Collaborative Research: Vortex dynamics and interannual variability in the Labrador Sea

合作研究：拉布拉多海的涡动力学和年际变化

• 批准号: 1048539
• 负责人: Jonathan Lilly
• 金额: $ 4.78万
• 依托单位: NorthWest Research Associates, Incorporated
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1048539&HistoricalAwards=false
• 关键词: Collaborative; Research; Vortex; dynamics; interannual

Accumulating evidence suggests that deep convective ventilation in the Labrador Sea is partly controlled by mechanisms other than local surface forcing and local density gradients. It now appears that there exists an active eddy-driven restratification which is modulated by variations in boundary current dynamics. Large inter-annual variations in both eddy shedding and buoyancy transport from the boundary current have been observed but not explained. This project will investigate the processes controlling eddy generation and associated buoyancy transport by combining realistic and idealized numerical modeling, data analysis, and theory. Ensembles of numerical experiments with a high-resolution regional model will explore the sensitivity of eddy generation and property transport to variations in local and external forcing parameters. Extended analysis of eddy and boundary current properties in data, centrally the now fifteen-year TOPEX/Poseidon and Jason altimeter records, will allow comparison of modeled and actual vortex characteristics over a wide range of oceanic conditions. Theory, supported by idealized experiments, will provide criteria to test candidate hypotheses as to the nature of the instability, and will suggest possibilities for its parameterization. The net result will be an understanding of the links between local and non-local forcing variability, and the eddy-driven buoyancy fluxes which limit deep convection. This process-oriented study should form an important step toward the larger goal of understanding and accurately modeling variability of the Atlantic Meridional Overturning Circulation in general.Intellectual Merit: This work has a direct benefit to the representation of the Labrador Sea branch of the Atlantic Meridional Overturning Circulation (AMOC) in large-scale climate models, in which details of the narrow boundary current instability are not possible to resolve. In the face of dramatically increasing freshwater discharge from the Arctic, it is critical to understand the transport of buoyancy from boundary current to the convection region, and in particular, to identify the factors underlying its variability. Furthermore, this collaborative project will contribute to the broader effort of realistically representing the effects of mesoscale features on the large-scale circulation in coarse-resolution numerical models.Broader Impacts: The primary societal benefit of this work is its relevance to understanding and possibly predicting variations of the AMOC. Results will be presented in graduate classes by two of the investigators, A. Bracco at Georgia Tech and J. Pedlosky at WHOI-MIT. The two graduate students supported by the project will benefit from exposure to modeling, analytical investigation and data analysis techniques. Analysis algorithms developed in this work will be freely distributed to the greater scientific community, by inclusion in JLAB, J. M. Lilly?s open-source software package for Matlab. The proposed research will also be incorporated into teaching material for high school teachers in the Atlanta area, with the support of the Center for Education Integrating Science, Mathematics and Consulting (CEISMC).

积累的证据表明，拉布拉多海中的深对流通风部分由局部表面强迫和局部密度梯度以外的其他机制控制。现在看来，存在一个主动涡流驱动的限制性，该限制由边界电流动力学的变化调节。已经观察到但未解释过从边界电流的涡流和浮力转运的大量年际变化。该项目将通过结合现实和理想化的数值建模，数据分析和理论来研究控制涡流产生和相关浮力传输的过程。具有高分辨率区域模型的数值实验的集合将探讨涡流产生和属性传输对局部和外部强迫参数变化的敏感性。对数据中涡流和边界当前性质的扩展分析，从中央是现在的15年TOPEX/POSEIDON和JASON高度计记录，将允许在广泛的海洋条件下比较建模和实际涡旋特性。在理想化的实验的支持下，理论将提供标准来检验不稳定性性质的候选假设，并提出其参数化的可能性。最终结果将是了解局部和非本地强迫变异性之间的联系，以及限制对流的涡流浮力通量。这项面向过程的研究应该构成重要的一步，朝着更大的目标迈出了一般的理解和准确建模的循环循环。智能优点：这项工作是直接的好处，可以使大西洋子午线的拉布拉多海分支在大尺度模型中的范围内的范围内构成范围的范围，这是在大规模callimate循环（AMOC）中的代表。面对从北极的淡水排放急剧增加，了解浮力从边界电流到对流区域的运输至关重要，尤其是确定其可变性的因素。此外，这个协作项目将有助于更广泛地代表中尺度特征对粗分辨率数值模型中大规模循环的影响的更广泛的努力。Boader的影响：这项工作的主要社会利益与理解和可能预测AMOC的变化有关。结果将由两名研究人员在研究生班上介绍，佐治亚理工学院的A. Bracco和Whoi-Mit的J. Pedlosky。该项目支持的两位研究生将受益于建模，分析调查和数据分析技术。在这项工作中开发的分析算法将通过包含在J.M. Lilly的J. M. Lilly的开放源代码软件包中自由分发给更大的科学界。拟议的研究还将在整合科学，数学和咨询中心（CEISMC）的教育中心的支持下，将亚特兰大地区的高中教师的教学材料纳入教学材料中。