A CEDAR Multi-Institution Research Initiative: Derivation of Upper Atmospheric O and N2 Densities for Spectroscopic Studies of Twilight Optical Emissions

上层大气受到来自太阳的紫外线和X射线的照射，这些辐射使分子和原子电离、解离并以电子方式激发。由此产生的光学发射可以在早晨和傍晚的黄昏期间在地面上检测到，此时高层大气仍然受到太阳的照射，但对流层没有，因此明亮的蓝色天空不再压倒较弱的高层大气发射。用现代光谱设备探测到的高层大气辐射光谱包含了足够多的信息来揭示高层大气的成分和温度，从而揭示重要的每日和季节性太阳周期和磁活动变化。对数据的分析包括与太阳辐照引起的光化学过程的数值模型的比较。航空学界通过CEDAR计划文件批准了一项暮光光谱观测计划，以提供成分信息。该奖项是一个发展这种能力的试点项目，涉及5所大学和一家私人公司，实验人员使用几种类型的光谱设备，与理论家在合作项目中合作。

The upper atmosphere is irradiated by ultraviolet and X radiation from the sun that ionizes and dissociates and electronically excites molecules and atoms. The resulting optical emission can be detected at the ground during the morning and evening twilight periods, when the upper atmosphere is still being irradiated by the sun but the troposphere is not, so the bright blue sky no longer overwhelms the fainter upper atmosphere emissions. The spectrum of the upper atmosphere emissions, as detected with modern spectroscopic equipment, contains more than enough information to reveal the upper atmosphere composition and temperature, and thus the important day to day and seasonal solar cycle and magnetic activity variations. An analysis of the data involves comparisons with numerical models of the photochemical processes resulting from the solar irradiation. The Aeronomy community through the CEDAR planning document have endorsed a program of twilight spectroscopic observations to provide the composition information. This award is for a pilot program to develop this capability, and involves 5 universities and a private company, with experimentalists using several types of spectrographic equipment, working with theoreticians in a cooperative program.