Noctilucent clouds altitude and particle size mapping based on spread observations by ground-based all-sky cameras

Abstract

We suggest the procedure of building the maps of noctilucent clouds (NLC) zonal and meridional velocity, mean altitude and particle size based on three-color photometry by identical all-sky RGB-cameras separated by 115 km in a close-meridional direction. The procedure is applied to the bright NLC event on July 3, 2023. The altitude is measured by precise triangulation technique, and effective particle radius is estimated by comparison of each definite NLC fragment intensity and colors at different scattering angles as it is registered from different observation sites. The results are compared with existing photometric methods for average altitude and particle size measurements. A significant difference in evening and morning twilight NLC parameters is found, which is discussed in comparison with existing analysis of diurnal NLC variations.