CEDAR: Solar Cyclic and Climatic Trends in Geocoronal Hydrogen

该项目的重点是利用威斯康星州长期中纬度地冠发射记录和NCAR全球平均模型，研究地冠氢的太阳周期和气候趋势。 这些数据是用位于威斯康星州和亚利桑那州的两个类似设计的地基法布里-珀罗干涉仪获得的。 在太阳活动周期23的高信噪比观测已经量化了一个统计上显着的太阳活动周期对地冕氢柱发射强度的影响。 从三个太阳极小期（1985年，1997年，2006年）的观测同意在15%以内的阴影高度范围。 该项目将继续分析威斯康星州北方半球地日冕数据集，该数据集目前跨越三个太阳周期，以调查太阳周期的影响，并建立更多的校准良好的数据集，供今后进行长期比较。 该项目包括一项档案研究，通过使用更新的分析技术和来自威斯康星州H-α制图仪Fabry-Perot的最新银河背景信息重新分析20世纪70 - 80年代的观测，向后扩展威斯康星州的数据集。Roble和Dickinson [1989]的一项开创性研究使用了NCAR的中间层、热层、和电离层，以研究中高层大气对二氧化碳和甲烷加倍的反应。 结果表明，甲烷的加倍会使热层上层的氢增加40-50%。 还利用全球平均模式对CO2和太阳紫外线通量随时间变化的历史值进行了进一步研究，以调查热层密度对太阳活动周期和CO2增加的反应。 该项目将扩大模型研究，在全球平均模型中增加甲烷的历史浓度，以调查威斯康星州长期中纬度数据集30年期间热层氢的预测太阳周期性和长期变化的幅度。 为了便于将这些模型预测结果与威斯康星州观测结果进行比较，全球平均模型的输出将被用作LYAO_RT全球共振辐射传输代码的输入，以将氢密度分布扩展到外逸层，并计算相应的氢柱发射强度。和低层-高层大气耦合。 这项研究还将导致汇编一个具有高信噪比的观测数据集，用于过去和未来的数据和模型比较。

The focus of the project is to investigate solar cyclic and climatic trends in geocoronal hydrogen using the Wisconsin long-term mid-latitude geocoronal emission record and the NCAR global mean model. The data have been acquired with two similarly designed ground-based Fabry-Perot Interferometers located in Wisconsin and Arizona. High signal-to-noise observations over solar cycle 23 have quantified a statistically significant solar cyclic influence on the geocoronal hydrogen column emission intensity. Observations from three solar minima (1985, 1997, 2006) agree to within 15% over most of the shadow altitude range. This project will continue the analysis of the Wisconsin northern hemisphere geocoronal data set now spanning three solar cycles to investigate solar cycle influences and to establish additional well-calibrated data sets for long-term comparisons into the future. The project includes an archival study to extend the Wisconsin data set backwards through reanalysis of observations taken in the 1970-80s using updated analysis techniques and the most recent Galactic background information from the Wisconsin H-alpha Mapper Fabry-Perot.A seminal study by Roble and Dickinson [1989] used the NCAR global mean model of the mesosphere, thermosphere, and ionosphere to study the response of the middle and upper atmosphere to a doubling of carbon dioxide and methane. The results showed found an increase of 40-50% in upper thermospheric hydrogen in response to a doubling of methane. Additional studies with global mean model were carried out with historical time-dependent values of CO2 and solar UV fluxes to investigate the thermospheric density response to the solar cycle and to CO2 increases. This project will extend the model studies by adding historical concentrations of methane to the global mean model to investigate the magnitude of predicted solar cyclic and secular changes in thermospheric hydrogen over the 30-year period of the Wisconsin long-term mid-latitude data set. In order to facilitate comparison between these model predictions and the Wisconsin observations, output from the global mean model will be used as input to the LYAO_RT global resonance radiative transfer code to extend the hydrogen density profile into the exosphere and to calculate the corresponding hydrogen column emission intensity.The project goal is to increase understanding of solar-terrestrial interactions, long-term variations, and lower-upper atmospheric coupling. The research would also result in the compilation of an observational dataset with high signal-to-noise ratios for past and future data and model comparisons.