Small-Scale Processes in the COASTal Ocean

沿海海洋的小规模过程

• 批准号: 0549836
• 负责人: James Moum
• 金额: $ 42.65万
• 依托单位: Oregon State University
• 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 2011-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0549836&HistoricalAwards=false
• 关键词: Small; Scale; Processes; COASTal; Ocean

Observations made as part of the COAST (Coastal Ocean Advances in Shelf Transport) project by the Ocean Mixing Group at Oregon State University have already led to new insights into the details of coastal flows. These are an extensive set of observations obtained over a broad range of both topography and flow states. The data are of uniformly high quality and include new types of measurements implemented specifically for this experiment (e.g., high-frequency Doppler velocity profiling and turbulence measurements from a bottom lander) which have enhanced our ability to infer the small-scale dynamics of these flows. However, due to the extensive nature of this data set a number of key issues still need to be addressed.In this study, a researcher at Oregon State University will continue his analysis of the small-scale COAST data set to determine a useful parameterization of small-scale topographic drag and mixing that can be used in coastal ocean circulation models; this will be done using the comprehensive bottom boundary layer data that includes near-bottom stratification, turbulence dissipation rate and current speeds over a broad range of bathymetry. A detailed characterization of mixing during downwelling, including an analysis of the dynamics of merged surface and bottom boundary layers will be constructed. The researcher will also assess the interaction of near-inertial waves and internal tide with the coastal jet and how the presence of the coastal jet alters mixing parameterizations that are based primarily on wave shear. Finally, both the energetic evolution of bottom-trapped nonlinear internal waves/bores of elevation and the net mass transports by these waves will be quantified. The primary objective of the work is to understand the flow physics to sufficiently aid in parameterizations, which can then be applied to coastal ocean models. In this way, the analyses of the physics of small-scale processes will contribute to our understanding of the larger scale circulation. A graduate student will also be trained on how to bridge the gap between small-scale dynamics and their parameterization in terms of larger-scale variables.

俄勒冈州立大学海洋混合小组作为 COAST（陆架运输的沿海海洋进展）项目的一部分进行的观测，已经使人们对沿海流的细节有了新的认识。这些是在广泛的地形和流动状态下获得的一组广泛的观察结果。这些数据具有一致的高质量，并包括专门为此实验实施的新型测量（例如，高频多普勒速度剖面和来自底部着陆器的湍流测量），这增强了我们推断这些流的小规模动力学的能力。然而，由于该数据集的广泛性，仍有许多关键问题需要解决。在这项研究中，俄勒冈州立大学的研究人员将继续对小规模 COAST 数据集进行分析，以确定有用的参数化可用于沿海海洋环流模型的小规模地形拖曳和混合；这将利用全面的底部边界层数据来完成，其中包括近底部分层、湍流耗散率和广泛测深范围内的水流速度。将构建下降流期间混合的详细特征，包括对合并的表面和底部边界层的动力学分析。 研究人员还将评估近惯性波和内潮与沿海急流的相互作用，以及沿海急流的存在如何改变主要基于波浪剪切的混合参数化。 最后，底部捕获的非线性内波/高程钻孔的能量演化以及这些波的净质量传输都将被量化。 这项工作的主要目标是了解流动物理学，以充分帮助参数化，然后将其应用于沿海海洋模型。通过这种方式，对小尺度过程的物理分析将有助于我们对更大规模循环的理解。研究生还将接受如何弥合小尺度动力学与其大尺度变量参数化之间差距的培训。