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

越来越多的证据表明，深对流通风在拉布拉多海部分控制的机制，而不是当地的表面强迫和当地的密度梯度。现在看来，存在着一个积极的涡流驱动restratification调制的边界电流动态的变化。已经观察到边界流的涡流脱落和浮力输送的年际变化，但没有解释。本计画将结合实际与理想化的数值模拟、资料分析与理论，探讨控制涡流产生与相关浮力输送的过程。利用高分辨率区域模式进行的数值试验将探讨涡动产生和财产迁移对当地和外部强迫参数变化的敏感性。扩展分析的涡流和边界电流的数据，集中在现在十五年的TOPEX/波塞冬和杰森高度计记录，将允许在广泛的海洋条件下的模拟和实际的涡流特性进行比较。理论，支持理想化的实验，将提供标准，以测试候选人的假设，性质的不稳定性，并建议其参数化的可能性。最终的结果将是了解本地和非本地强迫变率之间的联系，以及涡驱动的浮力通量，限制深对流。这项面向过程的研究应该是朝着更大目标迈出的重要一步，即理解和准确模拟大西洋经向翻转环流的总体变化。这项工作对在大尺度气候模式中代表大西洋经向翻转环流（AMOC）的拉布拉多海分支有直接的好处，其中窄边界电流不稳定性的细节是不可能解决的。面对北极淡水排放量的急剧增加，了解浮力从边界流到对流区域的传输至关重要，特别是要确定其变化的基本因素。此外，这个合作项目将有助于更广泛的努力，现实地代表中尺度功能的影响，在粗分辨率数值models.Broader影响的大尺度环流：这项工作的主要社会效益是它的相关性，了解和可能预测的AMOC的变化。研究结果将在研究生课堂上由两位研究者A.格鲁吉亚理工学院的Braveland和WHOI-MIT的J. Pedlosky。该项目支持的两名研究生将受益于接触建模，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被免费分发给更大的科学界，通过列入JLAB，J。莉莉？的Matlab开源软件包。拟议的研究也将纳入教材的高中教师在亚特兰大地区，与中心的支持教育整合科学，数学和咨询（CEISMC）。

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).