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

在中纬度地区，大尺度湍流海洋环流通常会演变成大尺度喷流和涡旋的模式，这就是所谓的地转湍流。虽然地转湍流理论已经研究了几十年，但它只是最近才被观察到，这些观察表明它在整个外层海洋中无处不在。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改地转湍流理论，因为赤道海洋中科里奥利参数的相对变化很大，地转失效。在这项研究中，他将采用理论和层次的数值模式，以发展在赤道地区的宏观湍流，这将补充现有的地转湍流理论的图片。理论的一个方面被认为是莱茵效应：由于罗斯贝波和湍流的相互作用，交替的带状射流形成。这种情况发生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。在简单的一层地转湍流中，能量守恒和涡度拟能的同时守恒导致运动向更大尺度发展。当考虑科里奥利参数的相对快速变化时，能量不仅必须朝向更高的长度尺度级联，而且还必须朝向更大的变形半径，从而朝向赤道级联。 除了这项工作的智力价值外，该项目还将支持一项创新的试点计划，其中一名美国物理海洋学研究生将在肯尼亚度过三个月，以促进工业化国家和发展中国家之间的科学合作。这一试点方案将与政府间海洋学委员会协调进行。

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.