The Dynamics behind Subinertial Variability along the Southeast Greenland Coast

格陵兰岛东南海岸的海洋环流具有全球意义的气候影响。流经丹麦海峡的稠密海水仍流入北大西洋盆地，形成全球环流，将热量分布到全球各地。此外，来自大西洋盆地深处的温水侵入格陵兰岛沿岸的寒冷峡湾，在那里融化冰川，从而导致全球海平面上升，并可能导致区域海洋环流的变化。这些流的强度以几天为一次的频率变化，这种变化的原因尚不清楚。该项目的主要目标是确定导致这种变化的潜在动力，特别是被称为海岸困波的波浪所起的作用。这项工作揭示了导致这种主要变率模式的原因，将有助于改进气候预测并帮助设计该地区的观测监测项目。这项工作的结果将使物理海洋学家和气候科学家受益，因为它将提供对格陵兰岛关键气候过程变化的基本理解。该项目将支持一名女性早期职业科学家，一名海洋数值模拟研究生的培训，以及通过发展个人研究项目对本科生进行教育。格陵兰东南海岸的中深交换流在全球气候系统中起着关键作用。最近对两个这样的交换流（深丹麦海峡溢流和中深度范围的峡湾-大陆架交换）的观测证据表明，它们都受次惯性变率（数天的时间尺度）的支配。此外，我们的初步结果表明，丹麦海峡溢流和格陵兰东南海岸峡湾-大陆架交换的变化是相互联系的，这使我们建议对它们进行整体研究。尽管次惯性变化在格陵兰东南海岸无处不在，但这些变化的潜在动力尚不清楚。我们假设它们是海岸困波的印记，并将利用现实的高分辨率数值模型模拟和理想化过程研究相结合，综合现有观测结果，研究它们的性质、强迫机制和对交换流的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Oceanic circulation along the southeast Greenland coast has climate impacts of global significance. The spillage of dense water over the Denmark Strait sill into the main North Atlantic basin, contributes to a global circulation that distributes heat over the globe. In addition, warm water from the deep Atlantic basin intrudes into the cold fjords along the Greenland coast, where it melts glaciers and thus contributes to global sea level rise and potentially to changes in the regional ocean circulation. The intensity of these flows varies with a frequency of several days and the cause of this variability is not known. The main goal of this project is to determine the underlying dynamics causing this variability, and specifically the role played by waves known as coastal-trapped waves. Shedding light on what causes this dominant mode of variability, this work will aid to improve climate predictions and help design observational monitoring programs in the region. The results from this work will benefit physical oceanographers and climate scientists, as it will provide a fundamental understanding of variability in key climatic processes operating in Greenland. The project will support a female early career scientist, the training of a graduate student in numerical ocean modeling, and undergraduate student education through the development of individual research projects. Mid-depth and deep exchange flows along the southeast Greenland coast play a key role in the global climate system. Recent observational evidence of two such exchange flows (the deep Denmark Strait Overflow and fjord-shelf exchange in the mid-depth range) suggests that they are both governed by sub-inertial variability (time scale of several days). Furthermore, our preliminary results suggest that variability in the Denmark Strait Overflow and fjord-shelf exchange along the southeast Greenland coast are connected, which leads us to propose that they should be studied holistically. Despite sub-inertial variations being ubiquitous along the southeast Greenland coast, the underlying dynamics of these variations are not clear. We hypothesize that they are the imprint of coastal-trapped waves, and will study their properties, forcing mechanisms and impact on exchange flows using a combination of realistic high-resolution numerical model simulations and idealized process studies, synthesized with existing observations.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.