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

CEDAR：地球极光热层小尺度流动结构的高分辨率多静态测绘

• 批准号: 1452333
• 负责人: Mark Conde
• 金额: $ 31.29万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1452333&HistoricalAwards=false
• 关键词: CEDAR; resolution; Multistatic; Mapping; Small

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.

该项目将测量地球极光热层约 250 公里高度处的风。人们对这些风的了解仍然知之甚少，特别是在空间尺度跨度约为 100 公里或更小的情况下。该项目基于以下假设：水平长度尺度约为 100 公里或更小的涡流和波是地球极光热层动力学的重要贡献者，并且它们的累积影响对于热层的基本物理和空间天气的操作预测都很重要。为了确定小规模的流动结构，目前位于阿拉斯加的所有七个法布里-珀罗光谱仪都将被配置为同时将注意力集中在与 PFISR 雷达视场大致重合的一个小地理区域上。这些仪器将同时监测热层温度和风矢量，生成温度和三分量矢量风的二维地图，空间分辨率约为 80 公里。该阵列将以这种模式运行三个活动，每个活动持续两个月左右。为了量化热层中小尺度涡流和波浪的重要性，该项目将解决三个重点科学问题：（1）在安静和活跃条件下，阿拉斯加极光热层中小尺度涡流和波浪的出现频率、强度、光谱分布和整体形态是怎样的？ (2) 是否可以根据这些小尺度特征相对于其他测量的发生时间、相前沿的空间排列以及它们传播的方向来识别这些小尺度特征的驱动机制和源区域？ (3) 是否可以根据温度和三分量风扰动的振幅、周期、水平和垂直波长以及这些量的时间演化来估计这些波的动量通量和耗散率？该项目将包括培训一名研究生、增强阿拉斯加 Toolik 湖的研究设施、支持 Poker Flat 的火箭任务，以及将尖端科学研究带到阿拉斯加偏远村庄。