Upgraded Three-Wavelength Lidar for Real-Time Observations of Volcanic Aerosol Optical and Microphysical Properties at Etna (Italy): Calibration Procedures and Measurement Tests oleh Matteo Manzo, Gianpiero Aiesi, Antonella Boselli, Salvatore Consoli, Riccardo Damiano, Guido Di Donfrancesco, Benedetto Saraceno, Simona Scollo