Peter Dalin, IRF

Observations of noctilucent clouds in Kiruna

Abstract: Noctilucent clouds (NLC) are the highest clouds in the Earth’ atmosphere, formed in the summer mesopause region (80-90 km altitude). NLC are observed from May to August in the Northern Hemisphere, and from November to February in the Southern Hemisphere. Two brilliant NLC displays were observed in August 2025 from Kiruna. We are investigating one NLC case on 20 August 2025 using optical cameras, spectrograph and meteor radars. This NLC display demonstrated complex dynamics, involving different movements of different layers in different directions and a high level of turbulence.