MRI: Development of a Thermospheric Wind Imager

该项目要求提供资金，以便在阿拉斯加建立一个全天成像法布里-珀罗多普勒光谱仪的三站阵列。这些仪器将在大约100公里高度以上的地球高层大气中获得温度和三分量风矢量的二维图，而不需要任何关于气流性质的先验假设。大约25万平方公里的三站重叠区域将涵盖国家科学基金会新的扑克平坦非相干散射雷达(PFISR)在F区高度观测到的所有大气体积，其中大部分在E区。三台三站成像所需的三台光谱仪中的一台已经在Poker Flat安装并运行；该项目将建造另外两台。基于现有扑克平板仪器的演示性能，三基地阵列将能够在PFISR视场内将真正的三分量风映射到每秒几米的精度，空间分辨率为50-100公里，时间分辨率为1-10分钟。温度将被测量到典型的5K精度。这些能力代表着比五年前甚至可能的水平提高了一个数量级。建立这一设施的科学动机是在短空间和时间尺度上研究热层动力学，这是以前遥感无法获得的。根据流体力学的Navier-Stokes方程(增加了描述焦耳加热和离子中性动量耦合的项)，电离层对流的狭窄通道应该会在地球中性热层上留下较慢但结构相似的小规模短暂流动的印记。这里的目标是检验这一预测，如果它是正确的，则研究这些小规模流动的性质和后果。此外，通过提供离子数密度、流动速度和温度的高分辨率测量，PFISR雷达将能够量化建立这些流动的能量和动量来源。新的全天成像仪器将与位于Poker Flat、Fort Yukon和Eagle的现有窄域光谱仪充分合作，导致史无前例的五个FPI聚集在一起，在阿拉斯加北部观看一个共同的体积。这项活动将建立一个合作伙伴关系，涉及几个现有的由美国国家科学基金会资助的项目：PFISR雷达、Toolik野外站和现有的窄场光谱仪阵列。由于新仪器将使用澳大利亚拉特洛布大学的设计，该项目还将建立一个新的国际合作，为阿拉斯加和澳大利亚之间的学生旅行提供一定的空间。这些新仪器的设计、建造、部署和操作将使参与的学生接触到广泛的实用研究技能，以及任何观察性研究项目中常见的数据分析和解释。

This project request funds to establish a tristatic array of all-sky imaging Fabry-Perot Doppler spectrometers in Alaska. These instruments will obtain two-dimensional maps of temperature and three-component wind vectors in Earth's upper atmosphere above approximately 100 km altitude, without requiring any a-priori assumptions about the nature of the flow. The roughly 250,000 square kilometer area of tristatic overlap will encompass all of the atmospheric volume observed by the National Science Foundation's new Poker Flat Incoherent Scatter Radar (PFISR) at F-region heights, and most of this volume in the E-region. One of the three spectrometers required for tristatic imaging is already installed and operating at Poker Flat; this project will construct the other two. Based on demonstrated performance of the existing Poker Flat instrument, the tristatic array will be able to map true three-component winds to a precision of a few meters per second across the PFISR field of view, with a spatial resolution of 50-100 km and a time resolution varying from 1 to 10 minutes. Temperatures will be measured to a typical precision of 5K. These capabilities represent an order of magnitude improvement over what was possible even as recently as five years ago. The scientific motivation for establishing this facility is to study thermospheric dynamics at short spatial and temporal scales, which have previously been inaccessible to remote sensing. According to the Navier-Stokes equations of fluid mechanics (augmented with terms describing Joule heating and ion neutral momentum coupling), narrow channels of ionospheric convection should imprint slower but otherwise similarly structured small-scale short-lived flows onto Earth's neutral thermosphere. The objective here is to test this prediction and, should it be correct, to study the nature and consequences of these small-scale flows. Further, by providing high-resolution measurements of ion number density, flow velocity, and temperature, the PFISR radar will enable quantification of the sources of energy and momentum that establish these flows. The new all-sky imaging instruments will operate in full collaboration with existing narrow-field spectrometers at Poker Flat, Fort Yukon, and Eagle, resulting in an unprecedented cluster of five FPIs viewing a common volume over northern Alaska. This activity will create a collaborative partnership involving several existing NSF-funded projects: The PFISR radar, the Toolik Field Station, and the existing narrow-field spectrometer array. Because the new instruments will use designs from La Trobe University in Australia, the project will also establish a new international collaboration, with some scope for student travel between Alaska and Australia. The design, construction, deployment and operation of these new instruments will expose participating students to a wide range of practical research skills, in addition to the usual data analysis and interpretation that are part of any observational research project.