Interaction of Oceanic Vortices with Steep Topography

不规则的地形是一个普遍的海洋特征，表现为海底的形状、沿着海岸线以及连接海岸和深渊的大陆架和斜坡。在地形附近经常观察到类似急流的强海流，其变异性很大，混合作用增强，这意味着大陆架和大陆坡、海脊和海山对海洋动力有很强的影响。过去的研究表明，涡地形相互作用的复杂性，其中小尺度的涡往往会产生，也就是说，地形催化在中尺度领域的前向级联，并可能提供重要的路线disulsified.The相互作用的海洋涡与大陆架和斜坡是一个更普遍的问题，在一个可变的介质中的波涡相互作用的一个方面。在海洋环境中的一个关键参数是陆架宽度与涡旋大小的比率，这一比率通常很小。为了发展适当的数学模型，并澄清基本的物理机制，我们提出了一个深入的调查，在封闭的陡峭地形附近的强涡旋的演变。由于一个陡峭的大陆坡附近的深水一侧的陆架坡折带的海洋动力学的适当的描述需要斜压效应考虑在内，我们将使用一个新的两层数值模式在深海区匹配正压模式在浅水区，海洋深度小于界面深度。正压斜压模式的这种组合捕捉当前的变化在沿岸的区，这仍然是目前相对unexplored.Previous研究表明，在大陆架平流的陆架水与高位涡进入公海的结果在强烈的初级涡周围的涡面的发展最基本的元素。随后卷起成较小尺度的气旋涡将研究数值使用我们的数值模型和轮廓动力学方法，可以预期一起捕捉基本的动力学过程。我们的研究结果将与其他数值模拟和观测数据的相关参数的范围进行比较。我们的总体目标是深入了解涡架相互作用的过程，这可以提供一个足够的描述的变化和混合附近封闭的地形。

Irregular topography is a prevalent ocean feature, appearing in the shape of the ocean bottom, along the coastline, and on the shelves and slopes that connect the coast to the deep abyss. Strong jet-like currents, with considerable variability and enhanced mixing, are often observed near topography, implying that the continental shelves and slopes, ridges and seamounts exert a strong dynamical oceanic influence. Past studies have illustrated the complicated nature of vortex-topography interaction in which smaller-scale vortices are often produced; that is, topography catalyzes a forward cascade in the mesoscale fields and may provide important routes to dissipation.The interaction of an ocean vortex with the continental shelf and slope is one aspect of a more general problem about wave-vortex interactions in a variable medium. A crucial parameter in the oceanic context is the ratio of the shelf width to the vortex size, which is typically small. In order to develop adequate mathematical models, and to clarify the basic physical mechanisms, we propose a thorough investigation of the evolution of a strong vortex in the vicinity of confined steep topography. Since a proper description of ocean dynamics over a steep continental slope adjacent to the deep-water side of a shelf-break requires baroclinic effects to be taken into account, we will use a novel two-layer numerical model in the deep area matched with a barotropic model in the shallow area, where the ocean depth is smaller than the interface depth. Such a combination of barotropic-baroclinic models captures the most essential elements of current variability in the littoral zone, which remain presently relatively unexplored.Previous studies have indicated that the on-shelf advection of shelf water with high potential vorticity into the open ocean results in the development of a vortex sheet around the intense primary eddy. The subsequent rolling-up into smaller-scale cyclonic vortices will be studied numerically using both our numerical model and contour dynamics methods which together can be expected to capture the essential dynamical processes. The results of our study will be compared with other numerical simulations and observational data for a range of the relevant parameters. Our general aim is to obtain a deep understanding of the process of vortex-shelf interaction, which can provide an adequate description of variability and mixing near confined topography.