Beyond Horizontal Convection

智力价值：这个项目扩大了调查人员的范围？水平对流是指沿流体水平边界的差热产生的环流，被认为是造成海洋子午线翻转环流(MOC)的最简单的动力要素。MOC的全部问题是复杂和困难的，涉及热、盐分和机械强迫。该项目的研究人员一直致力于理解单组分水平对流，这通常被视为MOC的简化概念模型。这项工作以及其他小组的工作表明，水平对流与MOC之间的差距不仅是定量的，而且是定性的。这个项目的目标是通过进行进一步的实验室和数值实验，从过于简化的水平对流问题转向更丰富的海洋动力环境。将讨论以下假设：1.深部层结主要是由深度变化的负浮力羽流中浮力的垂直输送和斜压涡旋引起的横向输送之间的相互作用决定的。有表面应力和无表面应力的旋转水平对流中的动能耗散主要发生在流动内部，而不是由于底部阻力。直接的数值模拟表明这是正确的，而参数化对流和湍流的海洋环流模拟则表明情况并非如此。以表面应力的形式输入机械能，而不是浮力驱动的环流，导致了一个两胞环流，在这种环流中，系统不再受经典标度论的支配。外加表面应力的空间变异性引入了新的动力响应和能量途径。因此，风和浮力之间的相对阶段是重要的。更广泛的影响：这个更新项目将使两名研究生完成他们的论文研究，并获得实验室工作和计算流体力学的技能。为了接触到大学预科学生，调查人员将继续为圣地亚哥联合学区高中教师的专业发展做出贡献。与美国国家科学基金会资助的海洋科学教育卓越中心合作？在加利福尼亚州，他们将为大约25名地球科学教师主办为期一天的研讨会。本项目中的数值模拟将作为科学计算研讨会的例子，旨在向国家科学基金会支持的超级计算设施介绍在斯克里普斯海洋研究所进行计算研究的研究生。

Intellectual Merit: This project extend the investigators? work on horizontal convection which refers to the circulation resulting from differential heating along one horizontal boundary of a fluid and is seen as the simplest dynamical element contributing to the oceanic Meridional Overturning Circulation (MOC). The full problem of the MOC is complex and difficult, involving thermal, haline and mechanical forcing. The investigators on this project have been working on understanding single-component horizontal convection, which is commonly viewed as a simplified conceptual model of the MOC. This work, and that of other groups, suggests that the gap between horizontal convection and the MOC is not only quantitative, but also qualitative. The goal of this project is to move from the overly simplified problem of horizontal convection toward the richer dynamical setting of the ocean by conducting further laboratory and numerical experiments. The following hypotheses will be addressed:1. Deep stratification is largely set by the interaction between the vertical transport of buoyancy in the depth-varying, negatively buoyant plume and the lateral transport due to baroclinic eddies.2. Kinetic energy dissipation in rotating horizontal convection with and without surface stress occurs primarily in the interior of the flow and is not due to bottom drag. Direct Numerical Simulations indicate that this is true yet ocean circulation simulations with parameterized convection and turbulence suggest otherwise.3. An input of mechanical energy in the form of a surface stress in opposition to a buoyancy-driven circulation leads to a two-cell circulation, in which the system is no longer governed by classical scaling arguments.4. Spatial variability of the applied surface stress introduces new dynamical responses and energy pathways. The relative phase between wind and buoyancy forcing is thus important.Broader Impacts: This renewal project will enable two graduate students to finish their thesis research and acquire skills in laboratory work and computational fluid dynamics. To reach pre-college students, the investigators will continue to contribute to the professional development of high school teachers in the San Diego Unified School District. In partnership with the NSF-funded Center for Ocean Science Education Excellence ? California, they will sponsor a one-day workshop for approximately 25 Earth sciences teachers. The numerical simulations in this project will be used as examples in a seminar class on scientific computing, aimed at introducing graduate students carrying out computational research at the Scripps Institution of Oceanography to the NSF-supported supercomputing facilities.