Collaborative Research: Three-Dimensional Numerical Investigation of Density Currents

合作研究：密度流的三维数值研究

• 批准号: 0209309
• 负责人: Traian Iliescu
• 金额: $ 9.48万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0209309&HistoricalAwards=false
• 关键词: Collaborative; Research; Three; Dimensional; Numerical

The oceanic thermohaline circulation is strongly affected by localizeddense-water formation in high-latitude oceans. Such dense water massesare released into the large-scale circulation in the form of ocean bottomdensity currents mostly from localized regions (e.g., Denmark Strait,Strait of Gibraltar for the Mediterranean overflow, Bab el Mandep Straitfor the Red Sea overflow). Because of the small space and time scalesrequired to resolve their dynamics, such density currents form the``bottle neck'' of the thermohaline circulation investigation. Despite theirimportance, we have a limited understanding of the dynamics of bottomdensity currents, and at present, the oceanic density currents are poorlyrepresented in global climate simulations. The main goal of this proposalis to enhance the understanding of the dynamics of ocean bottom densitycurrents from laboratory scale, to geophysical scale, through three-dimensional,nonhydrostatic numerical simulations. The investigators accomplish thisin three stages. First, benchmark a parallel high-order spectral elementNavier-Stokes solver, Nek5000, by reproducing existing laboratory resultsof bottom density currents by direct numerical simulations. Second,explore dynamics for which there are few or no laboratory results, inparticular dynamics of bottom density currents protruding into a stratifiedfluid, and in a rotating environment. Third, bridge the gap betweenlaboratory scale and geophysical scale by using large eddy simulations.Geophysical scale calculations are configured for the Red Sea overflow,and confirmed with data from the Red Sea Overflow Experiment. Variousmetrics are used to quantify density current dynamics.Variation of solar heating with latitude, and other factors, drive theso-called ``thermohaline'' circulation in the ocean, which is closelylinked to the role that the ocean plays in climate dynamics. This complexgeophysical problem, with its range of scales, physical, mathematical andcomputational constraints can only be approached through an orchestratedeffort involving cross-disciplinary expertise. The investigators conductphysically-guided numerical simulations, quantify dynamical behavior ofocean density currents, and describe the impact of density currents onthe climate. The investigators integrate this research project witheducation of three graduate students and contribute to the training ofUS technical workforce for the 21st century. This research projectenhances the scientific understanding of oceanic density currents, andhelps improve the representation of ocean density currents in globalclimate simulations and contribute to the climate change research.

海洋热盐循环受高纬度海洋中的局部密度 - 水的强烈影响。这种密集的水群以海洋底部密度电流的形式释放到大规模循环中，主要来自局部区域（例如，丹麦海峡，地中海溢流的直布罗陀海峡，红色海洋溢出的Bab el Mandep海峡）。由于空间和时间缩放以解决其动力学，因此这种密度电流形成了热盐循环研究的“孔颈”。尽管有重要的率，但我们对底密度电流的动力学有限，目前，在全球气候模拟中，海洋密度电流表现不佳。该提议的主要目标是通过三维，非静态数值模拟来增强从实验室量表到地球物理量表的海洋底部密度电流的理解。调查人员完成了这三个阶段。首先，通过通过直接数值模拟重现底部密度电流的现有实验室结果，基准测试了平行的高阶光谱元素navier-stokes solver，Nek5000。其次，探索几乎没有或没有实验室结果的动力学，底部密度电流的内部动力学突出到地层流体和旋转环境中。第三，通过使用大型涡流模拟弥合了实验室量表和地球物理量表之间的差距。地球物理量表的计算是为红海溢出配置的，并通过红色海洋溢流实验的数据确认。各种标准用于量化密度电流动力学。用纬度和其他因素变化太阳加热，驱动了海洋中的``热盐水''循环，该循环与海洋在气候动力学中扮演的作用紧密联系。这个复杂地球物理问题及其量表范围，物理，数学和计算限制只能通过涉及跨学科专业知识的编排效果来解决。研究人员通过电源引导的数值模拟，量化了孔密度电流的动力学行为，并描述了密度电流对气候的影响。研究人员将该研究项目与三名研究生的教育结合在一起，并为21世纪的US技术劳动力培训做出了贡献。这项研究对海洋密度电流的科学理解提高了Andhelps，改善了海洋密度电流在全球气候模拟中的代表，并为气候变化研究做出了贡献。