Collaborative Research: Turbulence and Wave Dynamics from the Mesosphere to the Lower Thermosphere above the Andes

该合同将支持智利Cerro Pachón的安第斯山脉激光雷达观测站（ALO）的Na风温激光雷达继续运行（30.26S，70.74W，elev. 2530米），以研究中间层和低热层（MLT）动力学和离子中性耦合过程。ALO的激光雷达是最先进的钠共振荧光多普勒激光雷达，能够在80-105公里高度范围内以高垂直分辨率（500米）和高时间分辨率（1分钟）高精度测量三维风、中性温度和钠密度分布。ALO激光雷达能力的两个关键进展是将激光雷达观测剖面扩展到较低的热层，风和温度测量高达140公里的高度，以及检测温度和风的湍流尺度扰动的能力，这将使研究重点放在处于MLT科学前沿的科学主题上。定义MLT中的动力学、结构和可变性的物理过程也在整个大气中以及所有分层和剪切的地球物理流体中起作用，例如，海洋、湖泊、其他行星大气层和恒星内部。该项目将为博士后研究人员、研究生和本科生提供参与科学、工程和观测的机会。在ALO用Na激光雷达获得的数据将为对从低层大气到高层热层的研究感兴趣的广大社区提供服务。通过应用收集到的测量数据，可以研究的科学目标有：确定湍流通量和热量与动量的涡流扩散系数以及普朗特数;研究各种尺度的重力波消散所引起的热量和能量的垂直输送，量化不同季节重力波、潮汐和行星波之间的相互作用;分析和模拟重力波在变化背景大气中的演化过程，理解热层Na层形成的离子-中性耦合过程。

This award would support the continued operations of the Na wind-temperature lidar at Andes Lidar Observatory (ALO) in Cerro Pachón, Chile (30.26S, 70.74W, elev. 2530 m) to study the mesosphere and lower thermosphere (MLT) dynamics and ion-neutral coupling processes. The lidar at ALO is a state-of-the-art Na resonance-fluorescence Doppler lidar, capable of measuring 3D wind, neutral temperature and Na density profiles at high vertical (500 m) and temporal (1 min) resolutions in the 80-105 km altitude range with high accuracy. Two key advancements of ALO lidar capabilities featuring the extension of lidar observing profile into the lower thermosphere, with wind and temperature measurements up to 140 km altitude, and the ability to detect turbulence scale perturbations in temperature and wind would enable investigations focused on scientific topics that are at the forefront of MLT science. The physical processes that define the dynamics, structure, and variability in the MLT also operate throughout the atmosphere and in all stratified and sheared geophysical fluids, e.g., oceans, lakes, other planetary atmospheres and stellar interiors. This project would provide opportunities for a postdoc researcher, graduate and undergraduate students to participate in the science, engineering and observations. The data acquired with the Na lidar at ALO will serve a broad community interested in research from the lower atmosphere to the upper thermosphere. Possible science goals that would be studied through the application of the measurements collected are: determination of turbulence fluxes and eddy diffusion coefficients of heat and momentum and the Prandtl number; investigation of the vertical transport of heat and energy caused by dissipating gravity waves at various scales,quantification of the interactions among gravity waves, tides, and planetary waves at different seasons;analysis and modeling of gravity wave evolution process through variable background atmosphere; and understanding the ion-neutral coupling processes underlying the formation of thermospheric Na layers.