The upper troposphere, stratosphere and mesosphere are key regions of the Earth system. These layers are coupled and evolve in response to variations in atmospheric composition (e.g. aerosols, ozone, ozone depleting substances, very short-lived halogen compounds, trace gases, etc.) and transport. We invite presentations that examine long-term variability and trends, coupling among composition, temperatures, dynamics, transport, and radiation throughout the middle atmosphere using measurements and model simulations. Topics of particular interest include ozone changes, upper troposphere/lower stratosphere composition, stratosphere/troposphere exchange, stratospheric dynamics, episodic impacts from megafires, volcanic eruptions, and rockets and orbital debris, and new field campaign research. Because ozone variability forms an overarching theme for the middle atmosphere, we welcome studies focused on Brewer spectrophotometer observations, ozone and UV products, commemorating the legacy of Tom McElroy, the co-inventor and lifelong champion of the Brewer spectrophotometer.