Churning the deep: ocean mixing by breaking internal waves

搅动深海：通过打破内波来混合海洋

• 批准号: RGPIN-2020-04163
• 负责人: Musgrave, Ruth
• 金额: $ 2.55万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=739714
• 关键词: Churning; deep; ocean; mixing; breaking

By investigating the physics behind ocean mixing, this proposed research program will address a key uncertainty in the field of numerical climate modeling and prediction. Ocean mixing occurs at scales that are too small to be explicitly resolved in global climate models, and as a result the influence of mixing must be represented indirectly, by physically based models, or parametrizations. Climate models are extremely sensitive to the distribution of parametrized mixing, and uncertainties in how to represent ocean mixing limit our ability to accurately predict and adapt to future changes in climate. The spatial and temporal distributions of ocean mixing is mostly determined by the dissipation of internal waves, waves that propagate across density interfaces in the ocean's interior and dissipate by breaking, much like waves at the beach. The focus of this proposed research program is on mixing by wind- and tide-driven internal waves, as parametrizations for these processes remain incomplete, only partially accounting for different dynamical regimes, as described below. The program has three objectives. The first is to explore the lifecycles of tidally-driven internal waves in coastal regions using numerical models, with an emphasis on the west coast of North America. This work will emphasize understanding when and where internal tides are dissipated and mix at the coast, with the goal of developing a parametrization for use in climate models. The depths at which wind-driven internal waves dissipate in the open ocean will be studied for the second objective, using multi-year moored observations from the Atlantic, Pacific and Southern Oceans. Theory and numerical models will be used with the observations to understand energy pathways from forcing to dissipation in these dynamically distinct regions. Finally, the third objective of this research program is to understand ocean mixing by the winds and tides on the Scotian Shelf, a conveniently accessible coastal environment with large tides and wind forcing. Historical and ongoing data collection in this region provides a large dataset for exploring these processes. This objective will additionally address the role of ocean mixing on ocean biology, contributing to an understanding of the processes that sustain the commercially important fisheries in the region. Anticipated outcomes of this research are contributions to our understanding of how and where ocean mixing occurs in the global ocean, and the development of new parametrizations that will increase the accuracy of global climate models, enabling us to forecast future changes both in Canada and globally with greater confidence. Over the next five years, this program will train three graduate students and four honours students, developing their skills in applied physics, numerical and computational analysis and oceanography.

通过研究海洋混合背后的物理学，该提出的研究计划将解决数值气候建模和预测领域的关键不确定性。海洋混合发生在太小而无法在全球气候模型中明确解决的尺度上发生，因此，必须通过基于物理的模型或参数化来间接表示混合的影响。气候模型对参数化混合的分布极为敏感，并且在如何代表海洋混合的情况下不确定性限制了我们准确预测和适应气候变化的能力。海洋混合的空间和时间分布主要取决于内部波浪的耗散，波浪在海洋内部的密度界面遍布密度界面，并通过破裂而消散，就像海滩上的波浪一样。 The focus of this proposed research program is on mixing by wind- and tide-driven internal waves, as parametrizations for these processes remain incomplete, only partially accounting for different dynamical regimes, as described below.该程序有三个目标。首先是使用数值模型探索沿海地区潮汐驱动的内波的生命周期，重点是北美西海岸。这项工作将强调了解内部潮汐何时散开并在海岸混合，目的是开发用于在气候模型中使用的参数化。使用大西洋，太平洋和南部海洋的多年停泊观察结果，将研究第二个目标的风向内波消散的深度。理论和数值模型将用于观察结果，以了解这些动态不同区域中强迫耗散的能量途径。最后，该研究计划的第三个目标是了解海洋混合，潮汐在斯科舍省架子上，这是一个方便的沿海环境，具有较大的潮汐和风力强迫。该地区的历史和正在进行的数据收集提供了一个用于探索这些过程的大数据集。该目标还将解决海洋混合在海洋生物学方面的作用，从而有助于理解维持该地区商业上重要渔业的过程。 这项研究的预期结果是我们对全球海洋中海洋混合如何以及在何处发生的理解以及新的参数化的发展，这将提高全球气候模型的准确性，使我们能够以更大的信心预测加拿大和全球的未来变化。在接下来的五年中，该计划将培训三名研究生和四名荣誉学生，并在应用物理学，数值和计算分析和海洋学方面发展他们的技能。