The Influence of Surface Waves on the Upper Mixed Layer

表面波对上部混合层的影响

• 批准号: 0927428
• 负责人: W Melville
• 金额: $ 88.58万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0927428&HistoricalAwards=false
• 关键词: Influence; Surface; Waves; Upper; Mixed

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Intellectual Merit: The momentum and energy fluxes from the atmosphere to the ocean pass through the surface wave field before giving rise to surface currents and mixing locally, while some of the fluxes extend across the ocean basins through propagation by swell. However, the detailed balances of energy and momentum in the upper ocean are poorly understood and are still the subject of speculative estimates. Recent Large Eddy Simulations (LES) of the upper ocean mixed layer, or Oceanic Boundary Layer (OBL), which include wave effects through Langmuir circulations and wave breaking, have shown that wave effects may be felt throughout the developing boundary layer through aspects of vortex dynamics common to both breaking and Langmuir circulations, and synergies between the two phenomena. For example, the numerical model shows that the same Craik-Leibovich vortex force and feedback that gives rise to Langmuir circulations may be seeded by breaking. Furthermore, turbulence generated at the surface by breaking may be transported into the entraining boundary layer by Langmuir circulations.The project will carry out a series of field experiments to test the assumptions and predictions of the LES models. The field measurements will be conducted from R/P FLIP in collaboration with planned ONR FLIP experiments on surface wave phenomena and air-sea interaction. These wave measurements are necessary to constrain the LES models and boundary conditions. The project will concentrate on the OBL measurements including currents and turbulence, temperature, salinity and entrained air (bubbles), from profiled instruments and a tethered surface float. The predictions of the models may be tested by measurements of the statistical moments of the velocity and temperature fields as a function of depth, including fluxes of momentum, heat and Turbulent Kinetic Energy (TKE) through the OBL. One of the important assumptions of the models is that the dynamical effects of the entrained air due to breaking can be neglected; a good approximation under certain environmental conditions. However, there is evidence that this approximation will break down near the surface at higher wind speeds. If air entrainment is dynamically significant it will act to suppress vertical mixing and may have a qualitative impact on the structure of the OBL. Direct measurements of the air entrained by breaking and its dynamical consequences will be made.Broader Impacts: This research will include an improved understanding of the coupling of the oceans and the atmosphere, leading to better coupled models of weather and climate. Our ability to predict seasonal fluctuations and secular climate change has an important impact on fisheries, agriculture, the energy industry, the commodity markets, the construction and insurance industries, and disaster/threat preparedness. Ultimately, good national and international environmental policy relies on a solid scientific basis for decision making, and the project will contribute to those policies. The project will support the integration of research and education at every academic level. This includes training and support of post-doctoral scholars and graduate students, as well as contributions to K-12 and public education. Results from this research will be disseminated in professional journal publications and more popular avenues of publication. Knowledge gained through this research will be incorporated into the education and training of students at Scripps Institution of Oceanography, UCSD. The resources from the project will support a doctoral student and provide material and facilities for undergraduate projects and minority undergraduate summer fellows. The results of this project will be used to promote science and research to a broader audience by working with the Center for Ocean Science Excellence/California (COSEE CA) to develop a website and present earth science workshops for science teachers from the San Diego Unified School District.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。智力上的优点：从大气到海洋的动量和能量通量在引起表面流和局部混合之前穿过表面波场，而一些通量通过膨胀传播而延伸到整个海洋盆地。然而，对上层海洋的能量和动量的详细平衡了解甚少，仍然是推测性估计的主题。最近对上层海洋混合层或海洋边界层（OBL）进行的大涡模拟（LES），包括通过朗缪尔环流和波浪破碎产生的波浪效应，表明波浪效应可以通过破碎和朗缪尔环流共同的涡旋动力学方面以及两种现象之间的协同作用在整个发展中的边界层中感受到。例如，数值模型表明，同样的Craik-Leibovich涡力和反馈，引起朗缪尔环流可以通过破碎播种。此外，由于破裂而在地面产生的湍流可能会通过朗缪尔环流输送到夹带边界层中。该项目将进行一系列现场试验，以检验LES模型的假设和预测。现场测量将从R/P FLIP与计划的ONR FLIP实验合作进行，这些实验涉及表面波现象和海气相互作用。这些波浪测量对于约束LES模型和边界条件是必要的。该项目将集中在OBL测量，包括电流和湍流，温度，盐度和夹带的空气（气泡），从轮廓仪器和系留表面浮子。可以通过测量作为深度函数的速度和温度场的统计矩来测试模型的预测，包括通过OBL的动量、热量和湍流动能（TKE）通量。模型的重要假设之一是，由于破裂而夹带的空气的动力学效应可以忽略不计;在某些环境条件下是一个很好的近似。然而，有证据表明，在更高的风速下，这种近似将在表面附近被打破。如果空气夹带是动态显着的，它将采取行动，以抑制垂直混合，并可能对OBL的结构产生质的影响。直接测量的空气夹带的断裂及其动力学后果将作出。更广泛的影响：这项研究将包括一个更好的理解海洋和大气的耦合，导致更好的天气和气候的耦合模式。我们预测季节性波动和长期气候变化的能力对渔业、农业、能源工业、商品市场、建筑和保险业以及灾害/威胁防备产生重要影响。最终，良好的国家和国际环境政策依赖于决策的坚实科学基础，该项目将有助于这些政策。该项目将支持研究和教育在各个学术层面的整合。这包括博士后学者和研究生的培训和支持，以及对K-12和公共教育的贡献。这项研究的结果将在专业期刊出版物和更受欢迎的出版渠道上传播。通过这项研究获得的知识将被纳入学生的教育和培训在斯克里普斯海洋学研究所，加州大学圣地亚哥分校。该项目的资源将支持一名博士生，并为本科生项目和少数族裔本科生暑期研究员提供材料和设施。该项目的成果将用于向更广泛的受众推广科学和研究，方法是与海洋科学卓越中心/加州（COSEE CA）合作开发一个网站，并为圣地亚哥联合学区的科学教师举办地球科学讲习班。