Collaborative Research: The Dynamics of Near-Surface Velocity Structure in the Coastal Ocean from Observations and Models

这项研究将集中于阐明影响水柱顶部的过程，从大约10米深的空气-水界面。这一层是无法解决的不同技术，用于测量海洋的近表面电流。例如，高频雷达可以分辨水柱的表层，但无法提供底层的信息。另一方面，流速剖面仪往往会错过水面以下的水柱部分。这项研究将试图借助一个数值模型来填补这一差距，该模型解决了海洋上层的流体动力学问题，并考虑到了表面波的影响。 研究亦会探讨表层不同水密度对表层海流的影响。最初的主张是，波浪作用将趋于均匀的垂直分布的近地表电流。该项目将支持一名研究生和一名本科生在缅因州大学的研究机会，并将与美国海岸警卫队学院的学员开展外联活动。该项目将研究沿海海洋上层米的流动动力学，包括表面重力波的影响以及分层和浮力通量对动力学的修正。水柱的这一部分很少被观测到，并且仅限于短时间内，这使得很难区分风和波浪对水流速度剖面的影响。该研究的方法是将现有的高频雷达测量与向上看的电流剖面仪配对，并将速度剖面与具有不同湍流参数化和垂直分层的一维数值模型（GOTM）结果进行比较。PI提出，波浪破碎和朗缪尔湍流将倾向于均匀化速度剖面中的垂直梯度，以及与斯托克斯-科里奥利机制相关的欧拉流。在生物指示剂方面，除了科学价值外，该提案还将为模型中波浪驱动的近地表过程和粒子轨迹研究提供参数化。该研究将支持缅因州大学的研究生和本科生的研究机会，并将与USCG学院学员一起开展外展活动。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

This study will concentrate on elucidating the processes that influence the top part of the water column, from about 10 m depth to the air-water interface. This layer is unresolved by different techniques that are used to measure ocean’s near-surface currents. For example, high-frequency radars resolve the skin of the water column but provides no information underneath. On the other hand, current velocity profilers tend to miss the portion of the water column right underneath the surface. This study will attempt to fill in the gap with the help of a numerical model that resolves the hydrodynamics of the upper-ocean layer and that considers the effects of surface waves. The study will also investigate the influence on surface currents of different water densities within the surface layer. The initial proposition is that wave action will tend to homogenize the vertical distribution of near-surface currents. The project will support one graduate student and undergraduate research opportunities at University of Maine, and will develop outreach activities with US Coast Guard Academy cadets.The proposal will study the dynamics of flows in the upper meters of the coastal ocean, including the influence of surface gravity waves and the modification to the dynamics by stratification and buoyancy fluxes. This portion of the water column is rarely observed and limited to short periods, which makes it difficult to distinguish the effects of winds and waves on water velocity profiles. The approach of the study will be to pair existing HF-radar measurements with upward-looking current profilers, and compare the velocity profiles to 1D numerical model (GOTM) results with distinct turbulence parametrizations and vertical stratification. The PIs propose that wave breaking and Langmuir turbulence will tend to homogenize vertical gradients in the velocity profile, together with an Eulerian flow related to the Stokes-Coriolis mechanism. In terms of BI, beyond the scientific merit, the proposal would provide parametrizations of near-surface processes driven by waves in models and for particle trajectory studies. The study would support a graduate student and undergraduate research opportunities at University of Maine, and will develop outreach activities with USCG Academy cadets.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.