CEDAR: Terrestrial Airglow Studies Using Astronomical Sky Spectra

在夏威夷莫纳克亚山的两台凯克望远镜进行天文观测时，作为副产品收集的夜空光谱被用来提高我们对上层中间层和热层化学和成分的理解。 数据采集最近扩大到包括来自智利欧洲南方天文台和德克萨斯州麦克唐纳天文台9米望远镜的类似光谱数据。 高空大气学数据的使用集中在以前的研究工作中的三个发现。 首先，钠D1到D2的发射强度的比率被发现有一个令人惊讶的半年振荡，初步调查表明，这是调制的O：O2数密度比在中间层上部。 这项研究试图证明这一假设，从而建立一个前所未有的代理，以确定高层大气中的主要物种的密度-一个长期存在的和难以捉摸的目标，地面高空大气学。 第二项研究任务调查了O（1D）：N（2D）比率（后者是这些大型望远镜的独特测量能力）相对于目前无法重现数据的模型值的比率。 第三项研究任务使用了OI Rydberg系列的迄今为止未被认可的细节，可以用于整个气辉观测社区的仪器灵敏度校准，从而提高了气辉数据的密度测定。

Spectra of the night sky gathered as a by-product of astronomical observations made at two Keck telescopes at Mauna Kea, Hawaii are used to improve our understanding of chemistry and composition in the upper mesosphere and thermosphere. The data acquisition has recently expanded to include similar spectrographic data from the European Southern Observatory in Chile, and from the 9-meter telescope at McDonald Observatory in Texas. The use of the data for aeronomy focuses on three discoveries made in a preceding research effort. First, a ratio of the sodium D1 to D2 emission intensity is found to have a surprising semiannual oscillation, which preliminary investigation indicates is modulated by the O:O2 number density ratio in the upper mesosphere. This research attempts to prove that hypothesis, and thereby establish an unprecedented proxy for determining the density of the dominant species in the upper atmosphere - a long standing and elusive target for ground-based aeronomy. The second research task investigates the ratio of the O(1D):N(2D) ratio (the latter a unique measurement capability of these large telescopes) relative to model values that currently do not reproduce the data. The third research task uses the heretofore unappreciated detail of the OI Rydberg series to peg ratios that can be used for instrument sensitivity calibration throughout the airglow observation community - and thereby improve density determinations made from airglow data.