CEDAR: Solar Cyclic and Climatic Influences on Upper Atmospheric Hydrogen Distributions

该项目从观测和模拟的角度探讨了太阳变化和温室气体增加对高层大气氢分布的影响。在跨越三个太阳活动极小期的时期内，对北方中纬度地区高层大气氢Balmer-alpha排放的法布里-珀罗观测建立了一套参考数据，可用于与未来的观测和大气模型进行比较。该数据集显示了氢光学排放量的明显上升趋势，其幅度比单独预测的要大，这是由于温室气体的增加导致氢丰度增加。为了确保这不是校准人为因素造成的，将通过使用关于背景银河发射强度的最新知识、现有分析工具和最新对流层散射校正码，提高北方半球长期Balmer-alpha数据集的准确性。此外，还将比较北方和南半球的观测结果。该项目要解决的主要科学问题如下：太阳周期和气候对含氢物质从低层到高层大气耦合的机制有什么影响？地球氢物种分布的上界-地冠氢-观测到的太阳周期性和可能的长期趋势是什么？含氢物质的变化预测值是多少？为了解决这个问题，将使用全大气群落气候模式（WACCM）进行太阳周期和气候对中高层大气氢物种分布影响的敏感性研究。NCAR全球平均模型将用于研究这些强迫如何通过热层传播。一名两年制华盛顿大学校园的教员和本科生将参与这项工作。将开展公众宣传活动，以提高公众对气候变化科学的认识，并为青年接触和参与科学提供机会。

This project addresses the influence of solar variability and greenhouse gas increases on upper atmospheric hydrogen distributions from both an observational and modeling perspective. Fabry-Perot observations of upper atmospheric hydrogen Balmer-alpha emissions from Northern mid-latitudes over the time period spanning three solar minima establish a reference data set that can be used to compare with future observations and with atmospheric models. This data set shows an apparent upward trend in hydrogen optical emissions of greater magnitude than predicted alone from increases in hydrogen abundance due to the rise in greenhouse gases. In order to ensure that this is not a result of a calibration artifact, the accuracy of the Northern hemisphere long-term Balmer-alpha data set will be improved through use of updated knowledge of the background Galactic emission intensity, current analysis tools, and an updated tropospheric scattering correction code. In addition, observations from the Northern and Southern Hemisphere will be compared. The major science questions to be addressed by this project are as follows: What are the solar cyclic and climatic influences on mechanisms governing lower to upper atmospheric coupling of hydrogenous species? What are the solar cyclic and possibly longer-term trends in emission observations from geocoronal hydrogen, the upper boundary of the Earth's hydrogenous species distribution? What are the predicted magnitudes for changes in hydrogen-containing species? To address this, the Whole Atmosphere Community Climate Model (WACCM) will be used to carry out sensitivity studies of solar cyclic and climatic influences on middle and upper atmospheric hydrogeneous species distributions. The NCAR Global Mean Model will be used to study how these forcings propagate through the thermosphere.A faculty member at a two-year UW college campus and undergraduate students will be involved in this work. Public outreach activities will be carried out aimed at increasing public literacy about the science of climate change, and facilitating opportunities for youth exposure and involvement in the sciences.