Measurements and Modeling of the Kinematics and Dynamics of Surface-Wave Breaking in Directional Wave Fields

定向波场中表面波破碎的运动学和动力学的测量和建模

• 批准号: 1155403
• 负责人: W Melville
• 金额: $ 117.82万
• 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: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1155403&HistoricalAwards=false
• 关键词: Measurements; Modeling; Kinematics; Dynamics; Surface

This project will use a high resolution scanning LIDAR along with visible and infrared imaging to measure the directional distributions of the surface wave field and wave breaking, and use this data to test and develop models of wave evolution and dissipation. The novelty is that it will give the directional wavenumber spectra of the surface waves from the scale of the swell, O(100) m, down to the scale of gravity- capillary waves, O(0.01)m. Similarly, it will give corresponding directional distributions of breaking across the same range of scales. These broadband data are expected to support a greatly improved understanding of the statistical description of wave breaking first proposed by Phillips (1985), based on the length of breaking fronts per unit area of ocean surface moving at around the phase velocity. The measurements of breaking front length in the literature are very limited and have a unimodal structure that is not understood. This program, including the analysis of field data, high-resolution wave breaking kinematics and directional wave measurements from the Scripps Institution of Oceanography (SIO) Per and airborne measurements during a R/P FLIP experiment and Santa Ana wind events offshore Southern California and Baja California, will allow more thorough testing of the current dissipation source function models in numerical wind wave models and development new models based on an analysis of the data constrained by the radiative transfer equation for the wave field. The data will also permit quantitative exploration of the transition from air-entraining whitecapping to microscale breaking, and the relationship between the kinematics and dynamics of breaking.Broader ImpactWhile the funded effort is focused on investigating hitherto inaccessible aspects of surface wave kinematics and dynamics, improvements in surface-wave and wave-breaking models will have a significant impact on coupled atmosphere-ocean models used for weather and climate prediction. The momentum and energy fluxes from the atmosphere to the ocean are a function of the directional wave spectra and wave breaking distributions. The air-sea transfer of greenhouse and other gases depend on air entrainment due to breaking.The SIO Pier experiments will be used as a hands-on teaching opportunity in graduate and undergraduate classes at SIO, UCSD. Currently, PI Melville uses the laboratory to provide demonstrations and hands-on experience for students taking classes in fluid mechanics and wave mechanics. The pier experiment will extend this experience for the students from the controlled environment of the laboratory to the uncontrolled environment of the field, thus providing a broader and qualitatively different experience for the students.This project will provide research experiences for undergraduate students at UCSD during the academic year and for fellowship programs during the summer sessions. From personal experience during his own undergraduate career, Melville understands the value of these programs in shaping careers and has worked to continue these programs in his laboratory.The results of this research and related material will be posted to Melville?s research web site (http://airsea.ucsd.edu).

该项目将使用高分辨率扫描激光雷达以及可见光和红外成像来测量表面波场和波浪破碎的方向分布，并使用这些数据来测试和开发波浪演化和耗散模型。新颖之处在于，它将给出表面波的方向波数光谱，从膨胀的尺度0 (100)m，到重力的尺度-毛细波，0 (0.01)m。同样地，它将给出在相同尺度范围内的相应的断裂方向分布。这些宽带数据有望大大提高对Phillips（1985）首次提出的海浪破碎统计描述的理解，该描述基于以相速度移动的海洋表面每单位面积破碎锋的长度。文献中断裂锋长度的测量非常有限，并且具有未被理解的单峰结构。该项目包括现场数据分析、高分辨率破波运动学和来自斯克里普斯海洋研究所（SIO） Per的定向波测量，以及在R/P FLIP实验和南加州和下加利福尼亚州近海圣安娜风事件期间的机载测量。将允许在数值风波模型中对当前耗散源函数模型进行更彻底的测试，并基于对波场辐射传递方程约束的数据的分析开发新的模型。这些数据还将允许定量探索从空气夹带白波到微尺度断裂的转变，以及断裂的运动学和动力学之间的关系。更广泛的影响虽然资助的努力集中在调查表面波运动学和动力学迄今为止无法触及的方面，但表面波和破波模型的改进将对用于天气和气候预测的耦合大气-海洋模型产生重大影响。从大气到海洋的动量和能量通量是方向波谱和破波分布的函数。温室气体和其他气体的海气转移依赖于破裂引起的空气夹带。SIO Pier实验将在加州大学圣地亚哥分校SIO的研究生和本科生课堂上作为动手教学的机会。目前，PI梅尔维尔使用实验室提供演示和实践经验，学生参加流体力学和波动力学类。码头实验将学生的这种体验从实验室的受控环境扩展到现场的非受控环境，从而为学生提供更广泛和质的不同体验。该项目将在学年期间为加州大学圣地亚哥分校的本科生提供研究经验，并在夏季会议期间为奖学金项目提供研究经验。从他本科生涯的个人经历来看，梅尔维尔理解这些项目在塑造职业生涯中的价值，并在他的实验室里继续这些项目。这项研究的结果和相关材料将发布在梅尔维尔？S研究网站（http://airsea.ucsd.edu）。