Toward a more complete understanding of coastal upwelling dynamics

更全面地了解沿海上升流动力学

• 批准号: 2343008
• 负责人: Xiaozhou Ruan
• 金额: $ 47.89万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-07-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2343008&HistoricalAwards=false
• 关键词: Toward; more; complete; understanding; coastal

This study will explore the widespread ocean phenomenon of coastal upwelling, in which nutrient-rich water is pumped toward the surface mainly by wind forcing on the sea surface. This phenomenon has pivotal influence on the appearance of fisheries in different parts of the world. The study will use mathematical models that represent idealized conditions for upwelling over a sloping continental shelf. Despite the idealizations, the models will add three-dimensionality aspects and dynamical effects caused by different water densities, i.e., by buoyancy. Results will be cast in a framework that includes the slope of the continental shelf, buoyancy effects and Earth’s rotation influence. As broader impacts, the study is expected to improve understanding on a process that affects dissolved and suspended materials near the coast. It also will train a postdoctoral scholar, a graduate student, and two undergraduate students. The proposal will explore three-dimensional pathways for coastal upwelling under vertically stratified ocean conditions. The study will use a series of idealized 3D numerical simulations, contrasting the customary 2D descriptions associated with Ekman dynamics. Simulations will be placed in a holistic framework that accounts for the interactions among wind-driven circulation, (sub)mesoscale turbulence, and boundary layer processes. Thus, simulations will address the coupling between surface and bottom boundary layers through a framework based on the slope Burger number, which compares buoyancy and Coriolis frequencies. The Burger number is expected to diagnose whether the onshore flow is along the bottom or in the interior of the water column. A particularity of this study, in addition to examining three-dimensional structures, is the assessment of the role of baroclinic instability in shaping the upwelling structure via eddy stirring along isopycnals. As broader impacts, this study will contribute advanced understanding of coastal upwelling, which affects dissolved and suspended matter. Also, the study will support one postdoctoral scholar, and train one graduate and two undergraduate students.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.

本研究将探讨广泛存在的沿海上升流现象，这种现象主要是通过海面的风力将富含营养的水输送到海面，这种现象对世界不同地区的渔业状况具有至关重要的影响。将使用代表倾斜大陆架上涌的理想化条件的数学模型，尽管有理想化，但该模型将添加由不同水密度（即由不同水密度）引起的三维方面和动力效应。研究结果将纳入一个框架，其中包括大陆架坡度、浮力效应和地球自转影响。作为更广泛的影响，这项研究预计将提高对影响海岸附近溶解和悬浮物质的过程的理解。该项目还将培养一名博士后学者、一名研究生和两名本科生。该研究将使用一系列理想化的 3D 数值模拟来探索垂直分层海洋条件下的沿海上升流。与埃克曼放置动力学相关的常规二维描述将在一个整体框架中进行，该框架考虑了风驱动环流、（亚）中尺度湍流和边界层过程之间的相互作用，因此，模拟将解决表面和底部边界之间的耦合问题。通过基于坡度伯格数的框架进行分层，该伯格数比较浮力和科里奥利频率，预计可以诊断陆上水流是沿着底部还是在水柱内部。除了检查三维结构之外，这项研究还评估了斜压不稳定性通过沿着等密度线的涡流搅拌塑造上升流结构的作用。作为更广泛的影响，这项研究将有助于对沿海上升流的深入了解，这会影响溶解和溶解。此外，该研究还将支持一名博士后学者，并培养一名研究生和两名本科生。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，认为值得支持。