Synthesis of Internal Wave and Turbulence Observations Across the Antarctic Circumpolar Current

本项目采用一种新的方法，对南极环极流（ACC）不同区域收集的内波和湍流数据进行重新分析和综合。这项研究将确定海洋中小规模流动的主要模式（即内波、湍流和混合），以及这些模式在不同地点的差异。这些过程很重要，因为它们控制着南极绕极流的行为，而南极绕极流反过来又影响全球海洋环流。ACC在太平洋、大西洋和印度洋之间提供了一个直接的联系，并影响了水、热、盐、营养物质和其他物质从表面到深海的运输（全球翻转环流）。这种基于新方法的再分析将揭示共同的流动特征，并识别归因于环境本身的差异。这些分析结果对提高我们对南大洋环流的认识具有重要的价值，对我们对海洋环流和细尺度过程的认识具有重要的广泛的应用价值。这项研究将为美国海洋学界提供一种经过验证的方法和软件，用于从观测中获得湍流参数，从而推进科学，同时也提高我们对海洋如何运作造福社会的认识。分析的重点是在过去十年左右的多个项目背景下在ACC地区收集的大量海洋数据，主要是降低的声学多普勒电流剖面仪（LADCP）和CTD剖面。先前对精细和微观结构数据的分析主要是针对具体项目的，并且强调区域动态过程。虽然这些分析揭示了一些共同的观察结果，包括湍流对地形粗糙度和近底流的依赖，但在内波能量和湍流水平之间的关系方面也存在不一致之处。在本研究中，将采用一种新的无偏置精细结构参数化方法来估计湍流耗散。这种新方法基于LADCP/CTD剖面的垂直动能（VKE）估算。该项目将为一些难以比较的现有工艺研究提供背景。作为该项目的一部分，将要估计的湍流和混合系数是发展南大洋湍流和混合气候学的第一步。这些系数预计将在许多不同的科学背景下发挥作用，并将公开提供。在本项目背景下实施的VKE方法/软件的改进将成为公共参考实施的一部分，可供其他科学家使用。

This project uses a new method to reanalyze and synthesize internal-wave and turbulence data already collected from different areas of the Antarctic Circumpolar Current (ACC) region. The research will determine the main patterns of small scale flow (i.e., internal waves, turbulence and mixing) in the ocean and how these differ from location to location. These processes are important because they control the behavior of the Antarctic Circumpolar Current, which in turn affects global ocean circulation. ACC provides a direct connection between the Pacific, Atlantic and Indian Oceans and affects the transport of water, heat, salt, nutrients and other material from the surface to the deep ocean (global overturning circulation). This reanalysis, based on a new method, will reveal common flow characteristics and identify differences that are attributed to the environment itself. The results of such analysis is very valuable in improving our understanding of ocean circulation in the Southern Ocean and it will have significant and broad application on our understanding of ocean circulation and fine scale processes. This study will provide the US oceanographic community with a tested method and software for deriving turbulence parameters from observations thus advancing science but also improve our knowledge on how the oceans operate benefiting society.The analysis focuses on a large amount of oceanographic data, mainly Lowered Acoustic Doppler Current Profiler (LADCP) and CTD profiles, that have been collected in the ACC region during the last decade or so in the context of multiple projects. Prior analyses of fine and microstructure data have been primarily project-specific, and have emphasized regional dynamical processes. While these analyses reveal some common observations, including dependence of turbulence on topographic roughness and near-bottom currents, there are also inconsistencies, regarding the relationship between internal-wave energy and turbulence levels. In this study, a new, bias-free fine structure parameterization method will be used to estimate turbulence dissipation. This new method is based on Vertical Kinetic Energy (VKE) estimates derived from LADCP/CTD profiles. The project will provide context for some of the existing process studies that are difficult to compare. The turbulence and mixing coefficients that will be estimated, as part of this project, are the first step toward the development of a climatology of turbulence and mixing for the Southern Ocean. These coefficients, which are expected to be useful in many different scientific contexts, will be made publicly available. Improvements to the VKE methodology/software implemented in the context of this project will become part of the public reference implementation and available for use by other scientists.