Collaborative Research: Characteristics and Origins of Eddies beneath Antarctic Sea Ice

合作研究：南极海冰下涡流的特征和起源

• 批准号: 2220968
• 负责人: Andrew Stewart
• 金额: $ 43.28万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2220968&HistoricalAwards=false
• 关键词: Collaborative; Research; Characteristics; Origins; Eddies

The world ocean is continuously in motion, and a large fraction of this motion takes the form of "eddies", nearly-horizontal swirls of water spanning tens to hundreds of kilometers. These eddies affect the ocean by mediating large-scale currents, redistributing heat, and supplying nutrients to oceanic ecosystems. Consequently, the ocean science community has historically invested substantial effort in characterizing the properties and impact of these eddies. In polar regions, the sea ice cover inhibits observations of eddies, and the relatively small horizontal size of the eddies hampers computer simulations of their behavior. Nonetheless, previous studies have identified an active population of eddies beneath the Arctic sea ice and shown that these eddies play a crucial role in maintaining the large-scale circulation in the Arctic seas. However, there has been no systematic attempt to study such eddies under Antarctic sea ice, leaving a significant gap in our understanding of eddies and their contribution to the large-scale ocean circulation around Antarctica.The proposed research combines multiple approaches to improve our understanding of the eddy dynamics. Statistical characterizations of the sub-sea ice eddy field will be derived using hydrographic observations under Antarctic sea ice from Argo floats and instrumented seals. High-resolution global ocean and sea ice models will be used to track the simulated eddies back to their formation sites to identify the eddy formation mechanisms. Theoretical calculations will be conducted to test the hypothesis that the eddies primarily originate from hydrodynamic instabilities associated with subsurface density gradients. These theoretical, modeling, and data analysis approaches will be combined to estimate the eddies' contribution to lateral tracer transports and their impact on mean circulations of the near-Antarctic ocean. The proposed work will facilitate future scientific endeavors by providing publicly-available databases of detected eddy properties. This project will support the research of several junior scientists: an undergraduate student, two graduate students, and an early-career faculty member.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.

世界海洋不断运动，其中很大一部分运动以“涡流”的形式出现，即跨越数十至数百公里的近水平水漩涡。这些涡流通过调节大规模洋流、重新分配热量以及向海洋生态系统提供营养来影响海洋。因此，海洋科学界历来投入了大量精力来描述这些涡流的特性和影响。在极地地区，海冰覆盖阻碍了对涡流的观测，并且涡流相对较小的水平尺寸阻碍了对其行为的计算机模拟。尽管如此，之前的研究已经发现北极海冰下存在活跃的涡流群，并表明这些涡流在维持北冰洋大范围环流方面发挥着至关重要的作用。然而，目前还没有系统地尝试研究南极海冰下的此类涡流，这使得我们对涡流及其对南极洲周围大规模海洋环流的贡献的理解存在很大差距。这项研究结合了多种方法来提高我们对涡流动力学的理解。海底冰涡场的统计特征将通过 Argo 浮标和仪器化海豹对南极海冰下的水文观测得出。高分辨率全球海洋和海冰模型将用于跟踪模拟涡流回到其形成地点，以确定涡流形成机制。将进行理论计算来检验涡流主要源于与地下密度梯度相关的流体动力学不稳定性的假设。这些理论、建模和数据分析方法将结合起来，以估计涡流对横向示踪剂传输的贡献及其对近南极海洋平均环流的影响。拟议的工作将通过提供检测到的涡流特性的公开数据库来促进未来的科学努力。该项目将支持几位初级科学家的研究：一名本科生、两名研究生和一名职业生涯早期的教员。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。