Weddell Gyre Mean Circulation and Eddy Statistics from Floats

威德尔环流平均环流和浮体涡流统计

• 批准号: 2148517
• 负责人: Cathrine Hancock
• 金额: $ 41.39万
• 依托单位: Florida State University
• 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: 2022-03-15 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2148517&HistoricalAwards=false
• 关键词: Weddell; Gyre; Mean; Circulation; Eddy

The Weddell Gyre is one of the major components of the Southern Ocean circulation system, linking heat and carbon fluxes in the Antarctic Circumpolar Current to the continental margins. Water masses entering the Weddell Gyre are modified as they move in a great circular route around the gyre margin and change through processes involving air-sea-cryosphere interactions as well as through ocean eddies that mix properties across the gyre boundaries. Some of the denser water masses exit the gyre through pathways along the northern boundary, and ultimately ventilate the global deep ocean as Antarctic Bottom Water. While in-situ and satellite observations, as well as computer modeling efforts, provide estimates of the large-scale average flow within the gyre, details of the smaller-scale, or "mesoscale" eddy flow remain elusive. The proposed research will quantify mixing due to mesoscale eddies within the Weddell Gyre, as well as the transport of incoming deep water from the northeast, thought to be a result of transient eddies. Since the Weddell Gyre produces source water for about 40% of Antarctic Bottom Water formation, understanding the dynamics in this region helps to identify causes of documented changes in global bottom waters. This in turn, will give insight into how climate change is affecting global oceans, through modification of dense polar waters and Antarctic Bottom Water characteristics. This project aims to track 153 RAFOS-enabled Argo floats in the ice-covered regions of the Weddell Gyre. The resultant tracks along with all available Argo and earlier float data will be used to calculate Eulerian and Lagrangian means and eddy statistics for the Weddell Gyre. The study will link RAFOS tracks with Argo profiles under ice, allowing one to characterize the importance of eddies in water column modification at critical ice-edge boundaries and leads. With RAFOS tracks near the northeastern limit of the gyre, the project will investigate the eddy-driven processes of incoming Circumpolar Deep Water, to understand better the mechanisms and volume fluxes involved. Previous work shows that a large fraction of the mean circulation in the southern and western limits of the gyre, where it contacts the Antarctic continent, occurs in a narrow boundary layer above the slope. The research here will integrate this flow structure into a complete interior and boundary layer mean circulation synthesis. The findings and products from the proposed work will improve the positioning of Argo profiles in the polar regions, which would allow for more accurate climatological maps and derived quantities. Estimates of meso-scale mixing may serve as a foundation for the development of new parameterization schemes employed in climate models, as well as local and global ocean circulation models in polar regions.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.

威德尔环流是南大洋环流系统的主要组成部分之一，将南极绕极流的热量和碳通量与大陆边缘联系起来。进入威德尔环流的水团被修改，因为它们在一个伟大的圆形路线周围的环流边缘和变化，通过涉及空气-海洋-冰冻圈相互作用的过程，以及通过海洋涡旋，混合跨环流边界的属性。一些密度更大的水团通过沿着北方边界的路径离开环流，最终以南极底层水的形式进入全球深海。虽然现场和卫星观测，以及计算机建模的努力，提供了大规模的环流内的平均流量的估计，小规模的细节，或“中尺度”涡流仍然难以捉摸。拟议的研究将量化混合由于威德尔环流内的中尺度涡旋，以及从东北部传入的深水运输，被认为是瞬态涡旋的结果。由于威德尔环流产生的源水约40%的南极底层水的形成，了解这一地区的动态有助于确定全球底层沃茨的变化的原因。这反过来将使人们深入了解气候变化如何通过改变密集的极地沃茨和南极底层水的特征来影响全球海洋。该项目旨在跟踪威德尔环流冰盖地区的153个RAFOS Argo浮标。所得到的轨迹沿着与所有可用的Argo和早期的浮动数据将被用来计算欧拉和拉格朗日的手段和韦德尔环流的涡流统计。该研究将把RAFOS轨迹与冰下Argo剖面联系起来，使人们能够描述涡旋在关键冰边缘边界和引线处水柱改变中的重要性。由于RAFOS的轨迹接近环流的东北边界，该项目将调查进入的绕极深水的涡流驱动过程，以更好地了解所涉及的机制和体积通量。以前的工作表明，大部分的平均环流在南部和西部界限的环流，在那里它接触南极大陆，发生在一个狭窄的边界层以上的斜坡。这里的研究将把这种流动结构整合到一个完整的内部和边界层平均环流合成中。拟议工作的结论和产品将改进阿尔戈剖面在极地区域的定位，从而能够制作更准确的气候图和得出的数量。中尺度混合的估计可以作为气候模式中采用的新参数化方案的发展基础，以及极地地区的局部和全球海洋环流模式。该奖项反映了NSF的法定使命，并被认为值得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来支持。

项目成果

Improved Acoustic Tracking of RAFOS-Enabled Profiling Floats through the New Software Package artoa4argo

通过新软件包 artoa4argo 改进了支持 RAFOS 的分析浮动的声学跟踪

• DOI: 10.1175/jtech-d-23-0020.1
• 发表时间: 2024
• 期刊: Journal of Atmospheric and Oceanic Technology
• 影响因子: 2.2
• 作者: Hancock, Cathrine;Boebel, Olaf
• 通讯作者: Boebel, Olaf

Observations of Upwelling and Downwelling Around Antarctica Mediated by Sea Ice

海冰介导的南极洲周围上升流和下降流的观测

• DOI: 10.3389/fmars.2022.864808
• 发表时间: 2022
• 期刊: Frontiers in Marine Science
• 影响因子: 3.7
• 作者: Ramadhan, Ali;Marshall, John;Meneghello, Gianluca;Illari, Lodovica;Speer, Kevin
• 通讯作者: Speer, Kevin