Proof of Concept: Exploiting Cooling Whitecap Foam to Quantify Wave Breaking Dissipation

概念验证：利用冷却 Whitecap 泡沫来量化破波耗散

• 批准号: 1736504
• 负责人: Andrew Jessup
• 金额: $ 32.46万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1736504&HistoricalAwards=false
• 关键词: Proof; Concept; Exploiting; Cooling; Whitecap

This project is a proof of concept for a remote sensing method to determine the amount of wave energy lost due to wave breaking, by observing the thermal signatures in the infrared imagery of the breaking wave and the foam it produces. When waves break, energy is dissipated and momentum is transferred from waves to surface currents. These processes are critically important both in the open ocean and in the surf zone. Quantifying the energy dissipation due to wave breaking is directly relevant to wave prediction models used for operational sea-state forecasting and the impact of storms on coastal regions. Bubbles generated by breaking waves are the primary mechanism for gas transfer at moderate to high wind speed. Bubbles also contribute to marine aerosol formation through spray droplets produced when bubbles in foam burst at the surface. Foam generated by wave breaking has increased reflectivity of solar radiation that can affect the Earth?s albedo. Foam also has increased microwave emissivity, which impacts space borne radiometer measurements of wind speed. Success in this proof of concept will open a new research direction with implications for momentum, gas, and heat across the air-water interface and global remote sensing applications. The project will contribute to the training of a postdoctoral fellow who will participate in all aspects of the work and involve two undergraduates in the summer experiments. The undergraduates will participate via the Washington Space Grant Summer Undergraduate Research Program (SURP), through which the PI has mentored students in the past. The PI will request students from an underrepresented group, which the program emphasizes. The project will also enhance research infrastructure by making a recently acquired wind-wave facility fully operational.The long-term goal of this research team is to develop and utilize a remote sensing technique to infer energy dissipation due to wave breaking by exploiting the unique thermal signature of cooling residual foam left behind by the breaking process. The approach is based on the original idea that the time from when breaking begins to when the residual foam starts to cool can be used as a proxy for the bubble plume decay time, which in turn can be used to parameterize the energy dissipated by an individual breaking wave. The resulting ability to remotely quantify energy dissipation due to wave breaking will provide a new and transformative tool for investigating and understanding the air-sea interaction processes driven by wave breaking in the open ocean and the surf zone. A critical requirement to exploit the cooling signature of foam to quantify breaking is that the onset of cooling is not affected by the natural variability surfactants. The scope of this project is limited to determining the effect of surfactants on cooling foam as a necessary proof of concept to developing this new and promising idea. Success in this first step could lead to a more complete investigation, which exploits the cooling of whitecap foam to quantify wave breaking dissipation.

该项目是对一种遥感方法的概念验证，通过观察破碎波及其产生的泡沫的红外图像中的热特征，确定由于波浪破碎而损失的波浪能量。 当波浪破碎时，能量被耗散，动量从波浪转移到表面流。这些过程在公海和碎波带都是至关重要的。对波浪破碎引起的能量耗散进行量化与用于业务海况预报和风暴对沿海地区影响的波浪预测模型直接相关。破碎波产生的气泡是中高风速下气体传输的主要机制。泡沫中的气泡在水面破裂时产生的喷雾液滴也有助于海洋气溶胶的形成。波浪破碎产生的泡沫增加了太阳辐射的反射率，从而影响地球？好的。泡沫还具有增加的微波发射率，这影响了对风速的星载辐射计测量。 这一概念验证的成功将开辟一个新的研究方向，对气水界面的动量、气体和热量以及全球遥感应用产生影响。该项目将有助于培训一名博士后研究员，他将参与工作的各个方面，并让两名本科生参加夏季实验。这些本科生将通过华盛顿太空资助夏季本科生研究计划（SURP）参与，PI过去曾通过该计划指导学生。PI将要求来自代表性不足的群体的学生，这是该计划强调的。该项目还将加强研究基础设施，使最近购置的一个风浪设施全面投入使用，该研究小组的长期目标是开发和利用遥感技术，通过利用破碎过程留下的冷却残余泡沫的独特热特征，推断波浪破碎造成的能量耗散。该方法是基于原来的想法，从破碎开始时，当残余泡沫开始冷却的时间可以被用作代理的气泡羽流衰减时间，这反过来又可以被用来参数化的能量消散由一个单独的破碎波。由此产生的能力，远程量化能量耗散由于波浪破碎将提供一个新的和变革性的工具，调查和理解的空气-海洋相互作用过程中驱动的波浪破碎在开阔的海洋和碎波区。利用泡沫的冷却特征来量化破裂的关键要求是冷却的开始不受自然变化性表面活性剂的影响。该项目的范围仅限于确定表面活性剂对冷却泡沫的影响，作为开发这一新的和有前途的想法的必要概念证明。这第一步的成功可能会导致更全面的调查，利用白顶泡沫的冷却来量化波浪破碎耗散。