Submesoscale frontal dynamics

亚尺度锋面动力学

• 批准号: 2882548
• 金额: --
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2882548
• 关键词: Submesoscale; frontal; dynamics

Ocean fronts develop where waters with different temperature and salinity meet. Fronts, which include large-scale current systems such as the Gulf Stream and smaller ephemeral features, are ubiquitous in the upper ocean. Fronts are extremely energetic and dynamic environments with important influences on the local biology and the global carbon cycle. By definition, fronts are places where density surfaces, or isopycnals, outcrop from the ocean's stratified interior. Recent evidence indicates that these outcropping isopycnals provide a pathway that allows direct and rapid transfer of important tracers such as dissolved carbon, oxygen, and nutrients between the ocean surface and interior. The rate of exchange of water between the ocean surface and interior in turn affects the ability of the ocean to mediate changes in the earth's climate. Despite their global significance, many fundamental questions about fronts remain unanswered. Why are fronts often much more biologically productive than surrounding areas? How do fronts modify the intensity of turbulent mixing? What physical processes balance the convergent surface flow at fronts, ultimately determining their width and strength?For this project, the student will use a combination of numerical simulations, mathematical theory, and field data to answer these important problems. Based on available hydrographic sections taken across several ocean fronts, we will identify important parameters including the density contrast, mixed layer depth, and vertical extent of the front. We will then build and analyse a suite of numerical simulations to study the evolution of fronts in different parameter ranges. A linear stability analysis will allow us to identify the disturbances that eventually develop into frontal eddies. Finally, we will compare our results with existing and new observational data. We will adapt the approach based on the results and the interests of the student and the project will have scope for open exploration of the topic.

不同温度和盐度的沃茨交汇处形成海洋锋。锋面，包括大规模的电流系统，如墨西哥湾流和较小的短暂功能，是无处不在的上层海洋。锋面是一种非常活跃和动态的环境，对当地生物和全球碳循环有重要影响。根据定义，锋面是密度面或等密度线从海洋分层内部露出的地方。最近的证据表明，这些出露的等密度带提供了一个途径，允许重要的示踪剂，如溶解的碳，氧和营养物质之间的海洋表面和内部的直接和快速的转移。海洋表面和内部之间的水交换率反过来又影响海洋调节地球气候变化的能力。尽管它们具有全球意义，但关于前线的许多基本问题仍然没有答案。为什么前线的生物生产力往往比周边地区高得多？锋面如何改变湍流混合的强度？什么物理过程平衡了锋面的会聚表面流，最终决定了它们的宽度和强度？对于这个项目，学生将使用数值模拟，数学理论和现场数据的组合来回答这些重要的问题。根据现有的水文截面采取了几个海洋锋，我们将确定重要的参数，包括密度对比，混合层深度，和垂直范围的前。然后，我们将建立和分析一套数值模拟，以研究在不同的参数范围内的前锋的演变。线性稳定性分析将使我们能够识别最终发展成锋面涡的扰动。最后，我们将我们的结果与现有的和新的观测数据进行比较。我们将根据结果和学生的兴趣来调整方法，该项目将有机会对该主题进行开放式探索。