Equatorial Macro Turbulence: Extending Mid-Latitude Macro Turbulence Studies to the Equatorial Region

赤道宏观湍流：将中纬度宏观湍流研究扩展到赤道地区

• 批准号: 0550658
• 负责人: Jurgen Theiss
• 金额: --
• 依托单位: Theiss Jurgen
• 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: 2006-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0550658&HistoricalAwards=false
• 关键词: Equatorial; Macro; Turbulence; Extending; Mid

In the mid-latitudes, the large-scale turbulent ocean circulation commonly evolves towards a pattern of large-scale jets and vortices, which is known as geostrophic turbulence. While the theory of geostrophic turbulence has been studied for decades, it has only been observed relatively recently and those observations suggest that it is ubiquitous throughout the extratopical ocean. Similar observations made in the equatorial ocean, prompted this scientist to consider how the theory of geostrophic turbulence must be modified in the equatorial ocean where the relative change in the Coriolis parameter is large and geostrophy fails. In this study, he will employ theory and a hierarchy of numerical models to develop a picture of macro turbulence in the equatorial region which will complement existing theories of geostrophic turbulence. One aspect of the theory that is being considered is known as the Rhines effect: alternating zonal jets form due to the interaction of Rossby waves and the turbulence. The length scale at which this happens varies near the equator more rapidly than in mid-latitudes and hence the dynamics are more complex. The cascade of energy is also being considered. In simple one-layer geostrophic turbulence, the concurrent conservation of energy and enstrophy causes motions to evolve towards larger scales. When the relatively rapid change in the Coriolis parameter is considered, then energy must not only cascade towards higher length scales but also towards larger deformation radii and hence towards the equator. In addition to the intellectual merit of this work, this project will support an innovative pilot program where a U.S. graduate student in physical oceanography will spend three months in Kenya to facilitate scientific collaborations between the industrialized and developing world. This pilot program will be done in coordination with the Intergovernmental Oceanographic Commission.

在中纬度地区，大尺度湍流海洋环流通常向大尺度急流和涡旋的模式演化，这种模式被称为地转湍流。虽然地转湍流理论已经被研究了几十年，但它是最近才被观察到的，这些观察表明，它在整个外星人海洋中无处不在。在赤道海洋中进行的类似观测，促使这位科学家考虑如何在赤道海洋中修正地转湍流理论，因为在赤道海洋中，科里奥利参数的相对变化很大，地转作用失效。在这项研究中，他将使用理论和一系列数值模式来绘制赤道地区宏观湍流的图景，这将补充现有的地转湍流理论。正在考虑的理论的一个方面被称为莱茵斯效应：由于Rossby波和湍流的相互作用，形成了交替的纬向喷流。发生这种情况的长度尺度在赤道附近的变化比在中纬度地区更快，因此动力学更复杂。能源的级联也在考虑之中。在简单的单层地转湍流中，能量守恒和辐合运动共同导致运动向更大的尺度演化。当考虑到科里奥利参数的相对快速变化时，能量不仅必须朝向较高的长度尺度，而且要朝向较大的形变半径，从而朝向赤道。除了这项工作的学术价值外，该项目还将支持一个创新的试点项目，一名美国物理海洋学研究生将在肯尼亚呆三个月，以促进工业化世界和发展中国家之间的科学合作。这一试点计划将与政府间海洋学委员会协调进行。