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: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=613146
• 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.

所有自然产生的流体都是分层的，这意味着它们的有效密度随着高度的增加而减小。这种下降可能是快速且局部的，例如海洋温跃层或大气逆温层。或者它可以是渐进的，就像在平流层一样。在这种分层流体中传播的是内波，其由于浮力而移动。由于波浪输送能量和动量并在破碎处引起湍流，因此对气候、环境、空中交通、渔业、海上石油和其他行业产生重要影响。然而，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方向，我建议进行实验室实验和数值模拟，以开发大气和海洋内波包的演化和分解的预测模型。 我将发展由模拟补充的理论，以检查对局部小振幅波包引起的流动的响应。我最近证明，在不破裂的情况下，垂直传播的波包会发射长的内波，从而在较宽的水平范围内重新分配波包的动量。  气候模型使用启发式方法来预测内波的动量传输，但没有考虑到这种效应，因此错误地预测了破碎区域的空间范围。  包括大振幅效应，我将研究诱发的长波对波包本身演化的影响，并将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型中内波的表示。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传输，目的是更好地了解海洋温跃层污染物和营养物的横向扩散。另一个研究方向将检查由于参数次谐波不稳定性（PSI）导致的厚界面处的内部波包的击穿，这种机制以前仅针对周期波进行了检查，最近针对波束进行了检查。这种对 PSI 造成的波包分解的更真实的检查将提供从大到小尺度的能量级联的洞察，该结果将用于海洋环流模型中使用的混合参数化方案。第三个研究方向将进行实验室实验和模拟，以研究大幅度界面内波在复杂地形上浅滩时的演变，重点是能量重新分配、沉积物再悬浮和床质输送。这项工作将用于评估与沿海底运行的海上石油平台和管道的开发和维护相关的危害。