Collaborative Research: CEDAR--High Time-Resolution Sprite Imaging

合作研究：CEDAR--高时间分辨率精灵成像

• 批准号: 0737605
• 负责人: Hans Nielsen
• 金额: $ 29.07万
• 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: 2008
• 资助国家: 美国
• 起止时间: 2008-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0737605&HistoricalAwards=false
• 关键词: Collaborative; Research; CEDAR; Time; Resolution

The scientific objective of this study is to determine the processes involved in the formation of sprites, how sprites fit into the larger field of streamer development, and the consequences of sprites on the middle atmosphere. To accomplish this goal, the project will use ground-based high speed cameras to image their spatial and spectral development with unprecedented high temporal resolution. Sprites are large (~50km vertical scale size) luminous events seen above thunderstorms often extending to ionospheric heights. Most sprites are associated with positive cloud to ground lighting strikes, and the optical emissions last only from a few milliseconds to a few 10's of milliseconds. Sprites start at 70 - 80 km altitude with downward propagating streamer heads. In some events upward moving streamer heads are also observed, but upward moving streamers always start later than the downward streamers and further, they start from a lower altitude and from existing bright spots in the sprite body. Previously funded research has shown sprite development to have essentially two phases: an active initial phase characterized by fast moving streamer heads followed by a decay phase in which there is little spatial activity. This analysis work will continue under this project and be augmented by observations taken with new high-speed imagers to record sprites with high temporal and spatial resolution. Slit less spectroscopy will also be used to obtain sprite spectra with ~500m altitude, 0.1 ms (or possibly less) temporal and 10 nm spectral (400-800 nm) resolution. For high spatial resolution a telescope will be used to obtain 3m spatial and possibly 100 s temporal resolution. The program will include use of a roving ground station to allow for triangulation. One field campaign per year will be undertaken. The observations are expected to provide new images with unprecedented temporal, spatial, and spectral resolution, which will aid in providing realistic estimates of the amount of energy and charge deposited into the mesosphere by sprites. The broader impacts of the project includes support of one full-time graduate student who will receive training in both observational and theoretical work suitable for a Ph.D. thesis. Undergraduate cadets from the Air Force Academy will participate in gathering and analysis of the basic data. The project may indirectly extend the use of high frame rate imagery to the ionosphere, thermosphere, and mesosphere community. The observations will be made available to the sprite community, thus providing fundamental observational constraints on the various sprite and streamer theories available.

这项研究的科学目标是确定精灵形成的过程，精灵如何适应更大的流光发展领域，以及精灵对中层大气的影响。 为了实现这一目标，该项目将使用地面高速相机以前所未有的高时间分辨率对它们的空间和光谱发展进行成像。 雪晶是在雷暴上方看到的大型（垂直尺度约50公里）发光事件，通常延伸到电离层高度。 大多数精灵都与积极的云到地面的闪电罢工，和光学发射持续只有几毫秒到几十毫秒。 精灵开始在70 - 80公里的高度与向下传播的拖缆头。 在某些事件中，也观察到向上移动的拖缆头，但向上移动的拖缆总是比向下的拖缆开始得晚，而且，它们从较低的高度和从精灵体中现有的亮点开始。 先前资助的研究表明，精灵的发展基本上有两个阶段：一个活跃的初始阶段，其特征是快速移动的流光头，然后是一个衰减阶段，其中几乎没有空间活动。这一分析工作将在该项目下继续进行，并通过使用新的高速成像仪进行观测以记录具有高时间和空间分辨率的精灵而得到加强。 无狭缝光谱学也将用于获得具有~ 500 m高度、0.1 ms（或可能更少）时间和10 nm光谱（400-800 nm）分辨率的子画面光谱。 对于高空间分辨率，将使用望远镜获得3米的空间分辨率和可能的100秒的时间分辨率。 该计划将包括使用一个流动地面站，以便进行三角测量。 每年将开展一次实地活动。 预计这些观测将提供具有前所未有的时间，空间和光谱分辨率的新图像，这将有助于对精灵沉积到中间层的能量和电荷量进行现实的估计。 该项目更广泛的影响包括支持一名全日制研究生，他将接受适合博士学位的观察和理论工作的培训。论文 来自空军学院的本科学员将参与收集和分析基本数据。 该项目可将高帧频图像的使用间接扩大到电离层、热层和中间层。 观测结果将提供给精灵社区，从而为现有的各种精灵和流光理论提供基本的观测约束。