Quantifying Oceanic Whitecap Energy Dissipation and Bubble-Mediated Air-Sea Fluxes

量化海洋白浪能量耗散和气泡介导的海气通量

基本信息

批准号：
NE/T000309/1
负责人：
Adrian Callaghan
金额：
$ 72.57万
依托单位：
Imperial College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2019
资助国家：
英国
起止时间：
2019 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FT000309%2F1
关键词：
Quantifying Oceanic Whitecap Energy Dissipation

项目摘要

The winds constantly transfer energy from the atmosphere to the global oceans and seas helping to generate surface waves, currents and tearing water droplets directly from the crests of the steepest waves. The interaction of the wind and the surface ocean is an extremely complex process that still remains to be fully understood by ocean scientists and engineers and remains an active area of research. Perhaps the most fundamental consequence of wind blowing over the surface of the oceans is the generation of waves. Our ability to forecast the generation, evolution, and decay of ocean waves is important for the way humans interact with the global oceans. For example, wave forecasts are routinely used to help shipping companies plan the transport of goods and people across the global oceans, marine engineers need to know how often large waves occur and how these waves will interact with the structures they build for use in the ocean, oceanographers need to predict the how ocean waves affect weather and climate, and recreational sailors, swimmers and surfers rely on accurate wave forecasts to safely enjoy the seas and oceans around our coastline.Of particular interest to oceanographers is the energy balance between the wind and the waves. Since the wind acts as the primary source of energy for the waves, there must be a mechanism for dissipating this energy input, otherwise the waves would continue to grow. Part of this energy dissipation occurs along our coastlines where incoming waves break as they enter shallow water, releasing their energy. This release of energy helps to entrain air into the water, to move sediment and sand, and to create chaotic turbulent water motions. However, the vast majority of wave energy is dissipated by waves breaking in the open ocean. These are easy to spot on a windy day because of the bubbles and white foam they produce, commonly called whitecaps. The importance of these whitecaps to how the Earth's climate evolves is an area of huge interest to oceanographers, atmospheric scientists and climate scientists. Within each whitecap there are thousands of bubbles ranging in size from the width of a human hair to about the width of a 5 pence piece. These bubbles are like tiny replicas of the atmosphere that exchange gas with the surrounding water. This bubble-mediated mechanism of gas transfer is very important to how much carbon dioxide is transferred from the atmosphere to the ocean. When each of these bubbles rises to the water surface and bursts it can send tiny sea spray droplets into the atmosphere, much like the fizz of a glass of soda drink that you see when you look at it from the side. When these tiny droplets are in the atmosphere they can help to form clouds over the ocean, transport bacteria from the ocean surface into the atmosphere and can scatter light from the sun. Gaining a better understanding of how much these bubbles and sea spray droplets matter to the Earth's climate is important to make accurate future projections of the Earth's climate.To tackle these difficult questions, our research will use state of the art wave making facilities to replicate breaking ocean waves in the laboratory at Imperial College, and will photograph whitecaps in the Adriatic Sea where we have access to a unique ocean observing platform that is operated by the Italian Institute of Marine Science. We will use a combination of wave height gauges, digital cameras and stereovision image processing techniques, to measure wave energy, photograph the breaking wave foam, and count the number and measure the size of bubbles generated by the breaking waves. These data will be used to improve computer models of ocean waves, and predictions of the exchange of gas between the atmosphere and the oceans for use in computer models of Earth's climate.

风不断地将能量从大气层转移到全球海洋，有助于产生表面波浪、洋流和直接从最陡峭波浪的波峰上撕裂的水滴。风与海洋表面的相互作用是一个极其复杂的过程，海洋科学家和工程师仍有待充分理解，并且仍然是一个活跃的研究领域。也许风吹过海洋表面最根本的后果是波浪的产生。我们预测海浪的产生、演变和衰减的能力对于人类与全球海洋的互动方式非常重要。例如，波浪预报通常用于帮助航运公司规划全球海洋上的货物和人员运输，海洋工程师需要知道大波浪发生的频率以及这些波浪将如何与他们建造的海洋结构相互作用，海洋学家需要预测海浪如何影响天气和气候，休闲水手、游泳者和冲浪者依靠准确的海浪预报来安全地享受我们海岸线周围的海洋。海洋学家特别感兴趣的是风和海之间的能量平衡。这波浪。由于风是波浪的主要能量来源，因此必须有一种机制来消散这种能量输入，否则波浪将继续增长。这种能量耗散的一部分发生在我们的海岸线，当传入的波浪进入浅水区时会破裂，释放出能量。这种能量的释放有助于将空气带入水中，移动沉积物和沙子，并产生混乱的湍流水运动。然而，绝大多数波浪能被公海中的波浪破坏而消散。在大风天很容易发现它们，因为它们会产生气泡和白色泡沫，通常称为白浪。这些白浪对地球气候演变的重要性是海洋学家、大气科学家和气候科学家非常感兴趣的领域。每个白帽内都有数千个气泡，其大小从人类头发的宽度到大约 5 便士硬币的宽度不等。这些气泡就像大气的微小复制品，与周围的水交换气体。这种气泡介导的气体转移机制对于有多少二氧化碳从大气转移到海洋非常重要。当每个气泡上升到水面并破裂时，它都会向大气中喷射微小的海浪水滴，就像你从侧面看时看到的一杯苏打水的嘶嘶声一样。当这些微小的水滴在大气中时，它们可以帮助在海洋上形成云，将细菌从海洋表面输送到大气中，并可以散射来自太阳的光。更好地了解这些气泡和海浪飞沫对地球气候的影响对于准确预测未来地球气候非常重要。为了解决这些难题，我们的研究将使用最先进的造浪设施来复制破碎的情况。我们将在帝国理工学院实验室的海浪中拍摄亚得里亚海的白浪，在那里我们可以使用由意大利海洋科学研究所运营的独特海洋观测平台。我们将结合波高计、数码相机和立体视觉图像处理技术，测量波浪能量，拍摄破碎的波浪泡沫，并计算破碎波浪产生的气泡的数量和尺寸。这些数据将用于改进海浪的计算机模型，以及对大气和海洋之间气体交换的预测，以用于地球气候的计算机模型。

项目成果

期刊论文数量（5）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

The influence of bandwidth on the energetics of intermediate to deep water laboratory breaking waves

DOI：
10.1017/jfm.2023.645
发表时间：
2023-09
期刊：
Journal of Fluid Mechanics
影响因子：
3.7
作者：
Rui Cao;E.M. Padilla;A. H. Callaghan
通讯作者：
Rui Cao;E.M. Padilla;A. H. Callaghan

Spatial Interpolation of Wave Fields Based on Limited Spatial Measurements

DOI：
10.1109/joe.2023.3274176
发表时间：
2023-10
期刊：
IEEE Journal of Oceanic Engineering
影响因子：
4.1
作者：
E. Padilla;Rui Cao;A. Callaghan
通讯作者：
E. Padilla;Rui Cao;A. Callaghan

The links between marine plastic litter and the air-sea flux of greenhouse gases

DOI：
10.3389/fmars.2023.1180761
发表时间：
2023-07
期刊：
Frontiers in Marine Science
影响因子：
3.7
作者：
L. Goddijn-Murphy;D. Woolf;R. Pereira;C. Marandino;A. Callaghan;J. Piskozub
通讯作者：
L. Goddijn-Murphy;D. Woolf;R. Pereira;C. Marandino;A. Callaghan;J. Piskozub

On the short-term response of entrained air bubbles in the upper ocean: a case study in the North Adriatic Sea

关于上层海洋夹带气泡的短期响应：北亚得里亚海的案例研究