Response of Atomic Hydrogen and Oxygen to Solar Radiation Changes: Measurements and Simulations

HYDOX项目下一部分的科学目标是区分中间层上层和热层下层的直接(光化学)和间接(动力)太阳周期效应。我们的工具是原子氧、氢和化学升温速率的全球场，以及NCAR ROSE大气环流模型。在项目的第一部分，我们通过对Envisat卫星上的Sciamachy和Gomos仪器的测量得出了这些场。我们确定了明确的太阳周期依赖关系，并通过ROSE模型对数据进行了首次模拟。通过模式区分数据中的光化学和动力太阳周期效应需要尽可能好地表示低层大气，因为UMLT区域的动力学是高度非局部性的。因此，我们建议积极参与最近在NCAR启动的ROSE模式的发展，以改善该模式的对流层强迫。这将更好地表示太阳潮汐，太阳潮汐主导着UMLT地区的大气变化。我们计划用模型的改进版本进行几个模型敏感性研究，以研究太阳强迫对潮汐来源和海浪过滤的作用。模拟将与测量数据进行比较，以区分UMLT地区光化学太阳强迫的动力效应。

The scientific objective of the next part of the HYDOX project is to distinguish between the direct (photochemical) and indirect (dynamical) solar cycle effects in the upper mesosphere and lower thermosphere (UMLT). Our tools are global fields of atomic oxygen, hydrogen, and chemical heating rates, and the NCAR ROSE general circulation model. During the first part of the project, we derived these fields from measurements of the Sciamachy and GOMOS instruments on board the Envisat satellite. We identified clear solar cycle dependencies and performed first simulations of the data by means of the ROSE model. The discrimination of photochemical and dynamical solar cycle effects in the data by means of a model requires the best possible representation of the lower atmosphere, because the dynamics in the UMLT region is highly non-local. Therefore, we propose to take active part in the advancement of the ROSE model recently started at NCAR to improve the tropospheric forcing of the model. This will give a better representation of solar tides, which dominate atmospheric variability in the UMLT region. We plan to perform several model sensitivity studies with the improved version of the model to study the role of solar forcing for tidal sources and wave filtering. The simulations will be compared to the measured data to discriminate the dynamical effects from the photochemical solar forcing in the UMLT region.