Collaborative Research: Exchange and Dispersion Across the Inner Shelf: Understanding the Importance of Spatial Variability

本研究旨在了解大陆架内部流场在数百米至数十公里尺度上的空间变异性，其对交换和弥散的贡献，及其对沿海系统的影响。最近对玛莎葡萄园岛以南沿海海洋的观测记录了令人吃惊的空间变化流的例子，这些流动有可能推动大陆架上集中的横向交换，这与经常检查的沿大陆架对上升流或下升流的均匀响应相媲美。然而，我们对这些尺度下的流场特征几乎一无所知，因为传统的观测技术和典型的现实大陆架模型不能充分解决这些尺度。这可能是第一次在100米到几十公里的尺度上对沿海海洋的洋流变化进行全面研究，方法是采用高分辨率高频雷达表面洋流、对地下速度和水文的密集观测以及大量漂流物释放的独特组合，并与现实和理想的数值模型进行比较。拟议的工作将量化横跨大陆架的水团总通量，风、分层和测深对交换的空间变异性的相对重要性，以及空间变量弥散的作用。以前量化沿海海洋交换率的努力通常集中在由于沿大陆架均匀的风驱动动力学而引起的运输上。虽然在大多数沿海地区发现了主要海角或海岬、测深不规则或不均匀风场造成的额外运输的证据，但这些变异性来源对大陆架交换和分散的相对影响尚未量化。此外，小规模和/或瞬态特征的影响，可能是依赖于空间的交换或分散的重要来源，从未得到解决。这种对玛莎葡萄园岛以南沿海海洋交换的综合看法，包括使用拉格朗日轨迹分析以及基于欧拉的运输研究，将能够捕获更广泛的空间变异性，并将量化瞬态事件的发生、驱动因素及其对沿海系统的重要性。从靠近海岸的浅水区向近海较大的沿海海洋的水团运动控制了近岸和全球海洋之间的热、盐、营养物质和污染物的流动。通过提供跨大陆架运输的整体视角，这项工作的结果将记录空间变异性对沿海系统的潜在影响。这一努力将提高我们量化和预测交换的能力，这对评估沿海地区的生产力至关重要，对监测有害藻华、污染物的命运以及搜索和救援行动至关重要。pi积极参与WHOI和马萨诸塞大学达特茅斯分校的教学和指导工作，并与沿海管理人员和规划人员进行互动。在与NOAA东北渔业科学中心的合作下，一项广泛的教育计划将引导该地区的K-12学生了解通过额外的漂流船部署进行的科学研究

This study seeks to understand spatial variability in the flow field over the inner part of the continental shelf at scales of 100s of meters to 10s of kilometers, its contribution to exchange and dispersion, and its implications for coastal systems. Recent observations of the coastal ocean south of Martha's Vineyard, MA have documented startling examples of spatially-variable flows with the potential to drive focused lateral exchange across the shelf rivaling that due to the frequently-examined along-shelf uniform response to upwelling or downwelling. Yet, we know almost nothing about the characteristics of the flow field at these scales because conventional observational techniques and typical realistic shelf models do not adequately resolve these scales. This will likely be the first comprehensive study of current variability in the coastal ocean at scales from 100s of meters to 10s of kilometers by employing a unique combination of high-resolution HF radar surface currents, dense observations of subsurface velocity and hydrography, and mass drifter releases along with comparisons to realistic and idealized numerical models. The proposed work will quantify the total flux of water masses across the shelf, the relative importance of spatial variability in the wind, stratification, and bathymetry on exchange, and the role of spatially-variable dispersion.Previous efforts to quantify the rates of exchange in the coastal ocean have generally focused on the transport due to along-shelf uniform, wind-driven dynamics. While evidence of additional transport due to major capes or headlands, bathymetric irregularities, or non-uniform wind fields has been found in most coastal areas, the relative impact of these sources of variability on exchange and dispersion across the shelf have not been quantified. Additionally, the effects of small-scale and/or transient features, potentially important sources of spatially-dependent exchange or dispersion, have never been resolved. This comprehensive view of exchange across the coastal ocean south of Martha's Vineyard, including the use of Lagrangian trajectory analyses in addition to the Eulerian-based transport studies, will enable a much broader range of spatial variability to be captured and will quantify the occurrence of transient events, their drivers, and their importance for coastal systems.The movement of water masses from the shallow waters adjacent to the coast to the larger coastal ocean offshore controls the flux of heat, salt, nutrients, and pollutants between the nearshore and the global ocean. By providing a holistic look at across-shelf transport, the results of this work will document the potential effects of spatial variability on coastal systems. This effort will improve our ability to quantify and predict the exchange critical to assessing the productivity of coastal areas and the dispersion rates critical to monitoring the fate of harmful algal blooms, pollutants, and search and rescue operations. The PIs are actively involved in teaching and mentoring at WHOI and UMASS Dartmouth as well as interacting with coastal managers and planners. In collaboration with the NOAA's Northeast Fisheries Science Center, a broad educational program will entrain K-12 students in the region into the science being conducted through additional drifter deployments