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

0136403 Gargett该项目旨在开发基于声学多普勒技术的新的和有前途的技术，用于连续估计海洋观测站的重要湍流变量。增加第5个垂直梁（VADCP）可以估算湍流动能的所有三个分量及其耗散率。该项目将评估它们在遥控海洋观测站提供湍流和平均流特性时间序列测量的潜力。主要的技术挑战是提供一个稳定的平台，以及足够的电力和数据传输的快速采样率所需的解决湍流速度场的大涡结构。主要的科学挑战是设计适合于特定时间产生湍流的特定混合过程的采样协议，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位置的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。LES速度场将被“采样”与不同的VADCP协议（时间/空间分辨率的选择），并使用的结果来估计的可靠性，湍流量可以估计从5束多普勒数据下的各种组合的湍流强迫和表面波污染。此外，数值结果将用于定义未来时间连续、空间局部VADCP测量结果与标准垂直剖面仪和/或自动驾驶车辆上携带的更传统湍流传感器的时间和空间间歇结果之间比较的统计显著性要求。观测结果可以反过来被用来检查常用的LES子网格参数化的假设的海洋有效性。

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.