Doppler Turbulence Techniques for Ocean Observatories: An Interactive Approach using In Situ Measurements and LES Models

海洋观测站的多普勒湍流技术：使用原位测量和 LES 模型的交互式方法

• 批准号: 0136403
• 负责人: Ann Gargett
• 金额: --
• 依托单位: Old Dominion University Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-15 至 2009-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0136403&HistoricalAwards=false
• 关键词: Doppler; Turbulence; Techniques; Ocean; Observatories

0136403 GargettThis project aims at developing new and promising techniques based on acoustic Doppler technology for continuous estimation of important turbulence variables at ocean observatories. Addition of a 5th vertical beam (VADCP) allows estimates of all three components of turbulent kinetic energy as well as its dissipation rate. This project will assess their potential to provide time series measurements of turbulent as well as mean flow properties at remotely operated ocean observatories. The major technical challenges are provision of a stable platform, and sufficient power and data transmission for the fast sample rates needed to resolve the large-eddy structure of turbulent velocity fields. The major scientific challenges are the design of sampling protocols appropriate to the particular mix of processes generating turbulence at a given time, and the separation of surface wave and turbulent velocities. A final question is how to verify that the results are "correct", i.e., consistent with what is known of various forms of turbulence in the ocean. To address these sets of problems simultaneously, exploratory coastal deployments of a VADCP, in both wave-protected and wave-exposed locations, will be combined with development and use of a large-eddy simulation (LES) model suitable for the coastal ocean. LES velocity fields will be "sampled" with different VADCP protocols (choices of time/space resolution), and the results used to estimate the reliability with which turbulent quantities can be estimated from the 5-beam Doppler data under various combinations of turbulence forcing and surface wave contamination. In addition, the numerical results will be used to define requirements for statistical significance of future comparisons between time-continuous, spatially localized VADCP measurements, and time- and space-intermittent results from more traditional turbulence sensors carried on standard vertical profilers and/or autonomous vehicles. The observational results may in turn be used to examine the oceanic validity of assumptions underlying commonly used LES sub-grid parameterizations.

本项目旨在发展基于声学多普勒技术的有前途的新技术，用于海洋观测站重要湍流变量的连续估计。添加第5垂直梁（VADCP）可以估计湍流动能的所有三个组成部分及其耗散率。该项目将评估它们的潜力，为远程操作的海洋观测站提供湍流和平均流动特性的时间序列测量。主要的技术挑战是提供一个稳定的平台，以及足够的功率和数据传输，以满足解决湍流速度场大涡结构所需的快速采样率。主要的科学挑战是设计适合于在给定时间产生湍流的特定混合过程的采样方案，以及分离表面波和湍流速度。最后一个问题是如何验证结果是“正确的”，即与已知的海洋中各种形式的湍流相一致。为了同时解决这些问题，在波浪保护和波浪暴露的地方，VADCP的探索性沿海部署将与适合沿海海洋的大涡模拟（LES）模型的开发和使用相结合。将使用不同的VADCP协议（时间/空间分辨率的选择）对LES速度场进行“采样”，并将结果用于估计在湍流强迫和表面波污染的各种组合下，从五波束多普勒数据中估计湍流量的可靠性。此外，数值结果将用于确定未来比较时间连续、空间局部化的VADCP测量结果与标准垂直剖面仪和/或自动驾驶汽车上搭载的传统湍流传感器的时间和空间间歇结果之间的统计显著性要求。观测结果可反过来用于检验基于常用LES子网格参数化的假设在海洋中的有效性。