CEDAR: Exploration of Trends in Thermospheric+Exospheric Hydrogen Using H-Alpha Emission Intensities and Hydrogen Column Abundances Retrieved from the Wisconsin Long Term Record

甲烷、水蒸气和分子氢等含氢分子的向上通量是中高层大气中含氢化学物种的主要来源。了解热层和地外圈对以下含氢物种分布、自然可变性来源以及可能的长期气候变化的敏感性是地冕研究的中心问题。威斯康星州H-Alpha映射器Fabry-Perot(WHAM)在1997-2001年太阳周期上升期间对热层和大气层中的H-Alpha柱发射的观测是威斯康星州第一次观测到地球日冕H-Alpha发射在统计上具有显著的太阳周期变化，在太阳活动高峰期排放较高。这些观测计划将在太阳周期的下降期间继续进行，至少持续到2005年。WHAM的观测证实了过去威斯康星州中纬度H观测到的这种趋势。总体而言，这一长期的、一致校准的数据记录现在跨越了两个太阳周期。研究的重点是：分析和检查热层和外层H强度的Fabry-Perot观测的趋势；使用全球共振辐射传输程序对热层和外层氢柱丰度进行正向模拟反演；将从H观测得到的氢柱密度与使用全球平均模式和热层-电离层-中间层电动力学一般环流模式的输出作为辐射转移程序输入的氢柱密度进行比较。了解地球气候和人类活动引起的气候变化的一个主要组成部分是了解大气中的自然变异性。这项研究通过调查太阳紫外线输出在太阳周期内的变化对高层大气氢气的影响，为这一努力做出了贡献。高层大气中的氢是中层大气中含氢物种化学的副产品，涉及甲烷和水蒸气等分子，这是两种主要的大气温室气体。预计大气层上层氢的特征以及大气层下层的观测诊断将有助于研究含氢物种的垂直模式及其相互影响。WHAM的数据增加了现在跨越20年的氢排放数据的长期主体。它们的高精度和信噪比便于与过去和未来的数据集进行比较。这项工作将继续当前的教育和公共宣传工作，重点是提高有关气候变化和其他大气问题的科学素养，并促进科学研究的多样性。

Upward fluxes of hydrogen containing molecules such as methane, water vapor, and molecular hydrogen are the primary source of hydrogen-containing chemical species in the middle and upper atmosphere. Understanding the sensitivity of the thermosphere and exosphere to hydrogenous species distributions below, to sources of natural variability, and to possible long-term climatic changes are central questions for geocoronal research. Observations of thermospheric and exospheric hydrogen-alpha column emissions by the Wisconsin H-alpha Mapper Fabry-Perot (WHAM) over the 1997-2001 rise in the solar cycle are the first Wisconsin-based observations to show a statistically significant solar cyclical variation in the geocoronal H-alpha emission, with higher emissions during solar maximum periods. These observations are scheduled to continue over the decline in the solar cycle, through at least 2005. The WHAM observations corroborate suggestions of such a trend seen in past mid latitude Wisconsin-based H observations. Collectively, this long term, consistently calibrated data record now spans two solar cycles. The research focuses on: analysis of and examination of trends in Fabry-Perot observations of thermospheric and exospheric H intensities; forward modeling retrieval of the thermospheric and exospheric hydrogen column abundance using a global resonance radiative transport code; and comparison of hydrogen column densities retrieved from H observations with those generated using output from a global mean model and the Thermosphere-Ionosphere-Mesosphere Electrodynamics General Circulation Model (TIME-GCM) as input to the radiative transfer code. A primary component to understanding the earth's climate and climate change due to human activities is knowledge of natural variability in the atmosphere. This study contributes to this effort by investigating the influence on upper atmospheric hydrogen of changes in the sun's ultraviolet output over the solar cycle. Upper atmospheric hydrogen is a byproduct of hydrogenous species chemistry in the middle atmosphere, involving molecules such as methane and water vapor, two primary atmospheric greenhouse gases. It is anticipated that characterization of upper atmospheric hydrogen, together with observational diagnostics lower in the atmosphere, will contribute to studies of vertical patterns in hydrogen containing species and their influence upon one another. The WHAM data add to a long-term body of hydrogen emission data now spanning a 20 year period. Their high precision and signal-to-noise facilitate comparisons with past and future data sets. This work will continue current educational and public outreach efforts focused on enhancing scientific literacy concerning climate change and other atmospheric topics, and on promoting diversity in the study of science.