NSFGEO-NERC: Energy transfer between submesoscale vortices and resonantly-forced inertial motions in the northern Gulf of Mexico

亚中尺度流动和近惯性运动是上层海洋普遍存在的特征。最近发展的理论认为，亚中尺度流和近惯性运动的相互作用可能在关闭平衡环流和不平衡波的能量收支方面发挥重要作用。由于在相对受控的环境中观察两种类型的运动的挑战，这些理论尚未在该领域得到充分的测试。墨西哥湾的北方是一个天然的实验室，是理想的这样做。在这里，密西西比-阿查法拉亚河羽流形成了一个丰富的亚中尺度漩涡和锋面，在夏季，中尺度涡旋由陆海风驱动，迫使惯性运动接近共振。拟议的研究将包括利用新的观测技术进行密集的实地活动，这些技术将与理想化和现实的数值模拟紧密结合，以研究亚中尺度涡旋和近中尺度涡旋的相互作用。密西西比-阿查法拉亚河羽流的惯性运动。目标是描述、量化和理解平衡和不平衡运动之间的能量交换以及相互作用可能导致的湍流级联。更具体地说，将设计数值和观测实验来检验锋面惯性运动引起的等密度线的周期性应变、低位涡水的俯冲以及等密度线的传播、捕获、近的，近的。惯性波与次中尺度涡旋的相互作用促进了能量交换，并导致整个水柱的混合增强。拟议的研究解决了一个突出的问题，在物理海洋学中，平衡环流中的动能是如何消散的，特别是通过波浪-平均流的相互作用。这个问题已经研究大多是理论上的理想化的流动配置，但它还没有被探索在一个受控的设置，如这里提出的观测。该研究将把观测与亚中尺度分辨模拟和大涡模拟相结合，这种结合已被证明在理解复杂的多尺度观测流的基础物理学方面是有效的。

Submesoscale flows and near-inertial motions are ubiquitous features of the upper ocean. Recently developed theories have posited that the interaction of submesoscale flows and near-inertial motions could play an important role in closing the energy budgets of both the balanced circulation and the unbalanced waves. These theories have yet to be fully tested in the field due to the challenges of observing both types of motions in a relatively controlled setting. The northern Gulf of Mexico is a natural laboratory that is ideal for doing this. Here, the Mississippi-Atchafalaya river plume forms a rich field of submesoscale eddies and fronts, which in the summer are driven by a land-sea breeze that forces inertial motions at near resonance.The proposed research will involve intensive field campaigns utilizing novel observational techniques that will be closely integrated with idealized and realistic numerical simulations to study the interaction of submesoscale eddies and near-inertial motions in the Mississippi-Atchafalaya river plume. The objective will be to characterize, quantify, and understand the energy exchanges between balanced and unbalanced motions and the turbulent cascade that can result from the interaction. More specifically, the numerical and observational experiments will be designed to test the hypotheses that periodic straining of isopycnals by inertial motions in fronts, subduction of low potential vorticity water, and the propagation, trapping, and reflection of near-inertial waves interacting with submesoscale eddies facilitate the energy exchange and result in enhanced mixing throughout the water column.The proposed research tackles one of the outstanding questions in physical oceanography of how the kinetic energy in the balanced circulation is dissipated, in particular through wave-mean flow interactions. This question has been studied mostly theoretically for idealized flow configurations, but it has not been explored observationally in a controlled setting, as proposed here. The research will integrate observations with submesoscale-resolving simulations and large-eddy simulations, a combination that has proven to be effective in understanding the fundamental physics of complex, multi- scale observed flows.