Collaborative Research: CEDAR: High-Resolution Imaging of Instability Dynamics and Breakdown

这是一个为期3年的合作调查之间的航空航天公司和GATS公司。在智利的安第斯山脉激光雷达观测站安装一台新的气辉相机，并利用这些数据研究中层顶附近的湍流过程。在80至100公里高度区域的数值模式中，湍流粘性是一个关键的未知参数。这是出了名的难以衡量。该项目将提供一种在湍流粘度可能变化3个数量级的这一重要大气区域测量该参数的方法。这项研究的结果也将有助于更全面地了解伴随流动不稳定性的流体动力学。 具体而言，该项目将利用航天公司？的新的高分辨率红外相机（AIC 2），使用快速光学和2048 × 2048红外探测器图像的OH气辉在30米像素大小与2秒的图像节奏。ALO站点还包括一个钠风温激光雷达和一个流星雷达。来自AIC 2和其他ALO仪器的数据将用于研究开尔文-亥姆霍兹不稳定性（KHI）的湍流分解并测量湍流粘度。这项新技术将允许表征湍流粘度的各种背景条件下，并在日常和季节的时间尺度。测量结果将与高分辨率直接数值模拟相结合，以产生迄今为止最完整的KHI崩溃及其演变为湍流的图像。

This is a 3-year collaborative investigation between The Aerospace Corporation and GATS Inc. to place a new airglow camera at the Andes Lidar Observatory (ALO) in Chile and use those data to study turbulent processes near the mesopause. Turbulent viscosity is a critical unknown parameter in numerical models of the 80 to 100 km altitude region. It is notoriously very difficult to measure. This project will provide a method of measuring this parameter in this important atmospheric region where turbulent viscosity may vary by 3 orders of magnitude. The results of this study will also contribute to a more general understanding of fluid dynamics accompanying flow instabilities. Specifically, this project will utilize the Aerospace Corporation?s new high-resolution infrared camera (AIC2) that uses fast optics and a 2048 x 2048 IR detector to image the OH airglow at 30 m pixel size with a 2 s image cadence. The ALO site also includes a Na wind-temperature lidar and a meteor radar. Data from the AIC2 and the other ALO instruments will be used to investigate the breakdown into turbulence of Kelvin-Helmholtz instabilities (KHIs) and to measure the turbulent viscosity. This new technique will allow characterization of the turbulent viscosity for a variety of background conditions and over daily and seasonal timescales. The measurements will be combined with high-resolution direct numerical simulations to produce the most complete picture to date of KHI breakdown and its evolution into turbulence.