Quantifying Energy Dissipation From Breaking Waves Using Time-Varying Properties of Whitecap Foam

拟议研究的目标是开发一种遥感技术，以量化破碎波的能量损失。这项工作的动机是波浪破碎在加强海气界面的热量，质量，动量和能量交换方面发挥的基本作用。此外，现有的遥感技术仍然是高度不确定的，由于大的变化，在断裂强度参数，激励需要开发替代的遥感技术。预计拟议的遥感技术将有助于提高我们的基本知识的波浪破碎和能量耗散，这是重要的气溶胶的生产和气体交换的理解。此外，新的遥感技术隐含地考虑了波浪尺度和破碎强度，这可以为海浪的详细建模提供有价值的信息。本科实习生参与实验室实验，帮助收集数据和进行初步分析，将进一步扩大研究的影响。该项目小组将参加由桦树水族馆主办的公众宣传系列讲座，遥感技术将利用关于在主动波浪破碎过程中白顶泡沫随时间变化的特性的高速和高分辨率数字图像，并将对照一系列使用海水和破碎波包的控制良好的实验室实验加以验证。目前的遥感技术依赖于测量破碎波的速度来估计破碎波的能量耗散，但是，关键的是，在文献中缺乏共识的最合适的方法来测量破碎波的速度。这对断裂强度参数的估计有直接影响，据报道断裂强度参数的变化为4个数量级。开发一种新的遥感技术将为目前的方法提供一种平行的方法。将寻求以下关键问题的答案：1）高分辨率和高速数字摄影能否用于量化波浪破碎过程中的能量耗散？2)利用线性波叠加产生的破碎波发展起来的新遥感技术，能应用于风力破碎波吗？3)利用现有的海面图像数据集，新的遥感技术是否可以应用于在风驱动的海洋中破碎波浪？拟议的研究将涉及实验室实验和现有的海面图像数据库的分析相结合，以开始估计单个破碎波的能量耗散。实验室实验将基于在斯克里普斯海洋研究所的33米玻璃波浪通道和40米风浪通道中对破碎波浪的观测。重要的是，这两个波浪通道的使用将确保破碎波在广泛的尺度范围内产生，并具有不同的强迫机制（波-波相互作用和风切应力）。将使用下视摄像机监测白浪泡沫、气泡羽流和波浪能量学，以监测通过倾翻破碎机的溢出，下视摄像机监测表面白浪特性，侧视摄像机监测气泡羽流特性，波浪测量仪准确表征破碎引起的能量耗散。这一综合性实验方法将为开发遥感技术提供必要的数据，供今后计划进行的实地研究使用。

The goal of the proposed research is to develop a remote sensing technique to quantify the energy lost by breaking waves. The work is motivated by the fundamental role that wave breaking plays in enhancing the exchange of heat, mass, momentum and energy across the air-sea interface. Furthermore, existing remote sensing techniques remain highly uncertain due to large variations in the breaking strength parameter, motivating the need to develop alternative remote sensing techniques. It is anticipated that the proposed remote sensing technique will help enhance our fundamental knowledge of wave breaking and energy dissipation, which is important for the understanding of aerosol production and gas exchange. Furthermore, the remote new sensing technique implicitly accounts for both wave scale and breaking intensity on a wave-by-wave basis, which can provide valuable information for detailed modeling of ocean waves. The impact of the study will be further broadened by the participation of undergraduate interns in the laboratory experiments to help with data collection and preliminary analysis. The project team will participate in the public outreach lecture series hosted by the Birch Aquarium.The remote sensing technique will utilize high-speed and high resolution digital images of the time-varying properties of whitecap foam during active wave breaking and will be validated against a series of well-controlled laboratory experiments using seawater and breaking wave packets. Present remote-sensing techniques rely on measuring breaking wave speed to estimate breaking wave energy dissipation, but, critically, there is a lack of consensus in the literature regarding the most appropriate way to measure breaking wave speed. This has direct implications for estimates of the breaking strength parameter, which has been reported to vary by 4 orders of magnitude. Development of a new remote sensing technique will offer a parallel approach to the present methodology. Answers to the following key questions will be sought: 1) Can high-resolution and high-speed digital photography be used to quantify energy dissipation during wave breaking on a wave-by-wave basis? 2) Can the new remote sensing technique, developed using breaking waves generated by linear wave superposition, be applied to wind-driven breaking waves? 3) Using existing datasets of sea surface images, can the new remote sensing technique be applied to breaking waves in wind-driven seas? The proposed research will involve a combination of laboratory experiments and analysis of an existing database of sea surface images to begin to estimate energy dissipation for individual breaking waves. The laboratory experiments will be based on observations of breaking waves in both the 33 meter glass wave channel and the 40 meter wind-wave channel at the Scripps Institution of Oceanography. Importantly, the use of these two wave channels will ensure breaking waves are generated across a wide range of scales and with different forcing mechanisms (wave-wave interaction and wind shear stress). Whitecap foam, bubble plume and wave energetics will be monitored for spilling through plunging breakers using a downward looking camera to monitor the surface whitecap properties, a sideward looking camera to monitor bubble plume characteristics and wave gauges to accurately characterize energy dissipation due to breaking. This comprehensive experimental approach will provide the necessary data to develop the remote sensing technique for use in future-planned field studies.