Experiments on the interaction of Large-Scale Oceanic Oirculation with Eddies, Jets and Internal Waves using Optical Altimetry

这是对海洋环流及其小尺度但能量大的成分的实验研究。将利用一种新发现的实验室遥感技术-我们称之为光学测高法-研究环流与涡流、内波和类似喷流的气流集中的相互作用。副极地北大西洋的环流是特别关注的焦点。在那里，已经确定了几个外部环流来源（风、深对流和来自南北方向的洋流入侵）。将利用具有显著海底地形特征的理想化海洋盆地，在详细的动力学实验中评估大气环流的一个内部来源，即位涡场的涡流搅动。将使用分层的流体静力学海洋模型进行平行的数值试验。计划进行的具体实验是：㈠将大气环流集中成急流和锋面，并与定常流相互作用于海底地形; ㈡在一片复杂的海底脊和海山上，由准地转、时变流驱动的大规模环流; ㈢涡旋地形与密度分层的相互作用，包括斜压不稳定沿岸流的生命周期; ㈣内波和对流与分层的，gesotrophic流相互作用。光学测高利用旋转流体表面的抛物线形状作为牛顿望远镜，允许整个表面高程场以优于1微米的分辨率和高横向分辨率成像。通过在表面上投影彩虹图像，我们恢复准确的高度，速度和涡度场。分层实验将使用内层厚度传感，也是光学的。第四组实验需要特别评论。这些高纬度海洋的数值模拟很少包含非流体静力学，非地转动力学，在这一领域的三维实验室实验可以有令人印象深刻的空间分辨率。利用我们新的实验能力，可以探索盆地尺度环流与内波、锋面、对流和三维湍流之间的来回相互作用。所有这些都在副极地海洋中很强大。当水流穿过显著的海底地形时，水力“下坡射流”的形成，以及它们与中尺度气旋涡流生成的相互作用将被研究;内波辐射和孤立涡流和涡流组合的捕获将被探索，以及边界层湍流和地转流之间能量的来回转换。位涡动力学是海洋和大气环流的基础场论。它表达了涡动活动和大气环流之间强有力的关系。发展和利用这种“光伏思维”是重要的基础科学，并作为支持全球气候模型的重要模拟，这不能解决所有详细的高纬度过程控制的光伏field.Broader影响：了解海洋气候系统是至关重要的更大的全球变暖的问题，其减缓全球海洋环流的预测效果。大多数气候模型在温室气体不断增加的情况下运行，发现在本世纪，大西洋南北翻转的速度减缓了40%。如果仔细观察，亚极地大西洋的动态是这种影响的关键组成部分。横向涡旋环流与全球纬向翻转环流相互作用。除了气候研究，这项关于基本PV动力学的工作影响了我们对大气环流和其他行星大气的理解。它与全球变暖下地球生态系统的命运有着密切的关系。

ABSTRACTOCE-0648575This is an experimental investigation of the oceanic circulation and its small-scale, yet energetic, components. Using a newly discovered laboratory remote-sensing technique which we call optical altimetry, the interaction of the circulation with eddies, internal waves and jet-like concentrations of flow will be studied. The circulation of the subpolar North Atlantic Ocean is the particular focus. There, several external sources of circulation have been identified (wind, deep convection, and incursion of currents from north and south). An internal source of general circulation, the eddy stirring of the potential vorticity (PV) field, will be evaluated in detailed dynamics experiments using idealized ocean basins with significant bottom topographic features. Parallel numerical experiments will be carried out using a layered, hydrostatic ocean model. The specific experiments planned are (i), the concentration of general circulation into jets and fronts with steady flow interacting bottom topography, (ii), large-scale circulation driven by quasi-geostrophic, time-variable flow over a field of complex seafloor ridges and seamounts, (iii), eddy-topography interaction with density stratification including the life-cycle of a baroclinically unstable coastal current and, (iv), internal waves and convection interacting with stratified, gesotrophic flows. Optical altimetry exploits the parabolic shape of the surface of a rotating fluid as a Newtonian telescope, allowing the entire surface elevation field to be imaged with better than 1 micron resolution, and high lateral resolution. By projecting a rainbow image on the surface, we recover accurate elevation, velocity and vorticity fields. Stratified experiments will use interior layer thickness sensing, also optically. The fourth set of experiments requires special comment. Numerical modeling of these high latitude oceans rarely incorporates non-hydrostatic, non-geostrophic dynamics, and in this area 3-dimensional lab experiments can have impressive spatial resolution. With our new experimental capability the back-and-forth interaction among basin-scale circulation and internal waves, fronts, convection and 3-dimensional turbulence can be explored. All are known to be strong in the subpolar oceans. Hydraulic 'down-slope jets' form as flow crosses significant bottom topography, and their interaction with mesoscale cyclonic eddy generation will be investigated; internal wave radiation and trapping by isolated vortices and vortex assemblages will be explored, as will the back-and-forth conversion of energy between boundary-layer turbulence and geostrophic flow.Intellectual Merit: Potential vorticity dynamics is the key, underlying field theory of thecirculation of oceans and atmosphere. It expresses powerful relationships between eddy activity and general circulation. Developing and exploiting this 'PV thinking' is important both as basic science, and as support for important simulations of global climate models, which cannot resolve all the detailed high-latitude processes which control the PV field.Broader impacts: Understanding the ocean climate system is of key importance to the largerproblem of global warming and its predicted effect in slowing the global ocean circulation. Most climate models run with increasing greenhouse gases find a slowing of the Atlantic meridional overturning, by as much as 40%, during this century. If one looks closely, the dynamics of the subpolar Atlantic is a crucial component of this effect. There is interaction of lateral gyre circulations interact with the global meridional overturning circulation. Beyond climate research, this work on basic PV dynamics impacts our understanding of circulations of the atmosphere, and the atmospheres of other planets. It has strong relationships with the fate of Earth's ecosystems under global warming.