Research in Linear and Nonlinear Instability and Ocean Circulation Theory

该项目包括两个主题：(1)海洋环流理论，特别是行星尺度岛屿周围的流动，包括地形“裙边”对岛屿的影响，以及(2)不稳定的线性和非线性动力学。在第一个主题的背景下，研究人员Pedlosky博士将研究岛屿周围环流的性质和类似的地形特征，当地形在岛屿周围产生封闭的、环境的、地转的潜在涡度等高线时。初步调查表明，地形对在岛屿周围的再循环中捕获流体的影响很大，从而改变了岛屿两侧从一个子盆地到另一个子盆地的流体交换的量度。这一问题与印度尼西亚Throughflow一样的水流具有海洋学和气候相关性。这个过程将在分析、数值和实验室中进行研究。对于第二个主题，研究人员将指导一名研究生的研究，研究海岸陆架上下行有利风应力所产生的锋面系统的不稳定性。初步结果表明，由此产生的涡旋可以在跨陆架的热量和质量传输中起到重要作用。更广泛的影响：拟议的工作将研究与海洋学直接相关的新的基本流体力学过程。这里提出的关于海岸不稳定问题的研究结果将应用于沿海地区的示踪剂运输，从而产生生态和动力后果。在印度尼西亚Throughflow的背景下，与岛屿周围和通过狭窄缝隙的流动有关的研究与行星颠覆环流相关，因此与气候问题相关。这项研究的一部分涉及一名参与研究的博士研究生的指导(由另一个项目资助)，并将作为其培训和智力发展的核心要素。与意大利同事的互动有助于科学专业知识的国际交流。

The project consists of two themes: (1) Ocean Circulation Theory, in particular the flow around planetary scale islands including the effects of topographic "skirts" to the island, and (2) the linear and nonlinear dynamics of instabilities.In the context of the first theme the investigator, Dr. Pedlosky, will examine the nature of the circulation around islands and similar topographic features when topography produces closed, ambient, geostrophic contours of potential vorticity around the island. Preliminary investigation has demonstrated the strong influence of the topography in trapping fluid in a recirculation around the island and hence altering the measure of the interchange of fluid from one sub basin to another on each side of the island. This issue is of oceanographic and climatic relevance for flows as the Indonesian Throughflow. The process will be studied analytically, numerically and in the laboratory. For the second theme, the investigator will be guiding the research of a graduate student in a study of the instability of the frontal system produced by downwelling favorable wind stress on a coastal shelf. Preliminary results indicate that the resulting eddies can play a significant role in the cross shelf heat and mass transport. Broader Impacts: The proposed work takes up the study of novel and fundamental fluid mechanical processes of direct oceanographic relevance. The results of the research proposed here on the coastal instability problem will have applications to transport of tracers in the coastal zone and thus have ecological as well as dynamical consequences. The research associated with the flow around islands and through narrow gaps, in the context of the Indonesian Throughflow, has relevance to the planetary overturning circulation and hence pertinence to the problem of climate. Part of the research involves the guidance of a Ph.D. graduate student participating in the research (funded on another project) and will serve as a central element in his training and intellectual development. The interaction with Italian colleagues aids in the international exchange of scientific expertise.