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

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的方向分布和波浪破碎，并使用这些数据来测试和开发波浪演变和消散的模型。它的新奇之处在于，它将给出从涌浪尺度O(100)m到重力-毛细波尺度O(0.01)m的面波方向波数谱，类似地，它将在相同的尺度范围内给出相应的破裂方向分布。这些宽带数据有望大大改善对Phillips(1985)首先提出的基于以相速度附近移动的单位面积海洋表面的破碎锋面长度的统计描述的理解。文献中对断裂前沿长度的测量是非常有限的，并且具有尚未被理解的单峰结构。这项计划，包括现场资料的分析，高分辨率波浪破碎运动学和来自斯克里普斯海洋研究所(SIO)的PER和R/P翻转试验期间的航空测量，以及圣安娜风事件在南加州和下加利福尼亚州近海，将允许在数值风浪模式中更彻底地检验电流耗散源函数模型，并基于对受波场辐射传输方程约束的数据的分析来开发新的模式。这些数据还将允许定量探索从引气白浪到微尺度破碎的转变，以及破碎的运动学和动力学之间的关系。布罗德影响虽然资助的努力集中在研究面波运动学和动力学迄今无法获得的方面，但面波和波浪破碎模式的改进将对用于天气和气候预测的大气-海洋耦合模式产生重大影响。从大气到海洋的动量和能量通量是方向波谱和波浪破碎分布的函数。温室气体和其他气体的海-气转移依赖于破碎时的空气夹带。SIO Pier实验将作为加州大学洛杉矶分校SIO的研究生和本科生课程的实践教学机会。目前，皮梅尔维尔利用该实验室为参加流体力学和波浪力学课程的学生提供演示和实践体验。PIER实验将把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的体验。该项目将为加州大学圣迭戈分校的本科生在学年期间提供研究经验，并在暑期课程期间为奖学金计划提供研究经验。从他自己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方面的价值，并努力在他的实验室继续这些项目。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).

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).