Lidar observations of the structure and evolution of aerosol clusters in the DELICAT project

The main goal of the DELICAT (DEmonstration of LIdar based CAT detection) project was to check the possibility of early detection of clear air turbulence regions by recording the intensity of reverse molecular scattering by means of a specially designed lidar mounted on the aircraft, operating in the ultraviolet range of wavelengths. Flight tests were conducted from July 17 to August 12, 2013 over the western part of Europe and the adjacent maritime territories. Although measurements in a clear sky were preferred, in most cases aerosol clusters of different power were present along the flight paths. Aerosol clusters should be considered as a source of interference, but their observations also provide an opportunity to obtain information on the properties of the aerosol and the spatial-temporal evolution of clusters. In this paper, we give statistics of observations of aerosol clusters in flights, describe the diversity of their types and trace the influence of flight parameters on the observed characteristics of clusters.