The Hotel Payload 2 campaign: Overview of NO, O and electron density measurements in the upper mesosphere and lower thermosphere

► Profiles of nitric oxide and atomic oxygen were measured in the winter polar vortex. ► The measurement took place after a long period of low auroral activity. ► A comprehensive ground-based support campaign with lidars and radars was organised. ► The measured profiles were controlled by large-scale dynamics. Satellite measurements from SciSat ACE-FTS confirm the interpretation.