CEDAR: High-resolution Multistatic Mapping of Small-Scale Flow Structures in Earth's Auroral Thermosphere

该项目将测量地球上约250公里高度的风--S极光热层。人们对这些风仍然知之甚少，特别是在跨度约100公里或更短的空间尺度上。该项目是基于这样的假设，即水平尺度为~100公里或更小的涡旋和波是地球-S极光热层动力学的重要贡献因素，它们的累积影响对于热层的基本物理和空间天气的业务预报都是重要的。为了确定小规模的流动结构，目前位于阿拉斯加的所有七台法布里-珀罗光谱仪将被配置为同时将注意力集中在一个与PFISR雷达视野大致重合的小地理区域。这些仪器将同时监测热层温度和风矢量，生成温度和3分量矢量风的二维地图，空间分辨率约为80公里。该阵列将在这种模式下运行三次战役，每次持续两个月左右。为了量化热层中小尺度涡旋和波的重要性，该项目将解决三个集中的科学问题：(1)在阿拉斯加？S极光热层，在平静和活跃条件下，小尺度涡流和波的发生频率、强度、光谱分布和总体形态是什么？(2)根据它们发生的时间相对于其他测量，它们的相锋的空间排列，是否有可能识别这些小尺度特征的驱动机制和源区，以及它们的传播方向？(3)能否根据波幅、周期和水平方向估计这些波的动量通量和耗散率；温度和三分量风扰动的垂直波长，以及这些量的时间演化？该项目将包括培训一名研究生，加强阿拉斯加图利克湖的研究设施，支持扑克平台上的火箭任务，并将尖端科学研究带到阿拉斯加偏远的村庄。

This project will measure winds at ~250 km altitude in Earth?s auroral thermosphere. These winds remain poorly understood, especially at spatial scales spanning ~100 km or less. The project is based on the hypothesis that eddies and waves at horizontal length scales of ~100 km or less are important contributors to the dynamics of Earth?s auroral thermosphere and that their cumulative impact is important both for the basic physics of the thermosphere and for operational prediction of space weather. To determine small-scale flow structures, all seven of the Fabry-Perot spectrometers now in Alaska will be configured to focus their attention simultaneously onto one small geographic region roughly coinciding with the field of view of the PFISR radar. These instruments will simultaneously monitor thermospheric temperatures and wind vectors, producing two-dimensional maps of temperatures and 3-component vector winds, with a spatial resolution of around 80 km. The array will operate in this mode for three campaigns each lasting around two-months. To quantify the importance of small-scale eddies and waves in the thermosphere, the project will address three focused science questions: (1) What is the occurrence frequency, intensity, spectral distribution, and overall morphology of the small-scale eddies and waves in Alaska?s auroral thermosphere, for both quiet and active conditions? (2) Is it possible to identify the driver mechanisms and source regions for these small-scale features, based on timing of their occurrence relative to other measurements, the spatial alignment of their phase fronts, and the directions in which they?re propagating? (3) Is it possible to estimate the momentum flux and dissipation rates of these waves, based on the amplitudes, periods, and horizontal & vertical wavelengths of the temperature and 3-component wind perturbations, and on the time evolution of these quantities? This project will include training one graduate student, enhancing the research facility at Toolik Lake in Alaska, supporting rocket missions from Poker Flat, and bringing cutting-edge scientific research to remote Alaskan villages.