US-France Cooperative Research: Laboratory and Numerical Modeling of Topographic Effects on Oceanic Currents Along Sloping Surfaces

该奖项将支持亚利桑那州立大学的Donald Boyer博士和法国格勒诺布尔Mecanique de Grioble研究所的Gabriel Chabert d‘Hieres博士之间的合作研究。这项研究试图调查沿模型海岸线(或深海倾斜海底)的均匀和两层旋转流动的性质，包括这种流动与地形的相互作用。该系统的模拟参数包括Rossby数、Ekman数和Burger数、沿海岸线的陆架坡度和表征地形的几何参数。将主要考虑Burger数较小的情况，以便可以忽略分层的影响。这项研究将包括实验室实验以及分析和数值准地转模式。实验室调查将在法国格勒诺布尔梅卡尼克研究所直径13米的旋转拖车水箱中进行。该设备允许用比更传统的转盘(即直径一到两米)上的陆架坡度小大约一个数量级的实验，从而允许人们更接近地模拟这一参数，以用于可能的海洋应用。最初的实验室实验将集中于了解沿岸流的背景流，在这种情况下，没有障碍物，海岸线要么在左边，要么在右边。然后将讨论这些背景流与地形的相互作用。将特别关注阻塞、涡流脱落和困住Rossby波等现象发生的条件。这一研究结果将有助于理解地形对坡面洋流影响的基本特征。格勒诺布尔工厂是独一无二的，在这个项目中获得的经验将对在美国进一步开发类似的工厂非常有价值。

This award will support collaborative research between Dr. Donald Boyer, Arizona State University, and Dr. Gabriel Chabert d'Hieres, Institut de Mecanique de Grenoble, France. This research seeks to investigate the nature of the flow of homogeneous and two-layer rotating flows along model coastlines (or sloping floors in the deep ocean), including the interaction of such flows with topography. The modeling parameters for this system include the Rossby, Ekman and Burger numbers, the slope of the shelf along the coastline and geometric parameters characterizing the topography. Primary consideration will be given to such cases in which the Burger number is small, so that the effects of stratification can be neglected. The research will include laboratory experiments and analytical and numerical quasigeostrophic models. The laboratory investigations are to be conducted in the 13 meter diameter rotating tow tank of the Institut de Mecanique, Grenoble, France. This facility permits experiments with shelf slopes approximately one order of magnitude smaller than those on more conventional turntables (i.e. one to two meters in diameter) and thus allows one to more closely simulate this parameter for possible oceanic applications. The initial laboratory experiments will concentrate on understanding the background flow for the case of along-shore currents in which no obstacle is present and for which the shoreline is either on the left or on the right. The interaction of these background flows with topography will then be addressed. Particular attention will be focused on the conditions for which such phenomena as blocking, eddy shedding and trapped Rossby waves occur. The results of this research will contribute to the understanding of basic features of topographic effects on oceanic currents along sloping surfaces. The Grenoble facility is unique and the experience gained in this project will be valuable for the further development of a similiar facility in the U.S.