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

南极绕极流内波和湍流观测的综合

• 批准号: 1737325
• 负责人: Andreas Thurnherr
• 金额: $ 15.85万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1737325&HistoricalAwards=false
• 关键词: Synthesis; Internal; Wave; Turbulence; Observations

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.

该项目使用一种新的方法来重新分析和合成内波和湍流数据已经从南极绕极流（ACC）区域的不同地区收集。该研究将确定小规模流动的主要模式（即，内波，湍流和混合）在海洋中，以及这些如何不同的位置到位置。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着全球海洋环流。南极洲环流直接连接太平洋、大西洋和印度洋，影响水、热、盐、营养物和其他物质从表层向深海的输送（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，并确定归因于环境本身的差异。这些分析结果对于加深我们对南大洋环流的认识是非常有价值的，对于我们理解南大洋的环流和精细尺度过程也有着重要而广泛的应用。这项研究将为美国海洋学界提供一种经过测试的方法和软件，用于从观测数据中获取湍流参数，从而促进科学发展，同时也提高我们对海洋如何造福社会的认识。分析重点是大量的海洋数据，主要是低声多普勒海流剖面仪（LADCP）和CTD剖面，在过去十年左右的时间里，在多个项目的背景下，在行政协调会区域收集了这些数据。先前的精细和微观结构数据分析主要针对特定项目，并强调区域动力学过程。虽然这些分析揭示了一些共同的意见，包括地形粗糙度和近底流湍流的依赖，也有不一致的内波能量和湍流水平之间的关系。在这项研究中，一个新的，无偏精细结构参数化方法将被用来估计湍流耗散。这种新方法是基于垂直动能（VKE）的估计来自LADCP/CTD的配置文件。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，将对湍流和混合系数进行估计，这是朝着发展南大洋湍流和混合气候学迈出的第一步。这些系数预计将在许多不同的科学背景下发挥作用，并将向公众提供。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，并可供其他科学家使用。