High-resolution Mapping of Thermospheric Wind and Temperature Fields near the Equatorward Edge of the Antarctic Polar Cap to understand Coupling to Layers both above and below

南极极冠赤道边缘附近热层风和温度场的高分辨率测绘，以了解与上方和下方各层的耦合

• 批准号: 1341545
• 负责人: Mark Conde
• 金额: $ 98.42万
• 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: 2014
• 资助国家: 美国
• 起止时间: 2014-07-15 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1341545&HistoricalAwards=false
• 关键词: resolution; Mapping; Thermospheric; Wind; Temperature

Earth's upper atmosphere at altitudes above 100-km is subjected to highly variable weather. Observations of this region, known as the thermosphere, commonly show long periods (days to weeks) of relatively placid conditions, punctuated by large disturbances that can only be described as "storms". However, even quiet times exhibit a substantial and often seemingly random background of day-to-day variability. In the troposphere, large storms develop internally, without a requirement for sudden impulsive changes by externally imposed forcing or regional boundary conditions. While internal instability does also play a role in Earth's ionosphere and thermosphere (especially at low latitudes); much of the thermospheric weather is instead directly driven from outside by forcing from regions above and below. Upward propagating waves and tides make a ubiquitous contribution to the low-level day-to-day variability, whereas fluctuations in the solar radiation, solar wind, and Earth's magnetosphere dynamics drive a broad spectrum of thermospheric perturbations - and are entirely responsible for driving storms and other large events. The primary goal of this project is to understand the origins of day-to-day fluctuations in thermospheric weather, both large and small. Two state-of-the-art remote sensing instruments measuring thermospheric wind and temperature will be deployed in Antarctica, at latitudes that have been shown by previous studies to host the most extreme and complex thermospheric weather behavior. While previous work has measured thermospheric winds and temperatures across the globe for many years, there have never been instruments at these geomagnetic latitudes with anything even close to the proven sensitivity, resolution, and field of regard that are achieved by the proposed all-sky imaging design. Demonstrated performance of these new Fabry-Perot Spectrometers exceeds that of the previous generation of instruments at the Antarctic McMurdo and South Pole stations by more than two orders of magnitude, which will open revolutionary new insights in the fluid dynamics of Earth's polar-cap thermosphere. This award will address a number of specific outstanding questions of aeronomical research: What is the main source of complex day-to-day variability that has been observed in the generally anti-sunward neutral flow across the polar cap? What are the mechanisms responsible for discrepancies between observed and modeled temperatures and tidal amplitudes within the polar cap? Do thermospheric gravity waves, propagating poleward from the auroral oval, deposit a significant flux of heat and/or momentum into the polar cap thermosphere? Are there any signatures of anthropogenic climate change and/or declining solar activity in the long-term record of thermospheric temperatures at South Pole?Cutting-edge science, international partnership, and travel to Antarctica provide an ideal opportunity to achieve the project's education and outreach goals. Anticipated broader impacts from this project include training of a Ph.D. graduate student, furthering international scientific collaboration and cooperation in Antarctica, and providing real-time and archive data that will be of operational value to satellite operators, communicators, and navigators.

海拔 100 公里以上的地球高层大气受到高度多变的天气影响。对这个被称为热层的区域的观测通常显示出长时间（数天到数周）相对平静的状况，期间不时出现只能被描述为“风暴”的大型扰动。然而，即使是安静的时期，也会表现出大量且往往看似随机的日常变化背景。在对流层中，大型风暴在内部发展，不需要外部施加的强迫或区域边界条件造成突然的脉冲变化。虽然内部不稳定性也在地球的电离层和热层中发挥着作用（特别是在低纬度地区）；相反，大部分热层天气是由上方和下方区域的强迫直接从外部驱动的。向上传播的波浪和潮汐对低水平的日常变化做出了无处不在的贡献，而太阳辐射、太阳风和地球磁层动力学的波动则驱动了广泛的热层扰动，并且完全负责驱动风暴和其他大型事件。该项目的主要目标是了解热层天气日常大大小小的波动的根源。南极洲将部署两台最先进的遥感仪器来测量热层风和温度，之前的研究表明，南极洲的纬度是最极端和最复杂的热层天气行为的所在地。虽然之前的工作多年来一直在测量全球范围内的热层风和温度，但在这些地磁纬度上从未有任何仪器具有接近所提出的全天空成像设计所实现的经过验证的灵敏度、分辨率和视场的仪器。这些新型法布里-珀罗光谱仪的性能比南极麦克默多站和南极站的上一代仪器高出两个数量级以上，这将为地球极冠热层流体动力学带来革命性的新见解。该奖项将解决航空研究中的一些具体的突出问题：在穿过极冠的总体反太阳中性流中观察到的复杂的日常变化的主要来源是什么？造成观测和模拟的极冠内温度和潮汐幅度之间差异的机制是什么？从极光椭圆区向极地传播的热层重力波是否会在极冠热层中沉积大量的热流和/或动量？南极热层温度的长期记录是否存在人为气候变化和/或太阳活动减弱的迹象？尖端科学、国际合作和南极洲旅行为实现该项目的教育和推广目标提供了理想的机会。该项目预计会产生更广泛的影响，包括培养博士生。研究生，促进南极洲的国际科学协作与合作，并提供对卫星运营商、通信员和导航员具有操作价值的实时和存档数据。