Environmental, Industrial and Climatological Impacts of Internal Gravity Waves

内重力波对环境、工业和气候的影响

• 批准号: RGPIN-2015-04758
• 负责人: Sutherland, Bruce
• 金额: $ 5.13万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=691588
• 关键词: Environmental; Industrial; Climatological; Impacts; Internal

All naturally occurring fluids are stratified, meaning that their effective density decreases with height. The decrease can be rapid and localized, as at a thermocline in the ocean or at an atmospheric inversion. Or it can be gradual, as in the stratosphere. Propagating within such stratified fluids are internal waves, which move due to buoyancy forces. Because they transport energy and momentum and cause turbulence where they break, the waves have important consequences for climate, environment, air traffic, fisheries, offshore oil and other industries. However, relatively little is known about the dynamics of localized internal waves. Through three interrelated research streams, I propose to perform laboratory experiments and numerical simulations to develop predictive models for the evolution and breakdown of atmospheric and oceanic internal wave packets.***I will develop theory complemented by simulations to examine the response to flows induced by localized small amplitude wave packets. I have recently shown that, without breaking, vertically propagating wave packets launch long internal waves that redistribute the momentum of the packet over a wide horizontal extent.  Climate models, which use heuristics to predict momentum transport by internal waves, do not account for this effect and so incorrectly predict the spatial extent of the breaking region.  Including large-amplitude effects, I will examine the influence of the induced long waves upon the evolution of the wave packets themselves and will predict where winds are accelerated when two- and three-dimensional wavepackets ultimately break in the atmosphere.  This work will be applied to improve the representation of internal waves in climate models. I will also use this theoretical approach to predict mass transport by localized internal waves at a thick interface, with the intent of obtaining a better understanding of the lateral dispersion of pollutants and nutrients about the oceanic thermocline. Another research stream will examine the breakdown of internal wave packets at thick interfaces due to parametric subharmonic instability (PSI), a mechanism that has previously been examined only for periodic waves and more recently for wave beams. This more realistic examination of wave packet breakdown due to PSI will provide insight into the energy cascade from large to small scales, a result that will be cast for use in mixing parameterization schemes used in ocean general circulation models. A third research stream will perform laboratory experiments and simulations to examine the evolution of large amplitude interfacial internal waves as they shoal upon complex topography, with a focus upon energy redistribution, sediment resuspension and bedload transport. This work will be applied to assess hazards associated with the development and maintenance of offshore oil platforms and pipelines that run along the ocean floor.**

所有天然存在的流体都是分层的，这意味着它们的有效密度随高度而降低。这种减少可能是迅速和局部的，如在海洋中的温跃层或在大气逆温中。也可以是渐进的，就像在平流层一样。在这种分层流体中传播的是由于浮力而移动的内波。由于它们会输送能量和动量，并在破裂时引起湍流，因此海浪对气候、环境、空中交通、渔业、海上石油和其他行业都有重要影响。然而，相对而言，人们对局域内波的动力学知之甚少。通过三个相互关联的研究流，我建议进行实验室实验和数值模拟，以建立大气和海洋内波包的演变和分解的预测模型。***我将发展理论并辅以模拟来检验局部小振幅波包引起的流的响应。我最近的研究表明，在不破裂的情况下，垂直传播的波包会发射很长的内波，在很大的水平范围内重新分配包的动量。使用启发式方法预测内波动量输运的气候模式没有考虑到这种影响，因此错误地预测了破碎区域的空间范围。包括大振幅效应在内，我将研究诱导长波对波包本身演变的影响，并预测当二维和三维波包最终在大气中破裂时，风在哪里加速。这项工作将用于改善气候模式中内波的表示。我还将使用这种理论方法来预测厚界面处局部内波的质量输运，目的是更好地了解海洋温跃层中污染物和营养物质的横向扩散。另一项研究将研究由于参数次谐波不稳定性（PSI）而导致的厚界面内波包的分解，这种机制以前只研究过周期波，最近研究过波束。这种对由PSI引起的波包破裂的更现实的检查将提供从大尺度到小尺度的能量级联的见解，该结果将用于海洋环流模型中使用的混合参数化方案。第三个研究流将进行实验室实验和模拟，以检查大振幅界面内波在复杂地形上的演变，重点是能量再分配、沉积物再悬浮和床质运输。这项工作将用于评估与开发和维护海上石油平台和沿海底运行的管道有关的危害