Thermohaline Interleaving in Baroclinic Frontal Zones

斜压锋区的温盐交错

• 批准号: 0622922
• 负责人: William Smyth
• 金额: $ 59.75万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-15 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0622922&HistoricalAwards=false
• 关键词: Thermohaline; Interleaving; Baroclinic; Frontal; Zones

ABSTRACTOCE-0622922Intellectual meritThermohaline interleaving is an important mechanism for the lateral mixing of water masses in virtually every ocean basin. Horizontal diffusivities due to interleaving are often comparable with those due to mesoscale eddies, Theoretical research into thermohaline interleaving faces two important obstacles: (1) the need to accurately parameterize microscale mixing processes, including salt fingering, diffusive convection, convective overturning and shear-driven turbulence, and (2) the mathematical challenge of including baroclinic effects in linear and nonlinear theories. In this project, a coordinated sequence of linear and nonlinear theoretical analyses will address both of these problems. The linear stability analysis will delimit the parameter range in which oblique modes can be ignored. Preliminary results indicate that this range covers essentially all ocean regimes except near boundaries. The one-dimensional nonlinear modeling of cross-front modes will extend to the final equilibrium state. The direct numerical simulations will extend these results into the regime of three-dimensional nonlinear interleaving. At every stage, results will be compared with existing observational data. Broader impactsThe proposed research is a significant step toward the development of parameterizations of frontal exchange due to thermohaline interleaving in basin and global-scale models. It will also provide a test bed for mixing parameterizations that can be used in a wider class of models. A graduate student will receive training in state of the art theoretical and numerical techniques and an international collaboration will be fostered.

ABSTRACTOCE-0622922智力价值温盐交错是几乎每个海洋盆地水团横向混合的重要机制。交错引起的水平扩散率通常与中尺度涡流引起的水平扩散率相当。温盐交错的理论研究面临两个重要障碍：（1）需要精确参数化微尺度混合过程，包括盐指作用、扩散对流、对流翻转和剪切驱动湍流；(2) 将斜压效应纳入线性和非线性理论的数学挑战。在该项目中，线性和非线性理论分析的协调序列将解决这两个问题。线性稳定性分析将限定可以忽略斜模态的参数范围。初步结果表明，该范围基本上涵盖了除边界附近以外的所有海洋状况。交叉前沿模态的一维非线性建模将扩展到最终的平衡状态。直接数值模拟将把这些结果扩展到三维非线性交织领域。在每个阶段，结果都会与现有的观测数据进行比较。更广泛的影响由于盆地和全球尺度模型中的温盐交错，所提出的研究是朝着锋面交换参数化发展迈出的重要一步。它还将为混合参数化提供一个测试平台，可用于更广泛的模型类别。研究生将接受最先进的理论和数值技术的培训，并将促进国际合作。