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.

高度100公里以上的地球高层大气会受到高度多变的天气的影响。对这一被称为热层的区域的观测通常显示出长时间（数天至数周）的相对平静的状况，偶尔会出现只能被称为“风暴”的大扰动。然而，即使是平静的时候，也会表现出大量的、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，不需要外部强迫或区域边界条件的突然脉冲变化。虽然内部不稳定性也在地球的电离层和热层（特别是在低纬度）中发挥作用，但大部分热层天气是由来自上方和下方区域的强迫直接从外部驱动的。向上传播的波和潮汐对低层的日常变化做出了普遍的贡献，而太阳辐射，太阳风和地球磁层动力学的波动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波动的起源，无论大小。将在南极洲部署两台测量热层风和温度的最先进的遥感仪器，以前的研究表明，该纬度是最极端和最复杂的热层天气行为的所在地。虽然以前的工作已经测量了地球仪的热层风和温度多年，但在这些地磁纬度上从未有过任何仪器，甚至接近所提出的全天成像设计所实现的已被证明的灵敏度，分辨率和视野。这些新的法布里-珀罗光谱仪的演示性能超过了南极麦克默多和南极站的上一代仪器两个数量级以上，这将为地球极冠热层的流体动力学提供革命性的新见解。这个奖项将解决一些具体的空气动力学研究的突出问题：什么是复杂的日常变化的主要来源，已被观察到在一般反向阳中性流穿过极地帽？在极冠内观测到的温度和潮汐振幅与模拟的温度和潮汐振幅之间的差异的机制是什么？从极光椭圆区向极地传播的热层重力波是否会将大量的热量和/或动量存款到极冠热层？在南极热层温度的长期记录中是否有任何人为气候变化和/或太阳活动下降的迹象？尖端科学、国际伙伴关系和南极旅行为实现该项目的教育和宣传目标提供了理想的机会。预计该项目将产生更广泛的影响，包括培训一名博士。研究生，促进南极洲的国际科学协作与合作，并提供实时和存档数据，将对卫星运营商，通信商和导航员具有业务价值。