Measurements of the Coupled Development of the Surface Wave Field and Marine Atmospheric Boundary Layer with Fetch

表面波场与海洋大气边界层耦合发展的Fetch测量

• 批准号: 0242083
• 负责人: W Melville
• 金额: --
• 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: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-03-15 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0242083&HistoricalAwards=false
• 关键词: Measurements; Coupled; Development; Surface; Wave

ABSTRACTPI/Institution: Melville / SIO Proposal No: OCE-0242083The coupled development of the wind-generated wave field and the marine atmospheric boundary layer as a function of fetch remains a fundamental problem in air-sea interaction. While simple power-law expressions for the dimensionless wave height and peak frequency have been obtained in terms of the dimensionless fetch, predictions of the evolution of the wave directional spectrum still depend on assumptions about the wind input, nonlinear wave-wave interactions and dissipation by breaking. Similar uncertainties exist in the modeling of the marine atmospheric boundary layer. The evolution of the boundary layer and the wave field are coupled, with the momentum, heat and moisture fluxes depending on the sea state, and especially on wave breaking. While the details of these processes may be averaged out, or relegated to subgrid-scale status in meso- and basin-scale models of air-sea interaction, improved models of small-scale air-sea fluxes are required to improve predictions under moderate wind and wave conditions. Moreover, first-order uncertainties remain at high winds. It is well known that much of the momentum flux from winds to currents (or the drag on the atmospheric boundary layer) first passes through the wave field. The primary mechanism for transferring that momentum flux to currents is wave breaking. Breaking is an important source of turbulence (that enhances heat and mass transfer), and of entrained bubbles and marine aerosols. Marine spray and aerosols are of particular importance for biogeochemisty, for cloud physics, and for the Earth's radiation balance. This proposal describes a program of airborne measurements of the evolution of the air-sea fluxes, the atmospheric boundary layer and the surface wave field as a function of fetch in moderate to high winds. Airborne experiments will be conducted from the NCAR C-130 in the Gulf of Tehuantepec, of the Pacific coast of Mexico during winter when northerly mountain-gap winds blow at up to 40 knots or more for several days out over the Pacific. Using modern remote imaging, ranging, mapping and positioning techniques, we will make detailed measurements of the wave field with fetch as winds blow offshore. Using modern airborne atmospheric turbulence and flux measurement techniques, we will measure the evolution of the atmospheric boundary layer and investigate the coupling with the wave field. Using air-deployable expendable dropsondes and AXBTs we will profile the development of the marine atmospheric boundary layer and the ocean mixed layer with fetch. Measurements will be compared with coupled models of air-sea fluxes and wind-wave evolution. We will develop fetch-dependent models of the atmospheric boundary layer and more detailed fetch-dependent models of surface-wave processes; especially breaking. This project will have a broader impact on science and society through a variety of mechanisms. The research is motivated by basic questions in small-scale air-sea interaction, but the results will find application in economically-important coupled ocean-atmosphere models for improved weather and climate prediction. The results of this research will be directly incorporated into classes at SIO/UCSD and UCI, and the equipment and techniques developed in this project will be used in graduate education and research across a variety of fields at both institutions. The project will provide research opportunities for summer undergraduate research fellows from diverse /underrepresented groups at both SIO/UCSD and UCI, and opportunities for undergraduate assistants will be provided during the school year. The project will be used to educate K-12 students in science, and career opportunities in science, at both institutions. A project web site will be established at SIO to broadly disseminate the results of the research.

摘要PI/机构：梅尔维尔/SIO 提案编号：风生波场和海洋大气边界层的耦合发展作为风场的函数仍然是海气相互作用中的一个基本问题。虽然简单的幂律表达式的无量纲波高和峰值频率已获得的无量纲取，预测的波方向谱的演变仍然取决于风输入，非线性波-波相互作用和破碎耗散的假设。在海洋大气边界层的模拟中也存在类似的不确定性。边界层和波场的演变是耦合的，动量、热量和水分通量取决于海况，特别是波浪破碎。虽然这些过程的细节可能会被平均，或降级到亚网格尺度的状态，在中尺度和海盆尺度的海气相互作用模型，改进的小尺度海气通量模型，需要改善预测在温和的风和浪的条件。此外，一阶不确定性仍然存在于大风中。众所周知，从风到海流的动量通量（或大气边界层上的阻力）首先通过波场。将动量通量转化为海流的主要机制是波浪破碎。破裂是湍流（增强热量和质量传递）以及夹带气泡和海洋气溶胶的重要来源。海洋喷雾和气溶胶对于海洋地球化学、云物理学和地球辐射平衡特别重要。该建议描述了一个空中测量方案，测量海气通量、大气边界层和表面波场的演变，作为中到强风的函数。空中实验将在冬季墨西哥太平洋沿岸特万特佩克湾的NCAR C-130上进行，当时太平洋上空的北风高达40节或更高。利用现代远程成像、测距、绘图和定位技术，我们将对风吹向近海时的波浪场进行详细测量。利用现代机载大气湍流和通量测量技术，我们将测量大气边界层的演变，并研究与波场的耦合。使用可展开的一次性空投探空仪和AXBT，我们将剖面的海洋大气边界层和海洋混合层的发展与fetch。测量结果将与海气通量和风浪演变的耦合模式进行比较。我们将发展大气边界层的取相关模型和更详细的表面波过程的取相关模型，特别是破裂。该项目将通过各种机制对科学和社会产生更广泛的影响。这项研究的动机是小尺度海气相互作用的基本问题，但其结果将在具有经济重要性的海洋-大气耦合模型中得到应用，以改善天气和气候预测。这项研究的结果将直接纳入SIO/UCSD和UCI的课程中，该项目开发的设备和技术将用于这两个机构各个领域的研究生教育和研究。该项目将为来自SIO/UCSD和UCI的不同/代表性不足的群体的暑期本科研究员提供研究机会，并将在学年期间提供本科助理的机会。该项目将用于教育K-12学生在科学和科学的职业机会，在这两个机构。将在SIO建立一个项目网站，以广泛传播研究结果。