The PI will use simultaneous ground-based measurements of the most prominent features of nightglow to observe dynamical and photochemical processes that control the mesopause region's thermal structure and composition. The PI will verify a detailed analysis scheme to deduce the atomic oxygen density maximum and its centroid height variation, compare these quantities for consistency with simultaneous sodium lidar density and temperature profiles, and verify tidal model predictions using the time variations of intensities of visible and near IR airglow features and rotational temperatures. Such an analysis will enhance understanding of the photochemistry of nightglow emissions and lead to an improved theoretical framework for studying oxygen atom density variations and atmospheric dynamics in the mesopause region.***