determine the shape and fate of ocean currents. When turbulence arises, mixing moves water and nutrients up from the cold abyss, and heat down from the sun-bathed surface. The friction happening between water molecules in the process of turbulence also removes excess energy in the ocean, closing its energy budget. In the past few years, physical oceanographers have grown increasingly confident that flows that are a few tens of kilometres wide or less are crucial to our understanding of these exchanges. These scales are at least one order of magnitude smaller than the current resolution of numerical climate models, leading to many unresolved processes. In order to properly include them, our community needs to come up with algorithms that are based on a rigorous understanding of the underlying physics to make up for this lack of resolution. This proposal focuses on improving our fundamental understanding of said ocean physics happening at these scales. We aim to investigate the possible routes to turbulence around the ocean boundaries, be they the wind-driven ocean surface or its rough bottom. When it comes to the ocean surface, this proposal also aims to accompany the preparation and first stages of the future Surface Water and Ocean Topography satellite mission, expected to launch in 2022. My group and I will use mathematical theories, numerical simulations of fluid motion, and machine learning algorithms to answer four (categories of) questions: 1. How do internal tides interact with slower, submesoscale currents? Internal tides are internal waves, waves that propagate in the volume of the oceans, and they oscillate at the same frequencies as the tide. Submesoscale currents are usually a few kilometres wide, and induce spinning that is as fast as that induced by Earth's rotation. These two processes are in the crosshairs of SWOT, and crucial for creating turbulence. 2. How does turbulence get created within submesoscale currents? That is, what destabilizes the currents, and can internal waves precipitate their demise? 3. What kind of turbulence do currents create when they encounter underwater topography? Do internal tides or underwater mountain waves play a role? 4. How do internal waves and currents create turbulence in the Arctic Ocean when the sea ice is receding? With this proposal, we plan to hire four graduate students and their replacements once they graduate, and to support a handful of undergraduate research experiences each year.