Upper Ocean Turbulence in Non-Equilibrium Conditions

非平衡条件下的上层海洋湍流

• 批准号: 1634578
• 负责人: Tobias Kukulka
• 金额: $ 31.43万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1634578&HistoricalAwards=false
• 关键词: Upper; Ocean; Turbulence; Non; Equilibrium

Turbulent processes near the surface of the ocean play a key role in weather and climate systems by coupling the ocean with the atmosphere and by distributing nutrients, pollutants, plankton, and bubbles. Wind and waves drive this turbulence, often through complex interactions. Our current conceptual and theoretical framework of these dynamics is based on an equilibrium assumption, in which waves and turbulence are in equilibrium with the wind forcing. However, recent investigations highlight that typical ocean conditions are rarely in equilibrium, but rather are characterized by swell and variable wind waves in terms of frequencies and directions. This study will integrate recent observational, theoretical, and computational progress to systematically assess the influence of non-equilibrium conditions on turbulence near the ocean surface and on the exchange of momentum and heat with the atmosphere. Improving the representation of air-sea interaction and ocean turbulence, will advance coupled ocean-atmosphere models of weather and climate. The ability to predict the distribution of ocean pollutants as well as seasonal fluctuations and secular climate change has important environmental, societal, and economical impacts. The knowledge developed in this study will be incorporated into courses at the University of Delaware. The project will uniquely foster training of students in a collaborative environment with computational and observational experts in oceanography. The PI will participate in public outreach events, such as the annual Coast Day, an open house day for the general public sponsored by the University of Delaware's College of Earth, Ocean and Environment. This occasion provides an opportunity for scientists to inform the general public of the scientific issues that influence the environment and to expose children of all ages to careers in the sciences and engineering.By critically evaluating traditional equilibrium assumptions, the proposed research promises to advance our basic conceptual understanding of ocean surface boundary layer (OSBL) dynamics. Specifically, the study will test the following hypotheses: (1) The evolution of the OSBL depends on complex, non-equilibrium sea states, so that for the same surface fluxes OSBL dynamics vary significantly. (2) A turbulence-resolving model based on the wave-averaged Navier-Stokes equations accurately captures the observed sea state dependent evolution of the turbulent OSBL. (3) The relative importance of breaking wave and Langmuir circulation (LC) effects depends on sea state and OSBL conditions, such as OSBL depth. (4) Extending the existing theoretical and conceptual framework of planetary boundary layers by including wave effects explicitly will provide a more physical description of realistic OSBLs. These hypotheses will be addressed by analyzing observations from recent field experiments in the coastal and open ocean in collaboration with the Woods Hole Oceanographic Institution. Those rare data sets include collocated measurements of waves, surface fluxes, and upper ocean structure, including unique observations of LC characteristics. Observations will be compared to large-eddy simulation (LES) results based on the wave-averaged Navier-Stokes equations. The LES model resolves turbulence and captures both LC and breaking waves. The breaking wave input to the model will be enhanced based on recent progress on wind-wave coupling theory that takes sea state effects into account in collaboration with the National Center for Atmospheric Research. In collaboration with the Leibniz Institute for Baltic Sea Research, the researchers will evaluate common OSBL turbulence models employed in regional and global ocean models. The combined analyses of OSBL observations and process-based LES will provide the needed insights for developing novel, accurate physics-based OSBL models. Thus, the research will contribute to improving the next-generation ocean models and to enhancing our understanding of the coupled ocean-atmosphere system.

海洋表面附近的湍流过程通过将海洋与大气并分配营养物质，污染物，浮游生物和气泡来在天气和气候系统中起关键作用。风和波浪通常通过复杂的相互作用来驱动这种湍流。我们当前这些动力学的概念和理论框架是基于平衡假设的，其中波和湍流与风强迫平衡。然而，最近的研究表明，典型的海洋条件很少在平衡状态，而是在频率和方向上以膨胀和可变的风波为特征。这项研究将整合最近的观察，理论和计算进步，以系统地评估非平衡条件对海面附近的湍流以及对大气和热量的动量和热量交换的影响。改善空气相互作用和海洋湍流的表示，将促进天气和气候的海洋大流模型。预测海洋污染物分布以及季节性波动和世俗气候变化的能力具有重要的环境，社会和经济影响。这项研究中发展的知识将纳入特拉华大学的课程。该项目将在与海洋学的计算和观察专家的协作环境中独特地培养学生的培训。 PI将参加公共宣传活动，例如年度沿海日，这是由特拉华大学地球，海洋和环境学院赞助的公共公众日子的开放日。这种场合为科学家提供了一个机会，向公众告知了影响环境的科学问题，并将各个年龄段的儿童暴露于科学和工程中的职业。通过严格评估传统的均衡假设，拟议的研究有望促进我们对海洋表面边界层（OSBL）动态的基本概念的理解。具体而言，该研究将检验以下假设：（1）OSBL的演变取决于复杂的非平衡海态，因此对于相同的表面磁通量，OSBL动力学差异很大。 （2）基于波浪平均纳维尔 - 螺旋式方程的湍流解析模型准确地捕获了观察到的湍流OSBL的海态依赖性演变。 （3）断裂波和Langmuir循环（LC）效应的相对重要性取决于海洋状态和OSBL条件，例如OSBL深度。 （4）通过明确包含波浪效应，扩展行星边界层的现有理论和概念框架将提供对现实OSBL的物理描述。这些假设将通过分析与伍兹霍尔海洋学机构合作的最新野外实验的观察结果来解决这些假设。这些罕见的数据集包括对波，表面通量和上海结构的共处测量，包括对LC特征的独特观察。将根据波平均的Navier-Stokes方程将观测结果与大涡模拟（LES）结果进行比较。 LES模型可以解决湍流并捕获LC和破坏波。基于风波耦合理论的最新进展，将增强对模型的破裂波输入，该理论与国家大气研究中心合作考虑了Sea State Effection。与莱布尼兹波罗的海研究所合作，研究人员将评估在区域和全球海洋模型中采用的常见OSBL湍流模型。 OSBL观测和基于过程的LE的组合分析将为开发新颖，基于物理的OSBL模型提供所需的见解。因此，这项研究将有助于改善下一代海洋模型，并增强我们对耦合海洋大气系统的理解。

项目成果

Wind–Wave Misalignment Effects on Langmuir Turbulence in Tropical Cyclone Conditions

• DOI: 10.1175/jpo-d-19-0093.1
• 发表时间: 2019-12
• 期刊: Journal of Physical Oceanography
• 影响因子: 3.5
• 作者: Dong Wang;T. Kukulka;B. Reichl;T. Hara;I. Ginis

Ocean Surface Boundary Layer Response to Abruptly Turning Winds

海洋表面边界层对突然转向的风的响应

• DOI: 10.1175/jpo-d-20-0198.1
• 发表时间: 2021
• 期刊: Journal of Physical Oceanography
• 影响因子: 3.5
• 作者: Wang, Xingchi;Kukulka, Tobias
• 通讯作者: Kukulka, Tobias

Interaction of Langmuir Turbulence and Inertial Currents in the Ocean Surface Boundary Layer under Tropical Cyclones

• DOI: 10.1175/jpo-d-17-0258.1
• 发表时间: 2018-09
• 期刊: Journal of Physical Oceanography
• 影响因子: 3.5
• 作者: Dong Wang;T. Kukulka;B. Reichl;T. Hara;I. Ginis;P. Sullivan

Wind Fetch and Direction Effects on Langmuir Turbulence in a Coastal Ocean

沿海海洋朗缪尔湍流的取风和方向效应

• DOI: 10.1029/2021jc018222
• 发表时间: 2022
• 期刊: Journal of Geophysical Research: Oceans
• 作者: Wang, Xingchi;Kukulka, Tobias;Plueddemann, Albert J.
• 通讯作者: Plueddemann, Albert J.

Comparing Ocean Surface Boundary Vertical Mixing Schemes Including Langmuir Turbulence

• DOI: 10.1029/2019ms001810
• 发表时间: 2019-11
• 期刊: Journal of Advances in Modeling Earth Systems
• 影响因子: 6.8
• 作者: Qing Li;B. Reichl;B. Fox‐Kemper;A. Adcroft;S. Belcher;G. Danabasoglu;A. Grant;S. Griffies;R. Hallberg;T. Hara;R. Harcourt;T. Kukulka;W. Large;J. McWilliams;Brodie C. Pearson;P. Sullivan;Luke P. van Roekel;Peng Wang;Zhihua Zheng